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Evaluation of C oxiella burnetii Status in Dairy Cattle Herds with Bulk‐tank Milk Positive by ELISA and PCR
Author(s) -
Piñero A.,
Barandika J. F.,
Hurtado A.,
GarcíaPérez A. L.
Publication year - 2014
Publication title -
transboundary and emerging diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.392
H-Index - 63
eISSN - 1865-1682
pISSN - 1865-1674
DOI - 10.1111/tbed.12013
Subject(s) - coxiella burnetii , herd , bulk tank , q fever , seroprevalence , veterinary medicine , biology , dairy cattle , seroconversion , serology , population , livestock , feces , zoology , antibody , virology , medicine , immunology , microbiology and biotechnology , environmental health , ecology
Summary Bulk‐tank milk ( BTM ) samples are frequently used to evaluate the health status of dairy livestock. A large‐scale investigation carried out in BTM samples from dairy cattle herds from a Q fever‐endemic region in N orthern S pain revealed a high degree of exposure to C oxiella burnetii . This study was aimed at assessing the value of BTM samples analysis as an indicator of the C . burnetii status in dairy cattle herds. Three herds with BTM samples positive for C . burnetii by ELISA and PCR were selected, and blood, faeces and individual milk and BTM samples were analysed by serology and PCR . In spite of the high antibodies titres found in BTM samples, only one of the three farms presented an active infection by C . burnetii , as revealed by the presence of bacterial DNA in vaginal mucus and in environmental samples collected in the calving area, a seroprevalence around 40% in heifers and the seroconversion rate observed in cows. Results obtained indicated that the analysis of BTM samples is a good epidemiological tool at the population level that can be used to discriminate between seropositive and seronegative herds, but at the herd level, additional tests are necessary to evaluate whether Q fever is a potential problem in the farm. When Q fever is suspected in a cattle herd, sera from a small group of 1‐ to 3‐year‐old animals need to be analysed to investigate recent contact with C . burnetii .