Neglected Tropical Diseases
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USAID, CDC, and WHO co-hosted a Stakeholders’ Meeting on the President’s Initiative for NTD Control on October 20–21, 2008, in Washington DC. Click here for more details.
Source: Andrea Peterson, 2007 |
Read a Statement by President Obama on the Global Health Initiative - 05/05/09
On February 20, 2008, former President Bush challenged the world to reduce and eventually eliminate the burden of neglected tropical diseases (NTDs) as a major threat to health and economic growth in the developing world. The new President's Initiative for NTD Control will increase the United States' commitment to NTDs from
$15 million in 2008 to $350 million over five years. These funds will provide integrated treatment to more than 300 million people in Africa, Asia, and Latin America. In addition, the new Initiative will expand the targeted number of countries from 10
in 2008 to approximately 30 by 2013.
Fact Sheet: USAID Fights Neglected Tropical Diseases – 02/22/08
Seven targeted NTDs:
Lymphatic Filariasis
Lymphatic filariasis (LF), a mosquito-borne disease, is caused by the infection of parasitic nematodes Wuchereria bancrofti (W. bancrofti), Brugia malayi (B. malayi), or Brugia timori (B. timori). Because the burden of the disease is determined by the intensity and the chronicity of the infection, the greater impact of LF is on older age groups. People with the disease can suffer from disfigurement and permanent disabilities due to lymphedema (swelling from fluid build-up caused by improper functioning of the lymph system). Elephantiasis is a crippling condition in which limbs or other parts of the body are grotesquely swollen or enlarged, and in men, swelling of the scrotum is called hydrocele. In addition, people with the disease suffer from hidden, internal damage to the kidneys and lymphatic system caused by the filariae. Furthermore, the psychological and social stigma associated with the disease is significant and can adversely affect productivity and quality of life.
More than 120 million people are currently affected by the disease, with 40 million suffering from serious incapacitation and disfigurement. More than 90 percent of infections are due to W. bancrofti. Currently, one-third of the people infected with the disease live in India; one-third are in Africa, and one-third are in South Asia, the Pacific, and the Americas. Over the past decades, the prevalence of bancroftian filariasis has decreased significantly in Latin America. Endemic foci persist in several islands in the Caribbean (Haiti, Dominican Republic, and Trinidad and Tobago) and coastal areas of South America (Brazil, Guyana, and Suriname). However, more concerning is that there are more than 1 billion people at risk in more than 80 countries. In tropical and subtropical areas, where lymphatic filariasis is well-established, the prevalence of infection is continuing to increase. In endemic communities, 10 to 50 percent of men and up to 10 percent of women can be affected.
Referral networks for management of acute bacterial adenolymphangitis and for patients with advanced lymphedema or lymphedema complicated by other diseases include:
Onchocerciasis
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Skin lesions with depigmentation
Source: APOC |
Onchocerciasis, also called river blindness, is an infection caused by the parasite Onchocerca volvulus (worm), spread by the bite of an infected blackfly (Simulium). The disease itself is not a direct cause of mortality, but the socioeconomic consequences of onchocerciasis are profound. In 2002, the global disease burden was estimated to be 0.95 millions disability-adjusted life–years. Onchocerciasis-induced blindness is associated with a life expectancy that is at least 10 years shorter than that of nonblind individuals in the same area. Unfortunately, the consequences of onchocerciasis extend beyond the individual and affect the family, the community, and the country.
The World Health Organization's (WHO's) expert committee on onchocerciasis estimates that approximately 50 million people are at risk of contracting the disease. Presently, there are about 17.7 million infected, of whom about 270,000 are blind and another 500,000 are suffering from some form of visual impairment. More than 99 percent of all cases of onchocerciasis and onchocerciasis-related blindness are found in Africa. Isolated foci of the disease also exist in Yemen and in six countries in Central and South America. Onchocerciasis in casual travelers is rare since, unlike malaria, contracting onchocerciasis requires more than one infectious bite. The infection is mostly transmitted in rural areas.
Success
Story: Onchocerciasis Control Program Ends Its
Work in West Africa
Schistosomiasis
Also known as bilharzia, schistosomiasis is a disease caused by parasitic worms and is considered second only to malaria as the most devastating parasitic disease in tropical countries. Schistosomiasis can be found in some 74 tropical countries in Africa, the Caribbean, South America, East Asia, and in the Middle East, with more than 600 million people at risk of infection and more than 200 million people infected worldwide. Schistosomiasis is associated with renal and bladder dysfunction (Schistosoma haematobium) or liver and intestinal disease (Schistosoma mansoni, Schistosoma japonicum, Schistosoma mekongi, and Schistosoma intercalatum) in affected populations.
Once infected, the symptoms associated with urinary and intestinal schistosomiasis are caused by the eggs that remain trapped in body tissues. Sickness due to schistosoma infection differs between the acute stages of infection and the later disease caused by chronic infection. Although schistosomiasis is not yet eradicable, the disease can be prevented and transmission controlled with a single annual dose of the drug praziquantel or two doses of praziquantel. Additional control measures, including improved water and sanitation, as well as reduction or elimination of intermediate host snails, could sustain and/or enhance control of transmission in endemic areas.
Soil-Transmitted Helminthiasis (whipworm, hookworm, and roundworm)
The human whipworm (Trichuris trichiura or Trichocephalus trichiuris) is the third most common roundworm found in humans. The name "whipworm" refers to the shape of the worm; the worms look like whips with wider "handles" at the posterior end. There are an estimated
800 million people infected worldwide. It is also highly prevalent in children. Co-infection of whipworm with Giardia, Entamoeba histolytica, Ascaris lumbricoides, or hookworm is common.
Human hookworm infection is a soil-transmitted helminthes infection caused by nematode parasites Necator americanus, Ancylostoma duodenale, or both. Mild infections with hookworm cause mild diarrhea and abdominal pain. More severe infections with hookworm can create serious health problems for newborns, children, pregnant women, and persons who are malnourished. Hookworm infection is the leading cause of anemia and protein malnutrition in developing nations, afflicting an estimated 740 million people.
Ascariasis, or roundworm, one of the most common human helminthic infections, is caused by the intestinal parasite Ascaris lumbricoides, affecting an estimated 1 billion persons at any one time worldwide. It affects 50 percent of populations in tropical and subtropical areas. Globally, ascariasis causes an estimated 20,000 deaths per year.
Trachoma
Trachoma is the result of infection of the eye with Chlamydia trachomatis (C. trachomatis). It is the leading cause of infectious blindness worldwide. In 2008, it has been estimated that 1.2 billion people live in endemic areas; 40.6 million people are suffering from active trachoma, and 8.2 million have trichiasis. More than 48 percent of the global burden of active trachoma is found in five countries: Ethiopia, India, Nigeria, Sudan, and Guinea. Fifty percent of the global burden is concentrated in three countries: China, Ethiopia, and Sudan. WHO estimates that 8 million people worldwide have been visually impaired by trachoma. In Africa, the prevalence of infection has been shown to reach 40 percent. The economic impact of trachoma has been estimated at $2.9 billion per year.
C. trachomatis spreads through direct contact with the eye, nose, or throat secretions of infected people. It is very contagious and almost always affects both eyes. Infection is frequently passed from child to child and from child to mother, especially where there are shortages of water, numerous flies, and crowded living conditions.
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