Progression of Q fever and <i>Coxiella burnetii</i> shedding in milk after an outbreak of enzootic abortion in a goat herd

Berri, Mustapha; Rousset, Élodie; Héchard, Céline; Champion, Jean-Luc; Dufour, Philippe; Russo, Pierre; Rodolakis, Annie

doi:10.1136/vr.156.17.548

Cited by 54 publications

(45 citation statements)

References 5 publications

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“…Low levels of C. burnetii DNA were also detected in milk (C T Ͼ30.5), which fits with the prevailing opinion among experts that sheep shed lower burdens of C. burnetii in milk than do cows and goats (3). We also confirmed that vaginal and fecal shedding durations varied among ewes (17,20) and that shedding may be discontinuous, as in goats (19,23,25,26,37) and cows (18,24). The latter finding suggests that the number of C. burnetii shedders may be underestimated if only one shedding route is investigated and/or if the animals are not repeatedly tested over time.…”

Section: Discussionsupporting

confidence: 65%

Circulation of Coxiella burnetii in a Naturally Infected Flock of Dairy Sheep: Shedding Dynamics, Environmental Contamination, and Genotype Diversity

Joulié

Laroucau

Bailly

et al. 2015

Appl Environ Microbiol

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Q fever is a worldwide zoonosis caused by Coxiella burnetii. Domestic ruminants are considered to be the main reservoir. Sheep, in particular, may frequently cause outbreaks in humans. Because within-flock circulation data are essential to implementing optimal management strategies, we performed a follow-up study of a naturally infected flock of dairy sheep. We aimed to (i) describe C. burnetii shedding dynamics by sampling vaginal mucus, feces, and milk, (ii) assess circulating strain diversity, and (iii) quantify barn environmental contamination. For 8 months, we sampled vaginal mucus and feces every 3 weeks from aborting and nonaborting ewes (n ‫؍‬ 11 and n ‫؍‬ 26, respectively); for lactating females, milk was obtained as well. We also sampled vaginal mucus from nine ewe lambs. Dust and air samples were collected every 3 and 6 weeks, respectively. All samples were screened using real-time PCR, and strongly positive samples were further analyzed using quantitative PCR. Vaginal and fecal samples with sufficient bacterial burdens were then genotyped by multiple-locus variable-number tandem-repeat analysis (MLVA) using 17 markers. C. burnetii burdens were higher in vaginal mucus and feces than in milk, and they peaked in the first 3 weeks postabortion or postpartum. Primiparous females and aborting females tended to shed C. burnetii longer and have higher bacterial burdens than nonaborting and multiparous females. Six genotype clusters were identified; they were independent of abortion status, and within-individual genotype diversity was observed. C. burnetii was also detected in air and dust samples. Further studies should determine whether the within-flock circulation dynamics observed here are generalizable.Q fever is a widespread zoonosis caused by Coxiella burnetii, a Gram-negative intracellular bacterium that has been reported in a broad range of host species. Livestock, especially small ruminants, are the main sources of human infections (1-3). In domestic ruminants, Q fever's major clinical manifestations are abortions and stillbirths, whose occurrence may translate into significant economic losses (1, 3). In humans, C. burnetii infections range from asymptomatic to severe. Acute forms of the disease may result in high fevers and severe pneumonia or hepatitis, and chronic forms are strongly debilitating and may be fatal when endocarditis develops in patients with underlying heart disease (4-6).Animals and humans become infected essentially through the inhalation of airborne particles contaminated with C. burnetii (3,7,8). Contaminated dust particles may remain infectious for long periods of time due to the capacity of the bacterium to differentiate into highly resistant spore-like forms (9, 10). Consequently, knowledge of C. burnetii's sources and shedding dynamics is essential to assessing the risks of disease transmission and pathogen persistence. On livestock farms, C. burnetii DNA has been found in various environmental matrices, such as dust (11-13) and aerosols (14-16). However, studies that examin...

