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Herpetomonas muscarum , a trypanosomatid "bien de chez nous".Jean-Claude Dujardin1, Alan Fauconnier2†, Bruno Pichon3, Dominique Le Ray1 and Bernard Couvreur2. 1 Prins Leopold Instituut voor Tropische Geneeskunde, 155 Nationalestraat,B-2000 Antwerpen. 2 Nivelles Laboratoires ASBL, 24 rue de l'industrie, B-1400 Nivelles. 3 University College of Dublin, Belfield, Dublin 4, Ireland. † Corresponding author.Trypanosomatids are primitive flagellated protozoa that comprise the agents of life-threatening leishmaniasis, sleeping sickness and chagas disease but also purely insect-dwelling species that are harmless to humans. We investigated the presence of endemic monogenic trypanosomatids in flies collected in the southern part of Belgium. During the first study, a number of fly species from the Namur area were screened for the presence of flagellates in the digestive tract. Whereas various monogenic trypanosomatids are described from a number of fly species, flagellates were only seen in the greenbottle Lucilia caesar. On the basis of its morphology, the flagellate was temptatively identified as Herpetomonas muscarum. Electron microscopy (EM) examination revealed structures reminiscent of endosymbiotic bacteria. Interestingly, no trypanosomatid could be observed in Calliphora vomitaria and Sarcophaga carnaria, which ecological niches are related to that of L. caesar. In a second study, seven L. caesar specimens were collected in the Rance area (Botte du Hainaut) and examined. All of them were found infected. From 4 dissected guts, three isolates were successfully grown in BHI medium without added hemin or blood extract, suggesting the presence of a bacterial endosymbiont. Molecular and EM characterisation of the new strains are now underway. Bacterial endosymbiosis have been described in Neotropical Herpetomonas roitmani, Crithidia oncopelti and Blastocrithidia culicis. However, only a few strains are actually available for experimental work. Endosymbiosis is currently the subject of an intense research effort as it may provide insights into the origin of organelles such as the mitochondria and the chloroplast. Résumé d'une présentation orale donnée lors de la réunion annuelle de la Société Belge de Microbiologie du 9 novembre 2001. |
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