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Global Health Glossary

Prepared and maintained by the Kaiser Family Foundation, this glossary provides an edited compilation of definitions of key terms in global health.  It is based on multiple source documents and Kaiser Family Foundation products. The glossary will be updated on a regular basis.

You may also be interested in these global health-related glossaries.



Refraining from sexual activity.  In the context of sexually transmitted diseases/infections, including HIV, this term also refers to delaying the age of first sexual experience or sexual debut.

Abstinence, Be Faithful, Use Condoms (ABC) Approach

The ABC approach to behavior change promotes the adoption of the following three behaviors as central to HIV prevention efforts: A – Abstaining from sexual activity or delaying the age of the first sexual experience B – Being faithful or practicing mutual monogamy with an uninfected partner C – Correct and consistent condom use.

Acquired Immunodeficiency Syndrome (AIDS)

A disease of the body's immune system caused by the human immunodeficiency virus (HIV). A person who tests positive for HIV is considered to have progressed to AIDS when a laboratory test shows that his or her immune system is severely weakened by the virus or when he or she develops at least one of about 25 different opportunistic infections—diseases that might not affect a person with a normal immune system but that take advantage of damaged immune systems. People who have not had one these opportunistic infections, but whose immune system is shown by a laboratory test to be severely damaged, are also considered to have progressed to an AIDS diagnosis. See also Human Immunodeficiency Virus (HIV).

Adolescent Health

The health of young people between the ages of 10 and 19 years. See also child health, infant health, newborn health, and under five mortality rate.

Anopheles Mosquito

The mosquito that transmits the malaria-causing Plasmodium parasite to humans. The mosquito is a vector (a vector carries the infectious agent) for four types of Plasmodium parasites, all of which cause malaria in humans: Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale, and Plasmodium malariae. See also parasite and vector.


Occurring before birth; prenatal.


Molecules in the body that identify and destroy foreign (unfamiliar) substances such as bacteria and viruses.  For example, standard HIV tests identify whether or not antibodies to HIV (HIV antibodies) are present in the blood.  A positive HIV test signals that antibodies are present. 

Antiretroviral Drugs (ARVs)

Drugs that inhibit the replication of retroviruses in the body, most notably HIV. When antiretroviral drugs are given in combination, virus replication and immune deterioration can be delayed, and survival and quality of life can be improved. See also antiretroviral therapy.

Antiretroviral Therapy (ART)

Refers to a range of treatments that includes antiretroviral drugs (ARVs). The drugs that are used in the treatment of HIV, a retrovirus, are designed to interfere with the virus’ ability to replicate itself and, therefore, slow the progression of the disease. See also antiretroviral drugs, highly active antiretroviral treatment, and treatment as prevention.

Artemisinin-Based Combination Therapies (ACTs)

A group of malaria medications that produces a very fast response in people with malaria and are active against multi-drug resistant Plasmodium falciparum malaria, the deadliest strain of malaria. ACTs are well tolerated by people who have malaria and have the potential to reduce malaria transmission by decreasing the presence of the parasite in the bloodstream. See also drug resistance, Anopheles mosquito, and parasite.


Not showing signs or symptoms of disease. In the case of HIV, for example, a person can be infected for many years before experiencing any symptoms, during which HIV can still be transmitted.

Avian Influenza (also: Avian Flu, Bird Flu, or H5N1)

Avian influenza, or "bird flu" is an infectious disease of animals caused by type A strains of the influenza virus. Transmission to humans is rare, but there is recent cause for concern. In mid-2003, the largest and most severe avian flu outbreak in history began in South-east Asia, caused by a sub-type of the virus called H5N1 and resulting in widespread transmission to poultry and some documented transmission to humans. Transmission of H5N1 to humans is of particular concern because it mutates rapidly and may therefore change into a form that is highly infectious for humans and more easily spread.



Plural for bacterium, which is a tiny microorganism that reproduces by cell division, usually has a cell wall, and causes many common infections. Tuberculosis is one example of a bacterium.

Bed Net

Bed nets (or mosquito nets) are used to prevent malaria transmission by forming protective barriers around persons and therefore limiting their exposure to mosquito bites. Bed nets have repeatedly been shown to reduce severe disease and mortality due to malaria, which is transmitted to humans by a mosquito carrying the malaria parasite, in endemic regions. The application of a residual insecticide on bed nets (called insecticide-treated bed nets or ITNs) greatly enhances their protective efficacy by killing mosquitoes. The insecticides also have repellent properties that reduce the number of mosquitoes that enter the house and attempt to feed. One type of ITN, a long-lasting insecticide-treated net or LLIN, retains lethal concentrations of insecticide for varying lengths of time, such as three or five years, depending on the treatment. Previously, ITNs had to be retreated at intervals of 6-12 months, more frequently if the nets were washed.

Bilateral Assistance

Direct foreign assistance from one government to, or for the benefit of, one or more other countries. Bilateral assistance generally consists of projects and programs, the content and direction of which is decided by the donor, providing more direct control over decisions about how and where funding is targeted (e.g., donors can stipulate countries, conditions, etc.). See also foreign aid, foreign assistance, and multilateral assistance.

Burden of Disease

A comprehensive demographic and epidemiological framework used to assess the comparative importance of diseases, injuries, and risk factors in causing premature death, loss of health, and disability.


Centers for Disease Control and Prevention (CDC)

CDC is one of the major operating components of the U.S. Department of Health and Human Services. Its mission is to develop and apply disease prevention and control, environmental health, and health promotion and education activities designed to improve the health of the people of the United States. The agency also achieves this through its involvement in global health.

Child Health

The health of children from birth through adolescence (note: the data on child health often refer to those under the age of five). See also adolescent health, infant health, newborn health, and under five mortality rate.

Childhood Diseases

Diseases that commonly occur among children (e.g., diarrhea, pneumonia, malaria, and measles). Many childhood diseases are preventable and/or treatable, although access to the proper interventions may be compromised in resource-poor countries.


Infectious disease that occurs in the small intestine and presents symptoms of watery diarrhea and vomiting, which can lead to severe dehydration and death. Transmission is often through contaminated food or water and the disease-causing bacteria are most often found in developing countries. Cholera is primarily treated with oral rehydration therapy or intravenous fluids.


A procedure in which the foreskin of the penis is removed. Also known as male circumcision or voluntary medical male circumcision (VMMC). It has been shown in randomized controlled trials to reduce the risk of HIV transmission from women to men. In 2007, the World Health Organization (WHO) and UNAIDS recommended that circumcision be considered "an important intervention" in reducing the risk of heterosexually acquired HIV infection in men, and it is considered to be one part of a comprehensive HIV prevention program.

Clinical Trial

A prospective biomedical or behavioral research study of human subjects that is designed to answer specific questions about biomedical or behavioral interventions (such as drugs, treatments, devices, or new ways of using known drugs, treatments, or devices).


Refers to the condition of an organism or individual cell infected by two pathogens, or infectious agents, simultaneously, such as HIV and tuberculosis.

Combination (Antiretroviral) Therapy

The use of two or more antiretroviral drugs in combination for HIV/AIDS treatment. The use of three or more antiretroviral drugs is often referred to as highly active antiretroviral therapy (HAART). See also antiretroviral drugs, antiretroviral therapy, and HAART.

Communicable (as in disease)

Capable of being transmitted from person to person, animal to animal, animal to human, or human to animal. See also contagious, infectious, and infectious disease.

