Prevalence study of Coxiella burnetii in aborted fetuses of small ruminants in various partum and seasons in Iran

摘要

Query (Q) fever is an ubiquitous zoonosis caused by?Coxiella burnetii, an obligate intracellular rickettsial organism that cause abortion and stillbirth in ruminants. The prevalence of?C. burnetii?in Iran is essentially unknown. Its traditional diagnosis is based on culture, serology and conventional polymerase chain reaction (PCR). In this present study, for more sensitive and accurate detection and prevalence's determination of C. burnetii in aborted Ovine and Caprine fetuses, the nested and real-time PCR methods are recommended. 98 (12.53%) and 122 (16.39%) out of 782 and 744 Ovine and Caprine aborted fetuses, were positive for presence of?C. burnetii?by nested PCR, respectively. After real-time PCR, it was recognized that 121 (15.47%) and 152 (20.43%) samples were positive for?C. burnetii?in Ovine and Caprine aborted fetuses, respectively. Results indicated that the real-time PCR was 7 times more sensitive than the nested PCR. Statistical analysis showed significant differences about P < 0.01 between presence of?C. burnetii?in aborted Ovine and Caprine fetuses by both nested and real-time PCR assays and P < 0.05 between ability of nested and real-time PCR for detection of?C. burnetii.?The Ct values obtained from real-time PCR had significant differences of about P < 0.01 for presence of?C. burnetii?between aborted Ovine and Caprine fetuses. Our results indicated that Caprine is more sensitive than Ovine to?C. burnetii's abortion. Khozestan and Gilan have the highest, and Khorasan and Sistan va balochestan provinces have the lowest prevalence of?C. burnetii, respectively. To our knowledge, this study is the first prevalence report of direct identification of?C. burnetii?in aborted Ovine and Caprine fetuses by evaluation of nested and real-time PCR assays in Iran. This study showed that the nested PCR for detecting?C. burnetii?are technically time-consuming and labor-intensive.