Transmission of Schistosomiasis

Schistosoma haematobium (urinary schistosomiasis) and S. mansoni (intestinal schistosomiasis) are microscopic parasites found in standing water.

Children are at greatest risk of becoming infected with this destructive disease because schistosomiasis is easily contracted while bathing or swimming in contaminated water. However, this disease can be transmitted simply through contact with contaminated water while performing daily chores, such as washing laundry, fetching water, and herding animals.

The parasite that causes schistosomiasis lives for years in veins near the bladder or intestines, where it lays thousands of spiny eggs that tear and scar tissues of the intestines, liver, bladder, and lungs. Damage to the urinary tract and intestine causes blood vessels to break creating internal bleeding. The blood resulting from internal bleeding carries the parasite eggs, which then enter the urine and stool.

When infected people, often children, urinate or pass feces in the water, the eggs are immediately released into the community water source. The eggs infect fresh water snails, such as the Bulinus, which than becomes an intermediate host. Inside the snails, the parasites develop and multiply; they are now able to re-enter the skin infecting new victims and continuing the cycle.

Community Impact

In the village of Kwa'al, Nigeria, like most rural communities in the developing world, there is only one water source. There are no alternatives if the source becomes contaminated. It is not a choice between the contaminated water and clean water for bathing, laundry, playing, or drinking; it is a choice between water contaminated with schistosomiasis and no water at all.

The blood in urine and stools is only one symptom of the damage caused by the infection. Victims of schistosomiasis suffer from stunted growth and poor school performance, as well as bladder dysfunction, kidney disease, and premature death. There is also increasing evidence of high rates of bladder cancer due to repeated schistosomiasis infections. The WHO states that bladder cancer is 32 times more prevalent in some areas of Africa than in the United States. Fatality usually occurs as a result of bladder cancer or intestinal bleeding.

Sadly, school-aged children shoulder the majority of schistosomiasis' consequences, especially poor growth and impaired cognitive function. For communities already burdened by poverty and ravaged by scourges such as malaria and HIV/AIDS, schistosomiasis is especially devastating.