Q-FEVER (COXIELLA-BURNETII) INVESTIGATIONS IN DAIRY-CATTLE - CHALLENGE OF IMMUNITY AFTER VACCINATION

  • 1 January 1976
    • journal article
    • research article
    • Vol. 37  (6) , 631-634
Abstract
The immunity of Holstein-Friesian dairy cows vaccinated against C. burnetii was challenged with 4 .times. 108 infective guinea pig doses of viable rickettsiae. Cows that were vaccinated had normal full-term calves; 2 nonvaccinated cows aborted late in pregnancy. Intrauterine infection of the fetus was indicated by recovery of the organism from tissues of the fetus. C. burnetii was recovered from milk, colostrum, and placenta of vaccinated and nonvaccinated cows after challenge inoculation, but the rickettsiae recovered were as many as 1000 times more numerous in nonvaccinated cows.