SUSCEPTIBILITY OF VARIOUS SPECIES OF ANIMALS AND STRAINS OF MICE TO GYMNOPHALLOIDES SEOI INFECTION AND THE EFFECTS OF IMMUNOSUPPRESSION IN C3H HEN MICE/

Susceptibility to Gymnophalloides seoi infection was studied in 8 spec ies of animals, including 7 strains of mice; the effects of immunosupp ression on susceptibility were examined in C3H/HeN mice. One hundred m etacercariae of G. seoi isolated from naturally infected oysters were orally administered to each animal. Worm recovery rate (WRR), worm dim ensions, and the number of uterine eggs were obtained at day 3 and day 7 postinfection (PT). Average WRR from gerbils, hamsters, and cats at day 7 PI was 28.0%, 14.2%, and 10.9%, respectively, the former 2 figu res of which were significantly higher than the rate of 0.0-4.0% from Sprague-Dawley rats, dogs, ducks, guinea pigs, and chicks. In the case of mice, average WRR at day 7 PI was 12.4% (KK strain), 11.8% (C3H/He N), 9.6% (ICR), 6.4% (BALB/c), and 6.3% (ddY), respectively; the first 3 figures were significantly higher than the rates from other strains , which were 1.8% (A) and 0% (C57BL/6). At day 3 PI, WRR was much high er in all strains except C57BL/6. Worm maturation was the highest in C 3H/HeN mice. Immunosuppression of C3H/HeN mice by injecting prednisolo ne for 7, 14, or 21 days prior to infection increased WRR at day 7 PI to 27.8%, 33.8%, or 67.5%, respectively. The results show that gerbils , hamsters, cats, and KK, C3H/HeN, ICR, BALB/c, and ddY mice are labor atory hosts that are fairly susceptible to G. seoi infection. In C3H/H eN mice, susceptibility was markedly enhanced by immunosuppression.