The pathogenicity of canine parvovirus type-2b, FP84 strain isolated from a domestic cat, in domestic cats.

Canine parvovirus type-2a (CPV-2a) and type-2b (CPV-2b) have recently been isolated from domestic cats. The pathogenicity of CPV-2b in domestic cats is still unclear. In this study, we performed infection tests to examine the pathogenicity of CPV-2b, FP84 strain, isolated from a domestic cat. The results demonstrated that the CPV strain FP84 is able to infect and replicate well in domestic cats. Two of the 3 cats used in the test died. They showed loss of appetite, diarrhea, leukopenia and dehydration. Since FP84 was found to be virulent to domestic cats, it is necessary to examine the efficacy of inactivated feline panleukopenia virus vaccines against CPV infection in domestic cats.

Establishment of a potency test by ELISA for a rabies vaccine for animal use in Japan.

The ELISA we developed was able to determine the antigen content and was suitable for a potency test, and we described a relative potency assay method which determines the potency of test vaccines by comparing the ELISA value of a test vaccine to that of a reference vaccine. In the present study, we standardized the reference vaccine used for determining the potencies of test vaccines, and established a potency test by ELISA. We evaluated the proposed reference vaccine by the neutralizing antibody responses in dogs after vaccination, by the challenge protection test in guinea pigs (GP potency test), which is the earlier official potency test used in Japan, and by the NIH potency test, which is widely used throughout the world. The results showed that a 4-fold dilution of the proposed reference vaccine induced sufficient immunity in dogs. A 3-fold dilution of the proposed reference vaccine passed the GP potency test. The international units (IU) calibrated by the NIH potency test were 3.7 IU/dose. From the results and the WHO recommendation that veterinary rabies vaccines should have a potency of at least 1.0 IU/dose, we determined to dilute the proposed reference vaccine by 3 fold and regarded it as the reference vaccine. Finally, we confirmed that there is a good agreement between the results of the potency test by ELISA and the results of the GP potency test. The establishment of the potency test by ELISA has made it possible to monitor the potency in the production process and has contributed to the stable production of the vaccine.