Kaiser Family Foundation

A Reporter's Guide to U.S. Global Health Policy

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The Basics of Global Health

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Some of the primary causes of illness and death in developing countries are the same as those found in wealthier nations, including heart disease, stroke, and respiratory infections.

However, due to a number of factors -- particularly poverty, lack of adequate access to clean water and food, and climate and environmental conditions -- low- and middle- income countries are hit much harder by a variety of infectious diseases and other conditions such as HIV/AIDS, malaria, tuberculosis, food insecurity, and food and water-borne illnesses. In addition, lower-income countries often have an inadequate health infrastructure, which inhibits their ability to prevent, diagnose, and treat diseases. It is these issues that are generally the focus of U.S.global health policy and development assistance. 

This section provides basic background on the major diseases and conditions facing low- and middle-income countries.

HIV/AIDS

What it is: HIV is the virus that causes acquired immunodeficiency syndrome (AIDS). The first cases were reported in 1981. People become infected with HIV primarily though sexual contact with an infected person. It can also be transmitted through blood -- e.g., by using a syringe that has been previously used by someone who is infected -- or from a mother to a baby during pregnancy, delivery, or breastfeeding. HIV/AIDS weakens the immune system, leaving those affected vulnerable to opportunistic infections and potentially death. 

The numbers:

  • 33.4 million people were living with HIV as of 2008.
  • About 2 million people died of AIDS-related causes in 2008, though deaths have been declining recently due to an increasing number of people receiving treatment.
  • There were 2.7 million new HIV infections in 2008, and the number of new infections likely peaked in the late 1990s.
  • Almost all of those living with HIV (97%) are in low- and middle-income countries, and two-thirds are in sub-Saharan Africa. HIV is the leading cause of death in Africa.
  • Goal 6 of the Millennium Development Goals calls for halting and beginning to reverse the spread of HIV/AIDS by 2015, and providing universal access to treatment to all who need it by 2010.
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Treatment: There is no cure for HIV, but there are now medications available to attack the virus -- known as highly active antiretroviral therapy (commonly referred to as HAART or ART) -- and to prevent and treat the many opportunistic infections that can occur when the immune system is compromised by HIV. These treatments have led to dramatic reductions in mortality and morbidity. In December 2008, 4 million people in low- and middle-income countries were receiving treatment (.pdf) (42% of those in need), up from 3 million people in 2007 (33% of those in need). In November 2009 the World Health Organization (WHO) issued new guidelines (.pdf) recommending that people with HIV start treatment earlier, potentially doubling the number of people who are in need of treatment and not receiving it. 

Prevention: There is no vaccine to prevent HIV infection, though there are proven prevention methods.  Effective prevention strategies include: use of condoms, behavior change (e.g., delaying sexual debut and reducing the number of sexual partners), HIV testing to increase the number of people who know their infection status, blood supply safety, harm reduction efforts for injecting drug users (e.g., making clean needles available), use of ART to prevent mother-to-child transmission, and male circumcision.  Access to prevention, however, remains limited; only one in five of those at risk has access to needed services. 

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Malaria

What it is: Malaria is one of the world's most common and serious tropical diseases, caused by parasites transmitted to people by Anopheles mosquitoes. It thrives in warm tropical and sub-tropical climates. Symptoms of malaria include fever, vomiting, and diarrhea, and in severe cases it can be deadly. 

The numbers:

  • Half of the world's population is at risk for malaria. It was endemic -- meaning that there are a constant, measurable number of new cases and natural transmission occurs over time -- in 108 countries in 2008.
  • Sub-Saharan Africa is the hardest hit region in the world, and parts of Asia and Latin America also face significant malaria epidemics.
  • In 2008 there were an estimated 243 million cases of malaria and 863,000 deaths (89% of which occurred in Africa).
  • Children are particularly at risk because they lack developed immune systems, and they represent 85% of all malaria deaths. Pregnant women are also at risk because pregnancy reduces immunity to malaria, increasing the risk of infection, severe illness, and death.
  • Millennium Development Goal 6 calls for halting and beginning to reverse the incidence of malaria by 2015.

