A longitudinal study of serological responses to Coxiella burnetii and shedding at kidding among intensively-managed goats supports early use of vaccines

AbstractVaccination againstCoxiella burnetii, the cause of Q fever, is reportedly the only feasible strategy of eradicating infection in ruminant herds. Preventive vaccination of seronegative goats is more effective in reducing shedding ofC. burnetii than vaccinating seropositive goats. The age at which goats born on heavily-contaminated farms first seroconvert toC. burnetii has not yet been documented. In a 16-month birth cohort study, the age at which goats seroconverted againstC. burnetii was investigated; 95 goats were bled every 2  weeks and tested for antibodies againstC. burnetii. Risk factors for seroconversion were explored and goats sheddingC. burnetii were identified by testing vaginal swabs taken at the goats ’ first kidding using acom1 polymerase chain reaction assay. The first surge in the number of goats with IgM toC. burnetii was observed at week 9. Thus, a first vaccination not later than 8  weeks of age to controlC. burnetii in highly contaminated environments is indicated. The odds of seroconversion were 2.0 times higher [95% confidence interval (CI) 1.2, 3.5] in kids born by does with serological evidence of recent infection (IgM seropositive) compared to kids born by IgM seronegative does, suggesting either in utero transmission or peri-parturient infection. The rate of seroconversion was 4.5 times higher (95% CI 2.1, 9.8) during than outside the kidding season, highlighting the risk posed byC. burnetii shed during kidding, even to goats outside the k...
Source: Veterinary Research - Category: Veterinary Research Source Type: research