|MadSci Network: Earth Sciences|
Dear Michael: I have been asked to answer your question about bilharzia. bilharzia, or schistosomiasis, is caused by several species of blood fluke. These are worms of the family Schistosomatidae, of the Class Trematoda, commonly known as flukes. The species of schistosome causing bilharzia in Africa is Schistosoma mansoni, and is also found in South America. As an aside, this divided distribution of members of this species is one of the kinds of evidence that were used to show that the Atlantic Ocean was once closed. Bilharzia is commonly transmitted when human feces from infected persons are used as fertilizer. This allows the eggs of the flukes to enter water where they hatch and parasitize certain kinds of snails. The flukes reproduce in the snails, producing a form that can parasitize people through skin contact in water. Thus, if the fluke is present in the Western Cape region and human feces are used for fertilizer then the disease is almost certainly present. I think the quickest way to find out for certain would be to contact South Africa's public health office in Cape Town. You might also ask a local doctor who treats infectious diseases. Finally, if you search the internet for schistosomiasis you will find hundreds of entries. This might be a slow way to find the information you want, but if you cannot find a doctor or public health official to help you, then you ought to be able to get the information you need off the Internet. I got the basic information I quoted above about trematodes from two books: Keeton, W. T., 1972, Biological Science, 2nd Edition, W. W. Norton Co., New York. Barnes, R. D., 1974, Invertebrate Zoology, 3rd Edition, W. B. Saunders Co., Philadelphia. Any good biology book will include this kind of information about flukes. I hope this has been of help. David C. Kopaska-Merkel
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