Bilharzia ‒ an unnecessary ill
During the South African War, the Boers found an unexpected ally: 600 British troops were rendered fatigued, fevered and with severe abdominal pain – all within weeks of taking a dip in a river next to their encampment at the height of the summer heat.
The river was the Dusi. The cause – and their enemy’s unexpected ally – was a tiny nondescript snail carrying the schistosomiasis parasite, better known as Bilharzia.
In the heat of the Eastern Cape summer, people are always looking for places to cool off. If you’re on a farm, chances are your first choice is a dam. But chances are you could be taking a chance with your health.
Chris Appleton, Professor Emeritus at the University of KwaZulu-Natal, has spent a lifetime researching parasitic diseases - and now he’s determined to share what he knows as widely as possible.
He has been in Grahamstown as a guest of the Albany Museum’s Department of Freshwater Invertebrates and spoke about urogenital schistosomiasis, better known as Bilharzia, in this neck of the woods.
A January 2012 paper published in the Southern African Journal of Science (2012;108(1/2), Art. #411, 11 pages.http:// dx. doi. org/ 10.4102/ sajs. v108i1/2.411 ) titled: Why did schistosomiasis disappear from the southern part of the Eastern Cape? explains the science, and the data, in detail.
Grocott’s Mail asked him for the Idiot’s Guide – and he obliged, starting with why it matters so much.
“In rural areas in parts of South Africa you find a range of parasites in kids, especially Bilharzia and intestinal worms,” Appleton said.
“Bilharzia is the most common cause of haematuria (urine in the blood), and after malaria is the most serious parasitic infection in the world.”
Schistosomiasis is in fact a parasitic worm. The blood in the urine, often accompanied by dysuria (difficulty in pass- ing urine) and other symptoms are caused by the body’s reaction to its eggs.
Untreated, further damage to the bladder and ureter, kidneys, and even the liver and the lungs, can ensue.
Light infections often go unnoticed. But heavier infections can be very debilitating, says Appleton.
“A severe infection makes a person lethargic. Kids battle to concentrate at school and they can’t do their schoolwork.
“It affects productivity, which has a knock-on effect on earning capacity.“
In an information sheet the World health Organisation (WHO) says, “The economic and health effects of schistosomiasis are considerable and the disease disables more than it kills.”
The culprit is a blood fluke, a parasitic flatworm, and certain types of freshwater snails are the enablers.
But the gold for schistosomes is humans. There are five human schistosomes, with similar life cycles, starting off with… a pee in a dam…
“In 2003 researchers discovered a serious, but localised outbreak of schistosomiasis on farmlands near Jeffreys Bay,” Appleton said .
“What they figured out was that there was a farm dam in the area, fed by the Kabeljous river, where the kids all swam on their way home from school. For kids, it’s a natural reaction to pee when they’re in water.”
They think the Bilharzia got that far south thanks to a migrant fisherman from KwaZulu-Natal who was infected and at some stage also swam in the dam - and urinated
in it. Appleton Photo: Chris
Infected people pee out the parasite’s eggs. As they hit fresh water, they hatch into miracidium – a stage of the organism that can swim, and has fine hairs (cilia) that help it latch on to and penetrate the foot of a freshwater snail.
Inside the snail, it settles and multiplies into yet another form, cercariae.
A wading or swimming hu- man is the cercaria’s target. It latches on, breaks down your skin with enzymes to penetrate it and then travels via a tiny blood vessel (venule) to your lungs.
There it changes form again, migrates to your liver, where they happily feed on red blood cells before moving into the urogenital system.
They produce eggs - and the cycle starts again (with a swim and a pee).
If you were thinking this parasite was devious beyond belief, absorb this fact: the snails can esterate (burrow in mud) for up to six months until the next rain comes. When they emerge, they can still carry the infection. This is one reason why seasonal water can be harmful.
Is there anywhere safe?
“The maps show the heaviest transmission in this area to be in Port Elizabeth, East London and King William’s Town. Some maps do show Grahamstown,” Appleton said.
The article referred to earlier says that in the Eastern Cape today, it is only in the former Transkei that prevalences above 20 percent are routinely encountered.
“This observation was confirmed in 2000 through routine surveillance by the Eastern Cape Health Department,” the article says.
The southern limit of the disease, according to the 2012 article, is in the southern Transkei.
“Health Department surveillance suggests that it lies in the vicinity of Willowvale (±32°15’S), approximately 80km south-east of Mthatha.
“A prevalence of 9.1 percent was recorded there in 1994.”
Bilharzia was identified in 1851 by Theodor Bilharz during an autopsy conducted in Cairo. Only 11 years later, in Uitenhage, a doctor identified cases of schistosomiasis in the town.
“In those days doctors read their literature,” Appleton said wryly. Bilharzia disappeared for a long time, though. Or at least became less prevalent.
That meant fewer people knew about the disease, and how to recognise the snails capable of carrying the infection. And the puzzle why it disappeared is the subject of Appleton’s article.
“It seems to have been a climatic event,” he says. “In 1900 there was a very bad drought.”
It was general practitioners in the former Transkei who first started to diagnose it again.
However, while a national control programme exists, two factors are among those slowing the cure rate, Appleton says.
First, the Medical Control Council has designated the drug of choice, Proziquantal, as Schedule 4. This means only doctors and registered nurses may issue it under the Medicines Control Act.
“In other parts of Africa, where treatment has been very effective, lay people are delegated the responsibility of issuing the drugs.”
Having someone in a community – particularly in rural areas – to make sure people complete their treatment, Appleton says, has reduced Bilharzia considerably in other parts of the continent.
The other hold on treatment of Bilharzia is the cost of the drug.
The cost of Proziquantal is prohibitive for poor people in rural communities in South Africa. The frustrating thing for Appleton is that there are 17 generics available, which are all very effective, he says, but none of these is approved for use in South Africa.
Who is at risk?
• Paddlers and other recreational users of dams and rivers infected with schistosomiasis. • People in 46 African countries (among 76 countries worldwide where the parasite is endemic). Particularly school-aged children, because they spend a lot of time playing in infested waters. People fishing, or doing household chores are also at risk in rural communities.
According to a 2011 article in the South African Journal of Epidemoiological Infection, there were 4.5
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