LECTURE 2 - Public Health And Hygiene PDF

LECTURE 2 2. IMPORTANT CONCEPTS IN PUBLIC HEALTH 2.0 INTRODUCTION This lecture discusses concepts in Public Health that are essential to the better understanding of issues relating to the HIV Pandemic. Being an incurable communicable disease with the potential to infect large numbers of people wi...

LECTURE 2 2. IMPORTANT CONCEPTS IN PUBLIC HEALTH 2.0 INTRODUCTION This lecture discusses concepts in Public Health that are essential to the better understanding of issues relating to the HIV Pandemic. Being an incurable communicable disease with the potential to infect large numbers of people within a short time, HIV is a problem of much Public Health importance. It is therefore necessary that you have an understanding of basic concepts in Public Health. 2.1. LECTURE OBJECTIVES By the end of the lecture you should be able to:  Define basic concepts in Public Health including Public Health, Hygiene, Epidemiology, Biostatistics, Prevalence, Incidence, Rate,  Discuss public Health measures that help to promote health and prevent disease  Discuss the different levels of prevention  Discuss the various Public Health measures in health promotion and prevention of disease  Highlight regional variations of HIV/AIDS prevalence, the trends and pattern of spread of HIV infections- locally and globally. Place here the objectives this unit. Use the lecture guidelines given in the accompanying template to create your lectures and paste them here to replace this section. 2.1. PUBLIC HEALTH, HYGIENE, EPIDEMIOLOGY, BIOSTATICS, HEALTH SERVICES. 2.1.1 Public health has been defined in different ways but the main focus is the same. Consider the following two definitions presented below. The first definition is as follows: “the science and art of preventing diseases, prolonging life and promoting health through the organized efforts and informed choices of society, organizations, both public and private, communities and individuals’(C.E.A Winslow, 1920). Source: Winslow, Charles-Edward Amory (1920). "The Untilled Field of Public Health". Modern Medicine. 2: 183–191. As cited in: https://en.wikipedia.org/wiki/Public_health An alternative definition is that Public health is: “the protection and improvement of the health of entire populations through community wide actions primarily by government agencies.” Maranga, Muya & Ogila, 2008. Both these definitions emphasize the aspect of prevention and the focus on the community level rather than concentrating on the individual. Public Health has three main branches-  Epidemiology,  Biostatistics and  Health services. On its part the concept of health is understood in a holistic way which is well captured in the way it is defined by the World Health Organisation (WHO). WHO defines health as: “the state of complete physical, mental, and social wellbeing and not merely the absence of disease or infirmity”(en. Wikipedia.org/wiki/Health). This definition encourages a broad view of health which if achieved, assures a high quality of life for the individual. Public health focuses on prevention as one way of assuring that health is maintained. Public health services are distinguished from the provision of Medical care to sick people ( Medical Services) in that Public Health focuses on preventing illnesses before they occur rather than waiting for people to get sick and present themselves for treatment. The preventive approach is the preferable way of addressing the health care needs of a community as it is more cost- effective and reduces the disease burden in a community. In the case of a disease like HIV/AIDS which is incurable and life-threatening, prevention becomes even more important. The other important characteristic of Public Health is that it focuses on the community rather than on the individual. Once the health care needs of the community are understood and addressed then the individual will benefit from these initiatives. 2.1.2 Hygiene -Has been defined as “the practice of keeping oneself and one’s environment clean so as to prevent illness and disease” Oxford advanced dictionary 5th Ed. Put in another way it is therefore the science that deals with the prevention of diseases by eliminating factors that favour the spread of disease. Personal hygiene involves practices such as :  hand washing with soap and clean water  trimming nails,  regular bathing and good grooming,  Brushing one’s teeth after meals. Environmental hygiene (also called environmental sanitation) addresses the following issues:  housing,  safe disposal of waste (sewage and garbage),  ensuring a safe water supply  removing vermin like rats and disease vectors such as mosquitoes, lice and fleas.  preventing pollution In the context of HIV safe sex practices like condom use and use of gloves when in contact with contaminated body fluids can be considered as hygienic practices. 