Resistance to Infection of Guinea Pigs with a Rat Streptobacillus Moniliformis

A rat S. moniliformis strain was dosed, orally and nasally, to two groups of 12 guinea pigs aged 10-15 weeks  and 4-5 weeks respectively. In the first experiment 3 animals were sacrificed 1, 2, 4 and 6 weeks after infection  and S. moniliformis was detected by culture in one animal at 2 weeks and by PCR in two animals at 4  weeks. In the second experiment 4 animals were sacrificed 2, 4 and 6 weeks after infection and S. moniliformis  was not detected by culture and PCR in any animal. Seroconversion to S. moniliformis was found  from 2 weeks after infection in 3 of 12 and 7 of 12 guinea pigs respectively. Clinical signs and gross lesions  in the ventral cervical area and the lungs were not observed in any animal. We conclude that guinea pigs  seem difficult to infect with a rat S. moniliformis strain.Â