The administration of a single dose of a multivalent (DHPPiL4R) vaccine prevents clinical signs and mortality following virulent challenge with canine distemper virus, canine adenovirus or canine parvovirus

Abstract

Four challenge studies following vaccination of dogs with a multivalent vaccine containing canine parvovirus (CPV-2b), adenovirus (CAV-1/-2) and distemper (CDV) are described. Six week old puppies received a single vaccination while non-vaccinated control dogs received water. In each respective trial, groups of dogs were challenged 21days after vaccination with heterologous viral isolates. Clinical observations, rectal temperature measurements, and blood and swab samples for analysis were collected throughout the study.Dogs in all studies had normal temperatures and general health up to challenge. Clinical signs of infection and temperatures outside the normal range were observed in non-vaccinated dogs challenged with CDV, CPV, CAV-1 and CAV-2; vaccinated dogs remained clinically normal after challenge. All dogs were sero-negative prior to vaccination, non-vaccinated dogs remaining negative until challenge. Vaccinated dogs all sero-converted by 21days after vaccination, with further increases seen after challenge. Non-vaccinated dogs sero-converted following challenge with CPV or CAV-2; no final blood samples were taken in the CDV and CAV-1 studies. Rectal swab analysis showed prevention of CPV shedding in vaccinated compared to non-vaccinated dogs, and nasal swab analysis following CAV-2 challenge showed longer duration and higher amount of viral shedding for non-vaccinated dogs.In conclusion, we demonstrated that a single administration of a minimum titre, multivalent vaccine to dogs of six weeks of age is efficacious and prevents clinical signs and mortality caused by CAV-1 and CDV; prevents clinical signs and significantly reduces virus shedding caused by CAV-2; and prevents clinical signs, leucopoenia and viral excretion caused by CPV.