[Bilharziasis or schistosomiasis].
Schistosomiasis has been known and described since Antiquity. However, the pathogens were not clearly identified until the 19th century for Schistosoma haematobium, the 20th century for S. mansoni, S. japonicum, then S. intercalatum and S. mekongi. The lastest identified species is a hybrid between S. haematobium and S. intercalatum (Gabon, Cameroon). Given the frequent population exchanges with Southeastern Asia, schistosomiases caused by S. japonicum and S. mekongi are given more and more importance. Major migrations, dam and irrigation schemes and the various control programs modify the prevalence of the different types of schistosoma. In the foci where different species coexist, phenomena of competition and hybridization have been reported. For certain species, the definitive animal hosts have not all been identified, which constitutes an additional obstacle in disease control. The evocative clinical signs are not observed until the acme. Before this stage, the clinical diagnosis is difficult to establish and the signs are misleading. In the invasive phase, the laboratory diagnosis is made based on serology, showing hypereosinophilia, while at acme, the diagnosis is confirmed by the finding of eggs with a spine. Currently, only praziquantel is used in clinical practice, both for individual treatments and mass treatment campaigns, despite the development of a resistance to this molecule in well-defined foci. Other therapeutic protocols based on artemether are being used. Control programs aiming at decreasing the incidence of schistosomiasis are hampered by the implementation of irrigation schemes favorable to the development of mollusks and to disease transmission.
Richard-Lenoble
Dominique
D
Service de parasitologie, CHRU hôpital Bretonneau, 37044 Tours. drl@med.univ-tours.fr
Duong
Thanh Hai
TH
D006801:Humans; D012552:Schistosomiasis / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology / Q000469:parasitology