Neglected Tropical Diseases (NTDs)

Commonly known as elephantiasis, lymphatic filariasis is a painful infection caused by nematodes (roundworms), which are transmitted through the bites of infected mosquitos. The worm larvae migrate to the lymphatic vessels where they develop into adult worms.

Also known as river blindness, onchocerciasis is a parasitic disease caused by a filarial work transmitted by bites of infected blackflies. In humans, the adult worms produce embryonic larvae that migrate to the skin, eyes, and other organs.

Buruli ulcer is caused by Mycobacterium and is an environmental bacterium that produces a unique toxin – mycolactone – that causes damage to the skin. Early diagnosis and treatment are essential to minimize morbidity and prevent long-term disability.

Chagas disease, also known as American trypanosomiasis, is an illness caused by the protozoan parasite Trypanosoma cruzi. It is mostly transmitted when humans come into contact with faeces and/or urine of infected triatomine bugs, which are blood-sucking.

Dengue and Chikungunya are mosquito-borne viral infections common in warm, tropical climates. The infections are caused by any one of four closely related viruses – dengue is caused by Flavirideae flavivirus and chiungunya by Togaviridae alphavirus.

Guinea-worm disease is caused by the parasitic worm Dracunculus medinesis, which is the largest tissue parasite that affects humans. Guinea-worm disease is transmitted by drinking contaminated water from ponds or shallow, open wells.

Echinococcosis is a parasitic disease that is transmitted when humans ingest parasitic eggs from the tapeworms Echinococcus granulosus and Echinoccocus multilocularis, which are found in the faeces of dogs, foxes, and other carnivores which harbour the adult worms in their intestines.

Foodborne trematode infections are caused by a group of parasites that, when ingested by humans via the consumption of contaminated food such as raw fish, crustaceans, or vegetables, cause infection that can result in severe liver and lung disease.

Human African trypanosomiasis (HAT), or sleeping sickness, is caused by trypanosome parasites that are transmitted by tsetse flies. HAT is only found in sub-Saharan Africa, and mostly affects poor rural populations.

The leishmaniases are a group of diseases that are caused by protozoan parasites from over 20 Leishmania species. The parasites are transmitted to humans via the bite of an infected female phlebotomine sandfly.

Leprosy, or Hansen’s disease, is caused by Mycobacterium leprae and is likely transmitted via droplets, from the nose and mouth, during close and frequent contact with untreated cases. Leprosy is curable, and early treatment can prevent disability.

Mycetoma is a progressively destructive inflammatory disease usually of the foot, although any part of the body can be affected. It is caused by certain bacteria and fungi found in soil and water, which may enter the body through a break or wound in the skin.

Rabies is a viral zoonotic disease transmitted through the bite of an infected animal that causes progressive and eventual fatal inflammation of the brain and spinal cord. Rabies is entirely avoidable with vaccines, medicines, and other technologies.

Scabies is an infectious skin disease caused by a mite called Sarcoptes scabiei. The microscopic mites can live on a person’s skin for months, reproducing on the surface and then burrowing into it to lay eggs, which causes an itchy, red rash to form on the skin.

Schistosomiasis, or Bilharzia, is an infection acquired when people come into contact with fresh water infested for the larval forms of parasitic blood flukes, called schistosomes. The microscopic adult worms live in the veins draining the urinary tract and intestines.

Soil-transmitted helminth (STH) infections are transmitted by eggs present in human faeces which, in turn, contaminate soil in areas with poor sanitation. The main species that infect humans are the roundworm (Ascaris lumbricoides), the whipworm (Trichuris trichiura), and hookworms (Necator americanus and Ancylostoma duodenale).

Snakebite envenoming is caused by toxins in the bite of a venomous snake or by having venom sprayed into the eyes by specific species of snakes that have the ability to spit venom as a defence mechanism.

Taeniasis and cysticercosis are caused by infection with the tapeworm Taenia solium. Taeniasis is caused by consumption of raw or undercooked, infected pork, and results in an intestinal infection. Cysticercosis is an infection of tissues such as muscles, skin, eyes, and the central nervous system, caused by ingestion of tapeworm eggs.

Trachoma is one of the leading infectious causes of blindness globally. It is caused by an intracellular bacterium called Chlamydia trachomatis and is transmitted by direct or indirect transfer of ocular and nasal discharges of infected people.

Yaws, or endemic treponematoses, is caused by the bacterium Treponema pallidum subspecies pertenue, and is a skin infection resulting in noncancerous lumps (papillomas) and ulcers.