Koichiro Gamoh

Efficacy of an inactivated feline panleucopenia virus vaccine against a canine parvovirus isolated from a domestic cat

Canine parvovirus type 2a (CPV-2a) and type 2b (CPV-2b) have recently been isolated from cats throughout the world, and CPV-2b strain FP84 has been reported to be virulent in domestic cats. Although live feline panleucopenia virus (FPLV) vaccines protect domestic cats from CPV infection, the efficacy of inactivated FPLV vaccines has not been established. In this study, two domestic cats were vaccinated with a commercial inactivated FPLV vaccine and challenged with CPV-2b strain FP84 isolated from a domestic cat. The cats were protected against CPV-2b strain FP84 infection and their clinical signs were suppressed, although the two unvaccinated cats showed the typical clinical signs of parvovirus infection.

Introduction of an update system for vaccine strains of veterinary influenza vaccines in Japan.

The basic countermeasures used to control highly pathogenic avian influenza (HPAI) are early detection procedures and the culling of affected chickens. However, if successive HPAI outbreaks occur, the vaccination may be an option for controlling HPAI. Therefore, avian influenza (AI) vaccines are stocked by the Japanese government. By contrast, equine influenza (EI) vaccine is an effective tool for preventing or controlling EI. Because antigenic drifts affect the efficacy of AI and EI vaccines, the vaccine strains should be updated rapidly. However, the development and registration of veterinary vaccines usually takes several years. In response to this issue, the Ministry of Agriculture, Forestry, and Fisheries (MAFF) established a system that allows AI and EI vaccine strains to be updated rapidly. National Veterinary Assay Laboratory, MAFF, established a vaccine strains selection committee for veterinary influenza vaccine. The main agendas involve determining whether the current vaccine strains need to be updated and selecting the most appropriate vaccine strains. The committee concluded that A/duck/Hokkaido/Vac-3/2007(H5N1) was added to the strains of stockpiled AI vaccines and that the EI vaccine strains did not need to be changed, but that the clade 2 viruses of the Florida sub-lineage strain, A/equine/Yokohama/aq13/2010(H3N8) was added to the EI vaccine strain.

Protective efficacy of stockpiled vaccine against H5N8 highly pathogenic avian influenza virus isolated from a chicken in Kumamoto Prefecture, Japan in 2014

H5 highly pathogenic avian influenza (HPAI) viruses have spread worldwide, and antigenic variants of different clades have been selected. In this study, the national stockpiled vaccine prepared from A/duck/Hokkaido/Vac-1/2004 (H5N1) strain was evaluated for the protective efficacy against H5N8 HPAI virus isolated in Kumamoto prefecture, Japan, in April 2014. In the challenge test, all of the vaccinated chickens survived without showing any clinical signs and reduced virus shedding. It was concluded that the present stockpiled vaccine was effective against the H5N8 HPAI virus.

Antigenic type distribution of parvovirus isolated from domestic cats in Japan.

FELINE panleucopenia virus (FPLV) and canine parvovirus (cpv) are pathogenic viruses affecting cats and dogs, respectively. FPLV has been prevalent since the 1940s (Goss 1942), whereas cpv was first isolated in 1978 in the USA (Appel and others 1978). cpv is antigenically and genetically very close to FPLV, showing a genome homology of 98 per cent (Truyen and Parrish 1992), and both cPv and FPLV are grouped along with mink enteritis virus (MEV), raccoon dog parvovirus, raccoon parvovirus (RPV) and blue fox parvovirus in the feline parvovirus subgroup. The origin of cpv is not clear; however, the most plausible hypothesis is that it arose from FPLV in domestic cats or from FPLv-like viruses in wild carnivores (Truyen and others 1995). After its appearance, cpv spread rapidly worldwide (Kelly 1978, Gagnon and Povey 1979, Azetaka and others 1981, Cesar and others 2000), and the strain was designated as cpv type 2 (CPV-2) (Parrish and others 1985). Soon after the appearance of CPV-2, a new antigenic variant termed cpv type 2a (CPV-2a) was isolated (Parrish and others 1985), and in around 1982, another antigenic variant termed cpv type 2b (CPV-2b) was isolated (Parrish and others 1991, Senda and others 1995). Both CPV-2a and CPV-2b differ from CPV-2 in host range as well as antigenic properties. Although CPV-2 did not replicate in cats, CPV-2a and CPV-2b replicated efficiently in domestic cats (Truyen and others 1996a). In recent years, CPV-2a or CPV-2b have been isolated from domestic cats in Japan, Germany, USA, Taiwan and Vietnam (Mochizuki and others 1996, Truyen and others 1996a, b, Ikeda and others 2000). Approximately 5 to 10 per cent of parvoviral infections in domestic cats in Germany and the USA are caused by CPV-2a or CPV-2b (Truyen

Update of inactivated equine influenza vaccine strain in Japan

Japan established a vaccine selection system, in which a committee evaluates veterinary influenza vaccines to determine if the vaccine should be updated. In 2013, it was concluded that the present equine influenza vaccine strains did not have to be updated, but clade 2 (Fc2) viruses of the Florida sublineage should be included. We collected three Fc2 viruses as candidates and conducted comparative tests. Results indicated that A/equine/Carlow/2011 (H3N8) is not suitable, because of its unstable antigenic characteristics. A comparison between A/equine/Richmond/1/2007 (H3N8) (Richmond/07) and A/equine/Yokohama/aq13/2010 (H3N8) (Yokohama/10) in eggs showed that they shared equal growth properties. Immunogenicity test in mice showed that Yokohama/10 induced higher HI antibody titers than Richmond/07. Therefore, we concluded that Yokohama/10 was the most suitable strain.