Role of maternally derived circulating antibodies in protection of neonatal swine against porcine group A rotavirus.

The ability of maternally derived antibodies in the circulation of neonatal pigs to protect against challenge with virulent porcine group A rotavirus (OSU strain) was evaluated. Groups of neonatal pigs with nondetectable (group 1), low (group 2), or high (group 3) serum levels of OSU rotavirus-specific maternally derived antibodies were challenged with virulent OSU rotavirus at 3 days of age and monitored for infection and disease. Control pigs were sham-inoculated with diluent at 3 days of age. Although all virus-inoculated pigs shed rotavirus and developed diarrhea, group 3 pigs developed significantly less severe diarrhea and shed for significantly fewer days than group 1 and 2 pigs, and they maintained appetites and weight gains comparable to sham-inoculated controls. It was concluded that circulating maternally derived antibodies play a significant role in mitigating clinical disease following rotavirus infection in neonatal swine and that the protection afforded by these antibodies is titer dependent.