Serological and Molecular characterization of Coxiella burnetii causing abortion in Livestock species in Isiolo County, Kenya.

Coxiella burnetii is the causative agent of Q fever, a zoonotic infection that poses serious threats to both animal and human health, particularly in the Global South. This bacterium primarily infects livestock such as cattle, sheep and goats and can be transmitted to humans through inhalation of contaminated aerosols or contact with infected products like milk and urine. The disease leads to livestock losses and febrile illnesses in humans. A longitudinal study was conducted to collect blood and serum samples from livestock; 18 Cattle, 22 Sheep, and 72 goats that aborted during the study period, from March 2022 – August 2023. Serological detection of C. burnetii immunoglobulin G (IgG) antibodies was performed using enzyme-linked immunosorbent assay (ELISA) and compared with baseline ELISA results. Molecular detection and genetic diversity assessment were conducted using quantitative PCR (qPCR) and nested PCR targeting the Cox IS1111 gene. Our results showed that Goats had the higher seropositivity (49.65%;95%CI: 41.97–57.75) followed by sheep (16.67%;95%CI: 10.37–25.69) and cattle (3.25%;95%CI: 1.40–7.37). Livestock species with a history of abortion had higher seropositivity (33.89%;95%CI:27.38–41.08) compared to non-aborting animals (14.39%;95%CI: 10.34–19.93). Conditional logistic regression model identified abortion as a significant risk factor, with goats being 26.71 times more likely to abort than cattle, and sheep 3.59 times more likely than cattle. Among the 112 blood samples, 54 tested positive by qPCR and 16 of these were subjected to Sanger sequencing. Phylogenetic analysis, performed using the maximum likelihood approach, provided insights into the genetic diversity and circulation of C. burnetii strains. This study provides both serological and molecular evidence of C. burnetii as in aborted and non-aborted livestock in Isiolo County. The findings enhance understanding of the pathogen’s epidemiology and can inform targeted disease control strategies.