Prevalence of CCHF Virus in Ticks and People and Public Awareness in Zhambyl Region, Kazakhstan

ObjectiveAs part of CDC’s Global Disease Detection work, in conjunction with Zhambyl Region Department of Health, we conducted a tick survey and human seroprevalence Knowledge, Attitudes, and Practices (KAP) survey of livestock-owning households in Zhambyl to assess CCHF seroprevalence and risk factors.IntroductionCrimean Congo Hemorrhagic Fever (CCHF) virus is a tick-borne pathogen that causes severe disease in people, with a distribution that extends from central Asia to southern Africa. In addition to tick bites, contact with bodily fluids from viremic livestock or from symptomatic humans are risk factors for infection. From 2000 to 2013, 73 cases of CCHF were reported in Zhambyl Region, Kazakhstan. CCHF virus is categorized as an “especially dangerous pathogen” in Kazakhstan and CCHF is prioritized for surveillance and treatment. Little is known about the seroprevalence of infection by CCHF virus in Zhambyl in ticks or people, and knowledge of risk factors for transmission of CCHF virus among at-risk populations is believed to be low.MethodsRural villages were classified as “endemic” or “non-endemic”, where endemic areas reported ≥1 CCHF case or a CCHF virus-positive tick in the past 5 years. In each group, 15 villages were chosen by population proportional to livestock population size. Livestock-owning households (n=969) were selected randomly from veterinary registries. One adult was randomly selected per house and ticks were collected from one randomly selected sheep or cow over 1 year of age per house. Data were weighted accounting for design and analyzed in R.ResultsKAP surveys were completed for 950 people (98%); of those, 923 (97%) submitted blood for ELISA testing using Vector-Best Kits. Median age of human respondents was 46 years (range: 19 – 90); 54% were male. Three individuals were anti-CCHF IgM positive, 12 anti-CCHF IgG positive and two positive for both. Weighted seroprevalence of CCHF in Zhambyl was 1.6% (95% CI: 0.9, 3.0). In endemic villages, seroprevalence was 1.8% (95% CI: 1.0, 3.0), compared to 1.2% (95% CI: 0.4, 4.0) in non-endemic villages. Of the 17 seropositive for CCHF, median age was 54 years; 58% were male. None reported previous CCHF diagnosis or illness with fever and hemorrhaging in the past five years. None reported high-risk tick exposure in the past four months. Controlling for age and sex, milking animals, an activity in which 40.3% of the population had engaged, was associated with infection in Poisson regression (O