Climate-Driven Shifts in Crimean-Congo Hemorrhagic Fever Epidemiology in Kazakhstan.

Background

Crimean-Congo Hemorrhagic Fever (CCHF) is a severe zoonotic viral disease that poses significant public health challenges in Kazakhstan, particularly in the southern regions where it has been endemic for decades. The natural focus of CCHF in this region has expanded significantly, a trend likely exacerbated by climate change. Objective(s): To analyze the outbreak trends of CCHF in four regions of Kazakhstan and assess the potential impact of climate variables on disease incidence.

Methods

This ecological study examined CCHF morbidity and mortality data from 2014 to 2023 in the Zhambyl, Turkistan, and Kyzylorda regions, and Shymkent City. Data were sourced from the national central data repository. Meteorological data (temperature and precipitation) were obtained from the Climatic Research Unit TS dataset. Regression analysis was performed to test the dependence of CCHF incidence on climate variables. Findings: A total of 214 CCHF cases were reported in the study regions over the decade, with an overall case fatality rate of 21.5%. In the Kyzylorda region, a strong positive correlation was observed between climate indicators and annual case numbers (R-squared = 0.8969, P = 0.011). However, in Zhambyl and Turkistan regions, no significant associations emerged between climate variables and incidence during this period. Both average and extreme temperatures showed a gradual increase across all regions over the 10-year period.

Conclusions

While the direct correlation between climate variables and CCHF incidence varied by region, long-term temperature trends likely influence tick ecology. The findings highlight the complexity of evaluating CCHF dynamics solely through a climate lens and underscore the need for a One Health approach, improved surveillance, and cross-border cooperation to mitigate this growing public health threat.