Schistosomiasis In Yemen [Archives:1998/02/Health]

January 12 1998

This parasitic disease, also known as bilharziasis, is endemic to much of Africa, the Middle East, South-East Asia, the Eastern Mediterranean and South America. Most of the people who would contract this in Yemen would be barefoot agricultural and dam workers and fishermen; the disease is transmitted through a skin lesion via an intermediate snail host found in contaminated waters. Many Egyptians are remembered to have contracted this disease during the construction of the Aswan dam because dam workers having lesions on their feet were exposed to the contaminated Nile waters.
The larval schistosome has also been introduced to peri-urban areas of cities in Africa. In Yemen the disease, which is third only to malaria and enteritis, is common in the capital, at Hodeidah and at Hajjah where 136,000 cases were registered in 1996. Two forms prevalent in Yemen are the intestinal variety or Schistosoma mansoni and the urinary one caused by S. haematobium. The intestinal form is also prevalent in neighboring Somalia where refugee migration north after the civil war has spread the disease. The urinary one has been linked to a form of bladder cancer. In fact, the occurrence of bilharzia induced bladder cancer is 32 percent higher than simple bladder cancer in the U.S.
The effects are also psychological as school performance drops and growth patterns of infected children are disturbed but 90 percent of the effects are reversible upon treatment. The disease also reduces worker performance by causing weakness. The urinary variety localizes in the veins of the urinary tract, after migrating there through the circulatory system. After two or three days the parasite migrates into the venous system and lays its eggs which then hatch and remain there. The infected individual eliminates the Sch. hematobium eggs through the urine or if infected by the intestinal variety, through the feces which then penetrate the antennae of an intermediate snail host. There they turn into the larval form. The miracide soon dies if it does not reach this host.
The disease is widely asymptomatic however gastrointestinal, hepatic and respiratory symptoms may occur. Diagnosis after a simple microscopic examination of the urinary sedimentation can reveal the parasite. Treatment of the disease is through antibiotics and praziquantel. Re-infection may then reoccur, however the risk of it developing into a severe disease are reduced.
Martin Dansky/ Yemen Times