Schistosomiasis, (also known as Bilharzia) an infection estimated to occur worldwide among some 200 million people, is caused by flukes - tiny flatworms- which are parasites of specific fresh water snails.
HOW THE DISEASE IS TRANSMITTED
Microscopic eggs deposited from human urine or faeces infect snails which in their turn release large numbers of minute free-swimming larvae (cercariae) that are capable of penetrating the unbroken human skin. The larvae develop into adult worms in human body organs. Even brief exposure to contaminated water can result in infection. Outbreaks of schistosomiasis have occurred among travelers as well as resident expatriates & Aid workers & volunteers in Brazil; Egypt, most of sub-Saharan Africa (particularly Malawi & Zimbabwe where most affected Australian travellers have acquired the infection) & southern China, the Philippines, & Southeast Asia. The greatest risk comes from wading or swimming in fresh water. Washing with contaminated fresh water can also transmit infection but it cannot be acquired in the sea or in well chlorinated swimming pools.
Most infections produce no obvious early symptoms so many people who develop chronic problems later cannot recall an acute infection. However, symptoms can occur within 2-3 weeks of exposure the most common being a non-specific flu-like illness with fever, headaches, weakness, aches & pains, nausea, diarrhoea, cough or gland swellings. Occasionally a skin itch may be noticed after swimming in infected water. Chronic infections cause disease of the intestines and/or bladder & sometimes the lung & liver. Very rarely the nervous system can be involved to produce convulsions or muscle paralyses.
PREVENTION & CURE
Since there is no practical way to distinguish infested from noninfested water, fresh water swimming in affected countries should be avoided. Water for washing can be made safe by heating it to 50° C (122° F) for 5 minutes or treating it with iodine or chlorine in the same way that water for drinking is treated will destroy cercariae. Filtering with a commercial water filter or even coffee filter papers may also remove the organisms. Since cercariae rarely survive longer than 48 hours allowing washing water to stand for 3 days will also render it safe. Vigorous towel drying after water exposure has been suggested as a way to remove cercariae in the process of skin penetration but while this is a useful precaution it is not a guarantee of protection & may give a false sense of security.
Diagnosis is made by finding the schistosoma worm eggs in urine or stool specimens or by finding antibodies in the blood. Such antibodies may not be detectable until after three months from the time of exposure. Currently there are no vaccines or drugs available for prevention but there is a highly effective, safe & simple treatment available to cure the infection before it has become chronic
The Travel Doctor-TMVC clinics are very much aware of the concerns regarding Schistosomiasis. Upon return from foreign travel, (especially Egypt or sub-Saharan Africa )if you think you may have been at risk whether by swimming in unchlorinated fresh water or by accidental exposure , be sure to see your doctor or a Travel Doctor -TMVC Clinic at least three months after exposure to undergo screening tests.