Coxiella burnetii seroprevalence and risk factors on commercial sheep farms in The Netherlands

Abstract

Coxiella burnetii seroprevalence was assessed on Dutch dairy and non-dairy sheep farms using ELISA. Risk factors for seropositivity on non-dairy sheep farms were identified at farm and sheep level by univariate and multivariate multilevel analyses. Based on 953 dairy and 5671 non-dairy serum samples, sheep seroprevalences were 18.7 per cent and 2.0 per cent, respectively, and 78.6 per cent and 30.5 per cent at farm level. Significant risk factors for non-dairy sheep farms were farm location in the south of the country, sheep kept on marginal grounds, one or several supply addresses for ewes during 2007-2009 and wearing farm boots and/or outfit by professional visitors. On sheep level, risk factors included among others farm location in the south of the country, lamb breeding as main farm purpose, goat density within 10 km farm radius, use of windbreak curtain or windshields, and presence of ≥6 stillborn lambs in 2009. Farm location in the south of the country and goat density suggests that infected goats have played a role in the transmission to non-dairy sheep. Other risk factors suggest introduction of the bacterium through sheep supply and professional visitors. Biosecurity measures should be strengthened, including avoiding infection during handling of stillborn lambs and birth products in the lambing period.

Exploratory investigation of Q fever in apparently healthy meat sheep flocks in Belgium

“…The sensitivity and specificity of the ELISA LSIV test were 87% and 99.1%, respectively, when applied to a set of sera derived from sheep, goats and bovines and using test accuracy in the absence of a gold standard (TAGS) (Horigan, Bell, Pollard, Sayers, & Pritchard, ). In this study, the low apparent seroprevalence measured in sheep is comparable to the one described in the Netherlands in two studies on dairy and non‐dairy sheep and goats (Schimmer, De Lange, Hautvast, Vellema, & Van Duynhoven, ; Van Den Brom, Moll, Van Schaik, & Vellema, ). In particular, these Dutch studies showed that dairy sheep and goats had a significantly higher chance of being seropositive than non‐dairy sheep and goats.…”

Risk factors and burden of acute Q fever in older adults in New South Wales: a prospective cohort study

“…Most epidemiological studies have been retrospective and focused on specific occupational groups, 9 , 10 and there are only limited data on factors associated with Q fever risk outside these populations. We therefore examined the risk and acute burden of Q fever in a population‐based prospective study of Australian adults aged 45 years and over living in NSW.…”

“…7 National notification rates suggest there was some decline in the incidence of Q fever during 2006e2009from 2.0 to 1.4 notified cases per 100 000 populationbut this was followed by a gradual return to 2.0 cases per 100 000 population by 2014; the highest reported rates were among adults aged 45e69 years. 8 Most epidemiological studies have been retrospective and focused on specific occupational groups, 9,10 and there are only limited data on factors associated with Q fever risk outside these populations. We therefore examined the risk and acute burden of Q fever in a population-based prospective study of Australian adults aged 45 years and over living in NSW.…”

A systematic knowledge synthesis on the spatial dimensions of Q fever epidemics

“…Attempts were made to identify risk factors for transmission of C. burnetii between goat herds (Schimmer et al, ), sheep herds (Schimmer, Lange, Hautvast, Vellema, & Duijnhoven, ) and dairy cattle herds (Van Engelen et al, ). Efforts were made to gain insight in direct transmission, via direct contact (e.g., via exchange of infected animals/materials) as well as indirect transmission.…”

“…Efforts were made to gain insight in direct transmission, via direct contact (e.g., via exchange of infected animals/materials) as well as indirect transmission. Proxies for direct transmission were identified (e.g., number of animal supply addresses; Schimmer et al, ; Van Engelen et al, ), origin of straw (Schimmer et al, ) and indirect transmission (e.g., distance to nearest infect farm (Schimmer et al, ), farm region (Schimmer et al, ) and animal density (Schimmer et al, ).…”