An experimental epidemiological study of porcine transmissible gastroenteritis

TGE virus was introduced experimentally into a small herd of pigs, consisting of 12 sows and their progeny housed in isolation, by the oral dosing of 1 litter of piglets with a suspension of the virus. Serum samples from all the pigs in the herd were examined for TGE virus-neutralizing antibodies at monthly intervals for 12 months. The infection spread rapidly and produced disease in almost all the groups of pigs in the herd. Several older animals escaped clinical disease and a few individuals did not develop virus-neutralizing antibodies. Infection of pigs which showed symptoms was confirmed serologically and by piglet inoculation. Susceptible sows and litters added to the herd, 3 4 and 5 months after the TGE outbreak did not become infected. Virus-neutralizing antibodies persisted in the sows for periods of 2 to 12 months. After the TGE outbreak, diarrhoea occurred intermittently in unweaned piglets, but this was not ascribed to infection with the virus. Inoculation of piglets with tissue suspensions did not reveal carriers of TGE virus among the sows which were killed at the end of the experiment, or in 2 sows killed 2 and 3 months after the outbreak.