Management of a <i>Coxiella</i> <i>burnetii</i>-infected sheep flock after an outbreak of Q fever in humans

Abstract

Following an outbreak of Q fever in a group of students who contracted the infection during a training course on a sheep farm, a detailed investigation of the sheep flock involved was conducted. Of 478 flock animals, 60 Coxiella burnetii ELISA-positive and 60 ELISA-negative ewes were selected for the trial and divided into four groups. A month after the initial ELISA screening, all ewes in the flock (except the control group) were vaccinated. Sequentially collected blood samples were tested with ELISA and PCR; feces, milk, manure, bedding, and soil were tested with PCR. The immune response to the vaccination was 92.7%, while the overall C. burnetii seroprevalence in the flock after the human outbreak was 64.9%. PCR was positive for 0.2% of milk samples and 34.4% of fecal samples of animals from all four trial groups. C. burnetii DNA was not detected in any of the blood samples. Manure was PCR-positive for about 35 months; bedding from the stable was also positive while samples of pasture soil were negative. It appears that extensive cleaning and disinfection combined with vaccination could be regarded as an appropriate approach to control/prevent Q fever in farm settings even in the short term.

Controlling Coxiella burnetii in naturally infected sheep, goats and cows, and public health implications: a scoping review

“…The positive results highlighted the implementation as a short-term control measure. The authors stressed the importance of manure as a source of environmental contamination with an infection persistence of 3 years ( 23 ). Finally, a positive effects of a 2-year control program combining goat vaccination with biosecurity and hygiene measures (no visitors, disinfection and safe disposal of placentas and manure, and keeping females in their last pregnancy stage indoors) was described.…”

“…Others ( 31 , 36 ) describe confirmed Q fever infections in humans or suggest ( 27 ) using their results to prevent zoonotic risk. Finally, six studies indicate that disease research in animals is motivated by outbreaks in humans ( 23 , 29 , 32 , 33 , 38 , 48 ). Six studies of sheep and goats used vaccination as a single control measure for Q fever.…”

“…Two small ruminant studies investigated the combination of vaccination with biosecurity and hygiene control measures. They concluded that this combination could be a short-term control option in sheep flocks in terms of environmental contamination control ( 23 ). The combination of vaccination, antibiotics, biosecurity and hygiene measures on a goat farm was effective in controlling a Q fever goat outbreak ( 31 ).…”

Efficacy of Phase I and Phase II Coxiella burnetii Bacterin Vaccines in a Pregnant Ewe Challenge Model

“…A wide range of animals, as well as humans, can be infected with C. burnetii ; however, domestic ruminants, principally dairy cows, sheep, and goats, are the main reservoirs and are responsible for most Q-fever outbreaks [ 4 , 5 , 6 ]. Infected livestock generally lack clinical signs prior to the onset of adverse reproductive outcomes, including the birth of weak offspring, abortion and infertility [ 7 ].…”

Genome-wide epitope mapping across multiple host species reveals significant diversity in antibody responses to Coxiella burnetii vaccination and infection

“…In pregnant women, its infection can provoke placentitis, leading to abnormal pregnancy outcomes, including miscarriage, pre-term delivery, and low birth weight (8). Domestic ruminants, in particular dairy cows, sheep, and goats, are the main reservoir of human infections (9)(10)(11). In ruminants, C. burnetii can cause abortion, stillbirth, and delivery of weak offspring (12), with these clinical signs more commonly observed in small ruminants than in cattle (13).…”