Larval distribution and histopathology of experimental Strongyloides ransomi infection in young swine.

Necropsy at various intervals of three week old pigs following experimental infection with larvae of Strongyloides ransomi showed distribution of the larvae through the body during the first 24 hours. Quiescent larvae at the 24 hour necropsy, as indicated by higher recovery before and after this period may be an indication of physiological changes preceding a moult. Whether or not a moult occurs in the lung prior to migration of the larvae to the intestine has not been determined. At the 72 hour necropsy, larvae were largely confined to the lung and juvenile worms were beginning to appear in the small intestine. Migration to the small intestine was completed by the 96 hour necropsy. Lesions were observed in the skin and lungs up to the 96 hour necropsy, and lymphocytic accumulations were observed in the skin and lungs to this point and lymphocytic accumulations were observed in the liver to the 72 hour necropsy. At 28 days post-application lung lesions were still evident and the duodenum and jejunum were heavily parasitized. Egg passage began on the sixth day post-application and peaked on the 12th day.