CONGENITAL INFECTION OF PIGS WITH RUMINANT-TYPE PESTIVIRUSES

Congenital infections of pigs were induced with two ruminant-type pest iviruses isolated from pigs. One of the viruses was bovine viral diarr hoea virus-like and the other border disease virus-like. Both produced symptoms similar to those observed with low virulence strains of clas sical swine fever virus. A striking effect of persistent virus infecti on in post-natal life was stunting in viraemic animals. It was also sh own that a congenitally infected pig shed virus for 2.5 years and in s ufficient quantity to infect other pigs, even by indirect contact. Unl ike ruminants, congenitally infected pigs sometimes had persistent vir aemia but eventually eliminated the virus. Clearance of virus from the blood was related to the appearance of neutralizing antibodies. Howev er, clearance from the tissues sometimes took as much as 5 months long er than from the blood.