2.1.3. Epidemiology Epidemiology can be defined as: “the study of incidence and distribution of diseases in large populations and the conditions influencing the spread and severity of diseases” Maranga, Muya & Ogila- 2008 pg 2 It studies the distribution and frequency of diseases by seeking to answer questions such as: What is the disease frequency? In other words how often is a disease occurring in a community, how many people are affected? Who is ill? Diseases do not affect individuals in a community equally. Depending on various factors that relate to age, gender, genetic makeup, physical environment, behaviours such as smoking, sexual activity, physical exercise, occupation, economic status and so forth, some individuals may be more likely to suffer some illness and not others. Where did they get ill? Geographical location sometimes makes it more likely that an individual suffers certain diseases. For example, there are some geographical areas that are free from malaria infection whereas in some others the risk of infection is ever present. In the case of HIV infections there are also different rates of infection in different geographical areas, both at the global and local levels. This has to do with the risk factors for transmission that are present in different populations. These will be discussed later. When did they get ill? The occurrence of some diseases can be influenced by factors that change with time. For instance the cold season may come with it an increased occurrence of respiratory infections such as the common cold and pneumonia. These and other factors are of interest to epidemiologists and information obtained in epidemiological studies is then used to guide and justify measures taken to prevent diseases. (Source: Wood C.H,, Vaughan J.P., Glanville H.,1997,2001) 2.1.4. Sources of Data in Epidemiology In Epidemiological studies information can be obtained from sites where regular health care activities are carried out such as dispensaries, health centre and even hospitals. These are referred to as “sentinel sites” and in HIV related research Antenatal Clinics (ANC) where expectant mothers go for health check-ups have been important sources of information. Sentinel sites are ready sources of information because clients who attend the clinics are examined and screened for diseases including HIV infections. Such information can be used to estimate levels of infection in a given community. Where information is not readily available it can be obtained in well- planned data-gathering exercises referred to as surveys. Such surveys are planned using methods that will increase the usefulness of the collected information by employing scientifically sound methods which will increase reliability and validity of data collected and reduce bias. Surveys can include:  Screenings to find out people with infections who do not know they have the disease or have not visited a health facility for treatment. Such surveys have been conducted in Kenya to determine rates HIV infection in Kenyan communities as well as examine factors that are associated with risk of infection. Examples of such surveys in Kenya include: *The Kenya Demographic and Health Survey of 2003, *The Kenya AIDS Indicator Survey of 2007 *The Kenya AIDS Indicator Survey of 2012  Knowledge, Attitudes and Practices (KAP Surveys)- These are studies to find out people’s beliefs, customs and behaviours. Surveys such as the ones cited above also collected data on KAP factors that are relevant to risk of HIV Infection such as attitudes to use of protective devices(condoms)  Prevalence Surveys to find out prevalence of various diseases can also be conducted. 2.1.5 Patterns of Disease Occurrence Prevalence, Incidence, Rates, Pandemic, Epidemic, Endemic, Sporadic In presenting information about the patterns of a disease in a community several terms are used which one needs to be familiar with in order to appreciate such information better. These are discussed below. Prevalence –This is a measure of the number of cases of a disease or other condition recorded in a given population at a given point in time. For example if a community with a thousand members is screened for HIV infection at a given time and found to have 50 infected members then the Prevalence of HIV in that community at the specified time would be 50 divided by a 1000 to give a prevalence rate of 0.5 per 1000. This prevalence could be the same, higher or lower at another point in time in the future depending on factors such as the rate at which new infections are occurring, deaths resulting from an infection or other demographic changes in the community such as migration. Incidence- This is the number of new cases or occurrences such as new infections that are recorded over a given period of time such as a month or year in a population under consideration. These are recorded as the number of new cases of an infection in the population at risk of getting that infection. Rates are measures used to make comparisons of occurrences such as infections in different areas or in the same areas at different points in time. For example if a community of 1000 people has 100 people infected with HIV and another with 3000 people has 200 of them infected you can compare the two areas and determine which has higher