Seroprevalence and Potential Interaction Between Bovine Leukemia Virus and Coxiella burnetii in Dairy Cattle of the United Arab Emirates

Bovine leukemia virus (BLV) and Coxiella burnetii are important infectious pathogens of dairy cattle with potential implications for animal health, productivity, and zoonotic transmission ( C. burnetii ). Given the immunomodulatory effects of BLV, we evaluated whether BLV infection in dairy cattle was associated with increased susceptibility to C. burnetii . This cross-sectional study aimed to estimate the prevalence of BLV and C. burnetii coinfections in dairy cattle herds in the Emirate of Abu Dhabi (EAD), and to assess their association. Sera from 492 adult Holstein-Friesian cattle were screened by ELISA for antibodies to both pathogens, and associations were evaluated using logistic regression. The overall seroprevalences of BLV and C. burnetii were 47.0% and 49.4%, respectively, with 24.2% of cattle dually seropositive. BLV seroprevalences across farms were 27.6%, 56.3%, and 50.9%, while C. burnetii seroprevalences were 42.9%, 29.2%, and 53.8% for Farms 1, 2, and 3, respectively. Logistic regression showed that BLV-positive cattle had 25% higher odds of C. burnetii seropositivity (OR = 1.25, 95% CI [0.88–1.79]), even though the association was not statistically significant (p = 0.212). The relatively high seroprevalences are consistent with ongoing intra-herd transmission of both pathogens, likely exacerbated by the absence of targeted control strategies. Although no causal relationship was established, the observed trend may reflect BLV-associated immunosuppression that could enhance susceptibility to C. burnetii . Further large-scale studies are warranted, and livestock health authorities in the UAE are encouraged to implement targeted surveillance and biosecurity measures.