Schistosomiasis is a parasitic infection. By definition, parasites require
hosts to complete their life cycles: in the case of Bilharzia, snails and us.
The Schistosomiasis parasite inhabits fresh water bodies across Africa,
Asia, South America, and some Caribbean islands. However, theheaviest
burden of the disease lies in sub-Saharan Africa. It occurs primarily in places
where there is poor sewage and sanitation management, resulting in the
contamination of water that people use for bathing, drinking, washing,
wading and other activities of daily life.Dr. Bilharz discovered the disease back in the 1840s, and since then the
names Bilharzia and Schistosomiasis have been used interchangeably.
Though most of the world has never heard of it, schistosomiasis infects over
200 million people worldwide. 20 million of those affected are seriously ill,
with life-threatening complications. Untreated, schistosomiasis infections
can produce serious long-term health problems and even death.The disease is caused by a trematode worm that infects a specific type
of snail host that lives in and alongside river, stream, pond and lake
shores. The two main species infecting humans in Africa are Schistosoma
haematobium, and Schistosoma mansoni. When human feces containing
schistosomiasis eggs end up in the water, the schistosomiasis egg hatch.
The hatchlings must then find and infect a snail host. Once inside the snail
host, the parasite completes another phase of its life cycle. This next phase
of the Schistosoma life cycle, known as the cercariae, leaves the snail in
a free-swimming state where it can survive up to three days looking for
its next host – us. The cercariae penetrate unbroken human skin – a good
reason to wear a rash guard and skip the skin-to-win approach to paddling
in Uganda.Once the cercariae penetrate the skin, they swim through the venous
blood system, where they take up residence in veins draining the liver, and
occasionally, the bladder. During this process the cercariae become adult
worms. These adult worms attach themselves to the blood vessels draining
the liver and bladder. The worms then copulate, producing eggs. Some
eggs will be excreted in feces to begin the life cycle again, while others
may become lodged in different organs of the body such as the liver,
bladder, brain, spinal cord, and brain. While the worms do not specifically
cause an immune response, the eggs do. Over time, the lodging of rogue
eggs in various body tissues can lead to serious complications such as
portal hypertension, irreversible liver damage, bladder cancer, or even
paralysis.Symptoms of Bilharzia infection include fever, malaise, diarrhea, shortness
of breath while exercising, and loss of weight. These symptoms do not
usually occur until several months after infection, often when a paddler’s
international travel holiday is over and they are home. There is a small
percentage of people who will have the above-mentioned symptoms, as
well as an itchy skin rash, within 2 weeks of being infected by cercariae.
These patients are having a hypersensitivity reaction to the worms migrating
through their tissues and require prompt treatment, as their condition can
worsen quickly and can be fatal without treatment.The good news is that effective treatment is available in both cases. The
small percentage of people experiencing the hypersensitivity reaction
(signaled by the itchy rash) will require treatment with praziquantel and
steroids immediately, as well as hospitalization to monitor treatment and
the patient. For the majority of people infected with schistosomiasis, they
need to be treated with praziquantel not sooner than 10 weeks after their
last exposure to infected water. The reason for the delay in treatment is
that the parasite is only susceptible to the drug during the adult phase
of its life cycle. Treating too soon will be ineffective. The required dose of
praziquantel is 40mg/per kilogram of body weight. This dose can be taken
at once, or divided into two doses taken 12 hours apart. Ensuring that you
have the correct timing and dosage of praziquantel for treatment is critical.Praziquantel is readily available in Uganda and other developing countries
and is quite cheap. In fact, if you wait to buy it in North America or Europe,
you will pay significantly more. Even if you have no symptoms many months
after paddling on the Nile, Zambezi or elsewhere in developing world,
it is highly advisable to treat yourself. There is no downside, and it may
ultimately save your health and your life!Words and photos: Jessie Stonedoctor river
by Dr. Jessie Stone
TECHNIQUE
Jessie Stone is an MD and kayaker. She is a graduate of New York Medical College and a three time member of the US Women’s Freestyle Kayak Team. She is also a factory team paddler for
Jackson Kayak and the founder of Soft Power Health, a non-profit healthcare delivery organisation based in Uganda.WHAT’S UP DOC?
One of the greatest things about Uganda is the Nile, but one risk of spending time
on this amazing river is getting infected with Bilharzia, aka Schistosomiasis. Doctor
Jessie shares information about this parasitic infection.By Je ssie Stone
DOCTOR RIVER
Besting Bilharzia