Revision Notes On Levels Of Disease Prevention PDF

REVISION NOTES BY MR. ONYANGO OUTHA LEVELS OF DISEASE PREVENTION a) Primary prevention is focused on avoiding disease entirely. b) Secondary prevention involves screening the patient to offer early detection and diagnosis. c) Tertiary prevention is focused on interventions to slow or stop the dise...

REVISION NOTES BY MR. ONYANGO OUTHA LEVELS OF DISEASE PREVENTION a) Primary prevention is focused on avoiding disease entirely. b) Secondary prevention involves screening the patient to offer early detection and diagnosis. c) Tertiary prevention is focused on interventions to slow or stop the disease and restore natural function as best as possible. TYPES OF DISEASE PREVENTION Three types of prevention strategies include primary, secondary, and tertiary prevention. Primary prevention strategies reduce the onset of disease, such as wearing seatbelts or helmets to avoid injury. Secondary prevention strategies include tests and recommendations to detect disease prior to symptoms and prevent severe disease. Tertiary prevention strategies are the diagnosis of disease and improving quality of life. Three Levels of Prevention The three levels of prevention are primary, secondary, and tertiary. In primary prevention, a disorder is actually prevented from developing. Types of primary prevention include the following: a) Vaccinations b) Counseling to change high-risk behavior c) Sometimes chemoprevention Example of primary level prevention Primary prevention Examples include: legislation and enforcement to ban or control the use of hazardous products (e.g. asbestos) or to mandate safe and healthy practices (e.g. use of seatbelts and bike helmets) education about healthy and safe habits (e.g. eating well, exercising regularly, not smoking) Primary prevention aims to deliver advice and guidance to prevent the onset of disease or illness. Recommendations have been shown to decrease the onset, or reduce the risk, of developing an illness. Examples of primary prevention: Vaccinations - Vaccines against measles, mumps, influenza, and covid have been shown to 1 reduce the onset of illness, or make the illness less severe. In secondary prevention, disease is detected and treated early, often before symptoms are present, thus minimizing serious consequences. Types of secondary prevention include the following: a) Screening programs, such as mammography to detect breast cancer and dual x-ray absorptiometry (DXA) to detect osteoporosis. b) Tracking down the sex partners of a person diagnosed with a sexually transmitted infection (contact tracing) and, if necessary, treating these people to minimize spread of the disease. Secondary prevention measures include tests to prevent or stop disease processes. Examples of secondary prevention include: a) Pap smear - early detection of cervical cancer b) Colonoscopy - early detection of colon cancer c) Mammogram - early detection of mammogram In tertiary prevention, an existing, usually chronic disease is managed to prevent complications or further damage. Types of tertiary prevention include the following: a) For people with diabetes: Control of blood sugar, excellent skin care, frequent examination of the feet, and frequent exercise to prevent heart and blood vessel disorders b) Providing supportive and rehabilitative services to prevent deterioration and maximize quality of life, such as rehabilitation from injuries, heart attack, or stroke c) Preventing complications in people with disabilities, such as preventing pressure sores in those confined to bed. Tertiary Prevention - It is implemented in symptomatic patients and aims to reduce the severity of the disease as well as any associated squeal. While secondary prevention seeks to prevent the onset of illness, tertiary prevention aims to reduce the effects of the disease once established in an individual. KAIS 2012 in AIDS Indicator Survey The KAIS 2012 builds upon the previous population-based HIV estimates derived in the rst Kenya AIDS Indicator Survey (KAIS 2007), allowing for comparisons of prevalence estimates and behavioural and programmatic indicators over time. AIDS Indicator Surveys are 2 standardized surveillance tools used by countries with generalized HIV epidemics to provide, in a timely fashion, indicators for effective monitoring of HIV. Such data should guide responses to the HIV epidemic, meet program reporting requirements, and ensure comparability of findings across countries and over time. Kenya has conducted 2 AIDS Indicator Surveys (KAIS 2007) and 