Genotypic diversity of Acanthamoeba strains isolated from Chilean patients with Acanthamoeba keratitis

Acanthamoeba spp. are the causative agents of a severe keratitis occurring mainly in contact lens wearers. The genus comprises more than 24 species that are currently divided into 20 different genotypes (T1-T20) according to sequence variations in the 18S rRNA gene. The objective of this study was to identify the genotypes and sub-genotypes of Acanthamoeba isolates collected at the Parasitology Laboratory of the Public Health Institute of Chile, the only laboratory in the country where Acanthamoeba screening is performed. This is the first report of genotypic identification of clinical isolates of Acanthamoeba in Chile and one of the few in South America. T2, T4 and T11 genotypes were predominantly isolated from the Acanthamoeba keratitis patients in Chile. Chilean predominant T4 sub-genotypes, which have also been reported worldwide, formed a separate cluster of the minority T4 variants. This study provides useful information about the predominant genotypes and subgenotypes that would be useful in selecting suitable strains to develop immunological and/or molecular diagnostic assays in Chile

First inter-laboratory comparison of Echinococcus granulosus sensu lato diagnosis in Latin America

To compare the performance of polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA) tests for diagnosing Echinococcus granulosus in dog feces among national reference laboratories in Argentina, Chile, Peru, and Uruguay

Phylogenetic analysis of microsatellite markers further supports the two hybridization events hypothesis as the origin of the Trypanosoma cruzi lineages

To better understand the evolution of the etiologic agent of Chagas disease, we cloned and sequenced 25 alleles from five Tripanosoma cruzi microsatellite markers. The study of the sequences showed highly conserved alleles present in T. cruzi clones belonging to TCI, TCIIc, and TCIIe. This result was also confirmed by the phylogenetic analysis of MCLE01 allele sequences. The examination by capillary electrophoresis of six microsatellite markers from 19 T. cruzi clones showed a high proportion of the alleles found both in the TCI and TCII sublineages. The phylogenetic reconstruction of these 19 clones produced a tree with two major clusters with bootstrap support of 100% and 95%. The first cluster includes T. cruzi clones belonging to the TCI and TCIIa lineages. The second cluster is composed of TCI, TCIIc, TCIId, and TCIIe T. cruzi clones. The analysis of five microsatellite markers in the CLBrener genome showed that almost all the microsatellite markers are synteny; non-Esmeraldo an

Seroepidemiological aspects of human Strongyloides stercoralis infections in Chile

To determine the frequency of Strongyloides stercoralis antibodies by means of the enzyme linked immunosorbent assay (ELISA) in Chile, in 2001-2003, 675 blood samples of patients of two psychiatric hospitals and 172 of healthy individuals (doctors, nurses and paramedicals) of these institutions, and 1,200 serum samples of blood donors of Northern region (Arica and Antofagasta), Central region (Valparaiso and Santiago) and Southern region (La Union) were collected. ELISA showed positivity of 12.1% in psychiatric hospitalized patients, none (0%) in the health personnel and 0.25% in blood donors (p < 0.05). Only in blood donors of Arica (1%) and La Union (0.5%) the ELISA test was positive suggesting that strongyloidiasis is focalized in determinate zones of the country. In Chile, human infections by S. stercoralis are endemic with very low frequency in apparently healthy individuals and high prevalence in risk groups such as the mentally ill hospitalized patients

Immunodiagnosis of Strongyloides stercoralis infections in Chile using an ELISA test Inmunodiagnóstico de las infecciones por Strongyloides stercoralis en Chile utilizando la prueba de ELISA

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 eosinophi

Effectiveness of sampling methods employed for Acanthamoeba keratitis diagnosis by culture

© 2018, Springer Nature B.V.Purpose: This retrospective, observational study was designed to evaluate the effectiveness of the sampling methods commonly used for the collection of corneal scrapes for the diagnosis of Acanthamoeba keratitis (AK) by culture, in terms of their ability to provide a positive result. Methods: A total of 553 samples from 380 patients with suspected AK received at the Parasitology Section of the Public Health Institute of Chile, between January 2005 and December 2015, were evaluated. A logistic regression model was used to determine the correlation between the culture outcome (positive or negative) and the method for sample collection. The year of sample collection was also included in the analysis as a confounding variable. Results: Three hundred and sixty-five samples (27%) from 122 patients (32.1%) were positive by culture. The distribution of sample types was as follows: 142 corneal scrapes collected using a modified bezel needle (a novel method develope

Intestinal protozoa and helminth infections in pre-school and elementary school-children from Colina county, Santiago, Chile, 2003

In may 2003 an epidemiologic-parasitological survey was carried out in 206 pre-school and schoolchildren 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