| Abstract |
While shedding routes of are identified, the characteristics of sheddingare still widely unknown, especially in dairy cattle. However, thisinformation is crucial to assess the natural course of infection within aherd and then to elaborate strategies to limit the risks of transmissionbetween animals and to humans. The present study aimed at (i) describing thecharacteristics of shedding by dairy cows (in milk, vaginal mucus, faeces)in five infected dairy herds, and at (ii) investigating the possiblerelationships between shedding patterns and serological responses. A totalof 145 cows were included in a follow-up consisting of seven concomitantsamplings of milk, vaginal mucus, faeces and blood (Day 0, D7, D14, D21,D28, D63, D90). Detection and quantification of titres were performed inmilk, vaginal mucus and faeces samples using real-time PCR assay, whileantibodies against were detected using an ELISA technique. For a givenshedding route, and a given periodicity (weekly or monthly), cows weregathered into different shedding kinetic patterns according to the sequenceof PCR responses. Distribution of estimated titres in was describedaccording to shedding kinetic patterns. shedding was found scarcely andsporadically in faeces. Vaginal mucus shedding concerned almost 50% ofthe cows studied and was found intermittently or sporadically, depending onthe periodicity considered. Almost 40% of cows were detected as milkshedders, with two predominant shedding patterns: persistent and sporadic,regardless of the sampling periodicity. Significantly higher estimatedtitres in were observed in cows with persistent shedding patternssuggesting the existence of heavy shedder cows. These latter cows weremostly, persistently highly-seropositive, suggesting that repeatedserological testings could be a reliable tool to screen heavy shedders,before using PCR assays. |
Vet.Res._0928-4249_2007_38_6/Vet.Res._0928-4249_2007_38_6_ART0006.pdf