Phlebotomus (Paraphlebotomus) alexandri: a probable vector of Leishmania infantum in Iran.

The incidence of human visceral leishmaniasis (VL) caused by Leishmania infantum, which is endemic in several parts of Iran, has recently increased in the Nourabad-Mamassani district of Fars province, in the south of the country. Between 2003 and 2005, 12,688 sandflies were caught in this focus, using CDC miniature light traps, sticky traps and aspirators, in an attempt to identify the main vector of L. infantum. When 120 of the parous, female Phlebotomus (Paraphlebotomus) alexandri caught were individually checked for Leishmania infection, in an assay based on PCR and kinetoplast minicircle primers (LINR4 and LIN17), five (4.2%) of the flies were found to be infected with L. infantum. Thirty-nine (32.5%) of the 120 blood-fed Ph. alexandri checked in an ELISA were found positive for human blood. Since Ph. alexandri was the third-most common species caught (representing over 17% of the total catch), was clearly anthropophilic, and was not infrequently infected with L. infantum, it is probably an important vector in the Nourabad-Mamassani focus. Although other sandfly species have been found naturally infected with promastigotes in Iran, Ph. alexandri is the first that has been proven to harbour L. infantum in the country.