The effect of climate variables on the incidence of Crimean Congo Hemorrhagic Fever (CCHF) in Zahedan, Iran

Abstract

Background The Crimean-Congo Hemorrhagic fever (CCHF) is endemic in Iran and has a high fatality rate. The aim of this study was to investigate the association between CCHF incidence and meteorological variables in Zahedan district, which has a high incidence of this disease. Methods Data about meteorological variables and CCHF incidence was inquired from 2010 to 2017 for Zahedan district. The analysis was performed using univariate and multivariate Seasonal Autoregressive Integrated Moving Average (SARIMA) models and Generalized Additive Models (GAM) using R software. AIC, BIC and residual tests were used to test the goodness of fit of SARIMA models, and R2 was used to select the best model in GAM/GAMM. Results During the years under study, 190 confirmed cases of CCHF were identified in Zahedan district. The fatality rate of the disease was 8.42%. The disease trend followed a seasonal pattern. The results of multivariate SARIMA showed the (0,1,1) (0,1,1)12 model with maximum monthly temperature lagged 5 months, forecasted the disease better than other models. In the GAM, monthly average temperature lagged 5 months, and the monthly minimum of relative humidity and total monthly rainfall without lag, had a nonlinear relation with the incidence of CCHF. Conclusions Meteorological variables can affect CCHF occurrence.

Knowledge, attitudes, and practices regarding Crimean-Congo hemorrhagic fever in a high-prevalence suburban community, southeast of Iran

“…Due to the high fatality rate of CCHF, it has been classified as a high-priority pathogen by the World Health Organization [ 32 ]. This study was conducted in a county with the most CCHF cases, a province with the largest high-risk area for occurrence, and a country that still has the highest incidence of CCHF in the world [ 15 , 25 , 33 , 34 ]. Although some studies were found on healthcare professionals and butchers’ KAP in Iran [ 35 , 36 ], it is the first KAP study on Iranian livestock farmers in a high CCHF burden community.…”

“…This arid ecosystem, with dust storms, and a hot desert climate, has a high prevalence of the Hyalomma spp. ticks [ 25 ]. The current study was conducted in “Shahrak-e− Gaavdaaran” one of the suburbs of Zahedan.…”

Temporal tendency, seasonality and relationship with climatic factors of Crimean-Congo Hemorrhagic Fever cases (East of Turkey: 2012–2021)

“…The mean age of CCHF cases in Turkey is between 45 and 51 [ [17] , [18] , [19] , [20] ], and the current study found similar results with the literature in terms of age distribution. However, while the average age of CCHF cases may fall as low as 30s in countries such as Afghanistan, Iran and Uganda in other studies [ [21] , [22] , [23] , [24] ], it has been reported to be approximately 60s in Spain, where only 10 cases were seen between 2013 and 2021 [ 25 ]. Besides general demographic structure, this may be related to the fact that the age distribution of individuals working in risky areas such as agriculture and animal husbandry shows differences between countries.…”

“…CCHF is more common in men than women [ [17] , [18] , [19] , [20] , [22] , [23] , [24] , 26 ]. In this study, male predominance was observed in CCHF cases, consistent with the literature.…”

Tick borne microbial agents in Iran and the adjacent countries: A meta- analysis based on the GenBank database

“…Severe drought is also recognized as a feature of Iran's climate (Amiri and Eslamian 2010). Also, changes in agricultural land and landscape alteration following climate change are good factors to the successful survival, reproduction, and colonization of ticks or possible establishment of new tick-borne pathogens that may trigger disease outbreaks (Nili et al 2020). Thus, widening the knowledge of tick-borne microbial agents and their infected host ticks actually is necessary to Iran and the neighbouring countries.…”