Occurrence of Coxiellosis in ruminants and its associated risk factors

Coxiellosis in animals is caused by the zoonotic pathogen, Coxiella burnetii. Although the disease is of public health importance it remains underdiagnosed and underreported. The cross- sectional study was aimed to estimate the occurrence of the disease in livestock of study area and also to identify the risk factors associated with the disease in animals. Blood, serum, and vaginal swabs samples were collected from 200 ruminants (cattle, sheep, and goats), across various farms in Karnataka, India. These samples were then screened using ELISA and PCR (com1 and IS1111). A questionnaire was administered to the farm owners to collect the risk factor-related information. About 5.26 % cattle, 12.3 % sheep, and 12.5 % goats were positive by ELISA. By PCR, 9.47 % cattle, 9.3 % sheep, and 10 % goats were positive. Overall, the occurrence of 14.73 %, 18.46 % and 17.5 % was estimated in cattle, sheep and goat, respectively. PCR targeting the IS1111 gene detected higher number of samples as positive as compared to the com1 gene PCR. Higher number of vaginal swab samples were detected as positive as compared to blood. History of reproductive disorders (OR: 4.30; 95 %CI:1.95- 9.46), abortion (OR: 30.94; 95 %CI:6.30- 151.84) and repeat breeding (OR:11.36; 95 %CI:4.16- 30.99) were significantly associated with coxiellosis (p < 0.005). Multivariable analysis by logistic regression model analysis suggested retained abortion, repeat breeding and rearing of animal in semi-intensive system as factors significantly associated with the infection. Cultural identification of the PCR positive samples were cultured using embryonated egg propagation and cell culture techniques and positivity was confirmed in six samples. Phylogenetic analysis of the com1 and IS1111 gene revealed clustering based on similar geographic locations. The study estimated the occurrence of the disease in the study area and identified the potential risk factors.