Diagnóstico parasitológico e imunológico da Strongiloidíase em crianças imunocompetentes e imunodeprimidas

Abstract

Strongyloidiasis is a parasitic disease resulting from of Strongyloides stercoralis infection, which can progress to hyperinfection, especially in immunocompromised individuais. Considering that Uberlândia is a hyperendemic area for this geo-helmint, it’s intended to perform and compare parasitologic and immunologic diagnoses of strongyloidiasis. A survey was conducted among 151 children, 68 immunocompetent ones (IC) and 83 immunocompromised ones (ID), aged from zero to 12, at the University Hospital, Universidade Federal de Uberlândia, Minas Gerais, Brazil, from February 1996 to June 1998. Three fecal samples from each child were analyzed for the parasitologic diagnosis by Baermann-Moraes and Hofímann, Pons and Janer methods. The immunonologic diagnosis to detect IgG and IgM antibodies was carried out by indirect immunofluorescence antibody test (IFAT) with cryo-microtome sections of Strongyloides stercoralis and S. ratti larvae as antigens and by ELISA test with alkaline extracts of S. ratti as the antigens. The rheumatic factor research was carried out in all through the “Reumatex Kit” IgM antibody positive serum samples and the FTA sorbent. The two parasitologic tests were 23.18% positive to parasites and intestinal commensals, being 5 (3.31%) positive to S. stercoralis (3 cases IC, 4.41% and 2 cases ID, 2.41%). The IFAT-IgG detected 9 (5.96%) serum samples positive (2 cases IC, 2.94%, being 2 by S. stercoralis antigen and 1 by S. ratti and 7 cases ID, 8.43%, being 7 by S. stercoralis and 4 by S. ratti). The ELISA-lgG test detected 11 (7.28%) serum samples positive (1 case IC, 1.47% and 10 cases ID, 12.05%). All positive IgM serums were negative in rheumatic factor research. The IFAT-IgM detected 9 (5.96%) positive cases (3 cases IC, 4.41%, being 3 by S. stercoralis and 1 by S. ratti and 6 cases ID, 7.22%, being 5 by S. stercoralis and 6 by S. ratti). The ELISA-IgM test detected 13 (8.61%) positive cases (3 cases IC, 4.41% and 10 cases ID, 12.05%). There is no statistical difference between the two antigens in to two group (p>0,05). Comparing the IFAT and the ELISA tests in the detection of IgG antibodies considering the S. ratti as antigens, there is agreement in one case in IC and 4 in ID, and for IgM antibodies 2 cases in IC and 4 in ID. The comparison between the parasitologic and immunologic diagnoses in the two groups, show statistical difference (p<0,05) in ED between the parasitologic tests and ELISA-lgG and IgM tests. It was conclued that the immunologic tests can help the diagnosis of strongyloidiasis in ID and IC children.