Community Health Workers (CHWs)

Individuals who are trained to carry out one or more functions related to health care. They are supported by the health system but are not necessarily a part of its organization, and have less training than professional workers. CHWs are usually members of the communities where they work and are selected by the communities. CHWs include traditional medicine practitioners, faith healers, assistant/community health education workers, community health officers, family health workers, lady health visitors, health extension package workers, community midwives, institution-based personal care workers, and traditional birth attendants.

Complementary and Alternative Therapies

Treatments that are outside the scope of Western medicine.

Concurrent Sexual Partners or Partnerships

Having more than one sexual partner at a time.  The practice raises the risk of contracting sexually transmitted diseases, including HIV. 

Confirmed Case (of disease or infection)

A case that: 1) meets the clinical case definition or has clinically compatible illness, and 2) is either laboratory confirmed or is epidemiologically linked to a confirmed case. See also probable case and suspected case.

Contagious (as in disease)

Communicable by contact; capable of being transmitted from one person to another by contact or close proximity. See also communicable, infectious, and infectious disease.

Control (of disease or infection)

The reduction of disease incidence, prevalence, morbidity or mortality to a locally acceptable level as a result of deliberate efforts; continued intervention measures are required to maintain the reduction. See also elimination, eradication, and extinction.



See disability-adjusted life year and also quality-adjusted life year (QALY).


See dichlorodiphenyltrichloroethane.


See directly observed treatment, short-course.

Death Rate

The average annual number of deaths during a year divided by the population at midyear (also known as crude death rate).


The outstanding financial liabilities arising from past borrowing. Debt may be owed to external or domestic creditors and typically debt financing is in the form of loans or bonds. The debtor may be either a public (government) or private sector entity. External debts are financial obligations to a creditor who is not a resident of the debtor's country. Outstanding debt has been cited as a barrier to improving health by resource-poor countries; relieving debt can free up resources to provide health and other services.

Debt Relief

Agreements by creditors to lessen the debt burden of debtor countries by either rescheduling interest and principal payments over a specified time period, sometimes on a concessional basis (a loan provided to poor countries at a lower interest rates and a longer repayment period than typical or standard market or multilateral loans), or by partially or fully cancelling debt payments during a specified period of time. Outstanding debt has been cited as a barrier to improving health by resource-poor countries; relieving debt can free up resources to provide health and other services.


Dengue is a mosquito-borne viral infection that often causes a severe flu-like illness. Symptoms, if they occur, usually begin 4-7 days after a mosquito bite, and last up to 10 days. Severe cases can involve plasma leakage, severe organ damage, shock, and death.

Development Assistance

See bilateral assistance, foreign aid, humanitarian assistance, multilateral assistance, and official development assistance.


The identification of the presence and/or cause of a disease in an individual or population often with the use of a medical device or test. It can also be used to correctly designate an appropriate course of treatment, monitor the effects of interventions, and determine drug resistance or the potential for the disease’s recurrence. See also confirmed case, drug resistance and health intervention.

Diarrheal Diseases

Diarrhea is usually a symptom of gastrointestinal infection, which can be caused by a variety of bacterial, viral, and parasitic organisms. Severe diarrhea leads to fluid loss, and may be life-threatening, particularly in young children and people who are malnourished or have impaired immunity. While preventable, diarrheal diseases are common in the developing world, often spread through contaminated food or drinking water or from person to person as a result of poor hygiene; they are a leading cause of childhood mortality. Some examples of diarrheal-associated infections include cholera, dysentery, malaria, and measles.

Dichlorodiphenyltrichloroethane (DDT)

DDT (dichlorodiphenyltrichloroethane) is currently recommended by the WHO for malaria control through indoor spraying. DDT has a history of being a highly controversial insecticide. It was the main insecticide used during the 1950s and 1960s in the World Health Organization’s (WHO) global campaign to eradicate the mosquitoes that carry malaria. Today it has been banned from agricultural use in almost all countries. See also indoor residual spraying (IRS).

Directly Observed Treatment, Short-Course (DOTS)

Directly observed treatment, short-course (DOTS) is the internationally recommended strategy to control tuberculosis (TB). DOTS detection is the process by which TB is diagnosed and reported within a national surveillance system and to the WHO. DOTS programs provide an indication of the effectiveness of national TB programs in finding and diagnosing people with TB. DOTS aims to decrease TB-related morbidity, prevent TB deaths, and decrease TB transmission and is comprised of five components: sustained political and financial commitment, quality diagnosis via sputum-smear microscopy, treatments taken under direct supervision, a regular and uninterrupted supply of drugs, and standardized data collection. See also tuberculosis.

Disability Adjusted Life Year (DALY)

A measure of the gap in healthy years of life lived by a population as compared with a normative standard. This single measure, designed to quantify the burden of diseases, injuries, and risk factors, adds together years of life lost due to premature mortality and years of life lived with disability or illness. DALYs can be used to quantify, compare, and help to determine which diseases (e.g., malaria, tuberculosis, or HIV, etc.), injuries (e.g., automobile accidents, etc.), and risk factors (e.g., smoking, etc.) have the greatest impact on premature death, loss of health, and disability among populations. See also quality-adjusted life year (QALY).

Discordant Couples

A pair of sexual partners in which one has a sexually transmitted infection, such as HIV, and the other does not.


Any impairment of normal physiological function affecting all or part of an organism, producing characteristic symptoms; illness or sickness in general.

Disease Surveillance

The systematic collection, analysis, interpretation, and dissemination of health data on an ongoing basis, to gain knowledge of the pattern of disease occurrence and potential in a community, in order to control and prevent disease in the community.

Drug Resistance

The ability of a disease to reproduce despite the presence of drugs to combat the disease. Drug resistance is an example of evolution in microorganisms. Mutations (changes in an organism’s genetic structure) arise during disease replication, making the disease capable of surviving drug treatment. Several factors contribute to drug resistance, including abuse, underuse or misuse of antimicrobials, poor patient compliance, and poor quality of available drugs. The consequences of drug resistance include treatment failure and increased direct and indirect health costs associated with the need to start more costly second-line treatment for patients. Drug resistance has become a challenge in treating some cases of HIV, malaria, and tuberculosis, among other diseases. See also antiretroviral drugs, first-line drugs, second-line drugs, MDR-TB, and XDR-TB.



See U.S. Environmental Protection Agency.


The extent to which a specific intervention, procedure, regimen, or service, when deployed in the field, does what it is intended to do for a defined population.


The extent to which a specific intervention, procedure, regimen, or service produces a beneficial effect under ideal conditions.

Elimination (of disease or infection)

Reduction to zero of the incidence of a specified disease (or infection) in a defined geographical area as a result of deliberate efforts; continued intervention measures are required. See also control, eradication, and extinction.

Emerging Disease

A disease that has appeared in a population for the first time, or that may have existed previously but is rapidly increasing in incidence or geographic range. See also incidence.


Having a constant measurable incidence both of cases and of natural transmission in an area over a succession of years. See also incidence.


The occurrence of more cases of disease than expected in a given area or among a specific group of people over a particular period of time. There are different ways to describe the distribution of an epidemic. In the case of an HIV epidemic in an area, for example, the distribution is often described as:

  • Low-level – HIV prevalence is low across the general population and is still low among higher-risk sub-populations
  • Concentrated – HIV prevalence does not exceed 1% of the general population but does exceed 5% of some sub-populations (e.g., among sex workers, injecting drug users)
  • Generalized – HIV prevalence exceeds 1% of the general population
  • Hyperendemic – HIV prevalence exceeds 15% of the general population.


The study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the control of health problems.

