Sunday, 13 November 2011

The Amazing Race 19, Episode 8

Senga Bay (Malawi) - Copenhagen (Denmark)

The Amazing Race 19 moved on from Africa to Europe this week without looking back. But if you tried to follow in the footsteps of the "reality" TV show, you'd probably have brought back more than just memories, souvenirs, and photos from your visit to Malawi.

As we saw on TV, the water in Lake Malawi looks clear and inviting. Let that be a lesson: You can't tell whether water is safe to drink or to swim in by how it looks to the naked eye.

One of the most widespread and serious of parasitic diseases, known as schistosomiasis or bilharzia, is endemic to Lake Malawi and all of the other lakes of the Rift Valley of eastern and southern Africa. The disease is caused by blood flukes (worms) that are carried by freshwater snails, enter the human body from the water by borrowing through the skin (eek!), and then reproduce within blood vessels and the body, mainly the liver, by feeding on blood.

Like malaria, schistosomiasis/bilharzia is rarely directly fatal, but if untreated it can persist indefinitely, producing a variety of chronic and debilitating effects. It takes days or weeks before symptoms become apparent, so it's often misdiagnosed in travellers when symptoms don't appear until well after they have returned home to a place where it's uncommon.

Among diseases caused by parasites, schistosomiasis/bilharzia may be exceeded only by malaria in its global impact on health. But unlike malaria, it's not something most travellers know to worry about. And it's not an infection for which there is any easy prophylactic treatment. (There are treatments for the disease, if you are infected, but only after the fact.) The only way to take precautions against infection with the parasites that cause this disease is never to swim or wade in potentially infected water. This includes any body of open fresh water in Africa or other infected regions -- lake, river, or irrigation ditch -- regardless of what local people tell you.

It's a major coup for promoters of the tourism industry in Malawi that The Amazing Race 19 included a challenge that required swimming in Lake Malawi, without mentioning the risk of schistosomiasis/bilharzia.

Medical researchers have reported that substantial percentages of Peace Corps volunteers, expatriate foreign citizens, backpackers, and other tourists who have lived in or visited Malawi show evidence of infection with the parasites that cause schistosomiasis/bilharzia.

Recognition of the risk of this waterborne disease would obviously be fatal to beach resorts along Lake Malawi. Some resort owners tell guests that that their particular part of the lake is safe, or give them prophylactic doses of antibiotics to take after their visit. But I wouldn't rely on advice from people with a financial interest in denying or minimizing the inherent danger.

Before you swim or wade in lakes, streams, or other fresh water in an unfamiliar part of the world, consult your own doctor and read the advisories about schistosomiasis/bilharzia from the World Health Organization and the U.S. Centers for Disease Control. Their advice is clear and unequivocal: "Avoid swimming or wading in freshwater when you are in countries in which schistosomiasis occurs."

Link | Posted by Edward on Sunday, 13 November 2011, 23:59 (11:59 PM) | TrackBack (0)
Comments

Edward, it's worth emphasizing that schistosomiasis is a specifically tropical disease, primarily (though not exclusively) in Africa. It is uncommon anywhere in the Americas, and of no concern to those visiting mid-latitude countries such as Argentina and Chile.

Posted by: , 28 November 2011, 09:23 ( 9:23 AM)
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