Neglected tropical diseases (NTDs) comprise several diseases that have a range of effects, from extreme pain to permanent disability to death. Here are some examples:
Caused by a parasitic roundworm called Ascaris lumbricoides, ascariasis is common in areas where sanitation and hygiene are poor. The disease often causes only mild symptoms (or no symptoms at all), but in cases of high worm infestation, ascariasis can lead to severe abdominal pain, vomiting, restlessness, and sometimes death.
Caused by Mycobacterium ulcerans, an organism from the same family of bacteria that causes tuberculosis and leprosy, Buruli ulcer can lead to massive skin ulceration, usually on the legs or arms. If untreated, the disease can spread to the bones and cause long-term disability.
Chagas' disease (American trypanosomiasis)
Caused by a parasite transmitted by blood-sucking “assassin bugs,” Chagas' disease can lead to swollen lymph nodes and organ damage.
Dracunculiasis (guinea-worm disease)
Contracted by drinking water contaminated with larvae of the parasitic worm Dracunculus medinensis, dracunculiasis can cause painful, erupting blisters as the worms emerge through the skin.
An infectious disease carried by mosquitoes and caused by any of four related dengue viruses. Formerly called "break-bone" fever, dengue can cause severe joint and muscle pain. Left untreated, patients may experience hemorrhage and shock, leading to death. Read more about dengue fever.
A common parasitic roundworm infection, hookworm disease can be contracted by walking barefoot on soil contaminated by feces. Symptoms of the disease include diarrhea, abdominal pain, and nausea. Chronic, or long-lasting, hookworm infections can cause severe blood loss and anemia.
Human African trypanosomiasis (sleeping sickness)
Caused by a parasite transmitted from tsetse flies, human African trypanosomiasis can lead to headaches, fever, weakness, and stiffness. If untreated, the parasite migrates to the central nervous system, causing seizures, psychiatric disorders, and ultimately death.
A parasitic disease transmitted by infected sand flies, leishmaniasis can cause skin ulcers or lesions and swelling of the spleen and liver. Read more about leishmaniasis.
Leprosy (Hansen's Disease)
A chronic infectious disease caused by mycobacteria, leprosy can lead to permanent damage to the skin, nerves, limbs, and eyes. Read more about leprosy (Hansen's Disease).
Lymphatic filariasis (elephantiasis)
A parasitic worm disease spread from human to human by mosquitoes, lymphatic filariasis can lead to disfiguring swelling of the legs, scrotum, and breast.
Onchocerciasis (river blindness)
A parasitic worm disease spread by infected black flies, onchocerciasis can cause extreme itching, blindness, and skin lesions.
A parasitic worm disease transmitted by fresh water snails, schistosomiasis can lead to blood in the urine, impaired growth, and malfunctioning of the kidney, liver, and spleen. Read more about schistosomiasis.
Caused by the bacterium Chlamydia trachomatis, trachoma can lead to scarring of the inside of the eyelid. If untreated, the disease can lead to irreversible blindness.
Trichuriasis (whipworm disease)
Contracted by ingesting soil or vegetables contaminated with feces containing whipworm eggs, trichuriasis can cause dehydration and anemia and impair growth and cognition.