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
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.
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
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.