Global Health

This glossary is designed to serve as a resource for those working on global health policy issues, reporting on global health for the news media, or conducting research more broadly. Prepared and maintained by the Kaiser Family Foundation, it provides an edited compilation of definitions of key terms in global health.  It is based on multiple source documents and Kaiser Family Foundation products, and several reference links are provided at the end of this resource. The glossary will be updated on a regular basis.

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A

ABC
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

Abstinence
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.

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 opportunistic infection.

Active TB Disease
One of two forms of tuberculosis (TB).  TB bacteria become active if the immune system cannot stop them from multiplying and the bacteria can cause active TB disease.  People with active TB disease can spread the disease to others.  Those with active TB will often exhibit symptoms such as heavy coughing, fatigue, chills, and fever. Some people develop TB disease soon after becoming infected with the bacilli, before their immune system can fight the TB bacteria.  Other people might get sick later, when their immune systems become weak for some reason.  Most people infected with TB do not develop active TB disease and instead have what is called latent TB.  See also tuberculosis and latent TB disease.
 
Acute HIV Infection (also:  Primary HIV Infection)
The first of four stages of HIV infection, this is the period immediately following infection with HIV.  The length of the acute stage can last anywhere from a few days to several weeks. HIV multiplies rapidly and can be transmitted to others during this time.  Acute HIV infection is also known as primary HIV infection (PHI).  The other stages of infection, after acute infection, are asymptomatic, chronic symptomatic and AIDS.

Adolescent Health 
The health of young people between the ages of 10 and 19 years.  See also child health.

AIDS 
See acquired immunodeficiency syndrome.

AIDS-Defining Illness
These include a variety of conditions that occur at late stages of HIV disease and that signal progression to AIDS.  According to UNAIDS, many individuals first become aware of their infection at this stage.

AIDS Orphan
See children orphaned by HIV.

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.
 
Antenatal
Occurring before birth (as in HIV exposure or transmission from mother to infant during pregnancy); prenatal.

Antibodies
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 (ARV) Drugs
Drugs that inhibit the replication of HIV.  When antiretroviral drugs are given in combination, HIV replication and immune deterioration can be delayed, and survival and quality of life can be improved.

Antiretroviral Therapy (ART)
Refers to a range of treatments that includes antiretroviral (ARV) medications.  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.

Arteminisin-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 caused by a parasite and transmitted to humans by a mosquito.  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. Artemisinin compounds—including artesunate, artemether, and dihydroartemisinin—are usually used in combination with other antimalarials to treat the parasite.  See also drug resistance, Anopheles mosquito, and parasite. 

Asymptomatic
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 (considered the second stage of HIV disease), during which HIV can still be transmitted. 

Avian Influenza/Flu
Avian influenza, or "bird flu" is an infectious disease of animals (usually birds, and less commonly pigs) 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. In addition, unlike normal seasonal influenza, H5N1 can cause severe disease in humans.

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B

Bacteria
(Plural for bacterium).  Tiny microorganisms that reproduce by cell division and usually have a cell wall.  They cause many common infections.  Tuberculosis is one example of a bacterium.  

Bed Nets
Bed nets are used to prevent malaria transmission by forming a protective barrier around persons using them and therefore limiting their exposure to mosquito bites.  Bed nets have repeatedly been shown to reduce severe disease and mortality due to malaria in endemic regions.  The application of a residual insecticide on bed nets greatly enhances their protective efficacy. These types of bed nets are called insecticide-treated bed nets (ITNs).  More recently, several companies have developed long-lasting insecticide-treated nets (LLINs) that retain lethal concentrations of insecticide for at least 3 years.

Bilateral Assistance
Direct 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 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.  The World Health Organization (WHO) and other partners carry out the Global Burden of Disease (GBD) Project to develop global estimates of burden.

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C

CDC (Centers for Disease Control and Prevention)
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.  The Coordinating Office of Global Health, one of the CDC’s six Coordinating Centers, provides national leadership, coordination, and support for CDC′s global health activities in collaboration with CDC′s global health partners.  The National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP), housed under CDC’s Coordinating Center for Infectious Diseases (CCID) works to prevent and control HIV/AIDS, viral hepatitis, sexually transmitted diseases, and tuberculosis at the community, state, national, and international levels.

Child Health
The health of children from birth through adolescence (the data on child health often refer to those under the age of five).  See also adolescent health.

Child Orphaned by AIDS (also: AIDS Orphan)
Any child under the age of 18 who has lost one or both parents to AIDS (not including children who are estimated to have already died from AIDS or other causes).

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

Circumcision (also: Male Circumcision)
A procedure in which the foreskin of the penis is removed.  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 scientific study designed to evaluate the safety, efficacy and medical effects of a treatment (e.g., antiretroviral therapy, vaccine). A treatment must proceed through several phases of clinical trials before it is approved for use in humans.

Co-Infection
Refers to the condition of an organism or individual cell infected by two pathogens, or infectious agents, simultaneously, such as HIV and tuberculosis. See also HIV-TB co-infection.

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 HAART or highly active antiretroviral therapy.

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 and infectious.

Community Health Workers (CHW)
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.  They are usually selected by the communities and are answerable to the communities for their activities.  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 Partnerships
Having more than one sexual partner at a time.  The practice raises the risk of contracting sexually transmitted diseases.  For example, concurrent sexual partnerships raise the risk of contracting HIV and are increasingly recognized as a significant factor in the high prevalence rate of HIV in Africa.

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 and infectious.

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.

Cross Resistance
The phenomenon where resistance to one drug (see drug resistance) used to treat a disease prompts resistance to other drugs in the same drug class. An example of this, in the context of HIV, is nevirapine resistance resulting in resistance to efavirenz.

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