Molecular detection of Leishmania DNA and identification of blood meals in wild caught phlebotomine sand flies (Diptera: Psychodidae) from southern Portugal.

Background: Zoonotic visceral leishmaniasis caused by Leishmania infantum which is transmitted by phlebotomine sand flies (Diptera, Psychodidae) is endemic in the Mediterranean basin. The main objectives of this study were to (i) detect Leishmania DNA and (ii) identify blood meal sources in wild caught female sand flies in the zoonotic leishmaniasis region of Algarve, Portugal/Southwestern Europe.

Methods: Phlebotomine sand flies were collected using CDC miniature light traps and sticky papers. Sand flies were identified morphologically and tested for Leishmania sp. by PCR using ITS-1 as the target sequence. The source of blood meal of the engorged females was determined using the cyt-b sequence.

Results: Out of the 4,971 (2,584 males and 2,387 females) collected sand flies, Leishmania DNA was detected by PCR in three females (0.13%), specifically in two specimens identified on the basis of morphological features as Sergentomyia minuta and one as Phlebotomus perniciosus. Haematic preferences, as defined by the analysis of cyt-b DNA amplified from the blood-meals detected in the engorged female specimens, showed that P. perniciosus fed on a wide range of domestic animals while human and lizard DNA was detected in engorged S. minuta.

Conclusions: The anthropophilic behavior of S. minuta together with the detection of Leishmania DNA highlights the need to determine the role played by this species in the transmission of Leishmania parasites to humans. In addition, on-going surveillance on Leishmania vectors is crucial as the increased migration and travelling flow elevate the risk of introduction and spread of infections by Leishmania species which are non-endemic.