FURTHER OBSERVATIONS ON THE DEVELOPMENT OF GONGYLONEMA PULCHRUM IN RABBITS

Third-stage larvae of Gongylonema pulchrum from naturally infected dung beetles were inoculated orally into 24 rabbits. Worm recovery ranged from 54 to 91% (mean = 67.5%) during the period from 24 hr to 52 wk postinoculation (PI). Two hours PI, the larvae entered the mucosa at the junction of the stomach and esophagus and migrated upward. Early development occurred primarily in pharyngeal mucosa, tongue, and buccal mucosa. The third molt took place 11 days PI and the final molt at 36 days PI. Male worms reached sexual maturity at 7 wk PI and females at 9 wk PI. Adult worms were found mainly in the esophagus but also occurred in the tongue and the wall of the oral cavity after 30 wk PI. Embryonated eggs appeared in the feces of 3 rabbits inoculated with 50 or 100 larvae on days 72–81 PI. Morphologically, the cuticle in young fourth-stage larvae exhibited bosses on the anterior portion on day 11 PI, and the left spicule length : total body length exhibited no remarkable change between 9 and 52 wk PI. The latter finding confirms the utility of the ratio for identification of the nematode.