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SummaryAbdominal angiostrongyliasis is a nematode disease produced by Angiostrongylus costaricensis, a metastrongylid parasite of wild rodents. Accidental human infection occurs through ingestion of food or water contaminated with third-stage larvae present in the mucous secretion of terrestrial molluscs. An ELISA test was standardized for detection of IgG antibodies recognizing a surface antigen prepared from female worms. Competitive absorption of sera with Ascaris suum crude antigen resulted in a test with 86% sensitivity and 83% specificity. The disease is endemic in Southern Brazil and a number of cases are diagnosed every year through anatomo-pathological examination of biopsies or surgical specimens, since no other diagnostic method is available. According to seroepidemiological studies, prevalences in two transmission foci are 29.8 and 66%, attesting to the widespread occurrence of the infection in those endemic areas. keywords angiostrongyliasis, ELISA, Brazil correspondence C. Graeff-Teixeira, Rua Marquês do Pombal, 799/801, CEP 90540-010,

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Os autores descrevem as lesões anatômicas de quatro casos de angiostrongilíase abdominal, destacando as modificações arteriais peculiares a esta parasitose.

In the sample studied the most common sites were in the back of men and in the legs of women. The predominant type clinical-pathological was superficial spreading.

Abdominal angiostrongyliasis is a zoonotic infection caused by Angiostrongylus costaricensis, a nematode with an intra-vascular location in the mesentery. Our objective was to address several aspects of the natural history of this parasitosis, in a longitudinal clinical and seroepidemiological study. A total of 179 individuals living in a rural area with active transmission in southern Brazil were followed for five years (1995-1999) resulting in yearly prevalence of 28.2%, 4.2%, 10%, 20.2% and 2.8% and incidences of 0%, 5.9%, 8% and 1.5%, respectively. Both men and woman were affected with higher frequencies at age 30-49 years. In 32 individuals serum samples were collected at all time points and IgG antibody reactivity detected by ELISA was variable and usually persisting not longer than one year. Some individual antibody patterns were suggestive of re-infection. There was no association with occurrence of abdominal pain or of other enteroparasites and there was no individual with a confirmed (histopathologic) diagnosis. Mollusks were found with infective third-stage larvae in some houses with an overall prevalence of 16% and a low parasitic burden. In conclusion, abdominal angiostrongyliasis in southern Brazil may be a frequent infection with low morbidity and a gradually decreasing serological reactivity.

Angiostrongylus costaricensis has a broad geographic distribution spanning from North to South America and the infections of vertebrates with this nematode can result in abdominal complications. Human infections are diagnosed by histological or serological methods because the isolation of larvae from feces is not feasible, as most parasites become trapped in intestinal tissues due to intense eosinophilic inflammation. Because A. costaricensis is difficult to maintain in the laboratory, an immunodiagnostic IgG enzyme-linked immunosorbent assay (ELISA) using antigens from the congeneric Angiostrongylus cantonensis species was evaluated against a panel of serum samples from patients who were histologically diagnosed with A. costaricensis infections. Sera from uninfected individuals and individuals infected with other parasites were used as controls. The sensitivity and specificity of the assay were estimated at 88.4% and 78.7%, respectively. Because the use of purified or cloned antigens has not been established as a reliable diagnostic tool, the use of heterologous antigens may provide a viable alternative for the development of an ELISA-based immunodetection system for the diagnosis of abdominal angiostrongyliasis

Veronicellid slugs are considered the most important intermediate hosts of Angiostrongylus costaricensis, an intra-arterial nematode of rodents. Studies undertaken in three localities in southern Brazil led to identification of molluscs other than veronicellid slugs as hosts of A. costaricensis: Limax maximus, Limax flavus and Bradybaena similaris. These data indicate a low host specificity of larval stages of A. costaricensis, as it has been reported to other congeneric species.