Coxiella burnetii seropositivity and associated risk factors in goats in Ontario, Canada

Abstract

Coxiella burnetii is a zoonotic bacterium, and infection in goats with this bacterium can result in abortion, stillbirth or birth of non-viable kids. A cross-sectional study was conducted to identify the seroprevalence and risk factors for C. burnetii exposure in Ontario goats. Sera were collected between August 2010 and February 2012, and tested for C. burnetii specific antibodies using an enzyme-linked immunosorbent assay (IDEXX). Overall, 63.2% (48/76, 95% CI=51.9-73.4) of farms had one or more seropositive goats. A higher farm-level seroprevalence of 78.6% (33/42) was found on dairy goat farms, compared to 44.1% (15/34) on meat goat farms (p<0.01). At the overall individual-animal level, 32.5% (714/2195, 95% CI=30.6-34.5) of goats were seropositive. Similarly, a higher individual-level seroprevalence was identified for dairy goats (43.7%, 633/1447) compared to meat goats (10.8%, 81/748) (p<0.001). A mixed multivariable logistic model that controlled for farm-level clustering identified risk factors associated with seropositivity (p<0.05). Increases in the female herd size (logarithmic scale) were associated with increased odds of seropositivity, while increases in male herd size had a negative association with seropositivity. If other sheep or goat farms were located in a 5-km radius, goats had 5.6 times (95% CI=1.01-30.8) times the odds of seropositivity compared to those that were not. Relative to goats from farms where all kidding pen hygiene was practiced (adding bedding, removing birth materials and disinfection after kidding), goats from farms which only added bedding and removed birth materials had a higher odds of seropositivity (OR=19.3, 95% CI=1.1-330.4), as did goats from farms which practiced none of these measures (OR=161.0, 95% CI=2.4-10822.2). An interaction term revealed kidding outdoors when there were no swine on farm had a protective effect on seropositivity compared to kidding indoors, or kidding outdoors with swine on the farm. These results can inform strategies to mitigate exposure to C. burnetii in Ontario.

Serological diagnosis and risk factors for Coxiella burnetii in goats and sheep in a semi-arid region of Northeastern Brazil

“…In Indiana, USA, no significant difference in seropositivity was found between milk and meat goat breeds (BAUER et al, 2016). In Ontario, Canada, where intensive breeding is more common and the presence of the microorganism may be more prevalent, a higher prevalence of seropositivity was reported among milk goats (MEADOWS et al, 2015b). However, a study in Kenya carried out by Muema et al (2017) found that animals raised in a pastoral nomadic system (similar to extensive farming) were three times more likely to test seropositive for C. burnetii than animals in other systems like mixed farming.…”

Management of Coxiella burnetii infection in livestock populations and the associated zoonotic risk: A consensus statement

“…Several studies have investigated risk factors of coxiellosis in ruminants in the past decade . Factors that were associated with lower risk of seropositivity in ruminants in these studies included quarantine of new animals entering the farm, use of stringent hygiene measures for visitors, limited introduction of new animals, prompt removal of birth materials immediately postpartum, and frequent cleaning or changing of bedding.…”

“…Recommendations regarding disinfection are described below. Routine cleaning and disinfection of lambing/kidding pens has been demonstrated to be associated with a lower risk of human seroconversion in producers . During this cleaning on farms with documented coxiellosis it is recommended that a fit tested N95 mask be used, and essential if another individual developed Q fever.…”

Serological survey of Coxiella burnetii at the wildlife–livestock interface in the Eastern Pyrenees, Spain

“…The higher seroprevalence consistently found in sheep as compared to cattle in the Eastern Pyrenees are in accordance with previous reports in semi-extensive and extensive grazing systems [ 17 ]. High C. burnetii seroprevalence with zoonotic risk has been reported in goats [ 12 , 13 , 18 , 19 ], but the low sample size of our study does not allow to draw strong conclusions. However, the absence of seropositive goats, altogether with the low goat population and the few goats per herd in the study area [ 10 ], do not allow to point to this species as important for C. burnetti spread in the Eastern Pyrenees.…”