Community Medicine Lectures Handout PDF

Community Medicine COMMUNITY MEDICINE FOR 4TH YEAR MEDICAL STUDENTS Department of Community, Environmental and Occupational Medicine 2021 -...

Community Medicine COMMUNITY MEDICINE FOR 4TH YEAR MEDICAL STUDENTS Department of Community, Environmental and Occupational Medicine 2021 - 2022 Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 i DEPARTMENT OF COMMUNITY, ENVIRONMENTAL AND OCCUPATIONAL MEDICINE Our Vision Our concern is Healthy People in Healthy Communities. Our Mission The mission of the department is to preserve, promote, and improve the health and well being of populations, communities, and individuals. To fulfill this mission, we prepare graduates to address the multifaceted health needs of their community and we foster collaborations among public health and the health professions in education, research, and service Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 ii Preface Health is a complex issue that has variable definitions and broad scope which is difficult to be achieved. Definitely, the progress of any community is dependent on the health of its citizens i.e. the health of the public. Public health is concerned with promotion, prevention, and restoration of the health of the community individuals. To achieve the goal of healthy community, there should be collaboration between governmental and non- governmental organizations through planned systematic activities. Our department of community, environmental and occupational medicine is one of the governmental institutions that is devoted and actively participating in achieving the planned mission through innovative education and training of the medical students and doctors. The department book is designed to provide medical students with essential information about the main concepts and important aspects of public health. The main book's concerns are; health promotion, prevention, early detection and reduction of disabilities and premature deaths in the entire population. The science of public health integrates a wide array of intellectual disciplines such as: vital statistics, demography, epidemiology, biostatistics; basic medical science such as microbiology, entomology, physiology, pharmacology, and toxicology; physical science such as physics and chemistry; engineering; social and behavioral sciences; and clinical sciences such as those that deal with communicable diseases, Non communicable disease , environmental and occupational sciences. This book includes different health issues covering different stages of human life cycle. As much as possible, the authors have used language which could be easily understood by undergraduate students. It is intended specifically for 4th year medical students, although many professional workers, trainers, and students of public health will find it beneficial and interesting. We wish to acknowledge the help received from staff members and colleagues at the department of Community, Environmental and Occupational Medicine, for their dedicated effort throughout the initiation, development and revision of this book. We express our attitude to previous chairpersons of the department (Prof. Aly Massoud, Prof. Rifky Faris, Prof. Ahmed Sherif Hafez, Prof. Akila Kaiser Khila, Prof. Abdel Aziz Kamal, Prof. Mohsen Gadallah, Prof. Sawsan El Ghazali , prof Wagida Anwer ,Mohamed Yahia El-AwadyandMervat Hassan Abd El Azizfor their cumulative effort and leadership that led to such product. Head of the Department Prof. Maha El Gaafary Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 iii  Sahar Ahmed Dwedar Staff Members Nahla Fawzy Abou El Ezz Hasnaa Abdel Aal Abou Seif Head of the Department Mona Abdel Aal Abdel Hamid Maha El Gaafary Dina Nabih Kamel Boulos Sally Adel Hakim Emeritus Professors Nayera Samy Mostafa Abdel Aziz Kamal Hoda Ibrahim Fahim Assistant Professors Mohsen Abdel Hamid Gadalla Sahar Khalil Ibrahim Mohamed Salah Ibrahem Gabal Walid Salah El Din Ahmed Ahmed Esmat Shoman Amany Mohamed Sayed Mostafa El Hosseini Mostafa Aya Mostafa Kamal El Din Wagida Abd Alrahman Anwar Moahmed Abdel Meguid Tolba Mahy Mahmoud Faheem AlTahawey Azza Mohamed Hassan Aisha Abu El Fetouh Lamiaa Mohamed Saiid Mohamed Yahia El-Awady Ghada Ossama Wassif Hisham Abdelfatah Mahaba Doaa Mahmoud El Hussenei Samia Ismail El Damaty Ayat Farouk Mohamed Diaa Marzook Abdel Hamid Hebatalla Mohamed Salah Mervat Hassan Abd El Aziz Lecturers Sahar Mohamed Sabbour Gihan Ibrahim Dena Ahmed Gamal El Deen Professors Maha magdy Wahdan Iman Mohamed Bakr Nashwa Ismail Ali Nanees Ahmed Ismail Iman El Sayed Ghanem Amany Mokhtar Noura Essam Eldin Ammar Ihab Shehad Habil Rasha Saad Hussein Khaled Mahmoud Abd Elaziz Mostafa Mohamed Mostafa Fatma Abd El Salam Meky Wafaa Mohamed Hussein El Sayed El Sayed El Okda Amal Mahmoud Ebrahim Hanan Ezz Elarab Isis Magdy Mossad Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 iv  Shaimaa Mohamed El Bokl Yomna Ayman Ghada Mahmoud Ismail Heba Mohamed Shaimaa Samy Yosef May Hassan Dena Ali Mahmoud Basma Hossam Dina Abbas Fatma Mokhtar Assistant Lecturers Aya Mostafa Abd Al-latif Shereen Fawzy Hassan Reviewers Yosra Samir Abd Al-ghafar Prof. Mervat Hassan Abd El Aziz Hebatala Osama Prof. Mohamed Yahia El-Awady Israa Ahmad Prof. Hoda Ibrahim Fahim Nadia Samy Prof. Mohsen Abdel Hamid Gadalla Manar Mohamed Prof. Ahmed Esmat Shoman Nabila Mohamed Prof. Mostafa El Hosseini Mostafa Viviane Farid Prof.Mahy Mahmoud Faheem Abeer Abd El Salam Altahawey Noha Magdi Prof. Aisha Abu El Fetouh Sara Ibrahim Prof. Samia Ismail El Damaty Norhan Badr Prof. Sahar Mohamed Sabbour Maha Awad Prof. Iman Mohamed Bakr Asmaa Gamal Prof. Maha Mohamed El Gaafary Prof. Amany Mokhtar Demonstrators Prof. Khaled AbdElaziz Abeer Hassan Prof. Fatma AbdEl Salam Meky Dalia Farouk Prof. El Sayed El Sayed El Okda Dina Hassan Aidaros Prof. Hanan Ezz Elarab Israa Ebrahim Hadeer Al Mahdy Remon Mosaad Editors Sara Mohamed Ghazal Dr. Wafaa Mohamed Hussein Amira Ayman Zainab Ashraf Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 v Contents Introduction........................................................................................................................................................ 1 General Epidemiology........................................................................................................................................ 6 2.1 Introduction.............................................................................................................................................. 7 2.2 Etiology of diseases.................................................................................................................................... 9 2.3 Levels of Prevention................................................................................................................................ 13 Demography, and Population Structure............................................................................................................. 14 3.1 Methods of Data Collection in Demography........................................................................................... 15 3.2 Population Pyramid (Age and Sex Structure Diagram)......................................................................... 16 Epidemiology of Communicable Diseases......................................................................................................... 22 4.1 Dynamics of Infectious Disease Transmission........................................................................................ 23 4.2 Prevention and Control of Communicable Diseases............................................................................... 25 Epidemiology of Non-Communicable Diseases................................................................................................. 35 5.1 Definition of Non-Communicable Diseases........................................................................................... 36 5.2 Burden of Non-Communicable Diseases............................................................................................... 37 5.3 Risk factors for Non-Communicable Diseases....................................................................................... 40 Health System & Services in Egypt and Travellers’ Health................................................................................ 45 6.1 Introduction............................................................................................................................................ 46 6.1.1 Levels of Healthcare Services in Egypt........................................................................................... 46 6.1.2 Sectors Providing Healthcare Services In Egypt.............................................................................. 46 6.2 Primary Health Care (PHC)................................................................................................................... 49 6.3 Health Services in Egypt......................................................................................................................... 52 6.3.1 Maternal Healthcare Services.......................................................................................................... 52 6.3.2 Child Healthcare............................................................................................................................. 56 6.4 Evaluation of Healthcare Services.......................................................................................................... 58 6.5 Health Services for Elderly...................................................................................................................... 58 6.5.1 Primary Healthcare for the Elderly.................................................................................................. 58 6.5.2 Acute Care for the Elderly.............................................................................................................. 63 6.5.3 Chronic Care for the Elderly........................................................................................................... 63 6.6 Travellers` Health.................................................................................................................................... 64 Health Programs and Campaigns in Egypt......................................................................................................... 70 7.1 National Health Programs in Egypt......................................................................................................... 71 7.1.1 National Programs Targeting Communicable Diseases.................................................................... 