infection rates. The second community would be found to be having a lower infection rate of around 67 per 1000 (200/3000* 1000) compared to the first one which has 100 infections per 1000 though the total number of cases are higher in the second. Pandemic This term is used to refer to a disease that affect a large number of people spread over a large geographical area in several continents. HIV is this kind of disease. Related terms include: Sporadic which describes a disease that occurs in a few numbers that appear almost at random without any particular pattern. Endemic which describes disease that appear in an area in significant numbers all the year round. For example, malaria is endemic in parts of Kenya such as the Coast region and risk of infection is ever present. Epidemic describes some diseases such as influenza which occur in outbreaks where many cases appear within a short time. These outbreaks are referred to as epidemics Ref: Wood C.H,, Vaughan J.P., Glanville H.,1997 Community Health Nairobi. AMREF 2.2.0 Prevention- A Priority in Public Health Prevention of diseases or other adverse events such as accidents is the foremost priority of Public Health Services. For those diseases that can be prevented this is often the most cost effective way of ensuring a healthy community. When an individual becomes infected with the HIV virus it can be expected that at some point this individual will require treatment for the viral infection as well as for the many opportunistic infections that they may suffer from for the rest of their lives. This treatment requires a lot of resources, sometimes cause serious side effects and some of these people may die from their condition in spite of the best treatment possible being availed to them. Prevention has therefore a lot of advantages in terms of cost as well as the reduction in suffering and other difficulties that confront those who become infected. Prevention aims to prevent diseases before they occur. However, even where infection does occur; harm, suffering and cost of care can be minimized through early identification of infection and providing quality care. This prevents deterioration and occurrence of complications that are difficult and more expensive to treat. Prevention is offered at three levels as explained below. 2.2.1. Levels of Disease Prevention Primary Prevention – This is the prevention of an infection before it occurs. When in the case of HIV infections people are advised to avoid unprotected sex this is a primary prevention measure that aims to prevent infections before they occur. Secondary Prevention. This type of prevention aims at reducing the harmful consequences of an infection in the individual through early identification of the infection even before symptoms occur and provision of comprehensive care so that serious complication can be avoided. Screening for infections such as HIV and other Sexually Transmitted Infections like syphilis and providing appropriate care early even before the disease has caused symptoms is possible. In the case of HIV Infections this is also an opportunity to empower those found to be infected so that they may not be a source of infection to others. Tertiary Prevention. This type of prevention applies when an infection has already caused symptoms in an individual by the time it is identified. It aims to treat the symptoms and restore the health of an individual to the highest extent possible. Sometimes infections result in disability and rehabilitative services become necessary in order to improve an individual’s level of function and quality of life. For example: Some people with advanced HIV infection may develop loss of vision due to retina damage. Such patient may require rehabilitative services including teaching them to use Braille in order to improve their function. Ways of preventing diseases in Public Health To prevent infections and promote health the following measures are important: Health Education Providing adequate and accurate knowledge to the community regarding safeguarding and promoting their health and how to address risk factors that may lead to illness in their particular environment. Good Nutrition- An adequate, well balanced diet which is grown, stored, prepared and served in hygienic conditions is an important prerequisite for maintenance of good health Personal Hygiene- Measures such as washing hands with soap and clean water after visiting the toilet and before eating help to reduce disease transmission Environmental Hygiene This ensures a clean environment, safe disposal of sewage and other waste, control of organisms such as mosquitoes that spread diseases ( disease vectors), ensuring a safe water supply, adequate housing and good living and working conditions. Vaccinations For some diseases vaccination also called inoculation provides an effective way of prevention. However for HIV no effective vaccine has been developed to help with prevention. Behaviour Change interventions Such measures aim at getting those at risk of a disease to adopt behavioural changes that will enable them to minimize this risk. Unsafe sexual practices and sexual violence, smoking and abuse of other substances and dangerous driving are examples of risky behaviours that can be modified through behavioural interventions. On the other hand promoting behaviours such as regular exercise, getting enough sleep and managing stressful experiences effectively will help to improve health outcomes and prevent diseases.. 