Treatment: Malaria can be treated with medications, including chloroquine, primaquine, and highly effective artemisinin-based combination therapy (ACT). ACT is recommended for areas with drug resistance or more deadly malaria strains. Multidrug-resistant malaria is now prevalent in Africa, South America, the Western Pacific, and South-East Asia. Distribution of ACT therapy, as reported by national malaria programs, rose from 2 million in 2004 to 73 million in 2008. However, access to treatment is still limited -- in a number of African countries surveyed in 2007-2008, less than 15% of children under age five with a fever received ACT. 

Prevention: Prevention centers around mosquito control activities and anti-malarial drugs to prevent infection. A malaria vaccine does not exist, though clinical trials are underway. National malaria programs report that the distribution of insecticide-treated bed nets increased from 20 million in 2004 to 68 million in 2008, but access remains limited, while the share of African households with at least one bed net stood at 31% in 2008, up from 17% in 2006. Indoor residual spraying is commonly used in the Americas and South-East Asia, and to a lesser extent in Africa and the Western Pacific. Spraying raises concerns about creating resistance to insecticides. Anti-malaria drugs -- which do not protect against infection from a mosquito bite but can prevent disease by inhibiting the development of parasites in the blood -- are used by travelers, and also may be provided to at-risk groups (such as pregnant women) in endemic areas. 

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Tuberculosis

What it is: Tuberculosis (TB) is an airborne, infectious disease caused by bacteria that primarily affect the lungs. TB can remain latent in otherwise healthy people, who exhibit no symptoms and cannot transmit the bacteria to others. However, if left untreated, a small percentage (5-10%) of those with latent TB may develop an active form of the bacteria later in life, which can make them sick and able to spread TB to others. In addition, it is a common and a serious threat to people with compromised immune systems, such as those living with HIV.

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The numbers:

  • TB is found in every country in the world, but the majority of TB cases are concentrated in developing countries, particularly those in Asia and Africa. Twenty-two countries are considered "high-burden countries," which account for approximately 80% of new TB cases each year.
  • One-third of the world’s population, or about 2 billion people, carry the TB bacteria, more than 9 million of whom become sick each year with "active" TB that can be spread to others.
  • In 2008 an estimated 11.1 million people were living with (active) TB, including 9.4 million new cases.
  • There were an estimated 1.8 million TB deaths in 2008, including about 520,000 among people who were HIV-positive.
  • The TB incidence rate appears to have peaked in 2004, but is declining slowly.
  • Millennium Development Goal 6 calls for halting and beginning to reverse the incidence of major diseases such as TB by 2015.

Treatment/prevention: Control of TB is based on DOTS, or "directly observed treatment, short-course," which aims to decrease TB-related morbidity, prevent death, and diminish transmission. Treatment makes use of a variety of drugs. 

Drug-resistant TB has emerged as a major challenge facing TB-control efforts, with the number of drug-resistant TB cases growing in recent years. There are two forms of drug-resistant TB: (1) Multidrug-resistant TB (MDR-TB), which fails to respond to standard first line drugs; and (2) Extensively drug-resistant TB (XDR-TB), which fails to respond to both first and second line drugs. Both types of resistance can result from inconsistent or partial treatment, incorrect prescribing, or interruptions in the drug supply. MDR-TB is treatable, but at a higher cost than standard TB. Treatment options for XDR-TB are very limited at this point. 

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Neglected Tropical Diseases

What they are: Neglected tropical diseases (NTDs) are a group of parasitic, bacterial and viral infections that primarily affect the most impoverished and vulnerable populations in the world. As such they have received scant attention until recently. Thirteen diseases represent the core of the highest burden NTDs, grouped together due to their chronic, disfiguring, and stigmatizing impact, intricate association with poverty, and geographic overlap. Among these, the seven most common form a subset targeted by the U.S. government and other programs. The President's Global Health Initiative calls for increased funding to address NTDs.

The numbers: An estimated 1.4 billion people are infected with one or more NTDs, and another 2 billion people are at risk. The burden is mainly concentrated in Africa, Asia, and Latin America.

