Seroprevalence of and risk factors for Q fever in dairy and slaughterhouse cattle of Jimma town, South Western Ethiopia

Abstract

Background Q fever is a zoonotic disease, caused by Gram negative bacterium C. burnetii, which imparts significant socio-economic burden due to production and reproductive loss (abortion, stillbirth, and infertility) in ruminants and debilitating clinical disease in human populations. While sheep and goats are considered the primary reservoirs of infection to humans, infection can also result from exposure to cattle. Recent studies indicate that in Ethiopia Q fever is a disease of growing public health interest. The top cattle producing region in Ethiopia is the Oromia region and Jimma is the zone that ranks first in the population of cattle within Oromia. While in Jimma zone livestock production plays an important role in people’s livelihoods and nutrition, to date, there is no available report on seroprevalence of Q fever in cattle. This is particularly important due to the low dairy farm biosecurity in Jimma town. This study aimed to evaluate the potential risk for public health from cattle production; a specific objective of this study included the estimation of the seroprevalence of C. burnetii infection and its potential risk factors in dairy cattle and cattle for slaughter in Jimma Town. Results The seroprevalence of C. burnetii in cattle present at dairy farms was significantly lower compared to cattle presented at slaughterhouse [6.17% (95% CI: 3.41–10.13) and 11.79% (95% CI: 7.63–17.17), respectively; (P = 0.04)]. As the age of dairy cattle increase by 1 year, they were 1.51 more likely to be positive of C. burnetii [OR = 1.51 (95%CI: 1.30–1.75; (P = 0.000)]. Cattle managed in semi-intensive production systems were 8.08 more likely to be C. burnetii seropositive compared to intensively managed dairy cattle [OR = 8.08 (95%CI: 1.03–63.68); P = 0.047]. Dairy cattle with access to nuisance animals like dogs, cats and mice were 5.65 more likely to be C. burnetii seropositive compared to dairy cattle without access to these animals. On the other hand, dairy cattle that have no tick infestation are 93% less likely to be seropositive for C. burnetii [OR = 0.07 (95%CI: 0.01–0.74); P = 0.027]. Concerning farm-level data, farms of larger herd sizes were 1.03 more likely to be C. burnetii seropositive than small herd farms [OR = 1.03 (95%CI: 0.99–1.06)]. The result from slaughterhouse indicates that as the age of cattle increase by 1 year their chance of being C. burnetii seropositive increases by 2.27 [OR = 2.27 (95%CI: 1.93–2.68); p = 0.000]. Conclusion Considering its zoonotic and economic burden the seroprevalence of Q fever recorded in this study is of eminent public health concern with a farm-level and slaughterhouse seroprevalence of 6.17 and 11.79% respectively. Based on modifiable risk factors identified in this study, Q fever management plans better be focused on health education and awareness campaigns for abattoir workers and dairy farm workers. Dairy farm Q fever management plans should contemplate improved dairy herd biosecurity with regards to cattle tick infestation, keeping different livestock species segregated and avoiding mixing of herd with others with unknown health status.

Geographical Variation in Coxiella burnetii Seroprevalence in Dairy Farms Located in South-Western Ethiopia: Understanding the Broader Community Risk

“…Our predictive C. burnetii seroprevalence map indicated that predictive risk was not constant in Jimma town and there were areas, particularly to the east of the town, where the risk of C. burnetii exposure was predicted to be higher. While our previous study demonstrated that cattle in Jimma town were under a high level of C. burnetii exposure [ 15 ], our study expanded current knowledge in that it demonstrated that the east area of the town presented the higher predicted seroprevalence compared to other parts of the town. Our seroprevalence prediction map might help with targeting resources to ensure that communities that are most at risk of Q fever infection to the east of Jimma town are surveyed.…”

“…To estimate the seroprevalence of C. burnetii infection in the Jimma dairy herds, a total of 227 cattle were tested in 25 dairy farms between October 2016 and October 2017 [ 15 ]. Blood samples were collected from the jugular vein from the 227 animals using a vacutainer tube [see reference [ 15 ] for more details]. A total of 14 animals were seropositive for C. burnetii [ 15 ].…”

“…Blood samples were collected from the jugular vein from the 227 animals using a vacutainer tube [see reference [ 15 ] for more details]. A total of 14 animals were seropositive for C. burnetii [ 15 ]. The highest farm-level seroprevalence was 20% and serum samples were tested using Indirect Enzyme-Linked Immunosorbent Assay (i-ELISA) from ID Screen ® Q Fever Indirect Multi-Species kits (ID.vet, Grabels, France) for the detection of antibodies against C. burnetii [ 15 ].…”

“…The seroprevalence of C. burnetii has previously been reported in pastoral livestock in south-east Ethiopia, Africa, with the highest seroprevalence found in camels (90%), followed by goats (54%) and cattle (31%) [ 14 ]. Between 2013 and 2015, the Jimma zone in the Oromia region, Ethiopia, was affected by an increasing trend of abortion episodes in ruminants over these years [ 15 ]. More than 11,487 cases were recorded, which included cattle, goats and sheep [ 16 ].…”

“…More than 11,487 cases were recorded, which included cattle, goats and sheep [ 16 ]. The overall seroprevalence in dairy cattle in the capital city of Jimma zone (Jimma town) was estimated to be close to 9%, with a higher seroprevalence in cattle at slaughterhouses than in cattle at dairy farms [ 15 ]. Despite the relatively high seroprevalence in livestock and the high cattle density in Jimma, the geographical variation in the distribution of C. burnetii exposure in the region is yet to be investigated.…”