Association betweenCoxiella burnetii shedding in milkand subclinical mastitis in dairy cattle

Abstract

-The objective of this research was to explore the potential association between Coxiella burnetii shedding in milk and chronic subclinical mastitis in dairy cattle. In two separate studies, we identified an association between PCR-based detection of C. burnetii in milk and chronic subclinical mastitis in lactating dairy cows. These studies were conducted in a commercial dairy herd where there was ongoing intensive monitoring of subclinical mastitis by aerobic bacteriology, but no prior knowledge or management of C. burnetii infections. In a case-control study, quarter level C. burnetii status determined by real-time quantitative PCR (RT-qPCR) was strongly associated with chronic subclinical mastitis as measured by milk somatic cell counts. In a subsequent cross sectional study, 147 (45%) of 325 lactating cows were positive for C. burnetii by RT-qPCR of composite milk samples. In a generalized linear model, accounting for the effect of covariates including aerobic intramammary infection status, C. burnetii PCR status was a significant predictor of linear somatic cell count score. In agreement with a small number of previous reports, this research provides evidence that there may be mammary gland specific manifestations of C. burnetii infections in dairy cattle. Coxiella burnetii / dairy cattle / mastitis

Dynamics of relationship between the presence of Coxiella burnetii DNA, antibodies, and intrinsic variables in cow milk and bulk tank milk from Danish dairy cattle

“…No association between qPCR results and increasing DIM was found, which corresponds to what was reported by Rodolakis et al (2007). However, an association between C. burnetii shedding and increasing DIM was reported by Barlow et al (2008). In contrast to their study, no association between SCC and C. burnetii shedding was found in the present investigation, indicating that in the Danish herds, the presence of C. burnetii in milk was not linked to mammary gland inflammation.…”

“…It can be expected that antibody production start weeks after onset of an infection, but as both DNA shedding and antibody secretion can be transient or intermittent (Guatteo et al, 2007a), a clear relationship between these 2 parameters cannot be expected. Barlow et al (2008) found a strong association between C. burnetii levels in milk measured by qPCR and chronic subclinical mastitis, indicating the possibility of mammary gland-specific manifestations of C. burnetii infections in cattle giving rise to local production of antibodies.…”

“…In the present investigation including 12 herds, 25% of the 1,514 individual cow samples were seropositive, whereas 32% were positive for C. burnetii DNA. Some of these animals probably excreted viable C. burnetii organisms, as viable bacteria in milk samples found positive for C. burnetii by PCR have been reported previously (Barlow et al, 2008;Loftis et al, 2010). Deoxyribonucleic acid shedding in individual milk samples was also investigated by Guatteo et al (2007b) who reported a mean within-herd prevalence of milk-shedder cows of 18.5% (range 0-45%) in 14 French dairy herds.…”

“…Coxiella burnetii is shed mainly in birth products such as fluids and placenta, but may also be excreted in feces, urine, vaginal mucus, and milk (Rodolakis, 2009;Hansen et al, 2011). In cattle, milk has been shown to be a significant route of shedding (Guatteo et al, 2007a) and indications exist that C. burnetii may induce inflammation of the mammary gland in cattle (Barlow et al, 2008). A direct relation between serology and PCR results has not been observed, as seronegative animals may shed C. burnetii and seropositive animals might not excrete the organism continuously (Guatteo et al, 2007a;Rodolakis et al, 2007).…”

Coxiella burnetii infection in sheep and goats: a public risk health, Colombia

“…C. burnetii is a frequent cause of reproductive disorders mainly in minor ruminants [3][4][5] . In goats, it has been reported as a cause of abortions and stillbirths 6,7 and in cows, infection is asymptomatic, but metritis and subclinical mastitis have been described 8 …”