2.3.0 BIOSTATISTIC- The study of Statistics has been defined as ” the collection, organization, analysis and interpretation of numerical data” and when the phenomena being studied is biological or related to health sciences it is referred to as “biostatistics”(Pagano & Gauvreau, 1996) In analysing data collected in surveys or other sources, statistical methods help to make reliable conclusions about what is being studied, establish relationships or lack thereof between variables under study. For example in studying risk factors for transmission of HIV one may want to establish if being at the poverty line living on a dollar a day makes one more likely to be infected with the virus. Statistical analysis of these two variables – poverty as defined and risk of getting infected with HIV have any relationship or not.This relationship or correlation may be positive where the one increases as the other increases or negative where one decreases as the other increases. In planning such a study one would need to control for factors that may confound the findings leading to unjustified conclusions. Other types of analysis use probability methods to help determine whether an observation is a significant finding or a mere random occurrence. 2.3.1. DATA ON HIV PREVALENCE AND EPIDEMIOLOGY GLOBAL AND LOCAL In the following tables figures that give a picture of how different regions have been affected by the HIV pandemic are presented. GLOBAL FIGURES of HIV INFECTIONS- AREA 2004 figures 2009 figures North America 1.0 million 1.4 million Caribbean 440,000 240 000 Latin America 1.7 million 2.0 milllion Europe 610,000 820 000 Africa North of the Sahara 540,000 310 000 Sub-Saharan Africa 25.4 million 22.4million Eastern Europe/Central Asia 1.4 million 1.5 million East Asia 1.1 milion 850 000 South and South East Asia 7.1 Million 3.8 million Oceania 35000 59000 SUB-SAHARAN AFRICA 2004 Total Number living with HIV/AIDS 25.4 million ( 60% of the total disease burden) People newly infected 3.1 million AIDS death in 2004 2.3 million Adult prevalence 7.4% Kenya 2004 update National adult prevalence age 15-49yrs 7% Number of adults infected 1,100 000 Number on Antiretroviral medicines 44000 Number needing antiretroviral medicines 200000 Number of children infected 150000 2.3.2.KENYA AIDS INDICATOR SURVEY, 2007 HIGHLIGHTS The Ministry of Health in Kenya carried out an extensive survey of the HIV situation in Kenya involving nearly 10000 households and 18000 adults. Highlights from this survey include the following:  1.42 million adults in Kenya are infected with HIV.  Adults aged 15-64 years have a HIV infection of 7.2% while those 15 to 49 years had the rate of 7.4%  Youth 15 to 24 years had infection rates of 3.8 %  Women have a higher infection rate of 8.4% compared to men who have a 5.4%  Women in the 15- 24 age group found to be four times more likely to be infected than men of the same age group 5.6% compared to 1.4%  Older adults (5.0% infection rates) age 50-64 showed higher infection rates than previously thought  Adults between 15-49 showed infection rates of 7.4% compared to 6.7% in 2003  Rural prevalence rates in 2007 were 7.4% compared to 5.6% in 2003.  190000 patients on Antiretroviral medicines compared to only 10000 in 2003.  Nyanza (14.9%). Nairobi (8.8%) Coast (8.1%) and Rift Valley (6.3%) are the regions with higher infection rates than others. The other provinces have infection rates below the national average- Western 5.4%, Eastern 4.6 %, Central 3.6% and North Eastern with 0.81% has the lowest rates.  Uncircumcised men have infection rates three times higher than the circumcised men (13.2 Vs 3.9%)  83% of those infected do not know they are infected  A high proportion of infected people are in discordant relationships where only one partner is infected with HIV. Approximately 344 000 couples in Kenya were in this category. 2.3.3. Highlights from Kenya AIDS Indicator Survey 2012 Some of the highlights from the Preliminary Report of KAIS 2012 are as follows.  Adult HIV prevalence of those aged between 15 to 64 years decreased from 7.2 % to 5.6 in 2012.  Prevalence for children 18 months to 14 years found to be 0.9 percent  Regional distribution of HIV prevalence in Kenya maintained similar pattern as 2007 with Nyanza region leading and North Eastern with the lowest  HIV testing increased from 34 % to 72 per cent in those aged 15 to 64 years  53 % of those infected not aware of status compared to over 80% in 2007.  Male circumcision rates increased from 85% to 91 %. In Nyanza rates increased from 48 percent to 66 %  Low levels of condom use in those having sex with discordant partners or those of unknown status  92 % of antenatal clients attending ANC clinic between 2007 and 2012 were tested for HIV.  58% percent of those between 15-64 years were eligible for ARVS going by a CD4 count of 350 cells/mm3 of blood.  