Peroral infection of pigs with Schistosoma japonicum cercariae

Infections with the zoonotic trematode, Schistosoma japonicum in pigs serve s as a valuable model for studying natural definitive host/parasite relatio nships and a model for human schistosomosis japonica. In the present study the efficiency of a peroral infection route was compared with that of an in tramuscular route of infection. Eleven specific pathogen-free Danish Landra ce/Yorkshire/ Duroc crossbred male and female pigs were divided into two gr oups of five and six pigs, respectively. Each pig was given 1000 cercariae, either placed in droplets on the mucosa in the buccal cavity, or as medium -suspended cercariae injected into musculus biceps femoris of one of the hi ndlegs. Ten weeks post infection, all pigs were killed with pentobarbital a nd the venous system perfused. Worm burdens and liver egg counts were deter mined and worm fecundity was calculated. S. japonicum infections were estab lished in all individuals in both groups of pigs. When comparing the two gr oups, the peroral group had significantly higher number of immature worms, whereas the intramuscularly infected group had significantly more worm nodu les. However, no difference was seen in total number of worms. No statistic al significant differences were found in neither tissue egg counts nor worm fecundity when comparing the two groups. The results from the present stud y showed a delay in maturation of infection following a peroral infection a s compared with an intramuscular infection, but comparability was seen betw een overall worm establishment and egg production. (C) 1999 Elsevier Scienc e B.V. All rights reserved.