Life cycle and development of Lagochilascaris sprenti (Nematoda: ascarididae) from opossums (Marsupialia: didelphidae) in Louisiana.

The life cycle of Lagochilascaris sprenti, a species which occurs in the stomach of opossums (Didelphis virginiana) in Louisiana, was determined. The larva in the egg developed to the infective stage after eggs from the feces of infected animals were in culture about 30 days. When eggs containing infective larvae were fed to mice, the larvae hatched, penetrated the intestinal mucosa, migrated through the liver and lungs, and eventually reached the skeletal muscles where they became encapsulated. Larvae were also found encapsulated in the skeletal muscles of rats, gerbils, hamsters, monkeys, and a rabbit fed infective eggs. No larvae were found in the muscles of opossums fed infective eggs. However, when opossums were fed mice with 39- to 204-day-old Lagochilascaris infections, larvae developed in the gastric mucosa to the adult stage within 21 days. Adult worms inhabited cavities in the submucosa of the stomach from which they could migrate through openings into the lumen. One to three abscesses, each containing a single adult worm, were found in the musculature of 16.4% of the mice fed infective eggs.