Information on the Disease Schistosomiasis
Information on the Disease Schistosomiasis
Schistosomiasis (also known as Bilharzia) is a disease caused by small parasitic flatworms, species of trematodes of the family Schistosomatidae, which are commonly called blood flukes. The major types that cause schistosomiasis in humans are Schistosoma mansoni leading to intestinal schistosomiasis, S haematobium leading to urinary schistosomiasis and S. japonicum leading to Oriental or Asiatic intestinal schistosomiasis.
Persons can get schistosomiasis when their skin comes in contact with contaminated fresh water in which certain types of snails are living. Schistosoma eggs contaminate fresh water when infected people urinate or defecate in the water. The eggs hatch, and if certain types of snails are present in the water, the parasites grow and develop into snails. When the parasites leave the snail, they can survive in water for about 48 hours. The parasites penetrate the skin of persons who have contact with this water, such as when they are wading, Swimming, Bathing or washing. The parasites penetrate the skin, and, within several weeks grow inside the blood vessels of the body and produce eggs. Some eggs get into the urinary bladder or intestines and are passed into the urine or feces.
The body’s reaction to the eggs produces by these worms and not the worms themselves cause the symptoms of schistosomiasis. Within days after becoming infected, some people have rash or itchy skin, and within a month or two they may have fever, chills, cough and muscle aches. Most people, however, have no symptoms at all in this early phase after infection. Usually the eggs of the parasite go to the liver or pass into the intestine or urinary bladder. Rarely, eggs are found in the brain or spinal cord and cause seizures, paralysis, or spinal cord inflammation. After many years of repeated infection, the parasite can damage the liver, intestines, lungs or urinary bladder. Even without treatment, damage to these organs occurs only rarely in people such as travelers who have relatively short periods of exposure and who avoid reinfection.
At risk are not only the infected people but others can be also. Persons who live in or travel to areas where schistosomiasis occurs and who have skin contact with fresh water (rivers, streams or lakes) are at risk of getting schistosomiasis. Areas around the world with Schistosomiasis include Africa, some countries in Latin America, parts of the Caribbean, some countries in the Middle East, southern China,...