Neglected tropical diseases, or NTDs, are a group of parasitic and bacterial infections that affect over 1.4 billion people worldwide. Closely linked to poverty, these diseases are often disabling or fatal if left untreated. Below are brief explanations of 17 major neglected tropical diseases.  Beyond their devastating impact abroad, many of these diseases are emerging in the United States.


Ascariasis is caused by parasitic roundworms. It can lead to abdominal pain, fever and a rare form of pneumonia if the worms enter the lungs.

Buruli ulcer is a bacterial infection that leads to the formation of large skin ulcers. If left untreated, it can cause irreversible deformities, restricted joint motion and skin lesions.

Chagas disease is spread through bloodsucking insects (kissing bugs). When a person is initially infected, they may experience mild symptoms such as swelling near the bite and fever. Several years later, Chagas causes digestive problems, enlarged liver and spleen, enlarged lymph nodes and heart abnormalities that can eventually lead to heart failure.

Cysticercosis is a parasitic infection that occurs when an individual ingests tapeworm eggs found in contaminated food. When worms move throughout the body, they can cause seizures as well as decreased vision, heart abnormalities and spinal damage.

Dengue fever is a virus spread by mosquitoes that begins with a sudden high fever (commonly up to 105 degrees) and a rash. Dengue is often called "break bone fever" because patients experience severe muscle and joint pain.

Echinococcosis is a parasitic infection that occurs when humans ingest the worm eggs in contaminated food. The infection leads to the formation of cysts in the liver, although cysts can also form in other organs such as the brain, kidney, spleen and lungs. 

Fascioliasis is a parasitic infection that occurs when humans ingest eggs in contaminated food or water. Adult worms migrate to the liver, causing high fever, abdominal pain and skin rashes. In the long run, the infection can permanently damage the liver and gall bladder.

Guinea worm disease is a parasitic worm infection that occurs when humans ingest eggs in contaminated water. The worms grow within the body, eventually reaching lengths of 2-3 feet. When fully mature, the worms come out of the body through the legs or feet in a slow, painful and often disabling process.

Human African trypanosomiasis, commonly known as sleeping sickness, is a parasitic disease transmitted by an insect that primarily exists in Africa. Initially, symptoms include fever, headaches and joint pain. Eventually the disease affects the central nervous system, causing seizures and coma, and is ultimately fatal.

Leishmaniasis is spread through sand flies and there are two major kinds: cutaneous and visceral. Cutaneous leishmaniasis causes disfiguring skin sores, difficulty breathing and ulcers in or around the mouth. Visceral leishmaniasis is more severe and can cause fever, enlarged spleen, liver and lymph nodes and other damage to internal organs.

Leprosy is a bacterial infection that causes discolored skin lesions. The infection can also cause muscle weakness and nerve damage that leads to numbness in hands, arms and legs.

Lymphatic filariasis, commonly known as elephantiasis, is a parasitic infection transmitted through mosquitoes. The parasite later develops into an adult worm, which can block lymphatic vessels (vessels that drain fluid from various parts of the body) and results in extreme swelling in the limbs. If not treated in time, the swelling is irreversible. Many people with elephantiasis also experience kidney damage.

Onchocerciasis, or river blindness, is a parasitic disease transmitted by insects that live mainly in fertile river areas. Symptoms include skin rashes and lesions, skin discoloration and severe visual impairment or blindness.

Schistosomiasis is a parasitic infection that is primarily transmitted when an individual drinks contaminated water. Depending on the type of infection, symptoms range from fever, enlarged lymph nodes, rash and abdominal pain. In the absence of treatment, it can lead to bladder damage, liver damage, chronic kidney failure and even seizures.

Toxocariasis is caused by parasitic roundworms in dogs and cats and mainly affects children. It can cause fever, abdominal pain, rash and a cough. In severe cases, it can lead to vision impairment and if the roundworms infect the brain or heart, can lead to neurological damage and heart failure.

Trachoma is a bacterial eye infection that can lead to painful and irreversible blindness. Exposure to the bacteria causes eye inflammation that eventually turns the eyelashes inward, scratching the cornea and leading to scarring and vision impairment.

Yaws is a bacterial infection transmitted through skin contact with infected individuals. The primary symptom is severe skin lesions that lead to permanent disfigurement.

Neglected Tropical Diseases