Molecular Detection of Coxiella burnetii by Nested PCR Method in Cattle and Buffalo Raw Milk, Urmia Region, Iran

Coxiella burnetii, a pleomorphic coccobacillus with a Gram-negative cell wallandthe cause of query (Q) fever. Amongst animals, farm animals, goats, and sheep are the main reservoirs of Q fever.

This study was conducted to outline the presence of C. burnetii in raw milk received from farm animals and buffalo in all 12 months of 2020 within the Urmia region, northwest Iran. A total of 600 milk samples were received from 3 regions by registering the animals’ ages. DNA extraction from milk samples was performed.

The nested-polymerase chain reaction (PCR) was efficient in the detection of C. burnetii based on the transposable com1 gene. The results showed that 12.33% (95% CI: 9.9 - 15%) of the total samples (12.66% buffalo and 12% in cattle raw milk) were positive for C. burnetii DNA. The prevalence of C. burnetii in raw milk samples was considerably higher in summer (12.66%, P < 0.05, 95% CI: 9.3 - 17%). In addition, the superiority of C. burnetii in livestock milk drastically varied (P< 0.05) amongst age groups. However, it was not significant in buffalo milk samples.

The farm animals and buffalo population in Urmia may be taken into consideration as an important parameter in the epidemiology of Q fever.