Eradication (of disease or infection)

Permanent reduction to zero of the worldwide incidence of a disease (or infection) as a result of deliberate efforts; intervention measures are no longer needed. See also control, elimination, and extinction.

Extensively Drug-Resistant Tuberculosis (XDR-TB)

Extensively drug-resistant tuberculosis is a strain of TB bacteria that is resistant to both first-line and second-line drugs used to treat the disease. It is virtually untreatable. XDR-TB usually arises when people take only enough medication to feel better, but not the full amount prescribed by a physician. The weaker bacteria are killed, but the stronger bacteria survive and reproduce. These stronger bacteria, when fully grown, cause sickness and cannot be killed with the same treatment or even larger doses of the drug. Even newer and stronger drug treatments are often ineffective. Though not as prevalent as multidrug-resistant tuberculosis (MDR-TB), XDR-TB is a large problem in developing countries, where continual supervision of treatment and access to health care are not always possible. See also drug resistance, first-line drugs, MDR-TB, and second-line drugs.

Extinction (of disease or infection)

When a specific infectious agent no longer exists in nature or in the laboratory. Theoretically, extinction of an infectious disease is possible; however, proving that the infectious agent no longer exists in nature or in any controlled environment has proven impossible. See also control, elimination, and eradication.



See fixed dose combination.

Family Planning

The ability of families or persons to anticipate and attain their desired number of children and the spacing and timing of births.

Feed the Future (FtF)

Feed the Future is the U.S. government's global hunger and food security initiative. Announced by President Obama at the 2009 G8 Summit, FtF is led by USAID and works through a variety of agencies, including the U.S. Departments of State and Treasury, the Peace Corps, and the Millennium Challenge Corporation.


The increasing impact or occurrence of a disease, characteristic, or condition among women.

First-Line Drugs

Therapeutic agents that are the immediate drug of choice used to treat a particular condition (as opposed to second-line drugs). See also second-line drugs.

Fixed Dose Combination (FDC)

Fixed dose combination treatment refers to a combination of two or more drug products, such as antiretrovirals, in a single pill. An example of an FDC is the single-pill combination of stavudine, lamivudine and nevirapine, three antiretrovirals used to treat HIV infection.

Food Security

Having access to sufficient, safe, nutritious food to maintain a healthy and active life, and includes both physical and economic access to food that meets people's dietary needs and food preferences. The World Health Organization (WHO) describes food security as being built on the three pillars of availability, access, and use as follows:

  • Food availability: sufficient quantities of food available on a consistent basis
  • Food access: having sufficient resources to obtain appropriate food for a nutritious diet
  • Food use: appropriate use based on knowledge of basic nutrition and care, as well as adequate water and sanitation.

Foreign Aid (or Foreign Assistance)

Financial flows (funds), technical assistance, and commodities that are (1) designed to promote economic development and welfare as their main objective (thus excluding aid for military or other non-development purposes); and (2) are provided as either grants or subsidized loans. See also bilateral assistance, humanitarian assistance, multilateral assistance, and official development assistance.


See Feed the Future.


GAVI Alliance (Global Alliance for Vaccines and Immunisations)

A public-private partnership created in 2000 to save children's lives and protect people's health by increasing access to immunization in poor countries.


See gross domestic product.


See Global Fund to Fight AIDS, Tuberculosis and Malaria.


See U.S. Global Health Initiative.

Gender Inequality

A situation in which gender norms and values can give rise to differences between men and women which systematically empower one group to the detriment of the other. Gender inequalities can lead to inequities between men and women in health status and access to health care.

Generic Drug

A drug that is identical, or bioequivalent, to a brand name drug in dosage, safety, strength, how it is taken, quality, performance, and intended use. Generic sometimes refers to less expensive, but chemically identical medications manufactured by companies that did not invent the drug. In some countries, generic drugs come on the market after a patent on the drug has expired. In other countries, generic drugs are manufactured and sold even before a patent expires. The generic name of a drug is the common name of a drug, which is not protected under any manufacturer’s copyright. It is the more commonly used format when referring to a drug in medical literature.

Global Fund to Fight AIDS, Tuberculosis and Malaria (Global Fund or GFATM)

An independent, public-private partnership, formally launched in 2001. Its primary objectives are to raise new resources to fight HIV/AIDS, tuberculosis, and malaria and then issue grants to countries with the greatest need, in support of prevention, care, and treatment programs.

Gross Domestic Product (GDP)

The value of all final goods and services produced within a nation in a given year.



See swine influenza.


See avian influenza.


See highly active antiretroviral treatment.


See high burden countries, TB.


Human immunodeficiency virus (HIV), the virus that causes AIDS. HIV can be transmitted through infected blood, semen, vaginal secretions, breast milk, and during pregnancy or delivery. HIV destroys certain white blood cells called CD4+ T cells. These cells are critical to the normal function of the human immune system, which defends the body against illness. When HIV weakens the immune system, a person is more susceptible to developing a variety of cancers and becoming infected with viruses, bacteria and parasites. AIDS is the most advanced stage of HIV disease. See also Acquired Immunodeficiency Syndrome (AIDS).

HIV Test

A diagnostic used to determine whether HIV infection is present. The standard HIV diagnostic test looks for the presence of HIV antibodies in the blood or in oral fluid. HIV antibodies are molecules produced by the body once it detects the presence of HIV. The production of HIV antibodies does not happen immediately after exposure to the virus. The period after infection, but before production of antibodies, is called the window period. During the window period, an HIV test may be negative. It is possible to test negative despite the presence of HIV in the body. There are several different kinds of HIV tests used to screen for the presence of antibodies. See also antibodies.

HIV-TB Co-infection

When a cell is co-infected by both HIV and tuberculosis (TB). HIV-TB co-infection is of particular concern because TB accelerates the progression of HIV-related immune suppression making it one of the leading causes of death among people living with HIV and AIDS. See also co-infection, HIV, and tuberculosis.

Health Infrastructure

The resources, structures, and institutions needed to deliver health services to individuals and communities, including the healthcare workforce (doctors, nurses, etc.), facilities, such as hospitals, clinics, laboratories, equipment, and information, and communication systems.

Health Intervention

An action or activity that helps in the prevention, modification, or treatment of health problems.

Health Policy

A statement designed specifically to promote health or a desired health outcome, or those aspects of other types of policy (e.g., education, transportation, and economic policy) not explicitly about health but acknowledged to have a health impact.

Health Systems

A health system consists of all organizations, people and actions whose primary intent is to promote, restore or maintain health.

High Burden Countries, TB (HBCs)

Twenty-two countries, most of which are in Africa and South-East Asia, that account for much of the world’s TB burden (approximately 80% of new TB cases each year).

Highly Active Antiretroviral Treatment (HAART)

A course of treatment that involves the use of three or more antiretrovirals. See also antiretroviral drugs (ARVs).

Horizontal Programming/Funding

A model of program delivery or funding that seeks to provide broad support (e.g., to provide a population with access to generalist health care workers or bolstering an overall system of care), rather than a targeted disease or issue specific program or funding mechanism. See also vertical programming/funding.

Human Immunodeficiency Virus (HIV)

See HIV.

Human Rights-Based Approach (HRBA) to Health

The general recognition that human rights must be promoted and protected in the context of dealing with health issues. This approach to health programming underscores the link between the protection of human rights—such as gender equality and non-discrimination—and providing an effective response to countries’ health needs.

Humanitarian Assistance

Development assistance provided to save lives and alleviate suffering caused by emergencies, including support for activities such as: disaster prevention and preparedness, reconstruction relief, relief coordination, protection and support services, emergency food aid and other emergency/distress relief. Humanitarian assistance is traditionally seen as short-term and differs from development assistance, which is seen as sustainable and long-term. See also foreign aid and official development assistance.


