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

Abstract

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)(2011)(2012)(2013)(2014) in Khuzestan Province could be the main reason for the change in epidemiology and transmission of CL.

An investigation of the effects of environmental and ecologic factors on cutaneous leishmaniasis in the old world: a systematic review study

“…After evaluation, 45 full-text articles were removed, and 23 full-text articles met the eligibility criteria for the systematic review. Finally, after removing nine articles, 14 full-text articles were included in the systematic review (shown in Table 1) [1,6,9,11,12,[15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30]. Based on the findings, the effects of environmental factors on the incidence of CL in the Old World are discussed below.…”

“…CL incidence was higher in areas with daily rainfalls, maximum/minimum temperature and humidity, and these environmental factors occurred mostly in hyperendemic areas of CL compared to the lowendemic ones. The substantial climatic variability in 2010-2014 in Khuzestan Province, Iran, was mentioned as the main reason for the change in the epidemiology and transmission of CL [11]. In another study, Nikonahad et al…”

“…Weather patterns can provide a favorable condition for the propagation and transmission of leishmaniasis in endemic areas [11]. CL incidence was higher in areas with daily rainfalls, maximum/minimum temperature and humidity, and these environmental factors occurred mostly in hyperendemic areas of CL compared to the lowendemic ones.…”

“…Leishmaniasis is an important parasitic disease prevalent around the world with serious health effects related to weather conditions [11]. Spatial analyses in different studies have shown that environmental factors, such as weather conditions, are the most important factors playing a role in CL incidence [1,11,12]. According to a review study, CL incidence varies in different provinces of Iran from 1.8 to 37.9%.…”

“…The geographic distribution of CL disease shows that CL cases mostly occur in the east, center and southern regions of Iran, and 62.6% of CL cases live in rural areas [7]. Thus, to prevent and control CL, effective and appropriate strategies need to be developed and the spatial pattern and detecting hotspots of CL should be carefully studied [1,11,12]. The epidemiology and morbidity of CL are related to weather conditions and other environmental factors that are related to the composition, distribution and behavior of sand flies as the main vector species [13].…”