Ecoepidemiological characteristics of a hypoendemic focus of zoonotic cutaneous leishmaniasis in north Iran (southeast of Caspian Sea).

BACKGROUND & OBJECTIVES: Leishmaniasis is an endemic parasitic disease reported sporadically throughout Iran. Golestan province is one of the 17 zoonotic cutaneous leishmaniasis (ZCL) foci. In this study, ecoepidemiological characteristics of ZCL were investigated in Gonbad-e Kavus County, Golestan province of Iran.

METHODS: This cross-sectional study was carried out in three endemic villages and one ZCL-free village by exploiting a stratified random sampling methodology in 2013. To understand particular time-allocation and activity patterns, sandflies were entrapped twice per month using sticky traps from May to October 2013. Records of daily maximum and minimum temperatures (°C) obtained from the meteorological station were used to calculate accumulated degree days (ADD) for Phlebotomus papatasi sandflies using an online software, viz. degree-day calculator, available from the website of Integrated Pest Management, University of California. The computational ADD and expected stage appearance for P. papatasi sandflies were evaluated along with the phenological events. Human infection indices were investigated in the study areas as well.

RESULTS: In the entomological survey, a total of 13 different sandfly species were identified. Sergentomyia sintoni (66.8%) and P. papatasi (20%) were observed to be the most dominant species. Monthly activity of the different species of sandflies started from early May to mid-October, with two peaks observed in early July and mid- September, and the peak of hourly activity occurred at night (1900-2000 hrs). According to the phenological study, population dynamics of P. papatasi was completely in agreement with ADD required for the various stages of their growth. Epidemiologically, the highest incidence of ZCL was observed in the age group of 30-34 yr (29.4%).

INTERPRETATION & CONCLUSION: Higher incidence of the disease was seen in the northern and the northeastern parts of the province bordered by Turkmenistan. The most effective alternative for controlling the disease in this hypoendemic focus is health education regarding personal protection from infected P. papatasi. The long-term studies are imperative for better understanding and estimation of the factors affecting ZCL transmission in the endemic areas.