Abstract
Q fever, caused by Coxiella burnetii, is a zoonosis with a worldwide distribution. The present study was conducted to estimate the sero-prevalence of Q-fever in cattle, goat and humans in selected areas of Bangladesh, phenotyping, detection of Coxiella burnetii from serum, milk, tick and also to determine the risk factors associated with the occurrence of Q-fever in livestock and humans. A total of 162 and 172 serum samples respectively from cattle and goats with the reproductive disorders, 159 serum samples from human patients with PUO lasting over a period of three weeks and who were in close contact with animal, 119 milk samples from cattle with reproductive disorders, 6 aborted materials from goat and 126 tick samples from cattle were collected from Kurigram, Sirajgonj, Pabna and Mymensingh district of Bangladesh for the detection of Coxiella antibody by ELISA and DNA by PCR assay. The research was performed with the collaboration of OIE reference laboratory for Q fever, Friedrich-Loeffler-Institute, Naumburger, Jena, Germany. The overall Sero-prevalence of Q fever was 3.01% (5/162) in cattle, 7.6% (13/172) in goats. The highest prevalence in cattle (4.5%) was recorded in Mymensingh district while 2.8%, 2.5% and 2.4% were recorded in Pabna, Kurigram and Sirajgonj districts respectively. Age-wise sero-prevalence of Q fever was found 4.4% in more than 5 years age group and 2.1% in 3-5 years age group. Breed-wise distribution revealed that higher prevalence in indigenous (4.2%) than the cross-bred (2.6%) cattle. With respect to various reproductive problems, the number of positive reactors was recorded and it was found that cattle with the history of retention of placenta (5.6%) showed higher prevalence of Q fever than abortion (2.3%) but no positive reactors were found in anoestus and repeat breeding. Breeding type wise sero-prevalence revealed that the prevalence in cattle with history of natural service and artificial insemination 5.9% and 2.3% respectively. However, in goat this study showed higher sero-prevalence in Kurigram (10.0%) than Sirajgonj (9.5%) and Mymensingh (9.3%) but no positive reactors were found in Pabna district. Sero-prevalence was higher in more than 2 years age group (14.1%) than up to 2 years age group (2.1%) of goat. The study revealed that prevalence of Q fever was higher with the history of abortion (10.0%) than retention of placenta (4.2%) in goat. Testing of 119 milk samples by ELISA revealed the prevalence of Q fever in cattle with the history of reproductive disorder was 21.85%. As a result, the prevalence was higher in 3-5 years age group (22.2%) than more than 5 years age (21.3%) group. Breed-wise distribution of Q fever revealed a higher prevalence in cross-bred (24.2%) than in indigenous (12.5%) cattle. Prevalence was recorded 33.3%, 24.4%, 21.7% and 8.3% in cattle with the history of anoestrus, retention of placenta, abortion and repeat breeding respectively. In case of breeding system cows with history of artificial insemination (23.5%) showed higher prevalence than natural (11.8%) service. The percentage of positive reactors were 30, 28.2 and 21.4 in Kurigram, Sirajgonj and Mymensingh districts respectively but no positive reactors were recorded in Pabna district. However, these differences were not statistically significant. In case of humans, only one human patient had positive for IgG phase. II ELISA. The prevalence recorded for acute Q fever was 0.63% but none were positive for IgG phase-I ELISA. C. burnetii DNA was detected in two sero-positive milk samples but all of the intermediate milk samples by ELISA were negative by PCR assay. This study revealed C. burnetii DNA in only one (0.79%) tick. Nevertheless, none of our sero-positive sera samples of cattle, goat and human were positive in PCR and none of the aborted material of goat were positive in PCR and cell culture. This is the first time that the presence of C. burnetii in human and C. burnetii DNA in ticks and milk samples using real-time PCR is reported for Bangladesh.