Seroprevalence and Presumed Bovine Leukaemia Virus and Coxiella burnetii Coinfections in Three Dairy Cattle Herds From the Al Ain Region, United Arab Emirates.

内容摘要

Bovine leukaemia virus (BLV) and Coxiella burnetii are important infectious pathogens of dairy cattle with potential implications for animal health, productivity and zoonotic transmission (in the case of C. burnetii). Because BLV may alter immune function, we hypothesize that infection with the virus could increase cattle susceptibility to C. burnetii. This cross-sectional study aimed to estimate the seroprevalence of BLV and C. burnetii in dairy cattle herds in the Emirate of Abu Dhabi (EAD) and to assess any association between the positive serostatus of the two pathogens. 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 being 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 higher odds of C. burnetii seropositivity (OR = 1.25, 95% CI [0.88-1.79]), even though the association was not statistically significant (p = 0.2258). The relatively high seroprevalences compared with previous reports suggest 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.