Health Terms Glossary
This page provides basic information about the major diseases that RESULTS addresses. Click on a link to read more below. Terms under other topics are defined in the glossary, or visit Background Information on the Legislative Process.
Directly Observed Treatment Short-Course (DOTS) — see NGOs, International Partnerships, and Initiatives
Diarrhea is widespread through the developing world and is a major cause of death, particularly for children. A person infected with the disease will pass loose or liquid stools more frequently than is usual. Diarrhea is caused by bacterial, viral, and parasitic organisms that are generally spread through contaminated water or through food that has been prepared or stored in unhygienic conditions. It can be transmitted through utensils, hands, or flies and causes severe dehydration, which can lead to death if not treated immediately. Around the world, there are approximately 1.1 billion people who lack access to safe water and 2.4 billion who have no basic sanitation. In 1998, diarrhea is estimated to have killed 2.2 million people, mostly children*; each year, about 4 billion cases of diarrhea occur worldwide according to the World Health Organization (WHO).
Diarrheal diseases can be prevented by increasing both access to clean drinking water and use of proper sanitation measures, such as washing one’s hands. It can be treated easily using oral rehydration solution, but investments in water and sanitation coupled with alterations in behavior are essential as a means of long-term treatment.
*(Source: the World Health Organization, 2000 report)
Extremely Drug Resistant Tuberculosis (XDR-TB) is a newly identified global health threat — a strain of tuberculosis resistant to at least three of the six classes of second-line drugs including isoniazid (INH) and rifampicin (RIF), the two most powerful anti-TB drugs available today. XDR-TB is entirely human-made, developing when patients undergo inconsistent or incomplete treatment to tuberculosis due both to poor funding or management of TB programs and to inadequate tools. Moreover, due to the high risk of death for HIV-positive patients co-infected with XDR-TB, XDR-TB threatens to reverse progress made against HIV/AIDS and global TB control. Treatment options are severely limited since XDR-TB is resistant to both first- and second-line drugs. However, if identified early, there is a possibility for successful treatment and cure, and its spread can be controlled.
TB programs must be strengthened and expanded in Africa (including resources increased to support better diagnostics, lab strengthening, and patient follow-up) and globally to prevent the development of MDR (Multidrug-Resistant)-TB and XDR-TB. (1) Surveillance must be strengthened to identify where MDR- and XDR-TB already exist. (2) Infection control measures must also be strengthened to prevent the spread of drug resistant strains (especially where HIV prevalence is high). (3) MDR/XDR treatment must be scaled up. XDR-TB also underscores the need for more investment in the research, development, and implementation of new TB diagnostics, drugs, and a more effective vaccine.
XDR-TB cases have been found so far on six continents and in 37 countries, including the United States. Those infected with XDR-TB have an 85 percent morality rate. Unless steps are taken now to strengthen TB control efforts in Africa and throughout the world, these deadly strains will continue to spread and multiply, not only undermining much of the recent progress in AIDS treatment scale-up and TB control, but also posing a risk to the U.S. and members of our armed forces serving overseas.
See the Drug-Resistant TB page to read more.
HIV/AIDS was first recognized in 1981 as a disease affecting the cells of the immune system by destroying or impairing their function and slowly diminishing the body’s ability to fight infections. More specifically, HIV stands for Human Immunodeficiency Virus and attacks the CD4 cells of the immune system. Losing too many of these CD4 cells leaves a person less able to fight off infection. Thus, HIV does not directly kill a person, but rather renders a person more prone to tumors and opportunistic infections — infections that usually cause disease only in a person with a weakened immune system.
HIV is the virus that causes AIDS, Acquired Immune Deficiency Syndrome, which is the most severe manifestation of the infection. AIDS has no known cure, though treatment can slow the virus’ progression. It is spread by way of direct contact with bodily fluids, usually through unprotected sex, the sharing of needles between injecting drug users, breastfeeding, or during pregnancy and birth. The rate of the disease’s progression varies from person to person, ranging from two weeks up to twenty years and affected by many factors including the strength of the person’s immune system. Anti-retroviral therapy is central to providing effective care for HIV/AIDS patients (and to the prevention of mother-to-child transmission of HIV) and serves to delay immune deterioration so that the patient’s quality of life may be improved. However, anti-retroviral drugs are expensive and an infected person unable to receive treatment usually will die within one year.
HIV/AIDS has become a global epidemic, claiming approximately 20 million lives in the last 20 years. AIDS is the leading cause of death in Africa and the fourth leading cause of death in the world, according to the Global Fund to Fight AIDS, Tuberculosis, and Malaria. Moreover, 95 percent of the 40 million people currently infected with HIV/AIDS live in developing countries.
A surge of HIV/AIDS infection can devastate a country psychologically, socially, and economically. Fighting this epidemic requires strategies to: (1) prevent the spread of the disease (such as through education of sexual health and promotion of the use of condoms); (2) treat those infected through greater access to anti-retroviral drugs (including early detection through testing); and (3) support and care for those communities and individuals affected by HIV/AIDS as well as those living with the disease.
Tuberculosis is the leading cause of death for people infected with HIV/AIDS. See Tuberculosis and HIV/AIDS: A Deadly Combination for a brief description of this situation or the TB and HIV page for greater details.
Each year, between 300 and 500 million cases of malaria occur worldwide, and this disease kills more than 1 million people each year, almost all of them young children under the age of five in Africa — that is one child dying every 30 seconds from a treatable and preventable disease.
Malaria is spread through the bite of an Anopheles mosquito. Once infected with the parasite that begins to multiply within red blood cells, a person may experience such general symptoms as fever, chills, nausea, flu-like illness, sweating, headache, and anemia. The illness may continue for several weeks to months, and when left untreated, an infected individual may develop serious complications and die. Moreover, children and pregnant women are much less likely to recover than adults whose immune systems are much stronger.
