Molecular detection of Leishmania infantum in naturally infected Phlebotomus perniciosus from Algarve region, Portugal.

BACKGROUND & OBJECTIVES: In Portugal, Phlebotomus perniciosus and P. ariasi, (Subgenus Larroussius; Diptera: Psychodidae) are the proven vectors of leishmaniasis caused by Leishmania infantum. The Algarve Region in southern Portugal has been considered an endemic focus of leishmaniasis since 1980s. The main objective of the present study was to validate a molecular approach to detect Leishmania infection in phlebotomines based on DNA extraction from the female sandfly whole body, minus genitalia, followed by PCR for application on epidemiological surveys.

METHODS

In Algarve Region, from early May until early November 2006, sandflies were captured by CDC miniature light-traps. kDNA-PCR and ITS1-PCR were used to screen the presence of Leishmania DNA in female sandflies after species identification by entomological keys.

RESULTS

A total of 474 sandflies were collected in 108 biotopes. One female of P. perniciosus, the predominant species, was found infected with L. infantum reflecting an overall infection rate of 0.47%.

INTERPRETATION & CONCLUSION: PCR associated with morphological characterization of the sandflies will be a powerful epidemiological tool for the determination of the number of phlebotomines infected with Leishmania spp in nature. In addition, the simultaneous occurrence of dogs and P. perniciosus infected with L. infantum shows that Algarve continues to be an endemic focus of canine leishmaniasis. Furthermore, as P. sergenti and P. papatasi which transmit L. tropica and L. major, respectively were present, the future introduction of these two Leishmania species in southern region of Portugal should not be neglected.