71 7.1.2 National Programs Related to Child Health..................................................................................... 76 7.1.3 National Programs related to Womens’ Health................................................................................ 81 7.1.4 National Health Campaigns in Egypt............................................................................................... 83 Second & Third Healthcare Levels.................................................................................................................... 85 Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 vi 8.1 Hospital-Acquired Infection................................................................................................................... 86 8.2 Hospital Waste........................................................................................................................................ 90 8.3 Medical Records...................................................................................................................................... 93 Health promotion, Health Education & Behavioral Medicine............................................................................. 95 9.1 Health promotion...................................................................................................................................... 96 9.2 Health education....................................................................................................................................... 97 9.3 Behavioral & Social Health Problems.................................................................................................... 103 9.3.1 Smoking....................................................................................................................................... 104 9.3.2 Exercise & Health......................................................................................................................... 106 9.3.3 Road Traffic Accidents................................................................................................................. 108 9.3.4 Health Risk Behavior Among Youth............................................................................................. 109 Environmental Health..................................................................................................................................... 110 10.1 Water................................................................................................................................................... 112 10.1.1 Water Quality............................................................................................................................. 112 10.1.2 Water Pollution........................................................................................................................... 113 10.2 Air........................................................................................................................................................ 115 10.2.1 Outdoor Air Pollution................................................................................................................. 115 10.2.2 Indoor Air Quality (IAQ)............................................................................................................. 117 10.3 Solid and Hazardous Wastes............................................................................................................... 121 10.4 Environmental Disasters..................................................................................................................... 123 Nutrition & Common Nutritional Disorders.................................................................................................... 125 11.1 Food constituents................................................................................................................................ 126 11.2 Feeding Children................................................................................................................................. 130 11.3 Malnutrition Disorders in Children.................................................................................................... 131 11.4 Nutrition and Women Health............................................................................................................. 133 11.5 Nutrition for Elderly........................................................................................................................... 135 11.6 Overweight and Obesity...................................................................................................................... 138 11.7 Food safety.......................................................................................................................................... 144 11.8 Food Fortification and Food Supplementation................................................................................... 145 Occupational Health....................................................................................................................................... 148 12.1 Work and Health................................................................................................................................. 149 12.1.1 Differences between occupational & work related diseases.......................................................... 149 12.1.2 Diagnosis of occupational lung diseases...................................................................................... 150 12.1.3 General methods of prevention of occupational diseases.............................................................. 150 12.1.4 Hazards of the workplace............................................................................................................ 152 12.2 Physical Hazards................................................................................................................................. 152 12.2.1 Noise.......................................................................................................................................... 152 12.2.2 Vibration.................................................................................................................................... 154 12.2.3 Radiation.................................................................................................................................... 154 Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 vii  12.2.4 Decompression sickness............................................................................................................. 157 12.2.5 High Altitude (Low atmospheric pressure).................................................................................. 158 12.2.6 Heat........................................................................................................................................... 158 12.3 Chemical occupational hazards.......................................................................................................... 163 12.4 Biological Occupational Hazards........................................................................................................ 166 12.5 Psycho-social Hazards at Work.......................................................................................................... 169 12.5.1 Work related stress..................................................................................................................... 169 12.5.2 Burnout syndrome...................................................................................................................... 172 12.6 Occupational Diseases......................................................................................................................... 174 12.7 Mechanical Hazards............................................................................................................................ 179 12.7.1 Workplace Accidents.................................................................................................................. 179 12.7.2 Ergonomics & Work-Related Musculoskeletal Disorders............................................................. 180 Quality of Healthcare...................................................................................................................................... 183 13.1 Definitions........................................................................................................................................... 184 13.2 Customers of health care.................................................................................................................... 184 13.3 Dimensions of Quality in Healthcare.................................................................................................. 185 13.4 External Evaluation of the Quality of Healthcare.............................................................................. 186 13.5 Accreditation Program in Egypt......................................................................................................... 186 13.5.1 Patient Safety............................................................................................................................. 187 13.5.2 Patient’s Rights and Responsibilities........................................................................................... 189 13.5.3 Performance Improvement (PI)................................................................................................... 191 Health Economics........................................................................................................................................... 192 14.1 What is Health Economics?................................................................................................................ 193 14.2 Economic Evaluation.......................................................................................................................... 194 14.3 Who Pays for Healthcare Service?..................................................................................................... 196 Public Health Informatics............................................................................................................................... 197 References...................................................................................................................................................... 