Assessing the within-herd prevalence of Coxiella burnetii milk-shedder cows using a real-time PCR applied to bulk tank milk.
Thirty-seven bulk tank milk (BTM) and individual milk samples of all contributing cows were tested for Coxiella burnetii detection by a real-time PCR assay and used to assess the relationship between the BTM PCR-response and (i) the within-herd prevalence of milk-shedder cows and (ii) the proportion of heavy milk-shedder cows. The within-herd prevalence of milk-shedder cows (i) was found to be significantly higher in herds with a positive BTM and (ii) increased significantly with the estimated titre in Coxiella burnetii obtained in positive BTM. The proportion of heavy milk-shedder cows among the milk-shedder cows increased significantly with an increased estimated titre in Coxiella burnetii in positive BTM. Therefore, a real-time PCR assay applied to BTM samples collected repeatedly over time appears to be a valuable tool to assess on a larger scale the status of herds towards Coxiella shedding, and to evaluate the efficiency of control actions aimed at controlling and/or preventing Coxiella shedding in dairy herds.
Guatteo
R
R
Unit of Animal Health Management, Veterinary School & INRA, BP 40706, 44307 Nantes Cedex 03, France. guatteo@vet-nantes.fr
Beaudeau
F
F
Joly
A
A
Seegers
H
H
D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology* / Q000209:etiology / Q000382:microbiology / Q000635:transmission; D016997:Coxiella burnetii / Q000235:genetics / Q000302:isolation & purification*; D004269:DNA, Bacterial / Q000032:analysis; D003612:Dairying; D005260:Female; D005602:France / Q000453:epidemiology; D008892:Milk / Q000382:microbiology*; D016133:Polymerase Chain Reaction / Q000662:veterinary; D015995:Prevalence; D011778:Q Fever / Q000453:epidemiology / Q000662:veterinary*
D004269:DNA, Bacterial