IAVI (International AIDS Vaccine Initiative)

A global not-for-profit organization founded in 1996 and focused on AIDS vaccine research, advocacy, and policy issues.


See injecting drug user.


See intellectual property rights.


See intermittent preventive treatment during pregnancy.


See indoor residual spraying.


Insecticide-treated bed nets; see bed nets.

Immune System

The body’s system of defense against foreign organisms such as bacteria, viruses or fungi. See also bacteria and virus.


The process whereby a person is made immune or resistant to an infectious disease, typically by the administration of a vaccine. Vaccines stimulate the body’s own immune system to protect the person against subsequent infection or disease. See also vaccine.


A state where the immune system’s ability to defend itself against infection is compromised or absent entirely. For example, HIV progressively weakens the immune system and causes immunodeficiency. See also immunosuppression.


A state where the immune system cannot function normally because it has been weakened, often by drugs, medical treatments, or diseases. See also immune system and immunodeficiency.

Improved Sanitation

The types of technology and levels of services that are more likely to provide adequate excreta disposal than unimproved technologies. Improved sanitation includes connection to public sewers, connection to septic systems, pour-flush latrines, simple pit latrines, and ventilated improved pit latrines. Not considered as improved sanitation are service or bucket latrines (where excreta is manually removed), public latrines, and open latrines. “Sustainable access to improved sanitation” attempts to measure the percent of the population with access to adequate excreta disposal facilities.

Improved Water Source

The types of technology and levels of services that are more likely to provide safe water than unimproved technologies. Improved water sources include household connections, public standpipes, boreholes, protected dug wells, protected springs, and rainwater collections. Unimproved water sources are unprotected wells, unprotected springs, vendor-provided water, bottled water (unless water for other uses is available from an improved source), and tanker truck-provided water. “Sustainable access to improved water source” attempts to measure the percent of the population with access to adequate water sources.


The number of new events, such as new cases of a disease, occurring over a specific period of time. It is often expressed as a rate, for example the number of cases per 100,000 in the population. See also prevalence.

Incubation Period

The period of time between disease infection and the onset of symptoms.

Indoor Residual Spraying (IRS)

The application of long-acting chemical insecticides on the walls and roofs of all houses and domestic animal shelters in a given area, in order to kill the Anopheles mosquitoes—the vector that can transmit the malaria parasite to humans—which land and rest on these surfaces. The primary goal of IRS in reducing malaria transmission is to reduce the life span of the Anopheles mosquitoes so that they can no longer transmit malaria parasites from one person to another, and to reduce the density of the mosquitoes in the area. See also Anopheles mosquito, parasite and vector.

Infant Health

The health of a child from birth through the first year of life. See also adolescent health, child health, newborn health, and under five mortality rate.


Potentially transferable to another (animal, individual, or other organism). May or may not be communicable (e.g., whereas tuberculosis is communicable, infections caused by toxins in the environment, such as tetanus, are not communicable). See also communicable, contagious, and infectious disease.

Infectious Disease(s)

Infectious diseases are caused by pathogenic microorganisms, such as bacteria, viruses, parasites or fungi; they are potentially transferable to others, directly or indirectly, but may not be communicable. Zoonotic diseases are infectious diseases of animals that can cause disease when transmitted to humans. See also communicable, contagious, and infectious.

Injecting Drug User (IDU)

Individual who uses needles/syringes to inject drugs. May also mean injecting drug use, which refers to the practice of using needles/syringes to inject drugs. This is a major risk factor for HIV infection in many parts of the world.

Innovative Financing for Global Health

Using new tools or funding mechanisms to improve health access, utilization, and outcomes. Some examples include the International Finance Facility for Immunization (IFF-Im), which utilizes new ways to generate funds to increase immunization efforts globally; tax relief for donating key medicines; advance purchasing commitments for vaccines and other products still under development; and new institutions such as The Global Fund for AIDS, Tuberculosis, and Malaria, The GAVI Alliance (Global Alliance for Vaccines and Immunisations), and UNITAID (the entity that receives and deploys the proceeds of the airline tax).

Insecticide-Treated Bed Net (ITN)

See bed nets.

Integrated Vector Management

A decision-making process for the management of vector populations, so as to reduce or interrupt transmission of vector-borne diseases. An integrated vector management approach takes into account the available health infrastructure and resources and integrates all available and effective measures across all sectors. See also vector.

Intellectual Property Rights (IPR)

Rights awarded to inventors or creators which allow them to prevent others from making unauthorized use of their property. They include patents and copyright, which offer protection for limited periods. In the context of public health, patents are the most important IPR. Patents provide the inventor with the right to prevent others from making, selling, distributing, importing or using their invention, generally for a period of 20 years. In the global health context, IPR issues most often revolve around drug patents. The temporary exclusion of direct competition provides an incentive for invention and innovation by allowing producers of a new medicine to set prices at a level necessary to recoup the costs of their research and development expenditure and make a return on their investment.

Intermittent Preventive Treatment During Pregnancy (IPTp)

Antimalarial drugs provided to pregnant women most often at antenatal consultations during the second and third trimesters of pregnancy. IPT can prevent transmission of malaria from a mother to her child by eliminating the parasites that are in the mother’s blood. Pregnancy reduces a woman’s immunity to malaria, increasing her risk of infection, severe illness, and death. Adverse pregnancy outcomes include low birth weight and spontaneous abortions. IPT reduces these risks. See also malaria.

International AIDS Vaccine Initiative (IAVI)



Life Expectancy at Birth

The average number of years that a newborn is expected to live if current mortality rates continue to apply.

Long-Lasting Insecticide-Treated Bed Net (LLIN)

See bed nets.



See Millennium Challenge Corporation.


See mass drug administration.


See Millennium Development Goals.


See multidrug-resistant tuberculosis.


See men who have sex with men.


See mother-to-child transmission.


Malaria is a disease caused by parasites that are transmitted to humans via mosquito bites. Symptoms of infection may include fever, chills, headache, muscle pain, fatigue, nausea, and vomiting. In severe cases, the disease can be life threatening. See also parasite and Anopheles mosquito.

Male Circumcision

See circumcision.


A lack of the nutrients needed by the body for appropriate growth and development.

Mass Drug Administration (MDA)

The distribution of drugs to an entire population of a given area (e.g., state, region, province) to control disease, usually irrespective of disease status. For example, MDA has been used as a strategy to control malaria in malaria-endemic areas and certain high prevalence neglected tropical diseases such as parasitic worm infections and trachoma. See also neglected tropical diseases (NTDs), tropical diseases, and USAID NTD Program.

Maternal Health

The health of women during pregnancy, childbirth, and the postpartum period.

Maternal Mortality

The death of a woman from any cause related to pregnancy that occurs during pregnancy or within 42 days of pregnancy termination (e.g., birth, stillbirth, miscarriage, or abortion).

Maternal Mortality Ratio

A measure to determine the frequency of pregnancy-related deaths, usually per 100,000 live births. Represents the risk associated with each pregnancy.


A highly communicable and deadly viral disease caused by the measles virus, a member of the genus Morbillivirus in the family paramyxoviridae. The disease is typically spread via droplets or direct contact with the nasal or throat secretions of those infected. Measles is one the most readily communicable and deadly childhood rash/fever illnesses. Measles is preventable by vaccine. See also vaccine and virus.

