Abortion and premature birth in cattle following vaccination with Brucella abortus strain RB51.
Brucella abortus RB51 is the vaccine strain currently licensed for immunizing cattle against brucellosis in the United States. Most cattle are vaccinated as heifer calves at 4-12 months of age. Adult cattle may be vaccinated in selected high-risk situations. Two herds of pregnant adult cattle in the brucellosis-endemic area of Wyoming were vaccinated with a standard label dose (1.0-3.4 × 10(10) organisms) of RB51. Reproductive losses in the vaccinated herds were 5.3% (herd A) and 0.6% (herd B) and included abortions, stillbirths, premature calves, and unbred cows (presumed early abortion). Brucella abortus was cultured from multiple tissues of aborted and premature calves (7/9), and from placenta. Isolates were identified as B. abortus strain RB51 by standard strain typing procedures and a species-specific polymerase chain reaction. Bronchopneumonia with intralesional bacteria and placentitis were observed microscopically. There was no evidence of involvement of other infectious or toxic causes of abortion. Producers, veterinarians, and laboratory staff should be alert to the risk of abortion when pregnant cattle are vaccinated with RB51, to potential human exposure, and to the importance of distinguishing field from vaccinal strains of B. abortus.
1Amanda M. Fluegel Dougherty, Department of Veterinary Sciences, University of Wyoming, 1174 Snowy Range Road, Laramie, WY 82070. afluegel@uwyo.edu.
Amanda M
AM
Fluegel Dougherty
Todd E
TE
Cornish
Donal
D
O'Toole
Amy M
AM
Boerger-Fields
Owen L
OL
Henderson
Ken W
KW
Mills
D037881:Aborted Fetus / Q000276:immunology / Q000382:microbiology*; D000034:Abortion, Veterinary / Q000453:epidemiology / Q000276:immunology / Q000382:microbiology*; D000818:Animals; D001428:Bacterial Vaccines / Q000276:immunology; D002003:Brucella abortus / Q000276:immunology*; D002006:Brucellosis / Q000453:epidemiology / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D002417:Cattle; D002418:Cattle Diseases / Q000453:epidemiology / Q000276:immunology / Q000382:microbiology*; D004196:Disease Outbreaks / Q000662:veterinary*; D005260:Female; D006651:Histocytochemistry / Q000662:veterinary; D011247:Pregnancy; D014611:Vaccination / Q000009:adverse effects / Q000662:veterinary; D014959:Wyoming / Q000453:epidemiology
D001428:Bacterial Vaccines
Abortion; Brucella abortus; RB51; bovine; cattle; placentitis; premature; vaccination; zoonotic disease