Modifications by Nematoda of the sensitivity of mice to Salmonella abortus ovis administered orally or subcutaneously]

Mice inoculated 6 to 9 days previously with Heligmosomoides polygyrus (=Nematospiroides dubius) become more frequently infected than controls after an oral challenge with a constant dose of Salmonella abortus ovis. But parasitism increases the LD 50 when the subcutaneous route of infection is used, probably by stimulating the immune system of the host.