Men Who Have Sex With Men (MSM)

For assessing disease risk, use of the term “MSM” is often used instead of “gay”, “homosexual” or “bisexual” because it refers to a risk behavior, rather than an identity that may or may not be tied to a behavior. In many countries and cultures, men who have sex with other men may not perceive themselves as gay or bisexual.


Microbicides are products designed to destroy microbes (bacteria and viruses) or to reduce their transmission. They are formulated for application to the surface of the vagina and/or rectum for the prevention of HIV transmission during sexual intercourse, and may come in many forms, including films, creams, gels, suppositories, or as a ring or sponge that releases the active ingredient over time. Research is currently underway to determine the efficacy and effectiveness of several microbicide candidates.

Millennium Challenge Corporation (MCC)

A U.S. government corporation established in 2004, the MCC provides development assistance to eligible countries. The MCC has a Board of Directors and is chaired by the Secretary of State. According to MCC, “For a country to be selected as eligible for an MCC assistance program, it must demonstrate a commitment to just and democratic governance, investments in its people, and economic freedom as measured by different policy indicators.” Countries are assessed according to a series of criteria and then reviewed by the MCC Board for final eligibility selection.

Millennium Development Goals (MDGs)

In 2000, eight Millennium Development Goals (MDGs) were agreed upon by all United Nations member countries. The MDGs provide a framework for improving health, education, gender equity, economic, and environmental conditions in developing countries. Specific and measurable targets were set for low- and middle-income developing countries with a goal to achieve them by 2015.


The number of people who became ill from a disease or at a certain stage of life.


The number of people who died from a disease or at a certain stage of life.

Mosquito Nets

See bed nets.

Mother-to-Child Transmission (MTCT)

This refers to transmission of a disease from mother to her child during pregnancy, birth or breast-feeding. Transmission from mother to child is also referred to as perinatal and vertical transmission. The term most often refers to transmission of HIV from mother to child, but it can also refer to other diseases a mother can pass on to her child such as malaria. See also prevention of mother-to-child transmission.

Multidrug Resistant Tuberculosis (MDR-TB)

A strain of tuberculosis that is resistant to standard first-line drugs used to treat the disease. MDR-TB usually arises when people take only enough medication to feel better but not the full amount prescribed by a physician. The weaker bacteria are killed, but the stronger bacteria survive and reproduce. These stronger bacteria, when fully grown and causing sickness again, cannot be killed with the same treatment and require larger doses of the drug or an entirely new, stronger drug. MDR-TB is a large problem in developing countries, where continual supervision of treatment and access to health care are not always possible. XDR-TB, the acronym for “extensively drug-resistant tuberculosis,” is an even stronger strain of bacteria that is resistant to both first-line and second-line drugs. See also first-line drugs, second-line drugs, tuberculosis, and extensively drug resistant tuberculosis (XDR-TB).

Multilateral Assistance

An arrangement whereby countries, governments, and institutions provide financial assistance to organizations that in turn provide assistance to or on behalf of one or more countries. Multilateral assistance generally consists of projects and programs, the content and direction of which is decided by the multilateral organization, using pooled funding from multiple donors. The World Bank, the United Nations, and the Global Fund to Fight AIDS, Tuberculosis, and Malaria are multilateral institutions. See also bilateral assistance and foreign aid.



See non-communicable diseases.


See non-governmental organization.


See neglected tropical diseases. See also tropical diseases and USAID NTD Program.

Neglected Tropical Diseases (NTDs)

Diseases that occur in the tropics, or hot humid areas, and are concentrated almost exclusively in impoverished populations, living in remote, rural areas, urban slums or conflict zones in the developing world. Currently, the WHO list of NTDs includes: Buruli ulcer, Chagas disease (trypanosomiasis), dengue, dracunculiasis (guinea worm disease), fascioliasis (flatworm), human African trypanosomiasis (sleeping sickness), leishmaniasis, leprosy, lymphatic filariasis (elephantitis), onchocerciasis (river blindness), schistosomiasis (snail fever), soil-transmitted helminthiasis (hookworm, roundworm, or whipworm), trachoma, and yaw. See also USAID NTD Program.

Newborn Health

The health of a child from birth through the first 28 days of life. See also adolescent health, child health, infant health, and under five mortality rate.

Non-Communicable Diseases (NCDs)

Non-infectious medical conditions or diseases, such as heart disease, cancer, diabetes, or asthma. These may be referred to as “chronic diseases” although there are also chronic diseases caused by transmissible infections (e.g., HIV/AIDS). The WHO estimates that collectively NCDs are the leading cause of death worldwide.

Non-Governmental Organization (NGO)

Private or nonprofit organizations that are not affiliated with a governmental body or institution.


The intake of food or nourishment, generally considered in relation to the body’s dietary needs. Good nutrition implies an adequate, well balanced diet combined with regular physical activity. Poor nutrition can lead to reduced immunity, increased susceptibility to disease, impaired physical and mental development, and reduced productivity.



See official development assistance.


See Organisation for Economic Co-Operation and Development.


See Office of the U.S. Global AIDS Coordinator.

Office of the U.S. Global AIDS Coordinator (OGAC)

Housed under the U.S. Department of State, OGAC’s mission is to lead implementation of the U.S. President's Emergency Plan for AIDS Relief (PEPFAR). See also President's Emergency Plan for AIDS Relief.

Official Development Assistance (ODA)

Grants or loans provided by donor governments to developing countries with the promotion of economic development and welfare as their main objective and provided at concessional financial terms (a loan provided to poor countries at a lower interest rate and a longer repayment period than typical or standard market or multilateral loans). Loans are considered ODA if they have a grant element of at least 25%. See also foreign aid and humanitarian assistance.

Opportunistic Infection (OI)

Diseases that rarely occur in healthy people but cause infections in individuals whose immune systems are compromised, including by HIV infection. These disease organisms are frequently present in the body but are generally kept under control by a healthy immune system. When a person infected with HIV develops an OI, they are considered to have progressed to an AIDS diagnosis.

Organisation for Economic Co-operation and Development (OECD)

Established in 1961, the OECD brings together over 30 member countries sharing a commitment to democratic government and the market economy. The OECD’s mission is “to promote policies that will improve the economic and social well-being of people around the world.” Within the OECD, the Development Assistance Committee (DAC) “helps ensure better lives for people in the developing world by tracking development finance, making sure it is invested effectively and promoting good policy.”

Outbreak (of disease or infection)

Often synonymous with "epidemic," generally refers to the spread of disease over a short period of time in a limited geographic area but may extend over a longer period time across several countries if the disease is not contained. See also epidemic and pandemic.



See post-exposure prophylaxis.


See President’s Emergency Plan for AIDS Relief.


See People Living with HIV/AIDS.


See President’s Malaria Initiative.


See prevention of mother-to-child transmission.

Pan American Health Organization (PAHO)

An international public health agency focused on improving health and living conditions for people in the Americas. PAHO serves as the World Health Organization’s Regional Office for the Americas.


A worldwide epidemic; occurring over a wide geographic area and affecting an exceptionally high proportion of the population.


Any organism that lives in or on another organism without benefiting the host organism. Examples of parasites include tapeworms and Plasmodium species (the parasite which causes malaria and is transmitted to humans by the Anopheles mosquito).


An organism or virus that causes disease.

Peace Corps

U.S. government agency that oversees an eponymous volunteer program established by President John F. Kennedy in 1961. The Peace Corps focuses on providing technical assistance to developing nations and generally works in the areas of social and economic development.

