The isolation of Leishmania tropica and L. aethiopica from Phlebotomus (Paraphlebotomus) species (Diptera: Psychodidae) in the Awash Valley, northeastern Ethiopia

Abstract

In a survey of Leishmania infections in phlebotomine sandflies in a highly suspected focus of leishmaniasis in the Awash Valley (northeastern Ethiopia) between January 1994 and August 1997, a total of 3307 females of 11 Phlebotomus species (P. orientalis, P. fantalensis, P. saevus, P. sergenti, P. gemetchi, P. alexandri, P. bergeroti, P. duboscqi, P. arabicus, P. martini, and P. rodhaini) were dissected. Promastigotes were detected in 17 females of three species (11 P. saevus, 4 P. sergenti and 2 P. arabicus). Of these, only two P. saevus (one from Upper Awash and one from Middle Awash) and three P. sergenti (from Upper Awash) positives were successfully isolated in culture and were typed by isoenzyme analysis. Four isolates (two each from P. saevus and P. sergenti) were identified as new zymodemes (Z) of L. tropica and one isolate from P. sergenti was typed as a new zymodeme of L. aethiopica. This is the first finding of natural infections of P. saevus and P. arabicus and the first evidence for the former to be a vector of L. tropica. This is also the first time P. sergenti has been implicated in L. tropica transmission in Ethiopia; the isolation of L. aethiopica from a Paraphlebotomus species (P. sergenti) is also a new record. The possible presence of human cutaneous leishmaniasis (L. tropica and L. aethiopica), and wild reservoir host(s) of the parasites, especially rock hyrax (Procavia capensis) in the Upper and Middle Awash Valley remain to be determined.

Distinct Transmission Cycles ofLeishmania tropicain 2 Adjacent Foci, Northern Israel

“…Thus, L. tropica and P. sergenti apparently originated in different continents and their geographic overlap probably arose at a later time. P. sergenti, P. (Larroussius) guggisbergi, P. (Paraphlebotomus) saevus, and perhaps P. arabicus are vectors in Africa ( 30 , 31 ). Since L. tropica variants from both foci develop in P. arabicus, but only the variant from the southern focus completes development in P. sergenti, we postulate that L. tropica was initially transmitted by P. arabicus or another permissive vector such as P. (Adlerius) halepensis ( 9 ).…”

Transmission and Epidemiology of Zoonotic Protozoal Diseases of Companion Animals

“…L. aethiopica causes ZCL and appears to be isolated to the highlands of Ethiopia. Reports identified this species at lower altitudes as well, indicating that the distribution is perhaps more widespread or that the area of endemicity is expanding (234). CL caused by L. tropica is considered anthroponotic.…”

Risk map for cutaneous leishmaniasis in Ethiopia based on environmental factors as revealed by geographical information systems and statistics

“…It is a zoonotic disease, in Ethiopia predominately caused by Leishmania aethiopica with the shrewmouse (small, herbivorous mammals in the order Hyracoidea) serving as the animal reservoir and Phlebotomus pedifer, P. longipes and P. sergenti as known vectors (Ashford et al, 1973;Gebre-Michael et al, 2004;Gadisa et al, 2007). The environmental factors affecting its eco-epidemiology are poorly understood.…”