title: USDA regulatory guidelines and practices for veterinary Leptospira vaccine potency testing.
abstract: Batch-release potency testing of leptospiral vaccines licensed by the United States Department of Agriculture (USDA) historically was conducted through animal vaccination-challenge models. The hamster vaccination-challenge assay was Codified in 1974 for bacterins containing Leptospira pomona, Leptospira icterohaemorrhagiae, and Leptospira canicola, and in 1975 for bacterins containing Leptospira grippotyphosa. In brief, 10 hamsters are vaccinated with a specified dilution of bacterin. After a holding period, the vaccinated hamsters, as well as nonvaccinated controls, are challenged with virulent Leptospira and observed for mortality. Eighty percent of vaccinated hamsters must survive in the face of a valid challenge. The high cost of the Codified tests, in terms of monetary expense and animal welfare, prompted the Center for Veterinary Biologics (CVB) to develop ELISA alternatives for them. Potency tests for other serogroups, such as Leptospira hardjo-bovis, that do not have Codified requirements for potency testing continue to be examined on a case-by-case basis.
authors.affiliation: Center for Veterinary Biologics, Animal and Plant Health Inspection Service, United States Department of Agriculture, P.O. Box 844, Ames, IA 50010, USA. Electronic address: Geetha.B.Srinivas@aphis.usda.gov.
authors.forename: G B
authors.initials: GB
authors.lastname: Srinivas
authors.forename: A
authors.initials: A
authors.lastname: Walker
authors.forename: B
authors.initials: B
authors.lastname: Rippke
mesh_terms: D000818:Animals; D001428:Bacterial Vaccines / Q000266:history / Q000276:immunology / Q000494:pharmacology*; D006224:Cricetinae; D049673:History, 20th Century; D049674:History, 21st Century; D007919:Leptospira / Q000276:immunology*; D007922:Leptospirosis / Q000266:history / Q000276:immunology / Q000517:prevention & control* / Q000662:veterinary*; D017410:Practice Guidelines as Topic; D014481:United States; D016885:United States Department of Agriculture; D064166:Vaccine Potency
chemical_list: D001428:Bacterial Vaccines
keywords: Leptospira; Leptospirosis; Potency testing; Regulatory testing; Standard Requirements; Vaccine