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The main aim of this study was to quantify the amount of virus shed in feces of pigs vaccinated with attenuated or inactivated vaccines and in unvaccinated pigs following challenge with Lelystad PRRS virus strain. Another aim was to detect IgA antibodies in fecal samples and to prove possible relationship between the amount of shed virus and the titer of IgA in feces.
Seventeen piglets divided into five groups were used in our study (three animals in each vaccinated group, five animals in control group). Commercially available inactivated (In-A, In-B) and attenuated (MLV-A, MLV-B) vaccines were used. Control group was left unvaccinated. Subsequently all groups were exposed to 106 TCID50 of PRRSV (Lelystad strain). Fecal samples were collected in one week intervals. Virus RNA was detected by qRT – PCR test, ORF7 specific IgA antibodies by ELISA test.
The virus was present in feces in almost all (but one) animals vaccinated with attenuated vaccine or following experimental infection. The titer of shed virus was not influenced by the type of used vaccine and reached 105 virus genome copies/g in all vaccinated and control groups of piglets. Nonetheless in some animals intermittent shedding was observed.
All vaccines were able to induce IgA antibody response in the gut of piglets. The titer of IgA antibodies didn´t correlate with the amount of shed virus.
J. Chlebovská, J. Frölichová, V. Celer. PRRS virus shedding and IgA antibody response in feces of vaccinated pigs. 2014 North American PRRS Symposium.
