Detection of Leishmania infantum and identification of blood meals in Phlebotomus perniciosus from a focus of human leishmaniasis in Madrid, Spain

Abstract

Since 2010, the number of cases of both human visceral leishmaniasis and cutaneous leishmaniasis in southwestern Madrid region (Spain) and more specifically in the town of Fuenlabrada has increased. Direct xenodiagnosis of leishmaniasis proved that hares (Lepus granatensis) from this focus are able to infect with Leishmania infantum colonized Phlebotomus perniciosus. To a better understanding of this focus of leishmaniasis, we conducted an entomological survey using CDC light traps, at the end of the seasonal transmission period of 2011 before the beginning of control measures of the disease, to study the phlebotomine sand flies species involved. Detection of Leishmania DNA in the sand flies captured was studied by kDNA-PCR and cpb-PCR. In addition, blood fed and gravid female P. perniciosus were analysed by a PCR based in vertebrate cytochrome b (cyt b) gene. Taxonomic identification of captured sand flies (n = 174) as P. perniciosus (n = 171) and Sergentomyia minuta (n = 3) together with the analysis of blood feeding in ten sand flies that shows a high preference for hares (n = 6), followed by humans (n = 3), and cats (n = 1) confirm a strong association between P. perniciosus hares and humans in the focus. Moreover, 79 out of 135 (58.5 %) P. perniciosus were positive to L. infantum by PCR approaches. These data support the increase of human leishmaniasis cases in the area and the existence of an unusual sylvatic cycle alternative to the classical domestic one, where the dog is the main reservoir of L. infantum.