201 Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 viii  1 Introduction By the end of this chapter, you should be able to: Differentiate between the concept of community medicine, public health, preventive medicine and clinical medicine  INTRODUCTION Definitions Community medicine, the delivery of health services to the individual and family, and Public health have vastly different missions. The mission of Public Health includes the delivery of community medicine services; surveillance of diseases; environmental protection; epidemiology; public education and information services, as well as immunization programs. Public health is “the art and science of promoting health , preventing diseases and increasing the span of healthy life through organized efforts of society”. We can promote, preserve and restore health by any of several methods or by a combination of them: a. Protection of the environment b. Enhancing immunity c. Maintaining good nutrition d. Prevention and control of communicable & non communicable diseases. e. Care of special groups as mothers, children, elderly and workers in certain hazardous occupations f. Assessment of health needs g. Planning and supporting the provision of health care services to the population. h. Providing health care prudently "A community is a group of individuals sharing an identity, culture, and operates through common institutions and organizations.”. A health center in a rural area or an urban area is responsible for the health of the community they serve within their catchment area Preventive Medicine is the science and art of application of the different levels of prevention at the population, community and individual levels." It is mainly carried by the efforts of clinicians, individuals and families to promote their own health and their neighbors’ health. Clinical medicine: It is concerned with diagnosing illness, treating disease, promoting health and relieving pain and distress in individual patient. The main differences between clinical medicine and community medicine are illustrated in the following table: Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 2  INTRODUCTION Comparison between clinical medicine and Community medicine Clinical Medicine Community Medicine Objective Patient care Health improvement Information Complaint, history and related factors Morbidity and mortality Target Diseased person Healthy and diseased persons Population Investigations Lab tests, x rays, other tests Epidemiological studies Diagnosis Differential diagnosis Community diagnosis and priority setting Resources Available therapy Health related services Management Treatment Health programs Successful preventive strategies in controlling some important diseases: - Smallpox vaccination with a good surveillance system were enough to eradicate the disease globally. - Modification of the behavior to control AIDS. - Screening for early detection of breast cancer - National program of Hepatitis C Virus screening & treatment of positive cases - National program of non communicable diseases screening (obesity, hypertension & diabetes mellitus) Work within the community: To be able to work effectively within a community one should define the boundaries of this community; geographic, demographic and administrative data, such as: 1. Population characteristics 2. Economic activities 3. Social background 4. Educational levels 5. Culture and traditions 6. Environmental sanitation problems 7. Existing community development projects 8. Governmental and non-governmental organization serving the community The 10 roles of public health are: 1. Monitor health status to identify and solve community health problems 2. Diagnose and investigate health problems and health hazards in the community 3. Inform, educate, and empower people about health issues Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 3  INTRODUCTION 4. Mobilize community partnerships to identify and solve health problems 5. Develop policies and plans that support individual and community health efforts 6. Enforce laws and regulations that protect health and ensure safety 7. Link people to needed personal health services and assure the provision of health care when otherwise unavailable 8. Assure a competent public and personal healthcare workforce 9. Evaluate effectiveness, accessibility, and quality of personal and population-based health services 10. Research for new insights and innovative solutions to health problems This is what we, as a department, promise to deliver to you through this course. Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 4  INTRODUCTION Epidemiology Demography&Popul Health Services ation Environmental &Occupational Nutrition health Social &Behavioral sciences Fig. 1: Core Public Health disciplines Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 5  2 General Epidemiology By the end of this chapter, you should be able to:  Determine the different concepts and uses of epidemiology of communicable diseases  Explain the etiology of communicable and non-communicable diseases  Differentiate between different levels of prevention and illustrate the role of community medicine in the natural history of disease  GENERAL EPIDEMIOLOGY 2.1 Introduction  The word epidemiology is derived from the Greek words epi= upon , demos= people and logus= science.  It was originally applied to the study of epidemics of acute infectious diseases and was defined as the science of epidemics. Nowadays, the science of epidemiology is expanded to include non communicable diseases and other health related states and phenomena such as smoking, violence, accidents and addiction. Definition of Epidemiology: Epidemiology is the study of the distribution, dynamics and determinants of health related states and events in a defined population and the application of this study to the control of health problems. ▪ Distribution includes a description of the disease frequency by person, time and place. In Egypt, Malaria is common in males than females, it affects all age groups and more common at the country sites near to Sudan (Wadi Halfa and Naser Lake). ▪ Dynamics means the interaction between different factors in transmission of diseases. Although the vector transmitting the yellow fever is present in Egypt, however the disease is absent because of the absence of the virus in Egypt (receptive area) and the cross immunity with the West Nile virus. ▪ Determinants are factors that determine the probability of occurrence of disease i.e. risk factors. TB is endemic in Egypt due to spread of slum areas, crowdness, smoking and malnutrition. Uses of Epidemiology: 1. Study the etiology of diseases and identify diseases’ risk factors. Epidemiological studies have contributed to the discovery of the importance of many variables as risk factors for the disease e.g. a) Maternal rubella is a risk factor of congenital defects in newborn b) Thalidomide has teratogenic effect c) Low-fiber, high animal-fat diet can contribute to the development of colorectal cancer d) Cigarette smoking is a risk factor of many cancers as lung cancer 2. Syndrome identification and describing the natural history of a disease by observing frequently associated findings in individual patients, e.g., AIDS 3. Identify the factors or conditions that can be modified to prevent the occurrence or spread of the disease. Epidemiological studies have been used to test the effectiveness of vaccination, mass treatment, and health education as measures to prevent the spread of the diseases among populations. 4. Identify the health needs of the community. e.g. to combat poliomyelitis, encourage family planning, prohibit teenage pregnancies or to prevent and control drug addiction Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 7  GENERAL EPIDEMIOLOGY 5. Measure trends of diseases (i.e. change of disease pattern by time, whether the disease is propagating, receding or stationary). Important Definitions in Epidemiology: Health: Health is more difficult to define than disease. The best-known definition of health comes from the preamble to the constitution of the WHO: " Health is a state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity".  This definition has the strength of recognizing that any meaningful concept of health must include all the dimensions of human life. Infection:The entry and multiplication of an infectious agent inside the body. An infection does not always cause an illness. Endemic:(En = in , demos = people). It refers to the constant presence of a disease within a given geographical area or population group. Epidemic:(Epi = upon, Demos = people). It refers to the occurrence of a disease in the community in excess number of cases more than expected to this specified location and during the specified period of time during the past years.  For example, if there were an average of 100 cases of typhoid fever reported in Al Abbassia fever hospital during every month of May in the last 5 years (2010-2014) and we have 250 cases during May 2015, we have to consider the possibility of an epidemic of Typhoid in the catchment area of that hospital.  From this example we should know that an epidemic can follow an endemic status of a disease.  On the other hand the occurrence of one case of Smallpox (a completely and globally eradicated disease) should ring the bell for the beginning of an epidemic.  The word epidemic has been used with non-communicable diseases as well, e.g., the epidemic of obesity or other health related events e.g. road traffic accidents. Outbreak: is the term used when the epidemic occurs in small confined-area, e.g., school, camp, hospital, hotel or prison, thus it is a localized epidemic. Pandemic:An epidemic affecting more than one country, i.e., wide geographical area or region e.g. Influenza pandemic in year 1917, H1N1 pandemic in 2009, COVID-19 pandemic in 2019 Zoonoses:An infectious disease transmitted from vertebrate animals to man, e.g., rabies, bovine tuberculosis, brucellosis. Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 8  GENERAL EPIDEMIOLOGY 2.2 Etiology of diseases Several models had been proposed to explain the occurrence and spread of communicable diseases. Etiology of communicable diseases The epidemiologic triad It is a triangle diagram that explains the interaction between the 3 elements for disease occurrence. For a disease to occur a harmful agent should come into contact with a susceptible host under specified environmental condition (Fig.2.1). Fig. 2.1: Epidemiological Triad 1) Agent factors: As biological, physical, chemical , nutritive agents….etc. 2) Host factors (Intrinsic) Non modifiable (risk attributes): The host factors include biologic traits such as age, sex, ethnic group, race, and any other genetically determined variable as the blood group. As these factors cannot be modified. Modifiable ( social traits): that include occupation, education, marital status, diet habits, smoking habits and physical activity. 