Seroepidemiological Investigation and Risk Factors of Q Fever and Rift Valley Fever in Livestock in Bangladesh

Rift Valley fever (RVF) is an emerging and re-emerging mosquito-borne zoonosis of major economic, public health, and veterinary importance, often causing great population-level impact. Q fever remains a neglected zoonotic disease of considerable public health and veterinary significance, responsible for notable economic losses for livestock farmers. Despite their significance, the epidemiology of RVFV and Coxiella burnetii (Q fever) remains poorly understood, with little evidence on their seroprevalence and associated risk factors. We conducted a cross-sectional study to estimate the seroprevalence of RVFV and C. burnetii , and to identify associated risk factors in domestic livestock. We collected a total of 568 blood samples from domestic livestock across three different districts using convenience sampling. Individual animal and herd-level data were obtained through a pre-tested structured questionnaire. Serum samples were tested for antibodies against RVFV and C. burnetii using a competitive Enzyme-Linked Immunosorbent Assay (cELISA). While none of the animals tested positive for RVFV antibodies, the overall seroprevalence of C. burnetii antibodies was 9.7% (95% CI: 7.4–12.4), which was highest in sheep (5.8%), followed by goats (2.1%), camels (1.1%), and cattle (0.7%). Animals from households (OR = 0.19, p = 0.04) and young livestock (OR = 0.10, p < 0.01) had lower odds of C. burnetii seropositivity than those from farms and adults, respectively, whereas animals with moderate BCS (OR = 3.1, p < 0.01), poor BCS (OR = 8.8, p < 0.01), and clinical signs (OR = 3.01, p < 0.01) had higher odds of seropositivity. These findings indicate the circulation of C. burnetii among livestock population of this country. Although no serological evidence of RVFV was detected in the studied animals, the possibility of exotic vector-borne disease being introduced into the country cannot be ruled out. Therefore, we recommended establishing a sustainable surveillance program in both livestock and vector populations to monitor and mitigate the burden of Q fever while maintaining vigilant for potential RVF emergence and other vector-borne viruses in regions where they are not currently endemic at the animal–human interface.