An enzyme-linked immunosorbent assay (ELISA) was adapted for the serological differential diagnosis of cystic or alveolar echinococcosis in man caused by Echinococcus granulosus or E. multilocularis respectively. By affinity chromatography using rabbit anti hydatid fluid IgG coupled covalently to CNBr-Sepharose 4B a protein fraction (Em 1) containing shared antigens of both parasites could be isolated from an extract of E. multilocularis metacestode tissue. From the same source another antigen fraction (Em 2) with a high degree of specificity for E. multilocularis was prepared by immunosorption. Antigen Em 1 was equally sensitive for the detection of antibodies against E. granulosus and E. multilocularis, whereas antigen fraction Em 2 appeared to be more specific for E. multilocularis. A correct serological differential diagnosis was achieved in 95% of 57 confirmed cases of human cystic or alveolar echinococcosis by the simultaneous use of both antigen fractions in the ELISA and by comparison of their reactivities.

Serological differentiation between Echinococcus granulosus and E. multilocularis infections in man.

Twenty-three patients with cystic or alveolar echinococcosis were treated with mebendazole in a prospective manner (50 mg per kg bodyweight per day per os). In cases of cystic echinococcosis, mebendazole was given for one month. Repeated consolidation courses were performed at regular intervals during the follow-up. In cases of alveolar echinococcosis, the intermittent scheme was also applied, but later on the drug was administered continuously. The follow-up period ranged from 4–40 months after the initiation of mebendazole treatment. Regular follow-up examinations during and following treatment were performed, and the effect of the chemotherapy was assessed by sensitive methods, i. e. conventional radiology, ultrasonics, computerized tomography. A reduction in cyst size after treatment with mebendazole was clearly visible only in patients with pulmonary lesions. Of the six patients with lung cysts, five were found to have improved considerably, as judged by conventional chest X-ray. Only two of the 11 patients with liver involvement showed a considerable reduction in cyst size. Regression in patients with alyeolar echinococcosis was moderate in two of seven cases. However, improvement of indirect parameters (e. g. liver enlargement, tenderness, cholestasis, hepatocellular damage or weight loss) was considerable in those patients presenting these clinical symptoms. Allergic and cardiopulmonary side-effects were only observed in patients presenting lung cysts, and were most probably due to the rupture of cysts after the administration of mebendazole; they always occurred during the first treatment cycle. Haematotoxic effects were observed in one patient after the fifth treatment cycle with mebendazole.

Human echinococcosis: follow-up of 23 patients treated with mebendazole.

A combined application of enzyme-linked immunosorbent assay (ELISA) and indirect haemagglutination test (IHA) for the diagnosis and post-operative surveillance of human alveolar and cystic echinococcosis is described. Since January 1985 each serum sample submitted for the detection of specific antibodies was examined with both an ELISA using Echinococcus multilocularis antigen (EmELISA) and an IHA using E. granulosus antigen (EgIHA).

In the course of our study altogether 72 human cases of Echinococcus infections were diagnosed. All 16 cases of alveolar echinococcosis (= 100%) and 48 out of 56 cases of cystic echinococcosis (= 86%) were revealed as Echinococcus infection at least in one of the two tests. Although crude antigens were used in both, EmELISA and EglHA, species-specific diagnosis was achieved in 57 (= 89%) of 64 cases of the infections with E. multilocularis or E. granulosus. The diagnostic value of EmELISA and EglHA for the post-operative surveillance is demonstrated by the follow-up of the immune response of one case of alveolar and three cases of cystic echinococcosis.

Combined application of enzyme-linked immunosorbent assay (ELISA) and indirect haemagglutination test (IHA) as a useful tool for the diagnosis and post-operative surveillance of human alveolar and cystic echinococcosis.

Summary After a common source outbreak of trichinosis in Bitburg, FRG, 107 patients, for whom time and source of infection were precisely known, were prospectively studied for a period of eight months in order to investigate the kinetics of the humoral immune response. Antibodies were assessed by IHA, and by ELISA to quantify IgG, IgM and IgE isotypes. For four different periods of the observation time sensitivity and predictive value of tests to identify acute or convalescent trichinosis were determined. The results demonstrated characteristic kinetics of the different antibody isotypes and varying diagnostic value of the tests. Only IgG-ELISA and double-sandwich IgM-ELISA reliably identified diseased patients shortly after onset of clinical illness and showed a negative predictive value of almost 100 % from seven weeks to eight months after infection. IgE antibodies and elevation of total serum IgE occurred only in about 20 % of patients and showed no consistent pattern during the course of the disease. Circulating immune complexes were moderately increased four weeks after infection. They rapidly returned to normal values, after the symptoms of the acute phase had disappeared.

Kinetics of Humoral Response During the Acute and the Convalescent Phase of Human Trichinosis

Crude soluble antigens were evaluated with indirect haemagglutination and ELISA for their specificity in the immunodiagnosis of alveolar and cystic echinococcosis. Using a combination of heterologous crude antigens, the ELISA method made a correct species-specific diagnosis in 96.3 % of the patients. These results are similar to those obtained by immuno-diagnosis with purified antigens.

Species-specific immunodiagnosis of human echinococcosis with crude antigens.

Serum samples of 107 patients with cystic and 30 with alveolar hydatid disease were tested for antibodies with hydatid fluid and extract from cyst material of E. alveolaris as antigens. Complement-fixation, indirect haemagglutination and an indirect enzyme immune (ELISA) technique were employed. The results indicate an antibody picture which confirms the value of serum-antibodies in the diagnosis of hydatid disease. Diagnostically insufficient antibody formation was present in seven patients with cystic and two with alveolar hydatid disease. The indirect haemagglutination test with alveolaris antigen proved to be the most sensitive reaction for antibody demonstration of both echinococci, while the same antigen in the ELISA technique gave species-specific results in patients with E. alveolaris.

[Serum antibodies in cystic and alveolar hydatid disease (author's transl)].

Serum samples of 66 persons who had eaten meat from a wild boar were tested two to three times within 11 months for antibodies against extracts from Trichinella larvae. Watery extract of Trichinella spiralis larvae served as antigen. Complement-fixation was of little use because of its lack of sensitivity. Indirect haemagglutination and the ELISA test (enzyme-linked immunosorbent assay) gave uncertain results only in individual cases. There was a relationship between the clinical picture and the mean antibody concentration, clearer in the ELISA test than the indirect haemagglutination one. A fall in antibody titre was observed within the period of observation in only one third of patients. Results with sera of control subjects were of only limited use in relation to the specificity of the demonstrated antibodies.

Lederer I

Papers

[Serum antibodies in cystic and alveolar hydatid disease (author's transl)].

[Serum antibody findings in trichinosis (author's transl)].