Phlebotomus (Paraphlebotomus) alexandri, the probable vector of visceral leishmaniasis (kalaazar) in southern Iran

Visceral leishmaniasis (kala-azar), the most dangerous form of leishmaniasis, is endemic in some parts of Iran, e.g. Ardabil, Fars, East Azerbaijan, Bushehr and Qom provinces. In recent years, the incidence of VL has increased in the Nourabad-Mamassani district in Fars Province. This study was carried out to detect VL vectors and infection rates in this region over the 2003-2004 period. Sand flies were captured in the selected villages by means of sticky traps, aspirators and CDC miniature light traps. Heads and distal abdominal segments were used for species identification and other body parts were used for DNA extraction. We employed a semi-nested PCR technique to detect Leishmania, with specific kDNA primers (LIN R4 - LIN 17 – LIN19). Some specimens were dissected for leptomonad infection. A total of 12688 sand flies were collected. Phlebotomus (Paraphlebotomus) alexandri was the second most prevalent species (17.34%). The anthropophilic index of this species was 32.5%. Five cases (4.17%) of L. infantum infection were detected among the 120 P. alexandri examined by PCR method. We also observed two cases of leptomonad infection among the 112 dissected specimens. : High prevalence rates and anthropophilic index of P. alexandri plus its natural infection with L. infantum provide enough evidence to implicate this species as the main vector species of VL in the region and the second proven kala-azar vector in Iran. Besides, the Mahoor-Milaty district of Noorabad-Mamassani was identified as a new endemic focus.