Small plaque variant transmissible gastroenteritis virus.

A small plaque (SP) variant transmissible gastroenteritis (TGE) virus strain that may be useful in the control of TGE in swine has been developed and tested. This strain was derived from a persistently infected swine leukocyte cell line originally infected with a virulent TGE virus. The SP viral strain was avirulent for 3-day-old susceptible pigs and pregnant gilts. The SP virus elicited protective antibody when inoculated into pregnant gilts oral/intranasally, or intramammarily, or by both of these routes. The morbidity and mortality of their passively immune suckling pigs were 62% and 14%, respectively.