Impact of climate variability on the occurrence of cutaneous leishmaniasis in Khuzestan Province, southwestern Iran

Leishmaniasis, one of the most important parasitic diseases worldwide, is frequently cited with respect to health risks related to climate change. The current variability of the climate may have different impacts on the transmission of cutaneous leishmaniasis (CL) depending on the various Leishmania species. The number and distribution of CL cases in Khuzestan Province, Southwestern Iran was analysed over the 2010-2014 period with regard to temperature, humidity, rainfall, sunshine hours, evaporation and wind-related climate issues. During the study period, there were 4672 recorded clinical cases of CL, the incidence of which was found to fall into three types of areas, such as high, intermediate and low-level endemic areas. Compared to the intermediate and low-endemic areas, the hyper-endemic areas showed significantly variable meteorological data with regard to rainy days, maximum/minimum temperature and humidity. Decreased temperatures in the eastern part of this province were found to promote the disease towards its centre. We conclude that the meteorological variables and incidence data of CL indicate that the number of rainy days, maximum and minimum temperatures and relative humidity are significant variables that can predict CL incidence. Indeed, the substantial climatic variability occurring during the recent 5-year period (2010-2014) in Khuzestan Province could be the main reason for the change in epidemiology and transmission of CL.