Seroprevalence of Crimean-Congo hemorrhagic fever virus in the population of Turkestan region.

Abstract

Purpose: To determine the level of seroprevalence to the virus of Crimean-Congo Hemorrhagic Fever (CCHF) in population of rural area of the particular districts of Turkestan region, Kazakhstan and its connection with epidemiological alerts.

Materials and methods: For determining the real Crimean-Congo hemorrhagic fever virus (CCHFV) circulation in Turkestan region, Kazakhstan, massive sero-epidemiologic studies were conducted. Healthy residents of Turkestan Region aged from 10 to 75 years were examined without having been previously registered with CCHF. After receiving an informed consent, 5 ml of venous blood was collected for ELISA assay using the following test kits: VectoCrimea-CHF-IgG and VectoCrimea-CHF-IgM by the Vector-Best JSC. Findings on CCHF morbidity rate along with prevalence of ticks were received from the reports of the Committee of Sanitary and Epidemiological Control of the Ministry of Healthcare of the Republic of Kazakhstan.

Results: Blood serum samples were collected prospectively from 4259 residents in all 16 districts of rural areas of Turkestan region. CCHF seroprevalence was detected in 2.39% of cases. Anamnesis of a tick-bite along with livestock contact in 18-30 years and 41-50 years age groups were considered as risk factors. The highest rate of CCHF seroprevalence was determined in the following recognized endemic regions and districts, namely Sozak District (4.04%), Turkestan Region (3.85%), Jetisu Region (3.6%). Reactivity probes were detected in residents of all 16 districts of Turkestan Region. The research statistics displayed that CHHF pathogen considerably increased its circulation in the endemic regions and the disease communicated into a number of new districts.

Conclusion: IgG ELISA was performed to screen CCH-FV in 4259 village inhabitants of Turkestan Region and revealed the presence of antibodies in 2.39% of its population. Weak linear correlation relationship was established between CCHFV seroprevalence rate and CCH-FV morbidity rate in the particular districts of Turkestan Region. As people grow older, CCHFV IgG detection rate increases. Living on CHHF endemic territories is a serious risk factor to become CHHF positive which is characterized by manifestation of the subclinical forms of this disease.