viral cause of the SMEDI syndrome in the U.K. (stillbirths, mummification and
embryonic deaths). Replicates in the epithelium of the alimentary tract with viraemia
without causing clinical signs in fattening and breeding stock. Virus recovered from most
excretions. Transplacental infection occurs. In early pregnancy, causes resorption and may
maifest as infertility; later in pregnancy, SMEDI syndrome. Congenitally infected pigs may
remain as excretors; some piglets in litter escape infection.