larva migration and eosinophilia in mice experimentally in­fected with gnathostoma spinigerum

background: gnathostoma spinigerum causes larva migran in human which is endemic in southeast asia. information regarding larva migration is limited. in this study, we investigated the parasite migra­tion by recovery of worms from the whole body of mouse after oral infection with advanced third stage larvae (al3). the percentage of blood eosinophils was examined in parallel. methods: mice were orally infected with al3 and histological study of organs was investigated in order to study the migration of al3, along with blood eosinophilia. results: at 1 hr post infection (pi), the larvae remained in the stomach, thereafter at 3, 5, 7, 10 and 24 hr pi; they were recovered from various organs including liver, mesentery, esophagus, diaphragm, lung, heart and dorsal fat. at day 15 pi, they were mostly found in muscles (76.47%). the average worm recovery (5 months) was 78.03%. the worms were found in the liver at every time point. larva encystment was detected. there was a significant difference in blood eosinophils between the 8 larvae- (average 9.33% + 6.25%) and the 15 larvae-infected groups (average 22.66% + 11.03%). surprisingly, the blood eosinophils (average 19.00% + 2.92%) were not higher in the higher infective dose- group (25 larvae). conclusion: liver was involved by g. spinigerum throughout the study. we detected larva encyst­ment which had never been reported in human gnathostomiasis. the highest percentage of eosino­phil occurred during the invasive stage.