| Summary: | <p>Abstract</p> <p>Background</p> <p>Visceral leishmaniasis (VL) has been known to exist in northwest Ethiopia (Humera-Metema lowlands) since the early 1970s associated with large scale agricultural development activities, often resulting in outbreaks. The latest outbreak of the disease that has started around 1995 in both regions, has led to the present preliminary entomological surveys (1996-2005) the results of which are reported here. Sandflies were collected using CDC light traps and <it>Phlebotomus </it>females were dissected for <it>Leishmania </it>detection and isolation; freshly fed <it>Phlebotomus </it>females collected were subsequently tested for their blood meal sources using ELISA. All <it>Phlebotomus </it>collections were identified to species.</p> <p>Results</p> <p>During the surveys (1996-2005), a total of 1963 sandflies of six <it>Phlebotomus </it>species (<it>P. orientalis</it>, <it>P. papatasi</it>, <it>P. bergeroti, P. duboscqi</it>, <it>P. rodhaini </it>and <it>P. alexandri</it>) were recorded from the study areas: the predominant species was <it>P. orientalis </it>in both localities. None of the total 618 <it>P. orientalis </it>females dissected (506 from Metema and 112 from Humera), nor the total 114 females of four other species dissected (<it>P. papatasi</it>, <it>P. duboscqi</it>, <it>P. bergeroti </it>and <it>P. rodhaini</it>) was infected with <it>Leishmania </it>promastigotes. ELISA-based blood meal analysis of 273 fresh fed <it>P. orientalis </it>females collected from Metema revealed a remarkably high bovine blood feeds (92%) with only 2.2% of human blood feeds.</p> <p>Conclusion</p> <p>Based on abundance and other circumstantial evidences (its proven role in Sudan), <it>P. orientalis </it>is the most likely vector of VL in northwest Ethiopia, pending further clarifications. The zoophagic feeding behaviour of <it>P. orientalis </it>detected in the present study could have epidemiological significance, but more investigations are required in this and other behavioural characteristics towards appropriate management of the vector.</p>
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