Sero-molecular investigation of Coxiella burnetii infection in domestic ruminants and humans and associated risk factors based on ‘One Health’ perspectives in Bangladesh

Background: Q-fever is an important zoonotic disease caused by the bacterium Coxiella burnetii with wide host range of mammals, birds and arthropods worldwide. The prevalence of C. burnetii infection has been reported in domestic ruminants in Bangladesh with no attention on the ‘One Health’ approach for the epidemiological investigation associated with risk factors for prevention of the disease. Objective: This study aimed to investigate the sero-molecular prevalence of Coxiella burnetii infection and associated risk factors in domestic ruminants and humans based on ‘One Health’ approach in Bangladesh Materials and Methods: This study on C. burnetii infection was conducted in cattle, goats and humans of the four randomly selected districts (Kurigram, Sirajgonj, Pabna and Mymensingh) in Bangladesh during the period from 2018 to 2021. A total of 162 and 172 serum samples respectively from cattle and goats with the reproductive disorders, 159 serum samples from human patients with pyrexia of unknown origin lasting over a period of three weeks and who were in close contact with animal, 119 milk samples from cows with reproductive disorders and 6 aborted materials from goat were collected from these selected districts for the detection of C. burnetii 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, Germany. Results: The overall sero-prevalence of C. burnetii infection by ELISA was 3.01% in cattle, 7.6 % in goats and 0.63% in humans. The highest sero-positivity was recorded in cattle in Mymensingh (4.5%) in comparison to Pabna (2.8%), Kurigram (2.5%) and Sirajgonj (2.4%) districts. Risk factors associated with higher sero-positivity of C. burnetii infection was recorded in cattle with  5 years (4.4%) than 3 to 5 years (2.1%), indigenous (4.2%) than cross-bred (2.6%), history of retention of placenta (5.6%) than abortion (2.3%) and natural service (5.9%) than artificial insemination (2.3%). The seropositivity of C. burnetii infection in goat showed highest in Kurigram (10.0%), followed by Sirajgonj (9.5%) and Mymensingh (9.3%) with no positive reactors in Pabna district. Risk factors associated with sero-positivity of C. burnetii infection in goats showed higher in > 2 years (14.1%) than up to 2 years (2.1%) age group and higher with the history of abortion (10.0%) than retention of placenta (4.2%). Risk factors associated with positivity of C. burnetii infection detected in milk samples of cows by ELISA showed an overall 21.85% positivity associated with history of reproductive disorders, with highest positivity in anestrus (33.3%), followed by retention of placenta (24.4%), abortion (21.7%) and lowest with repeat breeding (8.3%). In addition, higher positivity was recorded in cross-bred (24.2%) than in indigenous (12.5%) cattle. In case of humans, only one human patient (0.63%) had positive for IgG phase-II ELISA. C. burnetii DNA was detected in two seropositive milk samples but all of the intermediate positive milk samples by ELISA were negative by PCR assay and even none of the aborted material of goat was positive in PCR and cell culture. Conclusions: This study recorded the prevalence and risk factors associated with the zoonotic C. burnetii infection in both the domestic ruminants and humans but still it is unrecognized and underestimated in both human and animal health and research in Bangladesh. The findings of this study support the further research on C. burnetii in both human and veterinary medicine under ‘One Health’ approach particularly targeting epidemiology on the agent, host and environment for the control and prevention of the disease in Bangladesh.