Strongyloides ransomi: prenatal and transmammary infection of pigs of sequential litters from dams experimentally exposed as weanlings.

Prenatal infection of pigs with Strongyloides ransomi occurred in 12% of 104 pigs and in 14% of 21 litters farrowed by 13 sows experimentally exposed to infective larvae as weanlings. Transmammary passage was observed in 38 of 39 litters studied. Milk samples obtained from 14 sows showed that larvae were usually shed in the colostrum within 24 hours after farrowing; however, larvae were recovered from samples of milk of sows up to 20 days after parturition. Larvae were recovered from milk samples obtained after each parturition up to the fourth. Prenatal infection in pigs was not detected after the 1st litter.