People Living with HIV/AIDS

PLHIV/PWA/PLWA/PLWHA are acronyms for “People living with HIV,” “People with HIV/AIDS,” and “People living with HIV/AIDS.” PLHIV is the preferred description, according to UNAIDS, because it “reflects the fact that an infected person may continue to live well and productively for many years.”

Perinatal Transmission

See mother-to-child transmission.

Poliomyelitis (Polio)

A crippling disease caused by any one of three related viruses: poliovirus types 1, 2 or 3. Polio is transmitted solely through fecal and oral routes and enters the body through the mouth when people eat food or drink water contaminated with excreta. The virus is easily spread in areas with poor hygiene. Polio is preventable by vaccine. See also virus and vaccine.

Population Below $1 a Day

A measure of extreme poverty. The share of the population living on less than $1 a day (at 1985 international prices). The $1 a day poverty line is adjusted to local currency using purchasing power parity (PPP), and is then used to compare the consumption (including consumption from production inputs) or income (including income in kind) of each person in a population. It is commonly used to compare the fixed purchasing power across countries or areas and is often called the “absolute poverty line”.

Post-Exposure Prophylaxis (PEP)

Any treatment given after exposure to a disease in order to prevent development of the disease. In the case of HIV, PEP is a course of antiretroviral drugs initiated as soon as possible after exposure to HIV and continuing for 28 days, which studies have shown decreases the risk of infection.

Pre-Exposure Prophylaxis (PrEP)

Any treatment or procedure used before exposure to a disease in order to prevent acquisition of the disease. In the case of HIV, PrEP refers to the use of antiretroviral treatment to protect HIV-negative individuals from becoming infected after exposure. The first HIV antiretroviral was approved for use as PrEP for HIV by the U.S. Food and Drug Administration in July 2012.

President's Emergency Plan for AIDS Relief (PEPFAR)

The U.S. government's initiative to address global HIV/AIDS in developing countries. Led by the U.S. State Department’s Office of the Global AIDS Coordinator (OGAC), PEPFAR provides bilateral aid to countries to support HIV/AIDS prevention, treatment, and care programs. It also includes funding for the Global Fund to Fight AIDS, Tuberculosis, and Malaria. Announced by President Bush in 2003, PEPFAR was originally authorized for five years (FY 2004 to FY 2008) by the U.S. Congress under the “United States Leadership Against HIV/AIDS, Tuberculosis, and Malaria Act of 2003” (Public Law 108–25). In 2008, PEPFAR was reauthorized for another five years (FY 2009 to FY 2013) under the “Tom Lantos and Henry J. Hyde United States Global Leadership Against HIV/AIDS, Tuberculosis, and Malaria Reauthorization Act of 2008” (Public Law 110-293). The bills also authorized funding for U.S. efforts to fight global tuberculosis and malaria. See Global Fund to Fight AIDS, Tuberculosis, and Malaria, Tuberculosis, Malaria; HIV, AIDS, and President’s Malaria Initiative.

President’s Malaria Initiative (PMI)

The U.S. government’s initiative, launched in 2005, to fight malaria in the region most affected by the disease—Africa. The PMI is an interagency initiative led by USAID and implemented alongside CDC.


The number of cases of a disease or condition present in a given population at a specific time (e.g., number of people living with HIV). See also incidence.


Reducing the risk of disease infection and transmission. In the context of HIV, prevention activities are designed to reduce the risk of becoming infected with HIV (primary prevention) and the risk of transmitting the disease to others (secondary prevention).

Prevention of Mother-to-Child Transmission (PMTCT)

Preventing transmission of a disease from mother to her child during pregnancy, birth or breast-feeding. Since mother to child transmission (MTCT) is also referred to as perinatal and vertical transmission, PMTCT may also be referred to as preventing perinatal or vertical transmission. These terms most often refer to transmission of HIV from mother to child but may also refer to other diseases a mother can pass on to her child such as malaria. In the case of HIV, UNAIDS outlines a three-part strategy to prevent HIV transmission from an HIV-positive mother to her child:

  1. Protect females of child-bearing age against HIV infection
  2. Avoid unwanted pregnancies among HIV-positive women
  3. Prevent transmission during pregnancy, delivery, and breast-feeding by providing voluntary counseling and testing, antiretroviral therapy, safe delivery practices, and breast milk substitutes when appropriate.

Preventive Chemotherapy

A large-scale public health intervention that distributes drugs to at-risk individuals in a community identified as endemic for a target disease for the purposes of controlling disease and preventing morbidity and/or mortality. For example, preventive chemotherapy for the control of helminthiasis (worms) uses antihelminthic drugs, either alone or in combination, to prevent morbidity due to infection by usually more than one helminth at a time. See also neglected tropical diseases (NTDs), tropical diseases, and USAID NTD Program.

Probable Case (of disease or infection)

A case that meets the clinical case definition without laboratory confirmation and is epidemiologically linked to a clinically compatible case. See also confirmed case and suspected case.


Refers to the prevention or protective treatment of disease. Primary prophylaxis refers to the medical treatment that is given to prevent onset of an infection. Secondary prophylaxis refers to medications given to prevent recurrent symptoms in an existing infection.



See Quality-Adjusted Life Year.

Quadrennial Diplomacy and Development Review (QDDR)

In July 2009, U.S. Secretary of State Clinton announced the launch of the first-ever QDDR, an extensive review of the U.S. government's diplomatic and development efforts, intended to provide a strategic plan with specific guidance on policy development, resource allocation, staff deployment, and the exercise of legislative authorities. The plan also seeks to enhance coordination between and the role of the U.S. State Department and the U.S. Agency for International Development (USAID) in foreign policy. The QDDR is managed by a senior leadership team under the direction of the Secretary of State, which includes senior representatives from the State Department, USAID, and the Millennium Challenge Corporation. The first plan was released at the end of 2010, with subsequent releases planned for every four years.

Quality-Adjusted Life Year (QALY)

The QALY is a measure of disease burden that incorporates both the quality and quantity of life lived. QALYs are calculated by adding up the number of years of life lived discounted by the perceived quality of those life years, assigning higher values (up to 1.0) for good health and lower values for poor health. QALYs are often used to compare and calculate the cost-effectiveness of different health interventions. See also disability-adjusted life year (DALY).


Rapid Impact Package

In the context of neglected tropical diseases, uses a combination of 4 drugs to treat 7 of the most common NTDs considered “tool-ready”; these are: lymphatic filariasis (elephantiasis); schistosomiasis (snail fever); trachoma (eye infection); onchocerciasis (river blindness); and three soil-transmitted helminthiasis (hookworm, roundworm, and whipworm). See also neglected tropical diseases (NTDs), tropical diseases, and USAID NTD Program.

Reproductive Health

Refers to a state of complete physical, mental, and social well-being in all matters relating to the reproductive system and to its functions and processes at all stages of life. According to the World Health Organization (WHO), achieving good reproductive health requires attention to: sexual development, maturation, and health with special reference to adolescents; fertility regulation (i.e., family planning); maternal health; perinatal health; unsafe abortion; infertility; reproductive tract infections, including HIV/AIDS, other sexually transmitted infections, and cervical cancer; violence and its consequences for sexual and reproductive health; and female genital mutilation and other harmful practices.

Risk/Risky Behavior

Refers to any behavior or action that increases an individual’s probability of acquiring or transmitting a disease, such as HIV. Some examples of risky behaviors in the context of HIV include having unprotected sex, particularly with multiple partners, and injecting drugs with contaminated equipment. Alcohol use has also been linked to risky behavior because of its effect on an individual’s ability to make decisions and negotiate safer sex.