2012–2013 (KAIS 2012). These nationally representative surveys have provided essential epidemiologic, socio-demographic, behavioral, and biologic data on HIV and related indicators to evaluate the national HIV response and inform policies for prevention and treatment of the disease. We present a summary of findings from KAIS 2007 and KAIS 2012 and the impact that these data have had on changing HIV policies and practice. KEY FEATURES OF KAIS 2012 KAIS 2012 was the second AIDS Indicator Survey conducted in Kenya. a) Provided nationally-representative information about the status of the HIV/AIDS epidemic. b) Reached approximately 18,000 individuals from approximately 8,000 households. c) Excluded North Eastern region due to regional security issues during the survey. d) Included children aged 18 months to 14 years for the rst time in a national HIV survey. e) Estimated prevalence and incidence of HIV and measured CD4 cell counts and viral load for those with f) HIV infection- Measured use of and unmet need for HIV prevention, care and treatment services. g) Provided home-based testing and counselling services for persons who wanted to learn their HIV status on the day of the survey 4 C's of HIV The four Cs in HIV prevention are crisis, condoms, culture and community. 4 pillars of HIV The four strategies, called “pillars,” are Diagnose, Treat, Prevent, and Respond. HEALTH PROMOTION AND DISEASE PREVENTION Health promotion and disease prevention programs focus on keeping people healthy. Health promotion programs aim to engage and empower individuals and communities to choose healthy behaviors, and make changes that reduce the risk of developing chronic diseases and other morbidities 3 CONCEPT OF HEALTH PROMOTION AND DISEASE PREVENTION A major goal of the health promotion and disease prevention approach—both for individuals and for an entire population—is "to identify the health problems for which preventive efforts can result in more appropriate utilization of health services and improvements in health status Definition of health promotion Health promotion is the process of enabling people to increase control over, and to improve, their health. It moves beyond a focus on individual behaviour towards a wide range of social and environmental interventions. APPROACHES TO HEALTH PROMOTION These approaches are: medical; behavioural change; educational; client-centred, and societal change. DIFFERENCES BETWEEN HEALTH PROMOTION AND PREVENTION The goal is to create healthy living conditions and empower individuals to take responsibility for their own health. Prevention: Focuses on reducing the risk of specific diseases and health problems through early interventions and treatments. IMMUNODEFICIENCY HIV/AIDS lymphocyte CD4 T lymphocytes (CD4 cells) help coordinate the immune response by stimulating other immune cells, such as macrophages, B lymphocytes (B cells), and CD8 T lymphocytes (CD8 cells), to fight infection. HIV weakens the immune system by destroying CD4 cells. IMPORTANCE OF CD4 COUNT A CD4 count is mostly used to check the health of your immune system if you are infected with HIV (human immunodeficiency virus). HIV attacks and destroys CD4 cells. Without treatment, HIV may destroy so many CD4 cells that your immune system will have trouble fighting off infections. IMPORTANCE OF CD4 T CELL AND VIRAL LOAD COUNTS The amount of HIV in your blood is called “viral load.” Viral load shows how fast HIV is reproducing in your body – the lower your viral load, the better. Your “CD4 cell count” measures the health of your immune system. The higher it is, the better your body can fight infections. 4 BOOST MY IMMUNE SYSTEM TO FIGHT HIV Add protein to every meal. Protein is important because it is needed to make, repair and maintain cells in the body. It also plays a role in the immune system. Good protein sources include lean meats, poultry, fish, low-fat dairy foods, eggs, beans and lentils. Immunodeficiency results from a failure or absence of elements of the immune system, including lymphocytes, phagocytes, and the complement system. These immunodeficiency’s can be either primary, such as Bruton disease, or secondary, as the one caused by HIV infection Example of an immunodeficiency disease Acquired immunodeficiency may be a complication of diseases such as HIV/AIDS and malnutrition (especially if the person does not eat enough protein). Many cancers may also cause immunodeficiency. CAUSES IMMUNE DEFICIENCY While a weaker immune system is typically caused by certain diseases, malnutrition, and certain genetic