These finding show an improvement on important parameters on the HIV pandemic and preventive efforts. 2.3.4. Magnitude of the Pandemic HIV since being identified in 1981 has grown to become a health problem of gigantic proportions. Described now as a “pandemic” affecting most societies in the world it has taken a heavy toll on societies by for example:  Increasing morbidity (illness) and mortality (deaths).   Increasing health care costs and overburdening health services. Resources to fight other health problems such as malaria are reduced.  Reduced life expectancy and loss of the most productive members of society –in Kenya average life expectancy dropped from 62 years in the 80’s to 51 year by 2000.Currently estimated at 66 years (WHO- 2018) following improvements on treatment among other things..  Diverting resources from other services and developmental projects thus increasing poverty.  Creating a large number of orphaned children. 2011 Highlights (UN AIDS) 34 Million People Living With HIV/AIDS With 4.9 % of Adults Living With HIV/AIDS 2.5 Millions New Infections Occurred In 2011 With 1.7 Million Deaths 2.3.5 Highlight from 2017 Kenya- 2107  Kenya has the joint fourth-largest HIV epidemic in the world (alongside Mozambique and Uganda) with 1.6 million people living with HIV in 2016  In 2106 36,000 people died from AIDS-related illnesses, while this is still high it has declined steadily from 64,000 in 2010.  In 2016, 64% of people living with HIV were on treatment, 51% of whom were virally suppressed.  As of 2015, 660,000 children were recorded as being orphaned by AIDS . In 2014, it was estimated that 30% of new annual HIV infections in Kenya are among key populations. Global Highlights -2017  In 2017 an estimated 36.9 million people were living with HIV (including 1.8 million children) – with a global HIV prevalence of 0.8% among adults. Around 25% of these same people do not know that they have the virus.  Since the start of the epidemic, an estimated 77.3 million people have become infected with HIV and 35.4 million people have died of AIDS-related illnesses. In 2017, 940,000 people died of AIDS-related illnesses. This number has reduced by more than 51% (1.9 million) since the peak in 2004 and 1.4 million in 2010.  The vast majority of people living with HIV are located in low- and middle- income countries, with an estimated 66% living in sub-Saharan Africa. Among this group  19.6 million are living in East and Southern Africa which saw 800,000 new HIV infections in 2017. SUMMARY This chapter introduces concepts in Public Health that will help you appreciate various aspects of the HIV pandemic as a Public Health problem of great importance. These concepts include Public Health itself and its branches of epidemiology, biostatistics, and health services. NOTE Concepts used to measure the extent to which a community is affected by a health problem such as incidence and prevalence are also discussed in this chapter. Another concept that has been considered is prevention with a brief mention of ways of preventing diseases in general. Prevention of HIV infection in particular will be discussed in a later chapter. Data that gives an idea of how various communities have been affected by HIV as well as trends that have appeared over time have been briefly mentioned with a focus on the Kenyan scenario. Place here the unit summary, forming the body of this unit. Public Health focuses on preventing diseases at the community level and prevention is the most cost effective way of providing for the healthcare needs of the community. In dealing with HIV infections prevention is an important priority. Place an important point you want to emphasize here in your unit topics or subtopics. ACTIVITIES Place here the unit activities, forming the body of this module. Activity Visit the UNAIDS website and review the country fact sheets for HIV for different countries. Which countries have the heaviest disease burden of HIV? How is Kenya ranked in the various areas considered in the report? SELF-TEST QUESTIONS 1.9 References and Further Readings  Define the following terms: Public Health, Epidemiology, Incidence, Prevalence and prevention.  Discuss the three levels of prevention that are applied in Healthcare and give an example of each type.  Identify five highlights from the Kenya AIDS Indicator Survey (KAIS) of 2007 and for each compare the same highlights from KAIS, 2012.  Discuss measures that are applied in a community to prevent diseases and promote health. Place here the self-test questions for this unit. 1.Ref: Wood C.H,, Vaughan J.P., Glanville H.,1997, 2001 Ed. Community Health. Nairobi. AMREF 2. 3.Maranga, R.O., Muya S.M., Ogila K.O., 2008. Fundamentals of HIV/AIDS Education. Nairobi. Fragrancia. 3. Pagano M. Gauvreau, L.; 1996. Principles of Biostatistics. California. Duxbury Press Place here key references forming for this unit