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Section: Discussionsupporting

confidence: 65%

Circulation of Coxiella burnetii in a Naturally Infected Flock of Dairy Sheep: Shedding Dynamics, Environmental Contamination, and Genotype Diversity

Joulié

Laroucau

Bailly

et al. 2015

Appl Environ Microbiol

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“…In the United States there are currently no approved C. burnetii are inconsistent [8,15,24]. In past studies, a major limitation may have been the reliance on serology to define C. burnetii infection status, as serology is poor indicator of active C. burnetii shedding in individual animals [1,5,6,9,18]. Classically, confirmation of active infection in cattle required isolation of the organism either by laboratory animal or cell culture inoculation [1,4,7,13,16], and currently few laboratories carry out isolation due to legal limitations, risk of human exposure, and lack of sensitivity of the technique [1,9,18].…”

Section: Introductionmentioning

confidence: 99%

“…Classically, confirmation of active infection in cattle required isolation of the organism either by laboratory animal or cell culture inoculation [1,4,7,13,16], and currently few laboratories carry out isolation due to legal limitations, risk of human exposure, and lack of sensitivity of the technique [1,9,18]. A small number of recent studies have described PCR-based DNA detection to identify shedding of C. burnetii in ruminants, including dairy cattle with reproductive disorders [5,6,9,24].…”

Section: Introductionmentioning

confidence: 99%

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Association betweenCoxiella burnetii shedding in milkand subclinical mastitis in dairy cattle

et al. 2008

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-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

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“…A positive antibody titer result in an infected animal does not correspond to shedding of organisms, and some seronegative animals may still actively shed bacteria. [10][11][12][13][14] Quantitative PCR assay of biological matter or fluids (eg, feces, milk, or vaginal fluid) is a rapid and highly sensitive method of diagnostic testing for C burnetii infection. 15,16 It has the advantage of determining the number of animals in a herd currently shedding the organism and quantifying the bacterial load.…”

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confidence: 99%

Epizootiological investigation of a Q fever outbreak and implications for future control strategies

Anderson¹,

Szymanski²,

Emery³

et al. 2015

javma

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Objective-To describe the epizootiological investigation of an outbreak of Q fever (Coxiella burnetii infection). Design-Epidemiological study. Animals-17 goat herds in Washington, Montana, and Oregon. Procedures-In April 2011, an abortion storm at a commercial goat farm in Washington was determined to be caused by C burnetii. A joint epidemiological investigation by public health and veterinary professionals was subsequently performed to assess the extent of the outbreak by performing a trace-forward of goats sold from the index farm, to determine risk factors associated with infection, and to implement control measures. A herd management plan was developed to control the outbreak and reduce risk of human exposure. Quarantine and temporary holds preventing the sale or movement of goats allowed time for trace-forward investigation, education of farmers regarding disease risk, and testing to determine the scope of the outbreak. Results-17 farms were affected; 21 human Q fever cases were identified. Bacterial shedding in feces, vaginal fluid, or milk was confirmed in 156 of 629 (25%) goats tested by PCR assay. Seroprevalence of antibodies against C burnetii in goats, determined by ELISA, was 12%. The risk for C burnetii infection in goats was highest among females, those on farms associated with human Q fever, and those on Washington farms. A protective effect was observed for goats at farms where the primary form of goat carcass disposal was burial. Conclusions and Clinical Relevance-This outbreak illustrated the importance of a joint investigation for zoonotic pathogens and the need to expand and strengthen relationships between medical, public health, and veterinary partners. Heightened awareness and enhanced veterinary diagnostic capabilities for C burnetii are needed to identify and control outbreaks expediently. (J Am Vet Med Assoc 2015;247:1379-1386

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Progression of Q fever and Coxiella burnetii shedding in milk after an outbreak of enzootic abortion in a goat herd

Cited by 54 publications

References 5 publications

Circulation of Coxiella burnetii in a Naturally Infected Flock of Dairy Sheep: Shedding Dynamics, Environmental Contamination, and Genotype Diversity

Circulation of Coxiella burnetii in a Naturally Infected Flock of Dairy Sheep: Shedding Dynamics, Environmental Contamination, and Genotype Diversity

Association betweenCoxiella burnetii shedding in milkand subclinical mastitis in dairy cattle

Epizootiological investigation of a Q fever outbreak and implications for future control strategies

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