disorders, it can also temporarily be caused by medications such as anticancer drugs and radiation therapy. Your immune system can also be temporarily weakened by a stem cell or organ transplant. Symptoms of primary immunodeficiency a) Multiple courses of antibiotics needed to overcome infections. b) Developing problems after receiving a live vaccine. c) Enlarged spleen. d) Swollen lymph nodes. e) Weight loss or poor growth. f) Digestive issues like chronic diarrhea. g) Autoimmune diseases. EPIDEMIOLOGICAL Sources of epidemiological data The different sources of epidemiological data include mortality data, morbidity data, surveys of health and general populations, and surveillance systems of disease indicators, birth and death certificates, population census records, patient medical records, disease registries, insurance claim forms and billing records, public health department case reports, and surveys of individuals TYPES OF DATA COLLECTION IN EPIDEMIOLOGY 5 Today, epidemiology uses both primary and secondary data sources. Primary data is new, original data collected by researchers. It can be hard and expensive. Secondary data uses existing data, like from disease registries and healthcare records, for a broader view. STATISTICS Definition of statistics Statistics is a branch of applied mathematics that involves the collection, description, analysis, and inference of conclusions from quantitative data. The mathematical theories behind statistics rely heavily on differential and integral calculus, linear algebra, and probability theory. Statistics is the study of the collection, analysis, interpretation, presentation, and organization of data. In other words, it is a mathematical discipline to collect, summarize data. Also, we can say that statistics is a branch of applied mathematics. TYPES OF STATISTICS a) Measure of frequency b) Measure of dispersion c) Measure of central tendency d) Measure of position IMMUNITY The immune system's way of protecting the body against an infectious disease, the three types of immunity are innate, adaptive, and passive. Innate immunity includes barriers, such as skin and mucous membranes that keep harmful substances from entering the body. Humans have three types of immunity — innate, adaptive, and passive: Innate immunity: Everyone is born with innate (or natural) immunity, a type of general protection. For example, the skin acts as a barrier to block germs from entering the body. PASSIVE AND ACTIVE IMMUNITY Active immunity occurs when our own immune system is responsible for protecting us from a pathogen. Passive immunity occurs when we are protected from a pathogen by immunity gained from someone else. FACTORS CAUSING SPREAD OF HIV THE PANDEMIC GLOBALLY The following factors contributed to the early spread of HIV infection in one way or the other: a) International travel from one country to another 6 b) The use of intravenous drugs of abuse such as heroine often using contaminated needles by street children, drug users and others c) The Blood industry where treatments using blood and blood products became more common d) The changing sexual norms in communities such as increased acceptance of gay lifestyles, and more freedom regarding sexual choices such as having multiple partners and engaging in commercial sex work. e) Stigma towards the disease and the misconception that it was a disease of certain types of people f) Inadequate understanding about risk factors for contracting HIV. HIV TERMS AND DEFINITIONS a) AIDS: Acronym for acquired immunodeficiency syndrome.... b) Antibodies: Produced by your immune system when you're exposed to viruses like HIV. c) Antibody test: An HIV test that looks for HIV antibodies in your blood or oral fluid. d) Antigens: Foreign substances that cause your immune system to activate. HIV refers to the human immunodeficiency virus. There are two types of HIV: HIV-1 and HIV- 2. HIV-1 is responsible for the vast majority of HIV infections globally. Acute infection is the period between a person being infected with HIV and HIV antibodies being detectable by a serological assay. HIV stands for human immunodeficiency virus, which is the virus that causes HIV infection. The abbreviation “HIV” can refer to the virus or to HIV infection. AIDS stands for acquired immunodeficiency syndrome. AIDS is the most advanced stage of HIV infection. Accidental inoculation An occupational exposure to HIV that occurs during the performance of job duties (by a nurse or doctor, for example). Includes a needlestick or cut with a sharp object, contact of mucous membranes (mouth, eyes), or contact of skin (especially when the exposed skin is chapped, abraded, or afflicted with dermatitis — skin rash or sores — or the contact is prolonged or involves an extensive area) with blood, tissues, or other body fluids (stool, urine, vaginal secretions, saliva, mucous) to which universal precautions apply. 