An MLV Vaccine Elicits a Protective Serological Response to CPV Earlier than Three Other Vaccines
Canine parvovirus (CPV) remains one of the most significant and widespread infectious pathogens that is associated with high mortality rates in dogs and in particular in young animals. Some commercial CPV vaccines have shown to induce protective immunity in pups however very little information is available on the speed of onset of immunity. In this study the onset of seroconversion to CPV after primary vaccination in dogs using 4 different commercial vaccines was measured.
Forty-eight dogs were assigned to four treatment groups of twelve animals each according to a randomised block design with blocking based on litter. Animals were between 51 to 60 days old when they received their 1st vaccination on study day 0 and between 79 to 88 days old when they received their booster. All puppies were from vaccinated bitches and had CPV antibody titres < 1:10 pre-vaccination on study day 0. The animals in the first group (P) were vaccinated with VanguardTM 7 (Pfizer). The other 3 groups (M, V and I) were vaccinated with three different commercial DHPPi+L vaccines. Blood samples were collected from all animals on study day 0 and -28 prior to vaccination, and then daily from study day 1 to 7 inclusive and on study days 14, 21, 32, 35, 39, 42, 49, 56 and 63. The samples were analysed by haemagglutination inhibition (HAI) test for the detection of antibodies to CPV.
CPV antibody titres of 1:80 or greater using HAI test are considered to be protective (McCaw et al., 1998). Group P (VanguardTM 7) had a geometric least squares mean CPV HAI antibody titre > 80 within six days after the 1st vaccination. Group M had a geometric least square mean CPV HAI antibody titre > 80 within 21 days after the 1st vaccination. Group V and Group I had a geometric least square mean CPV HAI antibody titre > 80 within 14 days after the 1st vaccination. All animals that received VanguardTM 7 had protective CPV HAI antibody titres within 14 days after the 1st vaccination, before administration of the second vaccination dose. All animals that received the other 3 vaccines only had protective CPV HAI antibody titres within 35 days after the 1st vaccination.
VanguardTM 7 induced a more rapid CPV protective seroconversion compared to three other commercial vaccines.