Experimental infection in a monkey with Gnathostoma hispidum larvae obtained from loaches

Since the 1908s gnathostomiasis has occurred sporadically in Japanese who have eaten loaches, fresh-water fish imported from southeast Asia. Symptoms include creeping skin eruptions and eosinophilia. The symptoms disappeared in most patients within three months after the onset and the patients then remained symptom-free. To elucidate the causative factors, we fed one monkey with 80 gnathostome larvae collected from loaches and autopsied the animal 466 days later. Fifty-one viable larvae (64%) were recovered from muscle; these were in the advanced third stage and were encapsulated.