7 Acquired immunodeficiency syndrome (AIDS) The most severe manifestation of infection with the human immunodeficiency virus (HIV). The Centers for Disease Control and Prevention (CDC), the World Health Organization, and many national governments list numerous opportunistic infections and cancers that, in the presence of HIV infection, result in an AIDS diagnosis. AIDS is also defined on the basis of the degree of immunodeficiency in an individual with HIV infection Active immunity Protection from a disease as a result of previous exposure to the disease-causing infectious agent or part of the infectious agent (antigen). The protection can be a result of having had the disease or having received a vaccine to prevent getting the disease. Active tuberculosis (TB) Active disease caused by Mycobacterium tuberculosis, as evidenced by a confirmatory culture, or, in the absence of culture, suggestive clinical symptoms, including productive cough lasting >3 weeks, chest pain, hemoptysis, fever, night sweats, weight loss, and easy fatigability. Active TB is a communicable disease that is treatable, curable, and preventable. Persons with active TB disease should be under the care of a health care provider. Active TB disease may indicate immune deficiency. For people with HIV, active TB disease is considered an opportunistic infection and a qualifying condition for an AIDS diagnosis Acute HIV infection The period following infection when there is rapid production of virus. An estimated 80% to 90% of individuals with primary HIV infection develop an acute syndrome (disorder) characterized by flulike symptoms of fever, fatigue, swollen lymph nodes, sore throat, headache, aching muscles, and sometimes skin rash. Following infection, the immune system produces antibody and a cellular response to the virus (seroconversion) and a broad HIV-specific immune response occurs, usually within an average of 3 weeks after HIV infection. High levels of virus (HIV RNA) can be found in the blood during this time. Adherence The extent to which a patient takes the agreed-upon medication or other treatment as prescribed Anemia A lower than normal number of red blood cells. 8 Anorexia The lack or loss of appetite that leads to significant decline in weight. Antibody Substances in the blood or other body fluids that destroy bacteria, viruses, or other harmful agents (antigens). They are members of a class of proteins known as immunoglobulins, which are produced by special white blood cells called B-lymphocytes. Antigen A substance that, when introduced into the body, stimulates production of an antibody. Antiretroviral A substance that kills or suppresses a retrovirus, such as HIV. Antiretroviral drugs Substances used to kill or stop the multiplication of retroviruses such as HIV. Antiretroviral therapy (ART) Combination antiretroviral regimens that aggressively decrease HIV viral multiplication to halt the progress of HIV disease. The usual ART regimen combines three or more different drugs. These treatment regimens can reduce the amount of virus so that it becomes undetectable in a patient's blood. Antiviral A substance or process that destroys a virus or suppresses its replication (ie, reproduction). Asymptomatic Without symptoms or not sick. Usually used in HIV/AIDS literature to describe a person who has HIV infection but who shows no clinical symptoms of the disease and who is not sick. Even though a person is asymptomatic, he or is still undergoing damage to the immune system and may still infect another person with HIV. Bisexual Having sexual relations with both females and males. 