Abstract
Leishmania spp are distributed throughout the world and different species are associated with varying degrees of disease severity. However, leishmaniasis is thought to be confined to areas of the world where its insect vectors, sandflies, are present. Phlebotomine sandflies obtain blood meals from a variety of wild and domestic animals and sometimes from humans. These vectors transmit Leishmania spp, the aetiological agent of leishmaniasis. Identification of sandfly blood meals has generally been performed using serological methods, although a few studies have used molecular procedures in artificially fed insects. In this study, cytochrome b gene (cytB) polymerase chain reaction (PCR) was performed in DNA samples isolated from 38 engorged Psychodopygus lloydi and the expected 359 bp fragment was identified from all of the samples. The amplified product was digested using restriction enzymes and analysed for restriction fragment length polymorphisms (RFLPs). We identified food sources for 23 females; 34.8% yielded a primate-specific banding profile and 26.1% and 39.1% showed banding patterns specific to birds or mixed restriction profiles (rodent/marsupial, human/bird, rodent/marsupial/human), respectively. The food sources of 15 flies could not be identified. Two female P. lloydi were determined to be infected by Leishmania using internal transcribed spacer 1 and heat shock protein 70 kDa PCR-RFLP. The two female sandflies, both of which fed on rodents/marsupials, were further characterised as infected with Leishmania (Viannia) braziliensis. These results constitute an important step towards applying methodologies based on cytB amplification as a tool for identifying the food sources of female sandflies.
Highlights
Sandflies are natural vectors of various pathogens, including Leishmania spp
polymerase chain reaction (PCR) amplification of cytochrome b gene (cytB) was performed using DNA extracted from 38 engorged Psychodopygus lloydi females
The PCR-restriction fragment length polymorphisms (RFLPs) profiles of cytB digested with the HaeIII endonuclease were indistinguishable from the
Summary
Sandflies are natural vectors of various pathogens, including Leishmania spp. These insects are distributed throughout most regions of the world and present significant biodiversity in the neotropics, where their density is dependent on weather conditions. The genus Psychodopygus Mangabeira, 1941 includes species of medical and veterinary importance, several of which are involved in the transmission of Leishmania braziliensis or have been reported to show anthropophilic behaviours (Ward 1977, Lainson & Shaw 1979, Gil et al 2003). This genus is restricted to jungle areas and, with few exceptions, is rarely associated with humans (Carvalho et al 2006). The study described evaluated bio-ecological features associated with female sandfly food sources and the detection of Leishmania sp. in sandflies collected at Ibitipoca State Park, in MG
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