Gastrointestinal motor disturbance in rabbits experimentally infected with Strongyloides papillosus

Strongyloides papillosus is a common nematode in ruminants, and the rabbit is the only susceptible experimental animal that has been identified to date. It is known that heavy infection with S. papillosus causes death in a number of animals. However, even though a number of fatal cases have been reported, the mechanism by which S. papillosus infection leads to death remains unknown. In this study, the pathogenic effect of S. papillosus infection on gastrointestinal motility in infected rabbits was investigated by radiographic means. Gastrointestinal motility in rabbits experimentally infected with S. papillosus was assessed by contrast radiography after oral administration of barium sulfate on days 11 (group A) and 13 (group B) of infection. Body weight, food intake, fecal weight and egg count per gram of feces (EPG) were examined in order to investigate the effect of infection on gastrointestinal motility. Seven rabbits from each S. papillosus-infected and uninfected group were examined. Significant declines in body weight, daily food intake, and fecal weight, as well as gastrointestinal motor disturbances, were observed in association with elevated EPG counts in infected rabbits. This was only observed during the intestinal phase of S. papillosus infection. These results suggest that gastrointestinal motor disturbances underlie the anorexia, weight loss and subsequent death observed in rabbits infected with adult stage S. papillosus.