An outbreak of cutaneous leishmaniasis due to Leishmania major in an endemic focus in central Iran

Abstract

Zoonotic cutaneous leishmaniasis (ZCL) caused by Leishmania major is an important endemic disease and a major public health concern in Iran. Following an outbreak of leishmaniasis in 2013 in one of the important foci in Iran, the researchers were prompted to determine the underlying causes of the epidemic. Adult sand flies were collected using sticky traps and aspirating tubes and infection with Leishmania parasites was evaluated. Also, rodents were captured using Sherman live traps and stray dogs were hunted and were tested for the presence of leishmanial infection. Active case detection was also conducted and data related to each household were recorded using a researcher-designed form. Nested PCR and PCR-RLFP techniques were employed to determine Leishmania infection in the samples. Phlebotomus papatasi was the most dominant species among the 7 different species of sand flies collected in this study. Sergentomyia clydei, Sergentomyia theodori, and Sergentomyia grekovi were identified for the first time in the study area. 20 of collected Ph. papatasi species and one Meriones libycus were infected with Leishmania major. Stray dogs demonstrated no lesions on different parts of their body. The relative frequency of active lesions and scars on the dogs were respectively 5.49 and 1.23 in 2013 and 5.82 and 0.56 in 2014. The highest number of ZCL cases due to L. major was recorded in Ardestan city. Phlebotomus papatasi is the main vector and M. libycus seems to be the primary reservoir host of ZCL in the suburbs of this city. Furthermore, due to the low density of rodent reservoir hosts in the study area, we support the hypothesis that humans may have had a role in maintaining the parasite cycle in the population.