9 Body fluids Any fluid in the human body, such as blood, urine, saliva (spit), sputum, tears, semen, mother's milk, or vaginal secretions. Only blood, semen, mother's milk, and vaginal secretions have been linked directly to the transmission of HIV. CD4 (T4) or CD4+ cells A type of lymphocyte involved in protecting against viral, fungal, and protozoal infections. They are also known as T helper cells or simply T cells. HIV infects and destroys CD4 lymphocytes. Destruction of CD4+ lymphocytes is the major cause of the immunodeficiency observed in AIDS, and decreasing CD4 lymphocyte levels are the best indicator of someone's risk of developing opportunistic infections CD4 count A test that measures the number of CD4 lymphocytes in the blood, thus reflecting the state of the immune system. A normal count in a healthy adult is 600-1,200 cells/µL. When the CD4 count of an adult falls below 200 cells/µL, there is a high risk of opportunistic infection. Community planning Community planning groups are responsible for developing HIV prevention, treatment, and care plans that are used in their communities. The goal of HIV community planning is to improve the effectiveness of HIV programs and to be certain that the needs of the community are being met. Confirmatory test A second test, to show that the result of a previous test was correct. Because the diagnosis of HIV infection is so important, a second (confirmatory) test, is done. The confirmatory test should be of a different type than the first test. Confirmed positive For HIV, a blood sample that is positive on an initial ELISA test, repeatedly positive on a second ELISA run on the same specimen, or confirmed positive on Western blot or other supplemental test that indicates the client is infected Counseling Confidential dialogue between individuals and their health care providers. The term can refer to discussions between health care workers and clients/patients specific to HIV testing to help clients examine their risk of acquiring or transmitting HIV infection. 10 Endemic Pertaining to diseases associated with particular locations or population groups. Epidemic A disease that spreads rapidly through a part of the human population — such as within a given geographic area, a military base, school, or village — or persons of a certain age group or sex, such as the children or women within a region. Epidemic diseases can be spread from person to person or from a contaminated source such as food or water. Epidemiologic surveillance The ongoing organizing and collection, analysis, and interpretation of facts about a disease or health condition. Epidemiology The branch of medical science that deals with the study and distribution and control of a disease in a population. Exclusive breast-feeding Feeding an infant only breast milk from the mother or a wet nurse, or expressed breast milk and no other liquids or solids with the exception of drops or syrups consisting of vitamins, mineral supplements, or medicines. Gay Having sexual relations with an individual of the same sex. Usually refers to male-male relations. The term lesbian is most often used for female-female sexual relationships. Homosexual Pertaining to sexual activity with a person of the same sex. Human immunodeficiency virus type 1 (HIV-1) HIV-1 and HIV-2 are retroviruses that cause the immune destruction of HIV disease and AIDS. HIV-1 is classified as a lentivirus in a subgroup of retroviruses. Retroviruses are single-stranded RNA that convert themselves into DNA through the action of an enzyme, reverse transcriptase. HIV inserts its DNA product into the host cell's DNA, preventing the host cell from carrying out its natural functions and turning it into an HIV factory. 11 Human immunodeficiency virus type 2 (HIV-2) A virus closely related to HIV-1 that has also been found to cause AIDS. It was first isolated in West Africa. HIV-1 and HIV-2 differ in their geographic patterns of infection. HIV-1 remains the most common cause of AIDS and represents the major type distributed worldwide. Immunity A natural or acquired resistance to a specific disease. Immunity may be partial or complete, long lasting or temporary. Immunodeficiency Breakdown of the immune system in which certain parts of the immune system no longer function. This condition makes a person more susceptible to certain diseases. Infection The state or condition in which the body (or part of the body) is invaded by an infectious agent (eg, a bacterium, fungus, or virus) that multiplies and produces an injurious effect (active infection). As related to HIV, infection typically begins when HIV encounters a CD4+ cell. Infectious An infection capable of being transmitted by direct or intimate contact (e.g., sex). Integrase An enzyme that inserts HIV's genes into a cell's normal DNA. It plays a vital role in the HIV infection process. Integrase inhibitors A class of anti-HIV drugs that prevents the HIV integrase enzyme from inserting viral DNA into a host cell's normal DNA. Occupational HIV exposure Exposure to HIV as a result of work (job) activities. Exposure may include accidental exposure to HIV-infected blood following a needlestick injury or cut from a surgical instrument. 