Biological characteristics and host influence on a geographical isolate of Trichinella (wolverine: 55 degrees 00'N, 100 degrees 00'W, 1979).

Biological characteristics of Trichinella isolate (wolverine: 55 degrees 00'N, 100 degrees 00'W, 1979) were established in Crl: COBS CFW (SW) mice. Comparison of the wolverine isolate's biological characteristics with another Trichinella isolate (polar bear), both from closely related geographic areas, revealed there were stable and reproducible genetic differences between isolates. Differences were most pronounced for degree of infections causing a 50% mortality of mice, larval production by females in vitro, reproductive capacity indices, and survival of muscle larvae. Species and strain of host altered characteristics of the wolverine isolate such as worm position, sex ratios, % recovery, larval production by females in vitro, and reproductive capacity indices. Genetic differences between isolates of Trichinella and interaction with host genetics raises interesting questions on Trichinella speciation. Differences reported here, are best interpreted for the time being at least, as part of the normal biological variability of the species Trichinella spiralis.