Cross-sectional serosurvey of Coxiella burnetii in healthy cattle and sheep from extensive grazing system in central Italy

Abstract

A cross-sectional survey was carried out to estimate the seroprevalence of Coxiella burnetii in extensively grazed cattle and sheep from central Italy and to identify the related risk factors. Data on notified human Q fever cases in the area were also collected and described. A two-stage cluster sampling was performed. A total of 5083 animals (2210 cattle; 2873 sheep) belonging to 186 farms (92 herds; 94 flocks) were tested for the presence of antibodies against C. burnetii using a commercial enzyme-linked immunosorbent assay kit. The prevalence at the animal-level resulted three times higher in sheep compared to cattle (37.8% vs. 12.0%; χ2 = 270.10, P < 0.001). The prevalence at the herd-level was also higher in sheep than in cattle (87.2% vs. 68.5%; χ2 = 9.52, P < 0.01). The multivariate analysis showed a higher risk of seropositivity for cattle aged 67–107 months (OR 2.79, 95% CI 1.86–4.18), cattle >107 months of age (OR 2.07, 95% CI 1.36–3.14) and mixed breed cattle (OR 1.74, 95% CI 1.11–2.72). A herd size >92 animals was recognized as herd-level risk factor in cattle (OR 6.88, 95% CI 1.67–28.37). The risk of being seropositive was double in sheep belonging to flocks >600 animals (odds ratio (OR) 2.04, 95% CI 1.63–2.56). Sheep were confirmed to be the most exposed species. Nevertheless, the prevalence observed in cattle also suggests the potential involvement of this species in the circulation of the pathogen in the area. Seven confirmed human Q fever cases were reported. In five out of seven cases there was at least one exposed herd within a 5 km buffer. Even though the source of the infection was not identified, the possibility of C. burnetii circulating in the livestock and human population in the study area cannot be overlooked. The integration between veterinary and human surveillance will be crucial to understand the spread of this zoonosis and to support the adoption of appropriate control measures.

Monitoring Coxiella burnetii Infection in Naturally Infected Dairy Sheep Flocks Throughout Four Lambing Seasons and Investigation of Viable Bacteria

“…The four flocks were managed under a semiextensive system where animals are housed during lambing and milking and, afterwards, graze on communal mountain pastures in contact with livestock and wildlife. In a region like the Basque Country, where Q fever is endemic and vaccination is not frequently implemented, this system poses a risk for infection and reinfection (14,15,17). Nevertheless, the infection peak observed in yearlings in flock 1 during the second and fourth lambing seasons is difficult to explain since yearlings did not share grazing pastures with other flocks.…”

Apparent prevalence and risk factors of coxiellosis (Q fever) among dairy herds in India

“…A review comprising qualitative assessment of 69 publications indicated the detection of C. burnetii infection in all 5 continents (Africa, America, Asia, Europe and Oceania) with wide range of host species and median prevalence of C. burnetii infection among cattle was reported as 20% at the animal level [2]. In a recent cross-sectional serosurvey from Italy on C. burnetii in apparently healthy cattle (n = 2210), the prevalence at the animal-level was observed as 12.0% [17]. Globally, the epidemiology of coxiellosis in water buffaloes (Bubalus bubalis) is largely unknown [18].…”

“…However, the old animals were found to have higher odds for coxiellosis in univariate as well as multivariable binary logistic regression analysis (Tables 3 and 4). Earlier, the older animals have been reported to have increased odds of getting infected, most often after the first calving [28,30] and increasing of age might be associated with higher probability of being exposed to the pathogen [17].…”

“…It has been reported that after the pathogen entry coupled with poor biosecurity practices, the animals in intensive system are at greater risk as compared to the extensive system due to more time of exposure that could lead to direct or indirect transmission in the barn environment [29]. However, the free grazing herds on wider pastures have also been reported to have a higher risk for coxiellosis, due to the possibility of high contact rates with infected animals from different herds [17].…”

“…The inadequate floor spacing (Farm 1 and 2) is found to have 1.64 higher odds for coxiellosis as compared to farms having adequate floor spacing. It has been reported that an increasing animal density could result in a higher probability of being directly exposed to C. burnetii during the parturition or infectious abortions [17].…”