The objective of this study was to determine the presence of Strongyloides stercoralis in urban garbage collectors through the use of immunological and parasitological methods. A total of 92 individuals were evaluated from August, 1997, to June, 1998. For the parasitological diagnosis Baermann and Lutz' methods were applied. The immunological diagnosis involved the indirect fluorescence antibody test (IFAT) and the enzyme-linked immunosorbent assay (ELISA) to detect specific IgG antibodies. Of the 92 workers examined, six (6.5%) were infected with larvae of S. stercoralis. The IFAT detected 19 (16.3%) and the ELISA 17 (18.5%) positive serum samples. The differences between the results of parasitological and immunological methods were statistically significant (p<0.05). These results demonstrate that there is a need to improve the health conditions of this category of city employees.

Entre novembro de 2001 e dezembro de 2002, 600 amostras de fezes de cão foram coletadas nas principais praças e parques públicos de 13 cidades do Chile, localizadas nas regiões norte ao estremo sul da nação. No laboratório, as amostras foram processadas mediante os métodos de sedimentação por centrifugação e de Harada-Mori. Ovos de Toxocara canis foram encontrados em 12 cidades em freqüências que variaram entre 1,9 a 12,5% por cidade, com média de 5,2%. Sete por cento das amostras apresentaram ovos e 9,5% larvas rabditóides ou filarióides de Ancylostomatidae. Strongyloides stercoralis não foi encontrado nas amostras estudadas. Praças e parques públicos do Chile apresentam riscos potenciais para aquisição de larva migrans visceral, ocular ou cutânea.

Between November 2001 and December 2002, 600 dog fecal samples were collected in main squares and public parks of 13 cities in Chile, from the extreme north to the extreme south of the country. The samples were processed in the laboratory by centrifugal sedimentation and the Harada-Mori methods. T. canis eggs were found in 12 cities. Detection rates ranged from 1.9 to 12.5% with an average of 5.2%. Seven percent of the samples had eggs and 9.5% had rhabditoid and/or filariform larvae of Ancylostomatidae. Strongyloides stercoralis were not found. Squares and public parks in Chile pose a potential risk of exposure to visceral, ocular, and/or cutaneous larva migrans syndromes.

Entre novembro de 2001 e dezembro de 2002, 600 amostras de fezes de cão foram coletadas nas principais praças e parques públicos de 13 cidades do Chile, localizadas nas regiões norte ao estremo sul da nação. No laboratório, as amostras foram processadas mediante os métodos de sedimentação por centrifugação e de Harada-Mori. Ovos de Toxocara canis foram encontrados em 12 cidades em freqüências que variaram entre 1,9 a 12,5% por cidade, com média de 5,2%. Sete por cento das amostras apresentaram ovos e 9,5% larvas rabditóides ou filarióides de Ancylostomatidae. Strongyloides stercoralis não foi encontrado nas amostras estudadas. Praças e parques públicos do Chile apresentam riscos potenciais para aquisição de larva migrans visceral, ocular ou cutânea.

Between November 2001 and December 2002, 600 dog fecal samples were collected in main squares and public parks of 13 cities in Chile, from the extreme north to the extreme south of the country. The samples were processed in the laboratory by centrifugal sedimentation and the Harada-Mori methods. T. canis eggs were found in 12 cities. Detection rates ranged from 1.9 to 12.5% with an average of 5.2%. Seven percent of the samples had eggs and 9.5% had rhabditoid and/or filariform larvae of Ancylostomatidae. Strongyloides stercoralis were not found. Squares and public parks in Chile pose a potential risk of exposure to visceral, ocular, and/or cutaneous larva migrans syndromes.

In may 2003 an epidemiologic-parasitological survey was carried out in 206 pre-school and school-children from San Vicente de Lo Arcaya School in Colina, a semi-rural county of the Santiago Province in the Metropolitan Region of Chile.The most frequent parasitic elements were: Blastocystis hominis - in men and women respectively - 38.8% and 44.4%, Giardia intestinalis with 9.5% and 16.2% and Enterobius vermicularis with 12.9% and 10.0%. It is notewortly that the infected children were asymptomatic Cryptosporidium parvum was not observed and an ELISA test for Strongyloides stercoralis infections was positive in one children.This study confirms that intestinal parasitic infections in children remain with a high prevalence in Chile.

En mayo de 2003 se efectuó una encuesta epidemio-parasitológica en pre-escolares y escolares de la Escuela San Vicente de Lo Arcaya de Colina, comuna semirural de la Provincia de Santiago ubicada en la Región Metropolitana de Chile. Hay que destacar que los niños estudiados eran asintomáticos. Los elementos parasitarios más frecuentemente encontrados fueron: Blastocystis hominis - en hombre y mujeres respectivamente - 38,8% y 44,4%, Giardia intestinalis con 9,5% y 16,2% y Enterobius vermicularis con 12,9% y 10,0%. Cryptosporidium parvum no fue encontrado y ELISA para Strongyloides stercoralis resultó positiva en un niño.

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. Aim: To evaluate the yield of an ELISA test for the diagnosis of strongyloidiasis in Chilean patients. Material and 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 (Rev Méd Chile 2002; 130: 1358-64)

A limited epidemiological information on Strongyloides stercoralis infection excists in Chile. In 1983 a mentally retarded 53-year-old man died by disseminated strongyloidiosis associated with malabsortion syndrome, this case constitutes the first histopathological confirmation of the parasitose in Chile. Later on, cases have been described in hospitalized patients in mental institutions from the central part of the country, where the frequency of infection registered in studies carried out in the Psyquiatric Hospital of Putaendo in 1985 and 1987-1989 were 11.6% and 7.0%. In 1992 an outbreak of strongyloidiasis that affected 13 out of 55 children in a nutritional recuperation center in the north extreme of Chile was reported. In 2000 four cases were detected in a group of 20 hospitalized mental affected patients with elevated eosinophilia. Sensitive methods for detecting larvae in stool samples and seroepidemiological surveys would permit determine the importance of this human heminthic infection in Chile.

Two species of xiphidiocercariae probably belonging to the family Haematoloechidae (Trematoda) emerging from Lymnaea columella (Basommatophora, Lymnaeidae) and Biomphalaria tenagophila (Basommatophora, Planorbidae) collected in Miracatu City, São Paulo State, Brazil, between September 1996 and February 1999 were described. The xiphidiocercariae eliminated by L. columella presented a terminal membrane in the tail that morphologicaly differenciated them from those obtained from B. tenagophila. These late xiphidiocercariae were 1.3 times bigger than the former and with the of that ventral sucker bigger than the oral one, while the former presented a sucker size relation inverse. The stylet observed in the xiphidiocercariae eliminated by B. tenagophila oral sucker was shorter than that observed in xiphidiocercariae obtained from L. columella.