Bovine leucosis virus contamination of a vaccine produced in vivo against bovine babesiosis and anaplasmosis.
Contamination of a batch of tick fever (babesiosis and anaplasmosis) vaccine with bovine leucosis virus (BLV) was detected when a herd, in the final stages of an enzootic bovine leucosis (EBL) accreditation program, developed a large number of seropositive cattle following use of tick fever vaccine. Investigations incriminated a single calf used to produce Anaplasma centrale vaccine from which 13,959 doses were distributed. The failure of this calf to give a positive agar gel immunodiffusion (AGID) test before use was not fully explained. A total of 22,627 cattle from 111 herds receiving contaminated vaccine was tested to validate claims for compensation. Results showed infection rates of 62% and 51.8% in vaccinated dairy and beef cattle, respectively, compared with 6.1% and 1.5% in non-vaccinated cattle in the same herds. The results also indicated that infection did not spread from vaccinated to non-vaccinated in-contact cattle. Heavy reliance is now placed on purchase of calves for vaccine production from EBL accredited-free herds and on transmission tests from the calves to sheep to prevent a recurrence of contamination. The need for a BLV antigen detection test, with the sensitivity of the sheep transmission test but simpler and faster to perform, is evident.
Rogers
R J
RJ
Animal Research Institute, Queensland Department of Primary Industries, Yeerongpilly.
Dimmock
C K
CK
de Vos
A J
AJ
Rodwell
B J
BJ
D000709:Anaplasma / Q000276:immunology; D000712:Anaplasmosis / Q000517:prevention & control*; D000818:Animals; D000914:Antibodies, Viral / Q000032:analysis; D001315:Australia; D001404:Babesiosis / Q000517:prevention & control*; D002417:Cattle; D002418:Cattle Diseases / Q000517:prevention & control*; D004340:Drug Contamination; D005779:Immunodiffusion; D007938:Leukemia / Q000453:epidemiology / Q000276:immunology / Q000635:transmission*; D001909:Leukemia Virus, Bovine / Q000276:immunology / Q000302:isolation & purification; D012756:Sheep; D013997:Time Factors; D014765:Viral Vaccines / Q000627:therapeutic use*
D000914:Antibodies, Viral; D014765:Viral Vaccines