Diel locomotory activity of deer mice (Peromyscus maniculatus) infected with Trichinella nativa or Trichinella pseudospiralis

Abstract

The effects of infection by two species of sylvatic Trichinella on the diel locomotory activity of a wild rodent host, the deer mouse Peromyscus maniculatus, in a familiar environment were investigated in the laboratory using computer-linked activity chambers equipped with an infrared photocell. Locomotory activity data were collected on each mouse prior to and after sham inoculation or inoculation with graded doses of muscle-encapsulating Trichinella nativa or nonencapsulating Trichinella pseudospiralis larvae. Trichinella nativa infections induced activity deficits in deer mice that were proportional to the number of infective larvae recovered, whereas derived indices of locomotory activity of mice infected with T. pseudospiralis remained essentially within the range of those of sham-inoculated control mice. Quantitative differences between T. nativa and T. pseudospiralis in their potential to modulate the host's immune response may account for the observed difference in their effect on locomotory activity of the deer mouse host. Such variation in trichina-induced changes in diel locomotory activity may serve to channel transmission of the parasites to suitable hosts.