CROSS-RESISTANCE BETWEEN TRICHINELLA-SPIRALIS AND ANGIOSTRONGYLUS-CANTONENSIS IN LABORATORY RATS

Rats were sensitized with one dose of 20, 30, or 100, or three doses of 30 Trichinella spiralis larvae and then given a challenge infection with 100 third-stage larvae of Angiostrongylus cantonensis during different periods of development of T. spiralis. A significant reduction in the mean number of adult A. cantonensis was found in all the experimental groups. The mean number of lung worms found in the groups varied from 56 to 68, whereas a mean of 82 was found in the control. This reduction is probably caused by the non-specific inflammatory reaction and cell-mediated response induced by T. spiralis in the intestine and other organs of the host. A weaker and slower haemagglutinating antibody response against A. cantonensis was observed in animals infected with both species of nematodes. This may be attributed to a suppressive action elicited by T. spiralis against unrelated antigens. Changes in differential and total white blood cell counts were followed in some infected animals. An increase in neutrophils 3-4 weeks after infection with either or both species of parasites was observed. Eosinophilia occurred primarily in the lung phase of the metastrongyloid infection. © 1979 Springer-Verlag.