3) Environmental factors (Extrinsic) The environmental factors include: Physical environment (climate, residency, pollution of air or water), Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 9  GENERAL EPIDEMIOLOGY Biological environment (presence of the vector of the disease as mosquitoes) and Socio-cultural environment (overcrowding, poverty, dietary habits). Model explaining the occurrence of non-communicable diseases It is now universally accepted that a given disease is caused by more than one causal mechanism, each “cause” should be “sufficient” to produce the disease. Each “causal mechanism” is composed of a number of components called “risk factors” defined as a behavior, an attribute or exposure that increases the probability of disease occurrence in the individual. “See chapter of non communicable diseases for more details” Fig. 2.2: Simple disease causation and multiple risk factors Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 10  GENERAL EPIDEMIOLOGY Natural history of diseases Natural History refers to the course of a disease over time, unaffected by treatment. Each disease has its own natural history, which occurs through a sequence of stages (Figure.2.3). The role of community medicine is applied throughout the whole health spectrum of individuals. 1. Stage of Positive Health: Where the person has the highest degree of physical, mental, psychological and social wellbeing…………..Role of community medicine is primary preventive measures such as Health promotion, Counsling and Care of special groups 2. Stage of Susceptibility During this stage, the disease has not developed, but the presence of risk factors favor its occurrence. For example, high serum cholesterol levels increase the probability of coronary heart disease and would therefore be considered a risk factor.…… Role of community medicine is primary preventive measures such as Risk assessment, Preventive measures and Susceptibility detection Stage of Pre-pathogenesis and subclinical: During this stage, the disease process has begun, but there are no detectable symptoms and signs. For example, atherosclerosis (hardening of the arteries) is occurring months or years before any signs of diseases appear …………… Role of community medicine is secondary preventive measures such as Observation, Surveillance and screening 3. Stage of manifest disease (clinical disease) Recognizable symptoms and signs occur during this stage of disease. …… Role of community medicine is secondary preventive measures such as Control, Epidemiology, Registry and Disease burden 4. Stage of Disability Some diseases resolve completely and do not reach this stage. However, there are a number of conditions that leave a person temporarily or permanently disabled. For example, stroke can lead to paralysis. ………… Role of community medicine is tertiary preventive measures such as Disability evaluation, Assessment of burden and Rehabilitation 5. Stage of Death …………Registry, Mortality rates, and Economic impact Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 11  GENERAL EPIDEMIOLOGY Fig. 2.3: Natural history of disease and Levels of Prevention Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 12  GENERAL EPIDEMIOLOGY 2.3 Levels of Prevention The practice of Preventive Medicine includes all the activities done to keep the people healthy, that is to say to (i) prevent the occurrence of the disease in persons and communities, (ii) improve the physical and psychological well-being so that people can lead a longer, better and productive life i.e Health promotion and (iii) restore health impairment and minimize suffering. The levels of prevention are Primary, Secondary and Tertiary (Fig. 2.3). Primary prevention It includes actions taken prior to the onset of disease, which remove the possibility that a disease will occur. The main components of primary prevention are: A) Health promotion: it is the process of enabling people to increase control over and to improve their health. It is not directed against any particular disease, but is intended to strengthen the host health through a variety of approaches such as: 1. Health education with the aim of changing the knowledge, attitudes and practices of individuals, i.e., changes in behavior and lifestyles. Examples : anti-smoking campaigns, family planning campaigns, and nutrition education campaigns. 2. Environmental modifications: e.g. provision of safe water, installation of sanitary latrine, control of insects and rodents, and improvement of housing, road planning 3. Nutritional interventions: e.g., child feeding programs, breastfeeding program, food fortification and food supplementation. B) Specific protection measures 1. Immunization against infectious diseases 2. Chemo and sero prophylaxis 3. Protection against occupational hazards by using the personal protective tools (e.g. goggles) 4. Avoiding exposure to specific risk factors e.g allergens Secondary prevention It includes actions that are taken at an early stage of the disease that prevent its progress and prevent complications. The specific interventions are: Early diagnosis (e.g., screening tests, case finding programs) Adequate treatment: Treatment may take the form of mass treatment which is used in the control of certain diseases, e.g. Bilharziasis, filariasis to interrupt disease transmission or individual treatment. Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 13  GENERAL EPIDEMIOLOGY Tertiary prevention Includes all measures available to reduce or limit impairments and disabilities, as treatment of complications and rehabilitation The International Classification of Functioning, Disability and Health (ICF) defines disability as an umbrella term for impairments, activity limitations and participation restrictions. Disability is the interaction between individuals with a health condition and personal and environmental factors In the ICF, problems with human functioning are categorized in three interconnected areas: Impairments are problems in body function or alterations in body structure – for example, paralysis, blindness Activity limitations are difficulties in executing activities – for example, walking, eating……. Participation restrictions are problems with involvement in any area of life – for example, facing discrimination in employment or transportation. Disability refers to difficulties encountered in any or all three areas of functioning. “Health conditions” are diseases, injuries, and disorders, while “impairments” are specific decrements in body functions and structures, often identified as symptoms or signs of health conditions. Personal factors: such as motivation and self-esteem, which can influence how much a person participates in society. Environmental factors: inaccessible environment: Inaccessible environments create disability by creating barriers to participation and inclusion. Examples of the possible negative impact of the environment include: a deaf individual without a sign language interpreter a wheelchair user in a building without an accessible bathroom or elevator Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 14  3 Demography, and Population Structure By the end of this chapter, you should be able to:  Determine the concept of demography and its importance  Identify methods of data collection used in demography  Differentiate between different stages of demographic transition  DEMOGRAPHY Definitions Demography is an ancient Greek terminology composed of: “Demos-“ means the people and “-graphy”, means measurement. Demography is the statistical study of human populations. It includes the study of the size, structure, and distribution of the population and changes related to birth, migration, aging, and death. Why demography is of public health importance? Public health focuses on the health of "the population". To achieve this goal we have to study its dynamics i.e. study factors that change its size and characteristics. There are many examples illustrating the relationship between public health and population dynamics: 1. Aging: - the decline of death rate results in prolonged life expectancy and increased number of older people. When it is accompanied by decreasing fertility, the proportion of older people in the population increases. Therefore, health problems and health needs of that population will be different. 2. Teenage pregnancy: - early age of marriage creates a group of preventable health problems for both mothers and infants. Women married at an early age are exposed to frequent childbearing, unplanned motherhood and abortions, which negatively affected their nutritional status. 3. Urbanization: - more people living in cities create health problems related to increasing the needs of housing, environmental sanitation, food supply, transportation and more preventive and curative health services. 4. Refugees: - and other migrants may introduce or acquire new health problems such as malnutrition, infections, and increased violence. 3.1 Methods of Data Collection in Demography 1. Census A census is a national survey for systematically acquiring and recording information about the members of a given population. It includes counting the numbers and characteristics of the population like demographic (e.g. age, sex), social (e.g. marital status, occupation) and economic data (e.g. income) at the date of census. Usually it is done every 10 years. In Egypt, for example census 1996, 2006, 2016, etc… Population censuses typically use one of two approaches: 1) De facto – meaning enumeration of individuals as where they are found during the census day, regardless where they normally reside. It is the method used in Egypt. Advantages: Easy to conduct Disadvantages: Does not reflect the actual distribution of the population especially when conducted during times of movements Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 15  DEMOGRAPHY 2) De jure - meaning enumeration of individuals as where they usually reside, regardless of where they are on census day. It is the type used in most of western countries. Advantages: Reflects the actual distribution of population Disadvantages: It is more difficult to conduct. Needs a huge amount of administrative work to locate people in their actual residential place. 2. Registries of vital data: Vital data are births, deaths and in some cases immigrations and emigrations. 