Penetration sites and migratory routes of Angiostrongylus costaricensis inthe experimental intermediate host (Sarasinula marginata)

The intermediate hosts of Angiostrongylus costaricensis are terrestrian mol luscs, mostly of the family Veronicellidae. The present work aimed at clari fying more accurately the sites of penetration and the migratory routes. of A. costaricensis in the tissue slugs and at verifying the pattern of the p erilarval reaction at different times of infection. Slugs were individually infected with 5,000 L-1, and killed from 30 min to 30 days after infection . From 30 min up to 2 hr after infections, L-1 were found within the lumen of different segments of the digestive tube having their number diminished in more advanced times after exposition until complete disappearance. After 30 min of exposition, percutaneous infection occurred, simultaneously to o ral infection. Perilarval reaction was observed from 2 hr of infection arou nd larvae in fibromuscular layer, appearing later (after 6 hr) around larva e located in the viscera. A pre-granulomatous reaction was characterized by gradative concentration of amebocytes around larvae, evolving two well-org anized granulomas. In this work we confirmed the simultaneous occurrence of oral and percutaneous infections. Perilarval reaction, when very well deve loped, defined typical granulomatous structure, including epithelioid cell transformation. The infection also caused a systemic mobilization of ameboc ytes and provoked amebocyte-endothelium interactions.