Geohelminths

Geohelmintiasis

Date: 
01/10/2010
Investigation Line: 

Abstract

The serodiagnosis of Strongyloides stercoralis infection by enzyme-linked immunosorbent assays based on crude antigen (CrAg-ELISA), while useful, has been limited by the reliance on crude parasite extracts. Newer techniques such as the luciferase immunoprecipitation system assay (LIPS), based on a 31-kDa recombinant antigen (termed NIE) from S. stercoralis and/or the recombinant antigen S. stercoralis immunoreactive antigen (SsIR), or the NIE-ELISA have shown promise in controlled settings. We compared each of these serologic assays in individuals from both regions of the world in which S. stercoralis is endemic and those in which it is not. A comprehensive stool evaluation (sedimentation concentration, Baermann concentration with charcoal cultures, agar plate, and Harada-Mori) and four different serologic techniques using CrAg-ELISA or recombinant NIE-ELISA as well as LIPS using NIE alone or in combination with a second recombinant antigen (NIE/SsIR-LIPS) were compared among individuals with parasitologically proven infection (n = 251) and healthy controls from regions of the world in which the infection is nonendemic (n = 11). Accuracy was calculated for each assay. The prevalence of S. stercoralis infection was 29.4% among Argentinean stool samples (n = 228). Sedimentation concentration and Baermann were the most sensitive stool-based methods. NIE-LIPS showed the highest sensitivity (97.8%) and specificity (100%) of the serologic assays. The calculated negative predictive value was highest for both the NIE-LIPS and CrAg-ELISA (>97%) irrespective of disease prevalence. No cross-reactivity with soil-transmitted helminths was noted. NIE-LIPS compares favorably against the current CrAg-ELISA and stool evaluation, providing additional accuracy and ease of performance in the serodiagnosis of S. stercoralis infections irrespective of disease prevalence.

Date: 
01/09/2003
Investigation Line: 

Abstract

In a study, carried out in 2000, of the clinical and parasitological status of a Wichi Aboriginal community living in the suburbs of Tartagal, northern Salta, Argentina, 154 individuals were screened for parasitic infections. Ninety-five faecal samples were also obtained from the same population. Ninety-three percent of the subjects were positive for 1 or more of the parasites investigated by direct test and 70.5% of them had parasitic superinfection. The most frequent helminths were Strongyloides stercoralis (50.5%) and hookworm (47.4%). We found low reinfection rates and a long reinfection period after treatment and provision of safe water and sanitation. Serum reactivity of these patients was analysed by enzyme-linked immunosorbent assay and indirect immunofluorescent assay and 22.1% of them had anti-Toxocara antibodies, 16.2% were positive for a complex antigen of Leishmania braziliensis, 29.9% were positive for a complex Trypanosoma cruzi antigen, and 17.5% were positive for a specific Trypanosoma cruzi antigen, Ag 163B6/cruzipain.

Author: 
Date: 
01/01/1995
Investigation Line: 

Abstract

A fatal case of strongyloidiasis in a boy aged 8 months, referred to our hospital, with severe malnutrition, dehydration, brownish fluid through the naso-gastric tube and relapsing chronic diarrhea with bloody mucus. Through all symptoms and observation of rabditoid larvae, eggs and even adult females, parasitologic diagnosis was achieved. In spite of medical intensive care the patient died after 18 days of hospitalization. Disease's pathophysiology is discussed as well as a review about the trustfulness of the parasite biological cycle as is traditionally described in the literature. Ability is questioned of rabditoid larvae to follow the alternative way as free living adults or parasitic living in adults.

Date: 
07/01/1993
Investigation Line: 

Abstract

An enteroparasitological, clinical and epidemiological study was carried out in 36 infants who attended the Hospital San Vicente de Paul from Orán for medical assistance. The age of the children varied between 0 and 4 years with an average of 28 months. The main clinical causes for consultation were bronchitis (52.8%), inappetence (52.8%) and paleness (27.8%). The general characteristics of the stool samples were: formed 44.4% and diarrheic 55.6%. The frequency of intestinal helminthic and protozoan elements was the following: S. stercoralis 30(83.3%) N. americanus 5(13.9%), A. lumbricoides 7(19.4%), T. trichiura 3(8.3%), H. nana 5(13.9%), G. intestinalis 10(27.8%), I. belli 1 (2.8%) and E. coli 4 (11.1%). The nutritional condition found in the infants, according to the relation high/weight was: eutrophic 17(42.2%), lightly undernourished 9(20.0%), moderately undernourished 9(25.0%) and severely undernourished 1(2.8%). The mean values of hematocrit and hemoglobin found were under those established as minima by the W.H.O. The white blood cells and eosinophils countings were over the normal mean values.

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