[Immunodiagnosis of Strongyloides stercoralis infections in Chile using ELISA test].
BACKGROUND
Strongyloides stercoralis is a world wide distributed small intestinal nematode parasite. In immunocompetent individuals S stercoralis can produce asymptomatic infections or a moderate clinical picture of diarrhea, some cases become chronic. In immunocompromised patients, a disseminated disease may appear, sometimes fatal. In Chile, there is little epidemiological information about S stercoralis infections and appropriate diagnostic techniques are usually not used.


OBJECTIVE
To evaluate the yield of an ELISA test for the diagnosis of strongyloidiasis in Chilean patients.


METHODS
Ten serum samples from patients with S stercoralis infections confirmed by a positive stool examination, 66 samples from individuals with other infections by tissue helminthes (24 toxocariasis, 15 trichinellosis, 11 hydatidosis, 12 fascioliasis and 4 cysticercosis), 13 samples from subjects with autoimmune diseases and 49 samples from apparently healthy individuals with a normal eosinophil count, were studied. ELISA antigen was prepared using a filariform larval extract obtained from a murine species of Strongyloides, maintained in laboratory animals.


RESULTS
Using 0.33 optical density units as a cut off value, 9 of 10 sera of S stercoralis infected individuals, had a positive ELISA test. No cross reactions were observed with sera of patients with other helminthic infections, autoimmune diseases or in healthy individuals. Thus, specificity, positive and negative predictive values were 100%.


CONCLUSIONS
The results obtained are similar with those found by other investigators. ELISA test for strongyloidiasis is a useful tool for the diagnosis of clinical cases and for seroepidemiological studies of this nematode infection in Chile.
Mercado
Rubén
R
Unidad de Parasitología Norte, ICBM, Facultad de Medicina, Universidad de Chile, Casilla 9183, Santiago, Chile. rmercado@machi.med.uchile.cl
Jercic
María Isabel
MI
Torres
Patricio
P
Alcayaga
Sergio
S
Martins de Paula
Fabiana
F
Costa-Cruz
Julia María
JM
Ueta
Marlene T
MT
D000328:Adult; D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood; D000947:Antigens, Helminth / Q000097:blood; D001327:Autoimmune Diseases / Q000097:blood / Q000175:diagnosis / Q000276:immunology; D002648:Child; D002677:Chile; D004797:Enzyme-Linked Immunosorbent Assay / Q000592:standards; D006373:Helminthiasis / Q000097:blood / Q000175:diagnosis / Q000276:immunology; D006801:Humans; D012680:Sensitivity and Specificity; D017171:Strongyloides stercoralis / Q000276:immunology*; D013322:Strongyloidiasis / Q000097:blood / Q000175:diagnosis* / Q000276:immunology
D000909:Antibodies, Helminth; D000947:Antigens, Helminth