3. Household surveys: Household Surveys are methods used when there is no registries or the data in these registries are not accurate (in many areas of the developing world). Example: -Egyptian Demographic Health survey (EDHS): A series of surveys have been conducted since 1980 with the aim of obtaining data from the community on the current health situation. -Sisterhood method is a household survey where the researchers ask all the women on the survival of their adult sisters. This survey is conducted to estimate the maternal mortality rate in a developing country, where the cause of death is not accurately registered. 3.2 Population Pyramid (Age and Sex Structure Diagram) A population pyramid is a diagram illustrating the age and sex distribution of the population of a country. It is made up by putting two histograms side by side (one for males, on the left and the other for females, on the right). Age is shown in 5-years interval. The lengths of the bars reperesent the number of population in each sex and age group. While slightly more males are born in any given population,females are more than males in the older age groups, due to females' longer life expectancy. In developing countries the pyramid is characterized by a broad base of young and a small apex of olds. Young population: is considered when the pyramid displays a population percentage of ages “1–14” over 30% and ages “75 and above" under 6% (in Egypt they are 32.1% and 1.4% respectively- according to 2016 estimate- so it is considered a young population). In developed countries the population distributions are beginning to lose the "pyramidal" shape as they become more straight up and down with almost equal numbers of people in adjacent age groups until the age of high death rates which begins after age 65 Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 16  DEMOGRAPHY It is to be noted that span (length of pyramid) becomes shorter when the mortality increases in younger age groups (children or young adults) not in older age groups (Death in old age does not affect span as the pyramid has already reached its peak. Death in old age decreases or narrows the top only ( i.e. narrow apex). Dependent age group: is defined as those under 15 (children who are in full time education and therefore unable to work) and those over 65 (those who have the option of being retired). Dependency ratio : it is the ratio between the dependent group (65 years) to the independent group (15-65 years) Fig. 3.1: The Egyptian population pyramids for years 2013 & the expected at 2020 Source: U.S. Census Bureau, International Data Base Basic Demographic Indicators: Demographic characteristics of a country provide an overview of its population size, composition, territorial distribution, changes therein and the components of changes such as natality, mortality, and social mobility. This section on demographic indicators has been subdivided into two parts - Population Statistics and Vital Statistics. Population statistics include indicators that measure the population size, sex ratio, density and dependency ratio while vital statistics include indicators such as birth rate, death rate, and natural growth rate, life expectancy at birth, mortality and fertility rates. These indicators for the country as well as specific governorates will help in identifying areas that need policy and programmed interventions, setting near and far-term goals, and deciding priorities, besides understanding them in an integrated structure These are the measures used to: - Portray the health related problems in a population, - Identify the high risk groups, - Measure the success of the prevention and control measures and - Some measures are needed to evaluate the effect of intervention programs. Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 17  DEMOGRAPHY They include: - Mortality rates, - Fertility rates, - Rate of natural increase, population growth, and life expectancy (the number of years an individual, at any given age, is expected to live with the current mortality rates). Basic demographic equation: - It is the equation used to estimate the population size at any time between census years - Balancing equation is based on the number of births, deaths and migration. Population at year 2008 = population (at year 2006) + natural increase (from 2006 to 2008) + Net migration (from year 2006 to 2008) Natural increase = Births (during 2007+2008) – Deaths (during year 2007+2008) Net migration =Immigration (during 2007+2008) – emigration (2007+2008) Demographic transition: It is a model describing the population changes over long time. It refers to the transition from high birth and death rates to low birth and death rates as a country proceeds from the pre-industrial to an industrialized economic era. Using the demographic transition model, demographers can better understand a country’s current population growth based on its placement within one of five stages and then pass on that data to be used for addressing economic and social policies within a country and across nations. The demographic transition evolves in five stages: Fig 3.2: Demographic transition Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 18  DEMOGRAPHY Stage 1: Birth rate is high as there is no contraception and people have lots of children as many die. Death rate is high due to poor healthcare. Population growth rate is ~ zero. Life expectancy is low, and the population is mostly young. So population growth rates are slow but population is usually restored due to high birth rates. Stage 2: Birth rate is high as there is low utilization of contraceptive methods. Also children labor is considered as a source of family income in rural areas that predominate. Death rate falls due to improved health care. Population growth rate is very high. Life expectancy has relatively increased and, still more young people than older. Stage 3: Birth rate is rapidly falling due to women empowerment and better education. The use of contraception has increased. Community shifted from agricultural to industrial. The economy has changed to manufacturing. Death rate falls due to upto date medical care and advances. Population growth rate is high. More people are living to be older. Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 19  DEMOGRAPHY Stage 4: Birth rate continue to be low with movement of people to urban areas Death rate is low, but nearly equal to birth rate Population growth rate is almost zero. Life expectancy is high, more people are living to be older. Stage 5: Birth rate is slowly falling. Death rate is low but higher than birth rate. Population growth rate is rather negative. More older people than younger prevailing. Population problems in Egypt: ▪ Rapid population growth (Overpopulation). ▪ Unbalanced geographic distribution where people live on only 5.5% of all the surface area of Egypt. Table 3.1 Population size in Egypt From 2015 to 2021 (in million) 2015 2016 2017 2018 2019 2020 2021 92.4 94.4 96.4 98.4 100.3 102.3 104.2 Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 20  DEMOGRAPHY National hazards of overpopulation give rise to the following problems: 1. Housing: slum areas, with unsanitary living conditions and high crowding index. 2. Food supply: increasing food imports and rising prices, especially of animal protein foods 3. School education: crowded schools, and unsatisfactory educational process. 4. Public services: increasingly burdened, and not satisfying public needs. 5. Employment: reduced job vacancies and work opportunities due to the increase in the young generation and the development of mechanization and automation. 6. Increase rates of violence, accidents and child labor. 7. Increase in the endemicity of some diseases Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 21  4 Epidemiology of Communicable Diseases By the end of this chapter, you should be able to:  Explain the epidemiology of common communicable diseases.  Differentiate between various preventive measures of common communicable disaeses.  Describe guidelines for isolation precautions in hospital  COMMUNICABLE DISEASES 4.1 Dynamics of Infectious Disease Transmission Disease transmission is a dynamic process that occurs due to an interaction that evolves between the six elements of infection chain which are the infectious agent, the reservoir of infection, portal of exit and portal of entry, mode of transmission and the susceptible host. I. Etiologic agent (infectious agent): It could be 1. Parasitic agents e.g. Protozoa, Ascaris) 2. Fungi: unicellular organisms of plant kingdom (ringworm) 3. Bacteria and their toxins 4. Rickettsia: obligate intracellular parasites that are affected by antimicrobial agents. 5. Viruses: obligate intracellular parasites that do not respond to usual antimicrobial agents. II. Reservoir (source of infection): The reservoir is the natural habitat in which the organism survives. This may be a person, an animal, arthropod or soil, in which the infectious agent lives and multiplies and is completely dependent upon for survival. There are three reservoirs for infectious agents: 1- Human Reservoir. The human reservoir may be a case or carrier. a) Case: clinical case which manifest the disease. Clinical cases are not a public health threat as they are usually isolated at home and seek medical treatment. b) Carrier: an infected person that harbors a specific infectious agent in his body, without showing symptoms or signs and serves as a potential source of infection for others (shedding the infectious agent outside). Carriers may be classified according to: A. Disease status: 1. Incubatory carriers are those who shed the infectious agent during the incubation period. e.g. mumps, poliomyelitis and hepatitis B. 2. Subclinical case: Persons who are infectious but have subclinical disease are called carriers. 3. Convalescent carriers are those who continue to shed the disease agent during the period of convalescence, e.g. typhoid fever. 4. Healthy carriers (contact carriers) that emerge from clinical or subclinical cases, so they are apparently healthy but they are shedding the organisms outside the body to infect others, e.g., cholera and poliomyelitis. Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 23  COMMUNICABLE DISEASES B. Duration: 1. Temporary carriers are those who shed the infectious agent for short periods of time. In this category the incubatory, convalescent and healthy carriers may be included. 2. Chronic carriers are those who shed the infectious agent for indefinite periods of months or years, e.g. typhoid fever, hepatitis B, gonorrhea C. Portal of exit of the infectious agent: 1. Urinary carriers 2. Fecal carriers 3. Respiratory carriers Chronic typhoid carriers may be urinary or fecal. Epidemiological importance of carriers as a source of infection: 1. They are not recognized to people or even themselves. 