12 Opportunistic infection An illness caused by various organisms, some of which usually do not cause disease in persons with normal immune systems. Persons living with advanced HIV infection suffer opportunistic infections of the lungs, brain, eyes, and other organs. Opportunistic infections common in persons diagnosed with AIDS include Pneumocystis jiroveci pneumonia; Kaposi sarcoma; cryptosporidiosis; histoplasmosis; other parasitic, viral, and fungal infections; and some types of cancer. Oral sex A type of sexual intercourse in which a partner's genitals are stimulated by mouth and tongue. Palliative A treatment that provides symptomatic relief but not a cure. Palliative care Palliative care is an approach to life-threatening chronic illnesses, especially at the end of life. Palliative care combines active and compassionate therapies to comfort and support patients who are living with life-ending illnesses and their families. Palliative care strives to meet physical needs through relieving pain and maintaining quality of life while emphasizing the patient's and family's rights to participate in informed discussions and to make choices. This patient- and family-centered approach uses the skills of interdisciplinary team members to provide a comprehensive continuum of care, including spiritual and emotional needs. Pandemic A disease prevalent throughout an entire country or continent, or the whole world Sexually transmitted disease (STD) Also called venereal disease (VD) (an older public health term) or sexually transmitted infection (STI). STDs are infections spread by the transfer of organisms from person to person during sexual contact. In addition to the "traditional" STDs (syphilis and gonorrhea), the spectrum of STDs now includes HIV infection; Chlamydia trachomatis infections; human papillomavirus (HPV) infection; genital herpes; chancroid; genital mycoplasmas; hepatitis B; trichomoniasis; enteric infections; and ectoparasitic diseases (i.e., diseases caused by organisms that live on the outside the host's body). The complexity and scope of STDs have increased dramatically since the 1980s; more than 20 microorganisms and syndromes are now recognized as belonging in this category. 13 Syndrome A group of symptoms as reported by the patient and signs as detected in an examination that together are characteristic of a specific condition. T4 cell (Also called T-helper cell.) Antibody-triggered immune cells that seek and attack invading microorganisms. Macrophages summon T4 cells to the infection site. There, the T4 cell reproduces and secretes potent chemicals that stimulate B cells to produce antibodies, signal natural killer or cytotoxic (cell-killing) T cells, and summon other macrophages to the infection site. In healthy immune systems, T4 cells are twice as common as T8 cells. Thrush Patches in the mouth (sometimes painful) caused by the fungus Candida albicans. Thrush is one of the most frequent early symptoms or signs of an immune disorder. The fungus commonly lives in the mouth, but only causes problems when the body's resistance is reduced either by antibiotics that have reduced the number of competitive organisms in the mouth or by an immune deficiency such as HIV disease. Vertical transmission Transmission of a pathogen such as HIV from mother to fetus or baby during pregnancy or birth. Viral load The amount of HIV in the circulating blood. Sicker patients generally have more virus than those with less advanced disease. A viral load test is used to monitor the HIV viral burden. Suppression of the HIV viral load is the first goal of antiretroviral therapy (ART), and monitoring a person's viral load is key to assessing the success of ART. Virus Organism composed mainly of nucleic acid within a protein coat. When viruses enter a living plant, animal, or bacterial cell, they make use of the host cell's chemical energy, protein, and nucleic acid-synthesizing ability to multiply. Some viruses do not kill cells but transform them into a cancerous state. Some cause illness and then seem to disappear, while remaining dormant and later causing another, sometimes much more severe, form of disease. In humans, viruses cause measles, mumps, yellow fever, poliomyelitis, influenza, and the common cold, among others. Some viral infections can be treated with drugs. 