A disease commonly associated with poverty, malaria is also a cause of poverty and greatly hinders economic development. In Africa, it accounts for up to half of all hospital admissions and outpatient visits, while illness and death caused by malaria costs Africa about $12 billion a year in lost productivity. As the disease disproportionately affects people living in poverty, combating malaria is an essential poverty reduction strategy. Effective methods of fighting malaria include the use of insecticide-treated bed-nets, insecticides, and anti-malarial drugs. For a mere $10, a bed net can be distributed to a family and its use explained.
(Sources: the World Health Organization (WHO), Nothingbutnets.net)
Although one child can be vaccinated against measles for less than $1, the disease remains a major childhood killer in developing countries. In 2005, an estimated 345,000 people (most of whom were children) died from measles, which translates to about 945 deaths every day! Measles is a virus spread through respiration — by contact with nasal or throat secretions emitted when an infected person coughs or sneezes — and is highly contagious. Almost all children who have not been immunized contract the virus if exposed. Symptoms include a total body skin rash along with high fever, cough, and runny nose; however, complications coupled with measles, such as pneumonia, diarrhea, and malnutrition, are often fatal to the children of developing countries.
In 2003, the 56th World Health Assembly resolved to reduce measles deaths by 50 percent by the end of 2005 compared to 1999 levels, and the goal has been exceeded. The current goal was adopted by the 58th World Health Assembly in 2005 under the World Health Organization/UNICEF Global Immunization Vision and Strategy (GIVS). GIVS is working to reduce global measles deaths by 90 percent by 2010 compared to 2000 estimates.
MDR-TB describes strains of tuberculosis that are resistant to the two most powerful first-line TB drugs available today: isoniazid (INF) and rifampicin (RIF). It can develop if the four standard anti-TB drugs are misused or mismanaged. More specifically, MDR-TB is caused by inconsistent or partial treatment, when patients do not take all their medicines regularly for the six-month period because treatment is interrupted or because doctors/health workers prescribe the wrong drugs or wrong combination of drugs or because the drug supply is unreliable. MDR-TB takes longer to treat with second-line drugs, which are more expensive and have more side-effects. Standard TB can be cured in 6–8 months; treatment of MDR-TB can take up to 2 years. In the U.S., TB treatment for one standard case, normally several thousand dollars, can skyrocket a hundred times or more in cost to treat MDR-TB.
See the Drug-Resistant TB page to read more.
An illness of the lungs and respiratory system, pneumonia kills more children than AIDS, malaria, and measles combined yet remains a largely forgotten disease. It infects approximately 10–20 percent of all children under the age of five in developing countries and contributes between 750,000 and 1.2 million deaths each year. The illness is characterized by cough, fast and difficult breathing, fever, chest pains, and muscle aches. Children who are malnourished, suffer from other illnesses, or live in a poor environment are vulnerable to pneumonia. It is transmitted through person-to-person direct contact with infectious secretions.
The illness can be prevented through child survival interventions (including improved access to good nutrition) and vaccinations. These strategies would also have a beneficial effect upon maternal health, management or other common neonatal conditions, and both childhood and adult morbidity.
(Sources: UNICEF and the World Health Organization)
Tuberculosis (TB) is a contagious disease caused by mycobacterium tuberculosis bacteria, which usually attack the lungs but can also attack other parts of the body including the kidney, spine, or brain. It can usually be treated with a course of four standard, or first-line, anti-TB drugs; we have been able to treat this disease for over forty years for as little as $16 for a full treatment in the developing world. However, when left untreated, TB diseases kill more than half of those infected. Tuberculosis is spread through the air; bacteria is released into the air when a person with active TB of the lungs or throat coughs, sneezes, sings, or even talks. If an individual is close to a TB-infected person for a long period of time, he or she can breathe in the germs and could become infected. Not everyone who is infected develops the disease; the bacteria can be in the body, but for some people, the body’s defense system protects them from the germs so that they are not sick — this is called Latent Tuberculosis I. However, Active Tuberculosis II refers to a person sick with the TB disease that can spread the disease to others and needs to see a doctor immediately.
A person with active TB can infect up to 10 to 15 people every year. Nine million people develop active TB every year, while about 1.7 million people die of TB every year. TB is the number one killer of women of reproductive age. It is also the number one killer of people infected with HIV/AIDS. However, when correctly treated with DOTS, tuberculosis is 95 percent curable even in the poorest countries.
See the About TB page to read more and find links to other related information.
(Source: the World Health Organization)
Tuberculosis is the leading killer of people with HIV/AIDS. Up to half of the people living with HIV/AIDS will develop active TB. Active TB in an HIV positive person, if left untreated, will end their life in 5 to 6 weeks. HIV positive people are 30 times more likely to have their latent TB turn active because of their compromised immune systems. Treating an HIV positive person for active TB can extend his or her life by 2 to 5 years.
Recognizing the deadly links between TB and HIV/AIDS and addressing them in tandem is one of the most promising ways to make gains against both diseases. Access to TB treatment for all those co-infected can have an enormous impact on reducing deaths of people living with HIV/AIDS, and there is almost no better entry point for identifying individuals who need anti-retroviral therapy than expanding TB services and linking those with HIV testing and counseling. In Kenya, TB-HIV coordination has proved remarkably successful at increasing both the number of TB and HIV cases that are found and then treated. This model of robust coordination between TB and HIV/AIDS services offers great hope and should be a major priority for donors, especially the 15-country PEPFAR (President’s Emergency Plan for AIDS Relief) program.
See the TB and HIV page to read more.