  • Dengue hemorrhagic fever is caused by a virus transmitted via mosquitoes. It is now believed that 50 million dengue infections occur every year, with approximately 2.5 billion people in more than 100 countries at risk of infection. There is currently no treatment for dengue.
  • There are 350 million people in 88 countries at risk of Leishmaniasis, a parasitic infection transmitted by sand flies. Leishmaniasis has three forms: cutaneous, mucocutaneous, and visceral, the most serious. Visceral leishmaniasis, or kala azar, is deadly if left untreated.
  • Lymphatic filariasis , or elephantiasis, is caused by parasitic worms and transmitted by mosquitos. More than a billion people worldwide are at risk of the disease, which can cause severe disfigurement. One-third of the 120 million people already infected with the disease live in India, one third in Africa and most of the other in South Asia, the Pacific and the Americas.
  • Onchocerciasis , or river blindness, is a parasitic worm transmitted by a black fly that is the second leading cause of infectious blindness. The Onchocerciasis Control Program, a collaboration of U.N. agencies, has successfully beaten back the disease in large parts of West Africa, but it remains in an estimated 30 countries in Africa, Central and South America and the Arabian peninsula.
  • Schistosomiasis , or bilharzia, is caused by worms found in contaminated water and is considered the second most devastating parasitic disease in tropical countries after malaria. Found in more than 70 countries with more than 600 million people at risk, upwards of 200 million people are infected worldwide each year.
  • Together, the three soil-transmitted helminthiasis are the most common NTDs. Ascariasis (roundworm) affects about 807 million people, including an estimated 60,000 who die each year. It is typically found in sub-Saharan Africa and South-East Asia. Trichuriasis (whipworm) affects about 604 million people is typically found in sub-Saharan Africa, Latin America, and East Asia, as well as in the southern United States. Hookworm affects 576 million people and is the world’s leading cause of anemia and malnutrition. It is most prevalent in Africa, Latin America, Southeast Asia and China.
  • Trachoma , a bacterial infection, is the world's leading cause of infectious blindness. An estimated 1.2 billion people lived in endemic areas in 2008. Trachoma affects about 84 million people of whom about 8 million are visually impaired.

Other NTDs include: African trypanosomiasis (sleeping sickness); Mycobacterium ulcerans (Buruli ulcer); leprosy; and Dracunculiasis (Guinea worm).

Treatment: Many NTDs can be controlled and even eliminated with low-cost and effective interventions. The current recommended strategy is to target multiple NTDs simultaneously through mass drug administration at the community level. The rapid-impact package now available uses a combination of four drugs to treat the seven most common NTDs for as little as $0.25–$0.50 per person per year. 

Prevention: In addition to controlling disease through mass drug therapy, promoting clean water, vector control, sanitation, and hygiene also play a role in addressing the underlying causes of NTDs.  

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Maternal, Newborn and Child Health

What it is: There has historically been a particular focus in global health policy on women before and during pregnancy and childbirth, and as well as on newborns and young children. In contrast to developed countries, many lower-income countries face significant problems with maternal mortality and children dying of neonatal causes and diseases like pneumonia and diarrhea.

The numbers:

  • An estimated 536,000 women died in pregnancy or childbirth in 2005, with most of these deaths in sub-Saharan Africa. The major causes of maternal deaths in Africa include hemorrhage (33.9%), indirect causes (16.7%), sepsis (blood infection) (9.7%), hypertension (high blood pressure) (9.1%), and HIV/AIDS (6.2%).
  • Millennium Development Goal 5 calls for reducing the maternal mortality rate by three-quarters from 1990 to 2015, but the number of maternal deaths per 100,000 live births worldwide stood at 400 in 2005, largely unchanged since 1990. MDG 5 also calls for universal access to reproductive health by 2015.
  • The rate of maternal deaths is much higher in low-income countries. In 2005, the rate per 100,000 live births was 650 in low-income countries, 180 in lower-middle-income countries, and 91 in upper-middle-income countries.
  • About 9 million children under age five died in 2007, down 27% from an estimated 12.5 million in 1990. Millennium Development Goal 4 calls for reducing the death rate among children under five by two-thirds between 1990 and 2015.)
  • The risk of death is highest in the first month life, with most newborn deaths caused by pre-term birth, suffocation during birth, or infection.
  • Pneumonia (19%) is the leading killer of children under five. Together with diarrhea (17%), malaria (8%), measles (4%) and HIV/AIDS (3%) these five diseases account for half of all under-five deaths.

