Neglected Tropical Diseases Quick Facts


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  • Neglected tropical diseases (NTDs) are widespread in the world’s poorest regions, where water safety, sanitation, and access to health care are substandard.
  • An estimated 1 billion people—approximately one-sixth of the world’s population—suffer from at least one NTD.
  • NTDs are called “neglected” because they generally are not considered public health problems in wealthier nations and historically have not received as much attention as other diseases.
  • Some NTDs are found in parts of the United States, particularly among impoverished minorities.
  • NTDs comprise several diseases that have a range of effects, from extreme pain to permanent disability to death. Here are some examples:
    • Ascariasis: Caused by the soil-transmitted roundworm Ascaris lumbricoides, it can impair growth and cognition.
    • Buruli ulcer: Caused by Mycobacterium ulcerans, it can lead to massive skin ulceration.
    • Chagas disease (American trypanosomiasis): Caused by a parasite transmitted by blood-sucking “assassin bugs,” it 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, it causes painful, erupting blisters as the worms emerge through the skin.
    • Hookworm: Often contracted by walking barefoot on soil contaminated by feces, hookworm infections can causes blood loss and anemia.
    • Human African trypanosomiasis (sleeping sickness): Caused by a parasite transmitted from tsetse flies, it can lead to fever, weakness, stiffness, and death.
    • Leishmaniasis: A parasitic disease transmitted by infected sand flies, it can cause skin ulcers or lesions and swelling of the spleen and liver.
    • Leprosy (Hansen’s disease): A chronic infectious disease caused by bacteria, it can lead to permanent damage to the skin, nerves, limbs, and eyes.
    • Lymphatic filariasis (elephantiasis): A parasitic worm disease spread from human to human by mosquitoes, it can lead to disfiguring swelling of the legs, scrotum, and breast.
    • Onchocerciasis (river blindness): A parasitic worm disease spread from by infected black flies, it can cause extreme itching, blindness, and skin lesions.
    • Schistosomiasis: A parasitic worm disease transmitted by fresh water snails, it can lead to blood in the urine, impaired growth, and malfunctioning of the kidney, liver, and spleen.
    • Trachoma: Caused by the bacterium Chlamydia trachomatis, it can lead to scarring of the inside of the eyelid and blindness.
    • Trichuriasis: Contracted by ingesting soil or vegetables contaminated with feces containing whipworm eggs, it can cause dehydration and anemia and impair growth and cognition.
  • Despite their pervasiveness around the world, most NTDs are relatively easy to treat and can be prevented.
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