LONDON (Reuters) - Neglected Tropical Diseases (NTDs) are a group of 17 diseases that disproportionally affect the very poor. The World Health Organisation estimates that more than a billion people worldwide are affected by NTDs, including more than 500 million children.
Thirteen major drugmakers made a joint announcement in London on Monday with the Bill & Melinda Gates Foundation, the U.S., British and United Arab Emirates governments and other international donor groups of a coordinated plan to control or eliminate 10 NTDs by the end of this decade.
Following are details on the 10 diseases:
* Blinding Trachoma
- A bacterial infection of the eye that causes the eyelids to scar and ultimately turn inward. It is the leading infectious cause of blindness in the world and affects around 40 million people in 57 endemic countries. Africa is the most affected continent and India, Brazil and China are the countries with the highest burdens outside Africa.
- A bacterial infection that causes severe and disfiguring damage to the skin, peripheral nerves, lining of the upper respiratory tract, eyes and other organs. Around 200,000 new cases of leprosy are reported each year, concentrated in 17 countries. Southeast Asia is the source of roughly two-thirds of newly reported cases. Brazil and South Sudan also have high rates of the disease.
* Sleeping sickness, or Human African Trypanosomiasis
- Transmitted by the parasite Trypanosoma brucei through the bite of the tsetse fly, sleeping sickness threatens millions of people in 36 countries in sub-Saharan Africa. The parasite multiplies in the lymph and blood, causing headaches, fever, weakness and pain in the joints. In time, the parasite migrates to the central nervous system and causes severe neurological and psychiatric disorders, eventually leading to death.
* Guinea worm disease, or dracunculiasis
- The largest nematode worm infection affecting humans, growing up to three feet in length. It is transmitted by drinking water containing a small crustacean that serves as an intermediary host. After growing in human tissues, the female worm emerges painfully through the skin, usually in the feet, to release larvae into water bodies. Most cases occur primarily in four endemic countries, South Sudan, Mali, Ethiopia and Ghana, with 97% of the burden occurring in South Sudan.
* Lymphatic filariasis, or elephantiasis
- A mosquito-borne worm disease usually acquired in childhood that manifests clinically in late childhood and early adulthood. When the worms grow large enough, they block the lymphatic system, potentially leading to lymph fluid buildup that causes radical and disfiguring swelling of limbs and genitals known as elephantiasis. Around 120 million people have lymphatic filariasis, with 1.3 billion at risk. The disease is concentrated in Southeast Asia and Africa with a significant burden in Brazil.
* Chagas disease, or American trypanosomiasis
- A chronic debilitating condition caused by a parasite transmitted by the infected feces of blood-sucking bugs. It can also be contracted through transfusion of infected blood, by organ transplantation or congenitally from an infected mother to her fetus. About 10 million people are infected and 25 million are at risk, primarily in Latin America - although cases are increasingly detected in the U.S., Canada and Europe from immigration. More than 10,000 die each year from this disease, mostly from cardiac complications.
* Visceral Leishmaniasis or kala-azar
- A parasitic infection spread by sandflies. Its most lethal form, visceral leishmaniasis attacks the internal organs and, if left untreated, is fatal usually within two years. Even when treated, the parasite can reemerge, infect the skin and cause disfiguring lesions. The disease is most prominent in East Africa, South America and Southeast Asia. There are an estimated 500,000 new cases each year, mostly in South Asia, Sudan, South Sudan, Ethiopia and Brazil. About 50,000 people die from the disease each year.
* Onchocerciasis, or river blindness
- A black fly-borne parasitic disease of the skin and eyes caused by a filarial worm. The disease causes skin lesions, severe itching and visual impairment, including permanent blindness, and can shorten life expectancy by up to 15 years. It is the second most common infectious cause of blindness after trachoma. An estimated 37 million people worldwide are infected with the pathogen and 90 million people are at risk. More than 99 percent of those infected live in 30 endemic countries in Africa. The remainder are in Yemen, or in various Central and South American countries.
Schistosomiasis or bilharziasis
- Another parasitic disease transmitted through water-borne parasitic worms. The majority of suffering and deaths associated with schistosomiasis is the result of slow damage to the host organs caused by accumulation of parasite eggs in the tissues over many years.
Schistosomiasis is present in the Americas, Africa, the Middle East, Southeast Asia and the Western Pacific. The disease is most prevalent in sub-Saharan Africa, which has more than 90 percent of cases. At least 200 million people are estimated to have schistosomiasis and 800 million live in endemic areas.
* Helminthiasis, or hookworm, roundworm, or whipworm
- Soil-transmitted helminthes (STH) are intestinal worms transmitted through fecal-oral contamination or through the skin. Heavy worm burdens lead to malnutrition, anemia, diarrhea, abdominal pain, weight loss, loss of appetite and impaired cognitive and physical development in children. More than a billion people in tropical and subtropical regions are estimated to be infected. While the disease causes relatively few deaths, around 300 million people suffer severe, debilitating symptoms.
Editing by Kate Kelland