ABDOMINAL ANGIOSTRONGYLOSIS IN SOUTHERN BRAZIL PREVALENCE AND PARASITIC BURDEN IN MOLLUSK INTERMEDIATE HOSTS FROM 18 ENDEMIC FOCI

Angiostrongylus costaricensis is a parasitic nematode of rodents and m olluscs are the intermediate hosts. Nocturnal collection of molluscs a nd search for infective third stage larvae of A. costaricensis was car ried out in 18 endemic foci identified by the notification of a confir med diagnosis in human biopsies or surgical specimens. Molluscs were d igested 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 para sitic burden. Four species were found infected, with ranges of prevale nce in parenthesis: Phyllocaulis variegatus (7% to 33.3%); Bradybaena similaris (11.7% to 24.1%); Belocaulus angustipes (8.3%) and Phyllocau lis 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. angusti pes and 1 larvae in each of two specimens of P. soleiformis. P. varieg atus was present in all sites and was found infected with the highest prevalence figures and the highest individual parasitic but-dens. Thes e data stress the importance of veronicellid slugs as intermediate hos ts for A. costaricensis in the endemic areas in Rio Grande do Sul, Bra zil.