Amoebiasis
Amoebiasis, or Amebiasis refers to infection caused by the amoeba Entamoeba histolytica. The term Entamoebiasis is occasionally seen but is no longer in use; it refers to the same infection. Likewise amoebiasis is sometimes incorrectly used to refer to infection with other amoebae, but strictly speaking it should be reserved for Entamoeba histolytica infection. » Read more
Ascariasis
Ascariasis is an infection with Ascaris lubricoides, the intestinal roundworm, the most common worm infection in humans.
Ascaris eggs are found in the soil. Infection occurs when a person accidently ingests (swallows) infective ascaris eggs. Once in the stomach, larvae (immature worms) hatch from the eggs. The larvae are carried through the lungs then to the throat where they are then swallowed. Once swallowed, they reach the intestines and develop into adult worms. Adult female worms can grow over 12 inches (4.8 cm) in length. Adult male worms are smaller. Adult female worms lay eggs that are then passed in feces; this cycle takes between 2 and 3 months. Adult worms can live 1 to 2 years.
Infection occurs worldwide. It is most common in tropical and subtropical areas where sanitation and hygiene are poor. Children are infected more often than adults. In the US, infection is not common and occurs mostly in rural areas of the southeast.
Onchocerciasis
Onchocerciasis, also known as river blindness and Robles' Disease, is the world's second leading infectious cause of blindness. It is caused by Onchocerca volvulus, a nematode that can live for up to fifteen years in the human body though it can also live in other mammals. It is transmitted to humans through the bite of a black fly. The worms spread throughout the body, and when they die, they cause intense itching and a strong immune system response that can destroy nearby tissue, such as the eye. » Read more
Schistosomiasis
Diseases of liver, gastrointestinal tract and bladder caused by schistosomes, trematode worms that parasitize people. Infection is from infested water.
There are three main species of these trematode worms (flukes) --Schistosoma haematobium, S. japonicum, and S. mansoni -- that cause disease in humans. The larval forms of the parasite live in freshwater snails. The cercaria (form of the parasite) is liberated from the snail burrow into skin, transforms to the schistosomulum stage, and migrates to the urinary tract (S. haematobium), liver or intestine (S. japonicum, S.mansoni) where the adult worms develop. Eggs are shed into the urinary tract or the intestine and hatch to form miracidia (yet another form of the parasite) which then infect snails, completing the life cycle of the parasite. » Read more
Leishmaniasis
Leishmaniasis is a parasitic disease spread by the bite of infected sand flies. There are several different forms of leishmaniasis. The most common forms are cutaneous (cue-TAY-knee-us) leishmaniasis, which causes skin sores, and visceral (VIS-er-al) leishmaniasis, which affects some of the internal organs of the body (for example, spleen, liver, bone marrow). » Read more
Malaria
Malaria is an infectious disease caused by a parasite, Plasmodium, which infects red blood cells. Malaria is characterized by cycles of chills, fever, pain and sweating. Historical records suggest malaria has infected humans since the beginning of mankind. The name "mal 'aria" (meaning "bad air" in Italian) was first used in English in 1740 by H. Walpole when describing the disease. The term was shortened to "malaria" in the 20th century. C. Laveran in 1880 was the first to identify the parasites in human blood. In 1889, R. Ross discovered that mosquitoes transmitted malaria. Of the four species of malaria, the most serious type is Plasmodium falciparum malaria. It can be life-threatening. The other three species of malaria (P. vivax, P. malariae, and P. ovale) are generally less serious and are not life-threatening.
