Field studies towards intestinal helminthoses from north Ethiopia (1982) by means of microscopic and seroimmunologic methods.

In two villages of north Ethiopia (Gorgora and Zerema) helminthologic stool analyses were performed and compared with seroimmunologic examinations. Regional difference could be obtained. The infection rate of males was slightly higher than that of females (except Schistosomiasis in Gorgora). Ascaridiasis, Ancylostomiasis and Trichuriasis are probably life-long accompanying parasitoses--they were slightly more frequent in higher than in lower age in Zerema--in contrast to Schistosomiasis which was slightly more frequent in younger people (differences not significant, likely due to the small number of examined persons). Toxocariasis in man is probably not very common in this region. The values of such pilot studies and of seroimmunologic findings for epidemiologic field investigations are discussed.

[Epidemiological aspects of toxocariasis in Switzerland]. / Epidemiologische Aspekte der Toxokariasis in der Schweiz.

In the regions of Basel, Jura and Zürich (Switzerland) 765 blood donors completed a questionnaire with respect to symptoms, animal contacts and occupation, and their sera were tested for antibodies to tissue helminths in ELISA. 5.1%, 3.3% and 6.5% exhibited antibodies solely to the respective antigens of Toxocara canis, Fasciola hepatica, and Echinococcus granulosus. Combined seroreactions were mainly observed between F. hepatica and E. granulosus antigens. Reactivity to T. canis antigen was associated with animal contacts at work, as well as contacts with cattle and sheep but not dogs or cats. Toxocara antibodies were found in all age groups. Their prevalence varied markedly by region.

A collaborative study on larval excretory/secretory antigens of Toxocara canis for the immunodiagnosis of human toxocariasis with ELISA.

Two batches of excretory/secretory (E/S) antigens from second stage larvae of Toxocara canis maintained in vitro were prepared independently in two different laboratories (Zürich and Basel) and analysed in order to obtain information for future efforts to standardize the enzyme-linked immunosorbent assay (ELISA) used for the serodiagnosis of human toxocariasis. SDS-PAGE and "Western-blotting" revealed at least 10 different antigenic components common to the two antigen preparations. However, distinct qualitative and quantitative differences among the two E/S-antigens were observed, since one antigen had a more complex composition than the other. Despite these differences, an accordance of serodiagnosis was obtained in 80% of 25 sera from patients with suspected Toxocara infection tested independently in two different ELISA systems (Basel and Zürich) with the corresponding E/S-antigens. The specificity was 93% as determined (BS-antigen, BS-ELISA) by testing 46 out of 3396 sera from patients with parasitologically proven extra-intestinal helminthic infections. Cross-reactions occurred mainly with sera from patients infected with filariae (5 from 13 cases) exhibiting very high extinction values in their homologous ELISA-system. The reproducibility (intra- and inter-test variations) of two ELISA systems using the corresponding E/S-antigens varied from 5-15%. The results demonstrate that T. canis E/S-antigens may well be applicable for standardization of the ELISA used for the serodiagnosis of human toxocariasis.

[Toxocariasis in Swiss children]. / Toxocariasis bei Schweizer Kindern.

A report is presented on 6 clinical observations of toxocariasis in Swiss children and on an epidemiological study of toxocara infections conducted in an urban and a rural area. The ELISA test in 70 children from the city of Basel revealed no seropositive result. In contrast, 4 of 68 children tested in the village of Entlebuch were seropositive. All reported close and intensive contact with dogs (mainly puppies) or geophagia. The main presenting symptom in our 6 clinical observations was excessive and sustained eosinophilia. Additional clinical and epidemiological aspects, the clinical picture and current therapy are discussed.

[Liver fascioliasis with unusual abscess formation. Case report]. / Fasciolase der Leber mit ungewöhnlicher Abszessbildung. Ein Fallbericht.

The case is reported of a 34-year-old Swiss who presented with signs of liver abscess after returning from South America. The symptoms regressed under trial treatment with a tissue amoebicide. The initial blood hypereosinophilia could be explained only 8 months later by the presence of eggs of Fasciola hepatica in the patient's faeces. Serological investigations were negative for amoebiasis an hydatid disease but positive for fascioliasis. The possibility of abscess formation by infestation with F. hepatica is discussed.

IgE antibodies in human onchocerciasis. Application of a newly developed radioallergosorbent test (RAST).

A radioallergosorbent test (RAST) was developed to detect IgE antibodies against adult Onchocerca volvulus antigens coupled to CnBr-activated Sepharose. Twenty-four out of 25 (96%) onchocerciasis sera were reactive. The lower limit of sensitivity was estimated to be at approx. 3 ng/ml IgE antibodies. Tests of sera from patients with non-filarial helminth infections showed much less cross-reactivity with RAST than with an enzyme-linked immunosorbent assay (ELISA) detecting IgG and IgM antibodies against the same antigen preparation. At a specificity comparable to that of RAST, the sensitivity of ELISA was only 61%. A heterologous antigen, prepared from female Dipetalonema viteae worms, was comparatively evaluated with O. volvulus. In RAST and ELISA, onchocerciasis sera were less reactive than against the O. volvulus antigen. Since sera from patients with non-filarial helminth infections were more reactive in RAST and almost equally reactive in ELISA using the D. viteae antigen, sensitivity was 83% for RAST and only 22% for ELISA (compared at the specificity identical to that of the O. volvulus RAST).

Application of the enzyme-linked immunosorbent assay (ELISA) for the diagnosis of filariasis and echinococcosis.

The Enzyme-Linked Immunosorbent Assay (ELISA) was compared with the Indirect Fluorescent Antibody Test (IFAT), the Indirect Haemagglutination Test (IHA) and Counter Immuno Electrophoresis (CIE) in the serological examination for filariasis and echinococcosis. The ELISA was the most sensitive but least specific method. The most striking phenomena were the cross-reactions observed when filariasis sera and E. granulosus hydatid fluid antigen were tested and vice versa, when echinococcosis sera were tested with D. viteae antigen. Crossreacting antibodies could be absorbed with the non-corresponding antigens. ELISA proved to be the most convenient test for the screening of large numbers of sera. For a specific diagnosis however it was nevertheless essential to test ELISA reactive sera with other methods.

[Use of an enzymatic immune method (ELISA) for the serodiagnosis of amebiasis]. / Anwendung einer Enzym-Immunmethode (ELISA) für die Serologie der Amöbiase.

The Enzyme Linked Immunosorbent Assay (ELISA) was compared with the indirect immunofluorescence antibody test (IFAT) and with the counter-immunoelectrophoresis (CIE) in the serology of amebiasis. In cases of liver abscesses, the ELISA was as sensitive as CIE, but slightly more sensitive than IFAT. In cases where the patient asymptomatically passed cysts of E. histolytica, none of the three tests was positive. As a routine laboratory screening test, the ELISA proved to be the most convenient of the three.

Comparative evaluation of 7 helminth antigens in the enzyme-linked immunosorbent assay (E.L.I.S.A.).

112 sera from Europeans with parasitologically proven helminthiasis were tested in the enzyme-linked immunosorbent assay (E.L.I.S.A.) against 6 crude extracts of various helminths (2 of adult worms: Dipetalonema viteae, Fasciola hepatica; 3 of eggs: Ascaris suum, Toxocara canis, Schistosoma mansoni; and of Echinococcus granulosus scolices) and against bovine hydatid fluid. Each serum was tested simultaneously at a fixed dilution of 1:160 against all antigens. Extensive cross-reactions were observed, leading to the conclusion that non-purified helminth antigens, even in combination, are of limited value for reliable serodiagnosis in E.L.I.S.A.