Preliminary development of a live attenuated canine parvovirus vaccine from an isolate of British origin

Abstract

Canine parvovirus isolated from a case of haemorrhagic enteritis in a breeding kennel in England was passaged and cloned in cultured feline and canine cells. No significant evidence of pathogenicity was found during six serial passages of the modified virus back through young dogs. The attenuated virus was excreted by inoculated animals and spread rapidly to uninoculated animals held in contact. When high titre attenuated virus was given to the six-week-old offspring of a seropositive dam a prompt seroconversion was observed. When the attenuated virus was used as an experimental vaccine in 108 pups in an infected breeding colony a highly significant improvement was obtained in the accumulated morbidity and mortality compared with a parallel group vaccinated with modified live feline panleucopenia virus.

Differentiation of Wild‐ and Vaccine‐type Canine Parvoviruses by PCR and Restriction‐enzyme Analysis

“…Through the development and evaluation of ML CPV vaccines, the markers mainly used to differentiate the vaccine strains from the wild strains were virulence in dogs and in witvo growth characteristics (e.g. character of plaques formed on cultured cells; (CARMICHAEL, et al, 1981(CARMICHAEL, et al, , 1984CHURCHILL, 1987). Recently, a genetic typing method based on the PCR was reported (SENDA et al, 1995), in which only CPV of new types (types 2a and 2b) was detected using the new type-specific primers; thus, wild strains of new types could be distinguished from vaccine strains of old-type origin.…”

“…Although there is little question about the safety of the ML vaccine, most dogs inoculated with the vaccine seem to shed the vaccine virus in faeces, resulting in the U.S. Copyright Clearance Center Code Statement: 0931 -1793/95/4210 -0601$11.00/0 and 4 seem to have the same origin spread of the virus t o contact animals (CARMICHAEL et al, 1981(CARMICHAEL et al, , 1984BASS et al, 1982;POLLOCK, 1984;BRUNNER and SWANGO, 1985;CHURCHILL, 1987). Thus, there is some possibility that vaccine o r vaccine-related viruses are circulating in the dog population.…”

“…Thus, there is some possibility that vaccine o r vaccine-related viruses are circulating in the dog population. Currently available markers that can differentiate wild-and vaccine-type CPVs are, however, biological markers, which mark virulence in dogs and in vitro growth characteristics (CARMICHAEL et al, 1981(CARMICHAEL et al, , 1984CHURCHILL, 1987). Virus typing using these biological markers is laborious and time-consuming.…”

“…Virus typing using these biological markers is laborious and time-consuming. With regard t o this problem, it has already been suggested that restriction-enzyme analysis of the viral DNA is probably a useful genetic method of differentiating the virus strains (CHURCHILL, 1987). Better methods involving genetic analysis therefore seem to be necessary to clarify this possibility.…”

Overview of new vaccines and technologies

“…Effective vaccines against canine parvovirus have been available since the 1980s, when only the CPV2 type virus was present (Churchill, 1987). Since then, the virus has evolved in Europe and the US, producing CPV2a and 2b types but CPV2 vaccines can still protect against these new strains due to the antibody response against the VP2 protein (Greenwood et al, 1995,).…”