Roll Back Malaria

Launched in 1998 by the World Health Organization (WHO), the United Nations Children’s Fund (UNICEF), the United Nations Development Programme (UNDP), and the World Bank, it aims to ensure that the Millennium Development Goal related to malaria—to halt and begin to reverse the incidence of malaria by 2015—is achieved. See also Millennium Development Goals.



See sexually transmitted disease/infection.


Refers to the concept of achieving a sufficient level of coverage, uptake, intensity, and duration of a disease intervention to enable the intended effect.

Second-Line Drugs

Therapeutic agents that are not the first drug of choice (called first-line drugs) used to treat a particular condition but are generally used to treat those who have developed resistance to first-line treatments. See also first-line drugs.

Sex Worker

Someone who exchanges sex for money, drugs, shelter or other commodities. Sex workers can be male, female or transgender.

Sexual Health

A state of physical, emotional, mental, and social well-being in matters related to sexuality; it is not merely the absence of disease, dysfunction or infirmity.

Sexually Transmitted Disease/Infection (STD/STI)

Any disease or infection that is spread through sexual contact.

Skilled Birth Attendant

An accredited health professional—such as a midwife, doctor or nurse—who has been educated and trained to proficiency in the skills needed to manage normal (uncomplicated) pregnancies, childbirth and the immediate postnatal period, and in the identification, management, and referral of complications in women and newborns. Traditional birth attendants, trained or not, are excluded from the category of skilled attendant.

Smear Positive Case

The presence of TB bacteria in a patient's sputum (sample of mucus or phlegm from a patient’s respiratory tract) when examined under the microscope.

Social Marketing

An approach or technique that refers to the adaptation of commercial marketing techniques to achieve social goals and encourage the adoption of healthier behavior. For example, social marketing has been used to promote a range of HIV-related prevention techniques including condom use.

State Department (U.S.)

See U.S. Department of State.

Stigma and Discrimination

Occurs when people think about and act negatively toward a certain group of people. In the context of global health, stigma and discrimination can occur towards people infected or affected by a disease or health problem. For example, stigma and discrimination toward HIV-positive people, and those perceived to be HIV-positive, are recognized as obstacles to achieving full access to prevention, treatment and support services. The stigma and discrimination that those at risk, and those living with HIV, may face from governments, communities, and families make it less likely the at-risk will seek out care and information.

Suspected Case (of disease or infection)

A case with clinically compatible illness or that meets the clinical case definition without laboratory testing or a case with laboratory tests suggestive of a disease without clinical information. See also confirmed case and probable case.

Swine Influenza (also: H1N1 or Swine Flu)

A contagious acute respiratory disease of pigs (a type of swine) caused by one of several swine influenza A viruses (most commonly of the H1N1 subtype, but other subtypes - like H1N2, H3N1, and H3N2 - also circulate in pigs). Many countries routinely vaccinate swine populations against these viruses, as outbreaks among pigs are known to have occurred in several countries around the world. Until recently, transmission to humans was occasionally reported. In early 2009, several cases of human infection with swine influenza A (H1N1) were reported, the first of which occurred in Mexico, followed by several other countries, including the U.S. Confirmed deaths due to the disease have also been reported. Clinical presentation of swine influenza infection in humans resembles seasonal influenza and other acute upper respiratory tract infections but presentation of the disease can also range broadly from showing no symptoms of infection to severe pneumonia resulting in death. A novel vaccine for H1N1 Influenza was developed and first became available in the fall of 2009, according to the Centers for Disease Control and Prevention (CDC), and there are other basic preventive measures that can also be taken. In June 2009, the World Health Organization (WHO) declared the new strain of H1N1 a global pandemic, and in the fall of 2010, the WHO declared the H1N1 pandemic over, saying worldwide flu activity had returned to typical seasonal patterns.



See tuberculosis.

TB-HIV Co-infection

See HIV-TB Co-infection.


See treatment as prevention.

Treatment as Prevention (TasP)

A term increasingly used to describe HIV prevention methods that use antiretroviral medication to prevent HIV transmission. See also antiretroviral drugs, antiretroviral therapy, pre-exposure prophylaxis, prevention of mother-to-child transmission, and post-exposure prophylaxis.

Tropical Diseases

Diseases that occur solely, or principally, in the tropics. In practice, the term is often taken to refer to infectious diseases that thrive in hot, humid conditions, such as malaria, leishmaniasis, schistosomiasis, onchocerciasis, lymphatic filariasis, Chagas disease, African trypanosomiasis, and dengue. See also neglected tropical diseases (NTDs).

Tuberculosis (TB)

A bacterial infection caused by Mycobacterium tuberculosis, tuberculosis usually affects the lungs but can spread to other parts of the body in serious cases. An individual can become infected with TB when another person who has active TB coughs, sneezes, or spits. Not all people who become infected with TB will develop symptoms. Most people who become infected with TB are able to fight the bacteria and stop them from multiplying. Those who do not become ill are referred to as having latent TB -- when the bacteria that causes tuberculosis (TB) infection in humans lies dormant in the body -- and cannot spread the disease to others, although they usually have a positive skin test reaction but have no symptoms. In people with active TB disease, the bacteria become active, multiply, and cause TB disease; they can spread the disease to others and will often exhibit symptoms such as heavy coughing, fatigue, chills, and fever. People with latest TB can develop active TB disease if they do not receive treatment for latent TB infection.


U.S. Agency for International Development (USAID)

An independent U.S. federal government agency that receives overall foreign policy guidance from the Secretary of State. USAID’s role is to support long-term and equitable economic growth in countries and advance U.S. foreign policy objectives by supporting: economic growth, agriculture and trade, global health, democracy, conflict prevention, and humanitarian assistance. The agency focuses its support in five regions of the world: Sub-Saharan Africa; Asia; Latin America and the Caribbean; Europe and Eurasia; and The Middle East.

U.S. Department of Agriculture (USDA)

A U.S. federal government agency with the mission to provide "leadership on food, agriculture, natural resources, and related issues based on sound public policy, the best available science, and efficient management." Working both domestically and globally, USDA seeks to expand markets for agricultural products and support international economic development while also improving overall nutrition and health by providing food assistance, nutrition education and promotion, and enhancing food safety.

U.S. Department of Health and Human Services (DHHS, HHS)

The Department of Health and Human Services is the U.S. government's principal agency for protecting the health of all Americans and providing essential human services. The Office of Global Affairs (OGA), one of several offices housed within DHHS, provides policy guidance and coordination to other Federal departments and agencies, international organizations, and the private sector on international and refugee health issues.

U.S. Department of State (State Department)

The U.S. Department of State, often referred to as the State Department, is the Cabinet-level foreign affairs agency of the United States. The Department advances U.S. objectives and interests in the world through its primary role in developing and implementing the President's foreign policy. The Department also supports the foreign affairs activities of other U.S. Government entities including the U.S. Department of Commerce and the U.S. Agency for International Development (USAID). The Office of the Global AIDS Coordinator (OGAC) is also housed within the U.S. Department of State.

U.S. Environmental Protection Agency (EPA)

A federal agency established in 1970 which focuses on mitigating environmental hazards that represent inherently transnational threats, and building partnerships to enhance research, policy, and standards development capacity of developing nations.

