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| Bilharzia | |
 | |
| Schistosoma mansoni, couple (left), female (center) and male (right). | |
| Information | |
| Region (s) | Africa, central America and Caribbean, Asia |
|---|---|
| Cause | Parasitosis (Schistosoma) |
| Vector | bathing water |
| Contagiousness |  no |
| CIM-10 | B65 |
| CIM-9 | 120 |
| Handicap: | genital lesions, paraplegia |
| Prophylaxis: | |
| * vaccine |  yes (in phase III) |
| * medication | no |
| Therapy: | Yes |
| Location | |
 | |
| Geographical areas of bilharzia. | |
 Medical warning | |
The bilharzia also called schistosomiasis Where swimmer's dermatitis is a parasitosis caused by a blood-sucking worm of the genus Schistosoma transmitted during swimming, especially in Africa, in fresh and calm water. Without adequate treatment, this disease can become chronic.
Understand
Genre Schistosoma contains 18 species of blood-sucking worms, five of which are pathogenic for humans, and is responsible for the second parasitic endemic worldwide after the malaria.
For its development, the parasite needs two different hosts: an intermediate host which is a freshwater mollusc and a definitive host which is a mammal. Penetration into mammals is transcutaneous, during periods of swimming in fresh and stagnant water.
Morphologically, the female is longer but thinner than the male, measuring 15 to 25 mm and is cylindrical in shape. The male, flat, measures 8 to 12 mm. Both wear suction cups. When the female reaches her sexual maturity (six to ten days after penetration), it wraps around the male and is permanently lodged in the gynecophoric duct (a kind of gutter on its ventral face of the male which is used to receive the female at the time of mating) of the latter.
Parasite protection
The best protection against the parasite is to avoid swimming in soft, calm waters, especially if these contain shellfish.
There is also a vaccine, Bilhvax, but this one, currently in the testing phase on large populations, is only intended for children between six and nine years old and for people who have already suffered from this parasitosis.
Diagnostic
Symptoms
The first symptom is papular, itchy dermatitis of the parts in contact with water during swimming (mainly the feet and legs). May follow abdominal pain, cough, diarrhea, a feeling of general fatigue, fever.
Clinical signs
Clinical signs may show a eosinophilia, a hepatosplenomegaly, mild anemia, cystitis and an urethritis as well as pulmonary arterial hypertension. The definitive clinical sign is the presence of granulomas (cell papules) containing parasite eggs in the stool.
Therapy
Since the 1970s, the use of praziquantel has been shown to be effective and inexpensive, but beware of side effects which will be proportional to the parasite load. Niclosamide (administered as a first-line treatment for tapeworms) is also effective, but to a lesser extent. In the absence of praziquantel, the use of therapy containing a artemisinin derivative is also very effective when the schistosome is still in the juvenile stage, that is, for two to four days after penetration and when it is still in the dermal region. Please note that if you are already taking a antimalarial prophylactic drug, it is necessary, then, to stop taking it, unless otherwise advised by a doctor who has analyzed the medical risk.
However, since none of these therapies kill the parasite's eggs, annual medication with praziquantel is still necessary to prevent the disease from becoming chronic.
- Biltricide®
single annual dose or treatment for a single day with divided doses. 
box of 6 tablets of 600 mg quadrisecables - Belgium: parallel marketing - France: 26,3 €. – Drug information.
single annual dose or treatment for a single day with divided doses
box of 6 tablets of Possible consequences
Without treatment, the disease can become chronic but also lead to pulmonary arterial hypertension, lesions of the central nervous system, the genital system (especially in women) or the musculoskeletal system, which can go as far as paraplegia. . These lesions are due to granulomas present in the brain or in the spinal cord which is the site of the ectopic eggs and an important node in the transmission of messages from the brain to the rest of the body.
Remarks
- praziquantel is contraindicated during the first three months of pregnancy or during breast-feeding.
- Chloroquine (antimalarial) reduces the bioavailability of praziquantel.
Further information
- Media center, Schistosomiasis – The bilharzia page on the WHO website.
