INTERACTIONS OF CERTAIN SWINE ENTEROPATHOGENS. (VOLUMES I AND II) (ISOSPORA, ASCARIS, STRONGYLOIDES)
Abstract
The purposes of this study were to determine how the interaction of certain enteropathogenic agents in the bacterial family, Enterobacteriaceae, and certain swine enteric parasites would affect the host and one another. The effects of a previous inoculation with members of the genera Salmonella and Escherichia on an infection with Ascaris suum were studied in mice. Previous inoculation with Salmonella typhisuis and S. cholerae- suis var. kunzendorf decreased the recovery of migrating ascarid larvae from the mice lungs. This effect appeared to be due to entrapment of migrating larvae by inflammatory reactions in the liver. The number of A. suum larvae migrating to the lungs of mice previously inoculated with Salmonella typhimurium or enterotoxigenic Escherichia coli ETEC was not different from non-inoculated controls. Concurrent infections of neonatal pigs with ETEC and Isospora suis did not produce more severe effects on the pigs' growth or mortality rates than the sum of the effects of the two agents acting alone. The ETEC infection reduced the number of I. suis oocysts shed in the feces of the pigs. Concurrent infection of neonatal pigs with S. typhisuis and I. suis produced a more severe depression in growth and a greater death loss than could be accounted for by the effects of the two agents acting alone. The S. typhisuis infection appeared to reduce the number of oocysts shed in the pigs' feces. Concurrent infection of neonatal pigs with ETEC and Strongyloides ransomi accelerated the time of death but did not otherwise alter the mortality rate or weight gains when compared to single infections. The ETEC infection had no observed effect on the numbers of S. ransomi eggs produced. Sequential infections of pigs with ETEC at 24 hours of age, followed by I. suis at three weeks of age, did not produce effects on the host different from those seen with I. suis infection alone. The previous colibacillosis had no effect on the number of oocysts shed in the pigs' feces.
Degree
Ph.D.
Subject Area
Veterinary services
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