U.S. Global Health Initiative (also: GHI or Global Health Initiative)

Introduced in May 2009 by President Obama, the U.S. Global Health Initiative is an effort to develop a comprehensive, U.S. government-wide strategy for global health focused on the health challenges and needs of those in low- and middle-income countries. A strategy was released in March 2011, and lays out core principles, implementation components, and specific targets. The initiative and strategy encompass most of the federal government’s programs in global health, including those focused on HIV (through the President’s Emergency Plan for AIDS Relief, PEPFAR), malaria (through the President’s Malaria Initiative, PMI), tuberculosis, maternal and child health, family planning and reproductive health, neglected tropical diseases (through the U.S. Neglected Tropical Diseases Program), nutrition, and health systems strengthening.

UNAIDS (Joint United Nations Programme on HIV/AIDS)

Part of the United Nations system, UNAIDS is the main advocate for accelerated, comprehensive, and coordinated global action on the epidemic. UNAIDS' mission is to achieve universal access to HIV prevention, treatment, care, and support.


See United Nations Population Fund.


See United Nations Children’s Fund.


See U.S. Agency for International Development.


The U.S. government’s effort to control, in an integrated manner, seven NTDs. Run by USAID and implemented with some assistance from CDC, the program focuses on an integrated delivery of mass treatment for NTDs. The seven NTDs are: lymphatic filariasis (elephantitis); schistosomiasis (snail fever); trachoma (eye infection); onchocerciasis (river blindness); and three soil-transmitted helminthiasis (hookworm, roundworm, and whipworm). See also neglected tropical diseases (NTDs).


See U.S. Department of Agriculture.

Under Five Mortality Rate

Probability of dying between birth and five years of age. See also adolescent health, child health, infant health, and newborn health.


The outcome of insufficient food intake and repeated infectious diseases; includes being underweight for one’s age, too short for one’s age (stunted), dangerously thin for one’s height (wasted) and deficient in vitamins and minerals (malnutrition).

Unintended Pregnancy

A pregnancy that is either mistimed or unwanted at the time of conception. Unintended pregnancies can be linked to elevated maternal mortality and are often associated with short between-birth intervals, which can heighten the risk of infant, neonatal, and perinatal mortality.

United Nations Children’s Fund (UNICEF)

The United Nations’ General Assembly created this fund in 1946 in order to aid children in countries devastated by World War II. Today, UNICEF uses contributions from governments and private donors to provide long-term developmental assistance to children and mothers in developing countries.

United Nations Population Fund (UNFPA)

The United Nations’ General Assembly created this fund in 1967 and it began operations in 1969. UNFPA is an international development agency that supports programs in developing countries in promoting equal rights and opportunities to living healthy lives.

Universal Access

The ability of all people to have equal opportunity and access to prevention, care, treatment, and support interventions from which they can benefit, regardless of their social class, ethnicity, background or physical disabilities. One example in the field of global health is universal access to HIV treatment, a belief that all individuals living with HIV/AIDS should have access to HIV treatment. The “Universal Access” campaign, coordinated by the World Health Organization (WHO) and the Joint United Nations Programme on HIV/AIDS (UNAIDS), aims to increase universal access to HIV/AIDS prevention, treatment, and care for those infected and affected by HIV/AIDS.

Universal Precautions

Infection control measures used in health care settings aimed at preventing the transmission of HIV (and other blood-borne pathogens). These measures include the use of gloves and other protective gear, and the safe disposal of needles to prevent exposure to blood and other body fluids.



See voluntary counseling and testing.


A substance that contains a deactivated infectious organism designed to stimulate the immune system to protect against subsequent infection from the active organism. A preventive vaccine preempts infection from that organism, like a virus. A therapeutic vaccine improves the ability of the immune system of a person already infected with the organism to defend itself. See also immunization.


An organism such as a tick, a mosquito, or a person that carries a disease-causing microbe from one host to another. For example, the Anopheles mosquito is a vector for the malaria virus.

Vertical Programming/Funding

Programs that provide significant funding in support of focused, thematic objectives such as one disease or problem, as opposed to horizontal funding or programming which provides more general health systems support. Vertical funding has become an increasingly popular funding mechanism since the late 1990s after the creation of several large issue-specific funds. See also horizontal programming/funding.

Vertical Transmission

Transmission of a disease from a mother to her child during pregnancy, birth or breast-feeding. See also mother-to-child transmission.

Viral Load

The amount or concentration of a virus, such as HIV, in the blood. In the context of HIV, there is a correlation between the amount of virus in the blood and the severity of disease—the higher the viral load, the more progressive the HIV disease. A viral load test is an important tool for doctors in monitoring illness and determining treatment decisions.


A microbe that invades cells and is not subject to antibiotics. Viruses cause many common infections such as flu and colds. Vaccines can prevent the spread of some viral illnesses (including polio), and other medications can ease viral disease symptoms but not cure the illness. See also immunization and vaccine.

Voluntary Counseling and Testing (VCT)

Voluntary counseling and testing (VCT) programs are a critical component of both HIV prevention and treatment activities. VCT is an internationally accepted intervention designed to enable people to learn their HIV status and receive counseling about risk reduction and referral to care if they are HIV-positive. Voluntary HIV testing approaches have relied on both client-initiated or opt-in testing (where the client asks to be tested) and provider-initiated or opt-out testing (where a provider offers testing to a client). Recently, there has been a move to provider-initiated testing to encourage more people to get tested and to make testing a more routine procedure in the health care environment.

Voluntary Medical Male Circumcision (VMMC)

See circumcision.

Vulnerable Populations

Populations that are at increased risk of exposure to diseases due to socioeconomic, cultural or behavioral factors. Vulnerable populations include racial and ethnic minorities, refugees, poor people, men who have sex with men, injection drug users, sex workers, and women where gender inequality is pronounced.



See World Health Organization.

Water for the Poor Act (WfP Act)

Passed in 2005, the "Senator Paul Simon Water for the Poor Act of 2005" (P.L. 109-121) builds on existing international water and sanitation programs. The WfP Act requires the Secretary of State, in consultation with USAID, the main implementing agency, and other agencies, to develop a strategy "to provide affordable and equitable access to safe water and sanitation in developing countries." Among the key objectives of the WfP Act is to increase access to, and effective use of, safe drinking water and sanitation to improve human health. The Initiative includes the need to identify priority water countries and provides assistance through capacity building activities, institutional strengthening, and policy/regulatory reform; diplomatic engagement; direct investment; investments in science and technology; and through partnerships.

World Bank

The World Bank is a development institution that provides loans, policy advice, technical assistance, and knowledge sharing services to low- and middle-income countries to reduce poverty. It is made up of two unique development institutions owned by 185 member countries—the International Bank for Reconstruction and Development (IBRD) and the International Development Association (IDA).

World Health Organization (WHO)

The United Nations’ specialized agency for health. WHO's objective, as set out in its Constitution, is the attainment by all peoples of the highest possible level of health. Health is defined in WHO's Constitution as a state of complete physical, mental, and social well-being, and not merely the absence of disease or infirmity. WHO is governed by nearly 200 Member States through the World Health Assembly.



See extensively drug-resistant tuberculosis.


Yellow Fever (YF)

A viral fever transmitted by infected mosquitoes. The disease is caused by the yellow fever virus, which belongs to the flavivirus group. Infection causes a wide spectrum of disease, from mild symptoms (e.g., fever, muscle pain, headache, shivers, loss of appetite, nausea and/or vomiting) to severe illness (e.g., bleeding from the mouth, nose, eyes, or stomach; bleeding can be found in vomit and excreta) and death. The "yellow" in the name is explained by the jaundice that affects some patients. An effective vaccine for yellow fever has been available for several decades, but the number of people infected has increased in recent years. See also virus and vaccine.


Zoonotic Diseases

Diseases spread from animals to people.