Differences in Susceptibility of Rat Strains to Experimental Infection with Taenia taeniaeformis

Abstract

Age-matched, outbred, female, Sprague-Dawley-derived rats from different commercial suppliers were compared for their susceptibility to the establishment and growth of T. taeniaeformis. Two of the strains, Spb:[SD] and Kng:[SD], gave very similar results but the 3rd, Hap:[SD]f, was considerably less receptive. Approximately 1 in 8 of the Hap:[SD]f rats proved refractory to infection and worm growth was slower and more variable than in Spb:[SD] rats. Male Spb:[SD] rats were not detectably different from females in susceptibility or parasite growth rate. Female rats of 4 different inbred lines all accepted infection, though the proportion of infective eggs giving rise to hepatic cysts differed. These differences were overshadowed by variations observed in susceptibility of inbred rats of the same strain (Wistar-Lewis) purchased from different commercial suppliers. The results emphasize the need for careful standardization of laboratory procedures and rat strains for experimentation with this host-parasite system. They illustrate the dangers of extrapolation from the extensive literature on the influence of rat strain and sex on susceptibility to infection with T. taeniaeformis.