2. They move freely in the community. 3. Their number may be greater than cases. 4. Infectivity may persist for a long time (years). 5. The diagnosis needs laboratory investigations. 6. The danger in some occupations dealing with large number of community members, e.g., food-handlers, HCWs (health care workers), teachers or ticket collectors. 2. Animal Reservoir: The reservoir and source of infection may be vertebrate animals. The diseases which are transmitted from vertebrate animals to man are called zoonotic diseases. Examples include rabies, brucellosis, bovine tuberculosis, and leptospirosis. 3. Environment: The soil for tetanus spores III. Portal of exit: Portal of exit of the infectious agent from the reservoir may be: 1. Respiratory tract through expectoration, coughing, sneezing (influenza virus, TB bacillus, measles virus, mumps virus) 2. Gastrointestinal tract through saliva (Rabies) or feces (typhoid bacillus) 3. Genitourinary tract through urine (typhoid bacillus) or genital secretions (gonorrhea, HIV). 4. Skin through skin lesions (syphilis and chickenpox) or through abrasions (breaks) in the skins. Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 24  COMMUNICABLE DISEASES IV. Modes of Transmission: It is the route through which infectious agent is transmitted to the host. It may be classified into direct and indirect transmissions. 1. Direct Transmission Direct transmission occurs when microorganisms are transferred directly from one infected person to another person without a contaminated intermediate object or person. 1. Direct contact i.e. skin to skin touching, kissing, sexual relation, e.g. AIDS, gonorrhea, leprosy, eye infection 2. Droplet spread through coughing, sneezing, speaking and spitting, e.g. mumps and common cold. 3. Trans-placental, e.g., German measles (Rubella), AIDS, toxoplasmosis. 2. Indirect Transmission. It is the transfer of an infectious agent through a contaminated intermediate. 1. Vector borne: such as arthropods, mosquito that transmits an infectious agent to a susceptible individual e.g. Malaria, Plague, Filariasis, Rift Valley Fever. 2. Vehicle transmission: Common vehicles like contaminated water and food 3. Air-borne with droplet nuclei less than 5 microns in size that remain suspended in air for long periods and travel for variable distances, e.g., tuberculosis and influenza. 4. Fomite-borne: Fomites are inanimate articles that are contaminated by the infectious discharges from patients then are capable of transferring the infectious agent to a healthy person. Fomites include towels, linen, cups, and spoons. e.g., hepatitis A, eye diseases. V. Portal of entry: The mucous membrane, the skin, respiratory tract, gastrointestinal tract and genitourinary system. VI. Susceptible host: can be any person at risk i.e. non-immunized 4.2 Prevention and Control of Communicable Diseases Prevention and control of communicable diseases involves interventions to break the chain of transmission (include infectious agent, reservoir, route of exit, mode of transmission, route of entry and susceptible host). Prevention: refers to measures applied to prevent the occurrence of a disease. Control: refers to measures applied to prevent further transmission after the disease has occurred. Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 25  COMMUNICABLE DISEASES For prevention and control of communicable diseases, two periods must be well- defined: Incubation Period It is defined as the time interval between invasion of the body by an infectious agent and the appearance of the first sign or symptom of the disease. The length of the incubation period is characteristic of each disease. There is a minimum and maximum incubation period for every disease it varies from one person to another with the same disease, as it depends on the level of the host immunity, the microbial load and the virulence of the microorganism. Epidemiological importance of incubation period 1. Preventive measures may be carried out during the incubation period to prevent occurrence of the disease or at least attenuate its severity. If the incubation period is short, passive immunization or chemoprophylaxis may be used, e.g., measles and meningitis, but if the incubation period is long, active immunization may be used, e.g., rabies. 2. Surveillance of contacts of a communicable disease case: contacts should be kept under observation for the maximum incubation period for early case detection. 3. In quarantinable diseases (Yellow Fever, plague), travelling from endemic area to another country is prohibited during the incubation period except after having a valid certificate of immunization, otherwise one should be kept in the quarantine till the end of the international incubation period. 4. Tracing the source of infection among contacts especially for diseases with a short incubation period as in the case of food poisoning. 5. Estimating the prognosis of a disease. In some diseases such as tetanus and rabies, the shorter the incubation period, the worse the prognosis of the disease. Period of Communicability It is defined as the time during which an infectious agent may be transferred directly or indirectly from an infected person to another person, i.e. the time during which the infected person is infectious to others. It might include part of the incubation period, the whole disease and /or convalescence period. Preventive measures are taken during this period to prevent transmission of the disease to others through: 1. Isolation of the patient either at home or in the fever hospital. 2. Disinfection of secretion and excreta of the patient. 4.2.1 Interventions to break the cycle of infection (Fig.4.1) 1. Measures Directed Against the Agent/ Reservoir a) Measures applied to cases ▪ Case finding (early diagnosis) ▪ Reporting ▪ Isolation Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 26  COMMUNICABLE DISEASES ▪ Treatment (Chemotherapy) ▪ Disinfection either:  Concurrent disinfection: It is disinfection during the course of illness; the application of disinfectant measures as soon as possible after discharge of the infectious material from the body of an infected person. It consists of: disinfection of urine, faeces, vomit, sputum, contaminated linen, clothes, dressings, aprons…  Terminal disinfection: It is an application of disinfectant measures after the patient has been discharged by cure or death. Terminal cleaning is considered adequate along with airing and sunning of rooms, furniture and bedding Fig. 4.1. Breaking the chain of infection b) Measures applied to carriers ▪ Detection of carriers: It is important in certain diseases e.g. enteric fever. Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 27  COMMUNICABLE DISEASES ▪ Exclusion from work: in certain occupations for example; food handler (e.g. Typhoid carrier) or a teacher (e.g. Diphtheria carrier). ▪ Treatment for the carrier state. c) Measures applied to animal reservoir  Destruction of infected animals (in rabies, plague)  Inspection of slaughtering (in bovine tuberculosis)  Testing and immunization (in brucellosis)  Careful husbandry and sterilization of animal products (in anthrax). 2. Measures that interrupt the Mode of Transmission (MOT) a) Measures to reduce transmission of droplet infections: Examples for common droplet infections: Measles, rubella, Mumps, Chicken Pox, Rheumatic fever, Influenza, COVID-19, meningitis and Tuberculosis General measures 1. Town planning, slum area development, control of dust. 2. Education of the public & contacts (family members, classmates, teachers, caregivers) about personal hygiene including: a. Frequent hand washing especially after wiping or blowing the nose; after contact with any nose, throat, or eye secretions; and before preparing or eating food. b. Coughing or sneezing into a tissue and away from other people. Tissues should be properly disposed in a step can with a plastic liner. 3. Proper ventilation of public places & classrooms 4. Minimize close person to person contact (reduce overcrowding) 5. Avoid smoking in households especially with presence of children. Specific measures: 1. Immunization: ▪ Active immunization (e.g. measles, mumps, rubella, influenza, chicken pox and tuberculosis). ▪ Passive immunization by provision of antibodies (e.g. measles and chicken pox). 2. Chemoprophylaxis (e.g. meningitis and Tuberculosis). 3. Health education about the importance of immunization or chemoprophylaxis. Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 28  COMMUNICABLE DISEASES b) Measures to prevent transmission of foodborne diseases: Examples for food borne diseases: Typhoid fever, Cholera, Diarrheal diseases and dysenteries, Viral hepatitis (A and E), Food poisoning and Poliomyelitis General measures: 1) Educate the public regarding the importance of hand washing 2) Protect, purify and chlorinate public water supplies 3) Control flies by controlling fly breeding areas (garbage) and use of insecticidal baits and traps or, where appropriate, spraying with insecticides. 4) Use safe handling practices in food preparation, handling and storage 5) Pasteurize or boil all milk and dairy products. 6) Enforce suitable quality-control procedures in industries that prepare food and drink for human consumption. Specific measures: Active immunization (e.g. Typhoid fever, cholera, hepatitis A and poliomyelitis). c) Measures to reduce transmission of bloodborne diseases: Examples for bloodborne diseases: Acquired immunodeficiency syndrome (AIDs), and Viral hepatitis (B, C and D) General measures 1. Standard Precautions: Refer to isolation precautions in hospitals 2. Infection control and surveillance: Develop infection control surveillance system and units in each health care setting to report cases of accidental needle stick injury or contact with blood/body fluids. 3. Blood banks: a. All donated blood should be screened for HBsAg, HCV Ig, HIV EIA. Same applies to organ transplantation. b. Limit administration of unscreened blood in case of emergencies to those in clear/immediate need. c. Health education of patients and general population on autologous blood transfusion. 4. Safe community needle disposal and waste management: Never place loose syringes, needles, stylets and other sharps (those that are not placed in a sharps disposal container) in the household or public trash cans or recycling bins, and never flush them down the toilet. 5. Community health education to avoid high risk behaviors: such as sharing/re-use of syringes or needles, sharing barber tools, or personal hygiene tools such as tooth brushes, scissors and nail clippers. Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 29  COMMUNICABLE DISEASES Specific measures: Active immunization (e.g. hepatitis B). d) Measures to reduce transmission of sexually transmitted diseases (STDs): Examples: The most common sexually transmitted diseases are Chlamydia trachomatis, Gonorrhea, Syphilis, Trichomoniasis, Herpes simplex 2 and Human Papilloma Virus (HPV) (coinfection with multiple organisms is common). General measures: 1. Modify sexual activity and sex education. 2. Barrier methods of contraception 3. Proper genital hygiene Specific measures: 1. Immunization against HPV 2. Co-Treatment of sexual partners. 3. Screening for STDs: This is done for some STDs in high risk groups e.g. sexually active females, pregnant females and homosexuals E) Measures to reduce transmission of zoonotic diseases: Examples: Anthrax, brucellosis and rabies General measures: 1. Health Education: a) Know that animals may carry germs that can cause diseases b) Wash hands with soap and water right after dealing with animals c) Avoid consuming unpasteurized milk and milk derivatives. 2. Pasteurization of milk and adequate cooking of meat 3. Careful handling and disposal of animal and animal products. 4. Barrier precautions for hunters and professionals at risk (butchers, farmers, slaughterers, veterinarians) such as gloves, gowns and boots. Specific measures: 1. Vaccination of high risk personnel against zoonotic diseases (e.g anthrax and rabies) 2. Post-exposure Prophylaxis with the proper antimicrobials in cases of recent exposure to avoid infection. Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 30  COMMUNICABLE DISEASES F) Measures to reduce transmission of common contact diseases: Examples: tetanus, schistosomiasis, puerperal sepsis, Ebola virus disease General measures: 1. Proper chemotherapy whenever available. 2. Snail control as in Schistosomiasis 3. Health education 4. Environmental sanitation 5. Care during delivery and puerperium, using aseptic measures is very important. Use of sterile gloves, gowns and masks and proper hand washing for puerpural sepsis Specific measures: 1. Active immunization: eg. Tetanus 2. Mass and individual treatment e.g. schistosomiasis. G) Measures to reduce transmission of vector borne diseases: Examples: Malaria, lymphatic filariasis, leishmaniasis, plague, yellow fever, Zika virus disease, rift valley fever and West Nile fever General measures: 1. Health education: About methods of transmission and methods of protection 2. Environmental control (vector control): as in Malaria, lesihmaniasis, yellow fever and Zika virus disease. This can be done by: o Using insect repellent regularly; o Wearing clothes (preferably light-colored) that cover as much of the body as possible; o Installing physical barriers such as window screens in buildings, closed doors and windows; o Additional personal protection, such as sleeping under mosquito nets during the day; o Efforts must be made to eliminate mosquito breeding sites such as still water soon after rains and its accumulation in discarded containers and waste materials in and around houses 3. Elimination of the intermediate host in certain vector borne diseases as in leishmaniasis (sand fly) and plague (rat flea). Specific Measures: 1. Chemoprophylaxis: eg Malaria 2. Mass drug treatment as in lymphatic filariasis 3. Active immunization: Plague, Yellow fever and Rift valley fever Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 31  COMMUNICABLE DISEASES 4.2.2 Guidelines for isolation precautions in hospital: There are four isolation categories: A. Standard precautions B. Airborne precautions C. Droplet precautions D. Contact precautions A. Standard Precautions It is the infection prevention practices that should be applied routinely to all patients while providing care in any health care setting regardless of suspected or confirmed infectious status of the patient. It is designed to protect the patient, the health care workers and the whole community It is used with all patients and assumes that all patients are infectious and includes: 1- Hand hygiene. It is the single most important measure to prevent cross infection. Wash hands after touching blood, secretions, excretions, and contaminated items, and after removal of gloves. Use plain soap for routine hand washing.Use an antimicrobial cleaning agent for specific circumstances. 2- Personal protective equipment: Designed to shield the employee from blood and body fluid contamination. These equipments include: gloves, fluid resistant masks and gowns, splash shields, and eye protection, and is used whenever there is a risk of exposure to blood or other potentially infectious material. 3- Aseptic techniques: It refers to the practices performed just before or during a clinical or surgical procedure in order to reduce the patient’s risk of infection by reducing the likelihood that microorganisms will enter areas of the body where they can cause infection. These could be achieved by following the infection control guidelines for any practices 4- Reprocessing of instrument: Ensure that reusable equipment is not used for the care of another patient until it has been disinfected and sterilized appropriately. Single use equipment is preferred. 5- Sound waste management 6- Safe injection practice: a) Avoid reuse of syringes and needles b) Promote the use of safety-engineered products and services c) Avoid recapping of needles Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 32  COMMUNICABLE DISEASES d) Disposal of syringes and sharps in puncture-proof containers for incineration 7- Environmental cleaning Ensure that the hospital has adequate procedures for the routine care, cleaning, and disinfection of environmental surfaces. Contaminated articles should be appropriately treated 8- Respiratory hygiene and cough etiquette: They include health education of healthcare workers, patients, and visitors to: ▪ Cover the nose/mouth when coughing or sneezing ▪ Use tissues to contain respiratory secretions and dispose in the waste receptacle ▪ Perform hand washing after contact with respiratory secretions and contaminated objects ▪ Place a surgical mask on the coughing person when tolerated and appropriate In addition to standard precautions transmission based precautions (isolation) are designed only for patients that are known or suspected to be infected with highly transmissible or epidemiologically important pathogens for which additional precautions beyond “Standard Precautions” are needed to interrupt transmission in hospitals. B. Airborne Precautions: In addition to the standard precautions, airborne precautions, used for patients known or suspected to be infected with microorganisms transmitted by airborne droplet nuclei (small-particle residue less than 5 µm) which remain suspended in the air and can be dispersed widely by air currents within a room or over a long distance such as: Tuberculosis Airborne precautions include Standard Precautions plus a. Patients requiring negative air pressure room b. Limit movement and transport of the patient. c. Patient should use a surgical mask if they need to be moved C. Droplet Precautions: In addition to standard precautions, droplet precautions, used for a patient known or suspected to be infected with microorganisms transmitted by droplets (large- particle droplets 5 µm and larger in size) that can be generated by the patient during coughing, sneezing, talking, or the performance of procedures such as Droplet precautions include Standard Precautions plus a. Private/single room (patients with the same infection may share a room) b. HCW /visitors/contacts should wear surgical mask Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 33  COMMUNICABLE DISEASES c. Limit movement and transport of the patient. Patient should use a surgical mask if they need to be moved. D. Contact Precautions: In addition to standard precautions, contact precautions, used for specified patients known or suspected to be infected or colonized with epidemiologically important microorganisms that can be transmitted by direct contact with the patient (hand or skin-to-skin contact) or indirect contact with environmental surfaces or patient-care items (touching). Used in the care of patients with suspected or confirmed infections such as: ▪ Respiratory syncytial virus, parainfluenza virus ▪ Enteric infections with Clostridium difficile, Shigella, hepatitis A, or rotavirus ▪ Skin infections including: Herpes simplex virus, staphylococcal, Varicella, Herpes zoster and Viral hemorrhagic infections (Ebola, Lassa, or Marburg) Contact precautions include Standard Precautions plus a. Private room or room shared with patients with the same infection b. Limit patient movement c. Clean patient room daily using disinfectant, with attention to frequently touched surfaces d. Use dedicated equipment if possible (e.g., stethoscope) NB. Patients are isolated at home if sanitation requirements can be fulfilled Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 34  5 Epidemiology of Non- Communicable Diseases By the end of this chapter, you should be able to: 1. Describe the epidemiology of common non-communicable health problems. 2. Identify various measures of prevention and control for common non- communicable health problems.  