RESUMO
In Algeria, data on the epidemiology of coxiellosis in cattle are still lacking. In this study, bulk tank milk (BTM) samples from 200 randomly selected dairy cattle herds from Setif province of Algeria were analyzed by an indirect enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR). Results highlighted that 37% (95% CI: 30.31-43.69%) and 9% (95% CI: 5.03-12.96%) of BTM samples contained Coxiella burnetii antibodies and DNA, respectively. Based on Cohen's kappa coefficient, a very low agreement between the ELISA and PCR results was found (k = 0.0849) (95% CI: 0.00-0.189). For a second experiment, 186 whole blood samples of cows from farms with reproduction disorders were analyzed by molecular tools to detect C. burnetii. This study revealed an overall prevalence of 6.98% (95% CI: 3.32-10.65%). All positive samples determined by conventional PCR were analyzed by real-time quantitative PCR (qPCR). Eleven samples with cycle threshold (Ct) values lower than 35 were selected for genotyping by the multispacer sequence typing (MST) method. The MST12 genotype in BTM samples, the MST32 genotype and a new MST genotype (partial profile) in whole blood samples were identified. Obtained results have allowed us to better understand the epidemiology of bovine coxiellosis in the region of Setif.
RESUMO
A cross-sectional study was conducted to determine the seroprevalence and the risk factors associated with C. burnetii infection in cattle in the state of Setif in northeastern Algeria from March 2016 to April 2018. A total of 678 cows animals aged at least 24 months and belonging to 90 herds were randomly selected. A serum sample from each cow was tested for antibodies against C. burnetii using an indirect enzyme-linked immunosorbent assay (ELISA). A structured questionnaire focusing on risk factors for C. burnetii infection was administered to farm owners involved in the study. The individual animal prevalence was 11.36% (77/678) (95%CI 8.97-13.75%), the herd prevalence was 45.56% (41/90) (95%CI 35.27-55.84%), and the within-herd prevalence ranged from 9.09 to 57.14% (mean 23.71%; Q1 11.11%, Q2 or median 20%, Q3 30%). Multivariable logistic regression analysis revealed that contact with other herds (odds ratio (OR) 1.95, 95 CI 1.12-3.42) and purchased animals (OR 2.05, 95 CI 1.14-3.68) was identified as risk factors for seropositivity to C. burnetii, while the use of disinfectants (OR 0.32, 95 CI 0.14-0.72) was identified as protective factor. The results from the present study indicate that C. burnetii is circulating into cattle herds in the region of Setif in Northeastern of Algeria. It is recommended to implement good hygienic practices and measures of biosecurity to reduce the spread of infection between cattle herds and possible exposure of humans.