Angiostrongylus costaricensis is a parasitic nematode of rodents and
molluscs are the intermediate hosts. Nocturnal collection of molluscs and
search for infective third stage larvae of A. costaricensis was
carried out in 18 endemic foci identified by the notification of a
confirmed diagnosis in human biopsies or surgical specimens. Molluscs were
digested in acidic solution and isolation of larvae eventually present was
done in a Baermann funnel. Larvae identified by the presence of a delicate
groove in the tail were counted to assess the individual parasitic burden.
Four species were found infected, with ranges of prevalence in parenthesis:
Phyllocaulis variegatus (7% to 33.3%); Bradybaena similaris (11.7% to
24.1%); Belocaulus angustipes (8.3% ) and Phyllocaulis soleiformis (3.3% to
14.2%). Parasitic burden varied from 1 to 75 with P. variegatus, 1 to 98
with B. similaris, 1 to 13 with B. angustipes and 1 larvae in each of two
specimens of P. soleiformis. P. variegatus was present in all sites and
was found infected with the highest prevalence figures and the highest
individual parasitic burdens. These data stress the importance of
veronicellid slugs as intermediate hosts for A. costaricensis in the
endemic areas in Rio Grande do Sul, Brazil.
