Prevalence and Risk Factors of Q Fever in Smallholder Dairy Farms in Kenya

BACKGROUND: Q fever is a neglected zoonotic disease of global concern. In Kenya, it ranks among the top priority zoonoses, yet data on its prevalence and associated risk factors in smallholder dairy farms are limited. OBJECTIVES: To estimate the seroprevalence and molecular prevalence of Coxiella burnetii and identify risk factors for exposure in dairy cattle on smallholder farms in Kenya. METHODS: A cross-sectional study was conducted on 448 smallholder dairy farms across Nandi County and nearby dairy-producing areas. Serum (n = 1829), vaginal swabs (n = 1783) and preputial swabs (n = 52) were collected. Animal and herd-level data on Q fever risk factors were recorded. An indirect IgG ELISA was used for antibody detection, whereas real-time polymerase chain reaction (PCR) (quantitative PCR [qPCR]) was performed on the swab samples. RESULTS: The animal-level seroprevalence of C. burnetii was 8.7% (95% CI: 7.4-10.0), whereas herd-level seroprevalence was 29.0% (95% CI: 24.8-33.2). Molecular prevalence detected by qPCR was 1.5% (95% CI: 0.9-2.0). Cows with a history of abortion had increased odds of seropositivity (OR = 1.73, 95% CI: 1.14-2.61). Cattle on farms where dogs were kept-whether fed placentas or not-had lower odds of seropositivity compared to farms without dogs. CONCLUSION: This study confirms circulation of Q fever in smallholder dairy herds in Kenya. Investigating environmental persistence, farm management, interactions between susceptible hosts and sociocultural aspects of dog ownership in smallholder settings is essential to unravel the local transmission dynamics of Q fever. These findings highlight the need for coxiellosis control strategies, including improved biosecurity, surveillance and evaluation of vaccination approaches that have been successfully applied in other endemic settings.