14 Voluntary HIV testing An individual is usually counseled regarding HIV prevention and how HIV infection occurs. Participants have the opportunity to accept or refuse HIV testing. Wasting syndrome An AIDS-defining condition that is characterized by at least 10% weight loss in the presence of diarrhea, chronic weakness, and documented fever for at least 30 days that is not the result of another infection or disease. In developing countries, it is sometimes called "slim disease." Western blot A laboratory test for specific antibodies to confirm repeatedly positive results on the HIV ELISA or EIA tests. In the United States, Western blot is the validation test used most often for confirmation of these other tests. In developing countries, a rapid HIV test is utilized most commonly. A positive rapid HIV test should be confirmed by a second rapid HIV test made by a different manufacturer. Window period Time from infection with HIV until antibodies are detected.. 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. 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. 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 - describes a disease that occurs in a few numbers that appear almost at random without any particular pattern. 15 Endemic - This describes diseases 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 MEASURES COMMUNITY TO PREVENT DISEASES AND PROMOTE HEALTH An example includes improving access to an urban neighborhood to safe sidewalks to promote physical activity; this, in turn, decreases risk factors for obesity, cardiovascular disease, type 2 diabetes, etc. Primary prevention consists of measures aimed at a susceptible population or individual. a) Handle and prepare food safely in sanitary conditions. b) Wash hands often after visiting toilet, handling dirt, doing manual work or changing diapers. c) Clean and disinfect commonly used surfaces tables, toilets , open drainage and other touchable surfaces d) Cough and sneeze into your sleeve or avoid spitting in the open places. e) Don't share personal items such sharps, needles or personal clothing. f) Get vaccinated against immunizable diseases. g) Avoid touching wild and domestic animals like cats, lions etc MEASURES OF PREVENTION OF DISEASE a) Keep immunizations up to date. b) Wash your hands often. c) Washing with regular soap and rinsing with running water, followed by thorough drying, is considered the most important way to prevent disease transmission. HYGIENE Hygiene is a set of practices performed to preserve health. According to the World Health Organization (WHO), "Hygiene refers to conditions and practices that help to maintain health and prevent the spread of diseases." Personal hygiene refers to maintaining the body's cleanliness. Personal hygiene refers to regularly washing parts of the body and hair with soap and water (including washing your hands and feet), grooming nails, facial cleanliness, covering coughs and sneezes, and menstrual hygiene. Personal hygiene practices can help you to feel fresh and healthy. 16 IMPORTANCE OF HYGIENE Good hygiene is critical for preventing the spread of infectious diseases and helping children lead long, healthy lives. It also prevents them from missing school, resulting in better learning outcomes. For families, good hygiene means avoiding illness and spending less on health care. PERSONAL HYGIENE a) Cleaning your body every day b) Washing your hands with soap and water after going to the toilet c) Brushing and flossing your teeth twice a day d) Covering your mouth and nose with a tissue (or your sleeve) when sneezing or coughing e) Washing your hands after handling pets and other animals EPIDEMIOLOGY Epidemiology is the study of the determinants, occurrence, and distribution of health and disease in a defined population. Infection is the replication of organisms in host tissue, which may cause disease. A carrier is an individual with no overt disease who harbors infectious organisms. OBJECTIVES OF EPIDEMIOLOGY a) Identify the etiology or cause of disease. b) Determine the extent of disease. c) Study the progression of the disease. d) Evaluate preventive and therapeutic measures for a disease or condition. e) Develop public health policy. TYPES OF EPIDEMIOLOGY Epidemiologists employ a range of study designs from the observational to experimental and generally categorized as descriptive (involving the assessment of data covering time, place, and person), analytic (aiming to further examine known associations or hypothesized relationships), and experimental (a term often FUNCTIONS OF EPIDEMIOLOGY Five tasks of epidemiology in public health practice are: a) Public health surveillance b) Field investigation c) Analytic studies d) Evaluation e) Linkages 17