NON COMMUNICABLE DISEASES 5.1 Definition of Non-Communicable Diseases Non-communicable diseases (NCDs), also known as chronic diseases, are a group of diseases which are not transmitted from person to person. They are of long duration and generally slowly progressing. The four main types of NCDs of global concern are cardiovascular diseases (like heart attacks and stroke), cancer, chronic respiratory diseases (such as chronic obstructive pulmonary disease and asthma) and diabetes. (WHO definition) The commission on chronic illness in the USA has defined "chronic disease" as the disease with one or more of the following characteristics: 1. Permanent 2. Leave residual disability 3. Caused by non-reversible pathological alterations 4. Require special training of the patient for rehabilitation 5. May be expected to require a long period of supervision, observation and care. The etiology of any disease is multifactorial, i.e. the development of a disease needs the contribution of more than one risk factor. It can be caused by a number of sufficient causes (a bundle of many risk factors). Each sufficient cause (sufficient enough to produce the disease) consists of a combination of many risk factors (called component causes) that work in different combinations. Component causes change overtime and in different populations. Social determinants of health: Social determinants of health are conditions in the environments in which people are born, live, learn, work, play, worship, and age that affect a wide range of health, functioning, and quality-of-life outcomes and risks. Examples of social determinants of health: o Economic stability: e.g. employment, income and medical bills support. o Neighborhood and physical environment: e.g. housing, transportation and avialability of parks and playgrounds. o Education: e.g. Literacy, early childhood education, vovational and higher education. o Food: e.g. hunger and acess to healthy options o Social environment: e.g community engagement o Health care system: e.g. health coverage and quality of care Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 36  NON COMMUNICABLE DISEASES 5.2 Burden of Non-Communicable Diseases NCDs represent a major burden to individuals, governments and societies. On the individual level, they may cause premature death or severe disability among survivors. NCDs cut lives short, often claiming people at their most productive age. They can drive individuals into poverty due to lack of their productivity and the need to pay for medications and drugs for prolonged periods of time. On a governmental level, NCDs represent a huge burden that puts pressure on health systems and resources. They increase health care costs and out-of-pocket and catastrophic expenditure. On the societal level, they have detrimental socioeconomic consequences. NCDs as a cause of death: Worldwide (according to WHO, 2018), NCDs are collectively responsible for almost 70% of all deaths worldwide. Almost three quarters of all NCD deaths, and 82% of the 16 million people who died prematurely, or before reaching 70 years of age, occur in low- and middle-income countries. Cardiovascular diseases account for most NCD deaths, or 17.9 million people annually, followed by cancers (9.0 million), respiratory diseases (3.9 million), and diabetes (1.6 million). These 4 groups of diseases account for over 80% of all premature NCD deaths. In the Eastern Mediterranean Region of WHO, 2012, NCDs claimed over 2.2 million lives in the Region and caused 57% of mortality. Four groups of diseases – cardiovascular disease, cancer, diabetes and chronic lung disease – were responsible for 80% of this mortality; 65% of deaths were linked to risk factors. 60% of people with chronic diseases die young, under the age of 70. In Egypt, NCDs are the current leading cause of mortality, with NCDs estimated to account for 85% of all deaths. Cardiovascular diseases accounted for the most deaths of all NCDs (46%), followed by cancer (14%), chronic respiratory diseases (4%) and diabetes (1%). Alarmingly, NCD-related premature mortality (between ages 30 to 70 years) is occurring at (25%). Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 37  NON COMMUNICABLE DISEASES Fig. 5.1: Causes of death in Egypt (Egypt: Institute for Health Metrics and Evaluation http://www.healthdata.org/ ) In addition to being a major cause of death, most victims of chronic diseases will live a number of years suffering from the disease before dying mostly prematurely. Victim of chronic diseases will suffer from “bad quality of life”. Quality of Life, The quality of life aspects (physical, mental, psychological, social and sexual) will not be the same as a healthy individual. The disease burden is measured by:  Disability Adjusted Life Years (DALYs) = the sum of years of potential life lost due to premature mortality (Years of Life Lost = YLL) and the years of productive life lost due to disability (Years Lost due to Disability = YLD).  Years of life lost due to Premature death (YLL) YLL = Age at death – Life expectancy at this age.  YLD = Years Lived with Disability by multiplying the years lived by the victim while having the disease (disease duration) by the disability weight (DW). YLD = Disease Duration (years lived by the victim while having the disease x disability weight (DW)* Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 38  NON COMMUNICABLE DISEASES *DW: Weights have been assigned to each disease according to the degree of disability it causes that depends on its severity and complications. DW is a quantity measure of the reduction in the overall quality of life due to the disability. Example for calculation of YLD: The following are the disability weights of a patient with a stroke, (data are presented as the mean and the range of the disability weight): Degree of Stroke DW Long-term consequences, mild 0·019 (0·010–0·032) Long-term consequences, moderate 0·070 (0·046–0·099) Long-term consequences, moderate, plus cognition 0·316 (0·206–0·437) problems Long-term consequences severe 0·552 (0·377–0·707) Long-term consequences, severe, plus cognition problems 0·588 (0·411–0·744 From that we can calculate the YLD YLD = Disease Duration x DW YLD= 1x 0.552= 0.552 (55.2%) So, living for one year with the disability due to Long-term consequences of severe stroke makes the victim loses 55.2% of the productive life lived by a completely healthy individual. Example for calculation of DALY: Suppose that a male individual had a stroke and lived 10 years with severe Long-term consequences before he died at the age of 65 years. Life expectancy of the 65 years male is 12 year, (i.e., at the age of 65 years, it was expected that he would live another 12 years). Then the burden of stroke on this individual will be calculated as follows: DALY = YLL + YLD So, DALY for this individual = 12 + (10 x 0.55) = 17.5 years due to stroke. The purpose of DALYs is having a quantitative measurement that enables comparison of burden of different diseases among different socio-demographic groups and between various populations and countries. The WHO definition of DALY: “One DALY can be thought of as one lost year of "healthy" life. Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 39  NON COMMUNICABLE DISEASES The sum of these DALYs across the population, or the burden of disease, can be thought of as a measurement of the gap between current health status and an ideal health situation where the entire population lives to an advanced age, free of disease and disability”. (Metrics: Disability-Adjusted Life Year (DALY) Quantifying the Burden of Disease from mortality and morbidity. http://www.who.int/healthinfo/global_burden_disease /metrics_daly/en/) 5.3 Risk factors for Non-Communicable Diseases People of all age groups, regions and countries are affected by NCDs. These conditions are often associated with modifiable and non-modifiable risk factors: Modifiable risk factors: are risk factors which can be prevented, controlled or modified  Tobacco: it is a risk factor associated with all NCDs.  Smoke from a single cigarette is composed of over 4000 different harmful constituents.  Number of cigarettes smoked daily, duration of smoking in years, depth of inhalation, early age of initiation and tar content of the brand smoked are all determinants of the risk to develop NCDs.  Environmental tobacco smoke or passive smoking significantly increases the risk.  Diet, nutrition and lack of physical activity:  Overweight and obesity (High calorie intake and lack of physical exercise) increase the risk of endometrial and post-menopausal breast cancer, cardiovascular diseases.  Consumption of diets high in fat and red meat and high total energy intake and low in fiber content (cardiovascular diseases and, colon and breast cancer).  Contaminants and Additives: Food items may be contaminated by preformed carcinogens as aflatoxins in preserved humid cereals, nitrites in preserved food, salted fish and artificial sweeteners, smoked and cured food as well as charcoal broiled meat.  Excessive salt ingestion (hypertension and cardiovascular diseases).  Alcohol: Regular and heavy use of alcohol has been associated with increased risk of oral and esophageal cancers. Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 40  NON COMMUNICABLE DISEASES Fig. 5.2: Four Modifiable Shared Risk Factors for Non-communicable Diseases (CDC - https://www.cdc.gov/globalhealth/healthprotection/fetp/training_modules/new-8/overview-of- ncds_ppt_qa-revcom_09112013.pdf) The above figure showed that 4 NCDs shared Tobacoo use as a modfibale risk factor and three of NCDs (CVD, DM and Cancer) shared 3 modifiable risk factors)  Metabolic risk factor contribute to four key metabolic changes that increase the risk of NCDs: raised blood pressure, overweight/obesity, hyperglycemia (high blood glucose levels) and hyperlipidemia (high levels of fat in the blood). In terms of attributable deaths, the leading metabolic risk factor globally is elevated blood pressure (to which 19% of global deaths are attributed), followed by overweight and obesity and hyperglycemia.  Industrial or occupational exposure: There is a long list of potential occupational carcinogens such as asbestos, aniline, arsenic, benzene, DDT and others.  Air pollution: Burning of tobacco, coal, diesel fuel and wood all are sources of air contamination with a variety of carcinogens.  Contaminated drinking water: Arsenic, asbestos, radon, agricultural chemicals and hazardous wastes are potential sources of drinking water contamination and they are all carcinogens.  Sunlight: Ultraviolet (UV) radiation comes from the sun, sunlamps, and tanning booths. It causes early aging of the skin and skin damage that can lead to skin cancer.  Ionizing radiation: Equal doses of different types of radiation can produce different biological effects. Acute exposure differs from chronic or fractionated exposure to the same type of radiation. Breast, stomach, respiratory, leukemia, Community, Enviromental & Occuptional Medicine Department, ASU 2021-2022 41  NON COMMUNICABLE DISEASES urinary, colon, thyroid, ovary, skin and liver are the affected organs.  Hormones: Women taking hormonal contraception are at increased risk of breast cancer considering the age, general health, other risk factors like smoking and alcohol intake and her personal risk. [Early users (starting at young ages), and long term users are at higher risk]. Also, the risk of stroke, thromboembolism, and myocardial infarction increases.  Non hormonal drugs:  Phenacetin; an ingredient of certain analgesics and non-steroidal anti- inflammatory agents; is a known carcinogen to the kidney and lower urinary tract.  Antineoplastics (such as cyclophosphamide) and Immunosuppressants ( such as cyclosporin A) are associated with leukaemias, and lymphomas.  Infectious agents:  Cardiovascular diseases as rheumatic heart (beta streptococal infecti