Treatment/prevention: According to WHO, the vast majority of maternal deaths are preventable through "quality family planning services, skilled care during pregnancy, childbirth and the first month after delivery, or post-abortion care services and where permissible, safe abortion services."

Addressing health care for newborns and young children focuses on care during pregnancy, safe delivery, neonatal care, and breastfeeding, as well as prevention and treatment of diseases and conditions such as pneumonia, diarrhea, malaria, HIV/AIDS, and malnutrition. There are many low-cost prevention and treatment measures -- such as immunization, antibiotics, insecticide treated bed nets, and oral rehydration therapy -- that can be scaled-up to reduce infant and child mortality and improve their health.

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Water-Related Diseases

What it is:There are a variety of pathogens causing intestinal illnesses (e.g., diarrhea) that are transmitted through unclean water or poor sanitation. Rotavirus is the primary cause of acute diarrhea, accounting for 40% of hospitalizations among children under age five. Children -- especially those with poor health and nutritional status -- are particularly susceptible to dehydration from diarrhea because water represents a greater share of their bodyweight compared to adults. Diarrhea is also a leading cause of death during emergencies and natural disasters, which can cause the displacement of large populations into temporary shelters with polluted water and inadequate sanitation. Unsanitary conditions can also lead to cholera outbreaks, resulting from fecal-contaminated food or water. Cholera causes acute diarrhea, which can lead to death even in healthy adults.

The numbers:

  • Diarrhea is a leading cause of death among children under age five -- second to respiratory infections such as pneumonia -- resulting in about 1.5 million deaths in 2004 (16% of deaths to young children). This is down significantly from an estimated 5 million deaths among young children two decades ago.
  • Fifteen countries account for nearly three-quarters of all deaths due to diarrhea among children under five -- including the most (386,600) in India -- and 84% of such deaths occur in Africa and South Asia.
  • WHO registered 190,130 cases of cholera in 2008, including 5,143 deaths.
  • The share of people in developing countries with access to a source of improved drinking water rose from 71% in 1990 to 84% in 2008, though 884 million people -- 37% of whom live in Sub-Saharan Africa -- still lack access to clean water. In addition, about 2.6 billion people do not have improved sanitation facilities available to them.
  • Millennium Development Goal 7 calls for halving the share of the population without access to safe drinking water and basic sanitation by 2015.

Treatment: Treatment of diarrhea centers around fluid replacement to prevent dehydration (e.g., using a solution of oral rehydration salts). In addition, zinc may be provided, since episodes of diarrhea may create a deficiency of the mineral in the body, which is associated with higher rates of infectious diseases and mortality.

Prevention: Prevention involves improved water and sanitation, exclusive breastfeeding for the first six months of life, and promotion of hand-washing with soap. In addition, two rotavirus vaccines have been licensed for use in some countries, and WHO recommended in 2009 that rotavirus vaccination be included in national immunization programs.

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Food Insecurity

What it is:There is general agreement that sufficient food is available worldwide to feed everyone, but not necessarily an adequate distribution of resources. People considered undernourished are those who do not consume sufficient calories for an active life (about 2,100 calories per day). Malnutrition can result from an inadequate food supply or from insufficient intake of certain types of food (e.g., protein and micronutrients). Malnutrition increases the risk of certain diseases and can lead to premature death.

The numbers:

Causes: The underlying drivers of food insecurity include poverty, food prices, insufficient local infrastructure to grow and distribute food, natural disasters (e.g., floods and drought), and conflicts that displace people or interrupt food supplies. 

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Information provided by the U.S. Global Health Policy Program
Publish Date: 2010-03-29