An enzyme-linked immunosorbent assay for detection of IgG1 antibodies specific to human cystic echinococcosis in Egypt.

Human cystic hydatidosis (cystic echinococcosis) is a chronic zoonotic disease that results from infection with the dog tapeworm Echinococcus granulosus. In Egypt, cystic echinococcosis (CE) is recognized in slaughtered livestock by veterinarians, however, there is little information about human CE infection rates. We describe an immunological assay useful for the diagnosis of human cystic hydatidosis. Sera were collected from surgically confirmed hydatid cases (34), nonendemic subjects free from parasitic infection (20) and from subjects (109) infected with other helminths (Hymenolepis nana, Schistosoma mansoni, Fasciola hepatica and Ancylostoma duodenale). Hydatid cyst fluid (HCF) of camel origin was used as antigen in an ELISA format to measure total E. granulosus specific IgG antibodies and IgG subclasses. Sensitivity measurements of total IgG, and IgG1-4 were 100, 100, 79.4, 61.8 and 55.9%, respectively, whereas respective specificity reached 65.1, 97.7, 98.4, 96.1 and 83. 7%. The diagnostic value of measuring IgG1 (97.7%), as assessed by a rating index (J) for combined sensitivity and specificity, was superior to total IgG (65.1%) and IgG2-4 (77.8, 57.9 and 39.6%, respectively). These findings set the stage for field evaluation of the IgG1 assay in areas endemic with human cystic hydatidosis.

Human cystic echinococcosis: diagnostic value of different antigenic fractions of hydatid cyst fluid with different specific immunoglobulin G subclasses by enzyme linked immunoelectrotransfer blot.

The present study intended to evaluate the usefulness of immunoblot analysis of hydatid cyst fluid (HCF) for diagnostic verification of human cystic echinococcosis (CE). HCF of camel origin was resolved by SDS-PAGE gel electrophoresis and transblotted on nitrocellulose membrane. Immunoglobulin G (IgG) subclass-specific antibody responses in 25 sera from surgically confirmed CE cases, 44 persons with other parasitic infections and 20 normal controls were analyzed. Total IgG and IgG subclass1-4 in CE sera preferentially recognized several polypeptide bands in the range of 14-200 kDa. The most predominant band recognized by total IgG antibodies was at 21 kDa (sensitivity, 96%; specificity, 98.5%; J index, 94.5%), by IgG1 at 38 kDa (sensitivity, 92%; specificity, 100%; J index, 92%) and by IgG3 at 60 kDa (sensitivity, 96%; specificity, 100%; J index 96%). Sera from the normal controls did not recognize any of these polypeptides. These data suggest that detection of any of these polypeptides bands could be used for confirmation of human cystic echinococcosis in Egypt.

Evaluation of specific immunoglobulin G avidity enzyme linked immunosorbent assay (IgG avidity ELISA) in diagnosis of early and chronic Schistosomiasis mansoni.

This work was performed to study variations of Schistosoma specific immunoglobulins between early and chronic schistosomiasis mansoni in both children and adults. A modified enzyme linked immunosorbent assay (ELISA), based on dissociation of antigen antibody complexes with 8 mol/L urea (8 M urea) solution, was used to measure levels of low avidity immunoglobulin G antibodies (IgG Abs) against Schistosoma mansoni soluble egg antigen (SEA). The study included eighty (80) patients with active mansonian schistosomiasis. They were classified according to age, history, clinical symptomatology and examination and direct parasitological methods of diagnosis into early and chronically infected children and adults. Sera of all patients were subjected to: ELISA measuring Schistosoma specific IgM and IgG., immunoglobulin G (IgG) avidity ELISA and indirect haemagglutination test (IHA). Schistosoma specific IgG avidity ELISA detected higher levels of both urea IgG inhibition percentage and low avidity IgG Abs in early cases of schistosomiasis than chronic ones in both children and adults. Levels of urea IgG inhibition percentage were higher in children than adults. Schistosoma specific IgM/IgG ratio was more than one (> 1) in early cases in both children and adults and less than one (< 1) in chronic cases in children and 70% of adults. IHA titres were statistically higher in chronic cases than early ones in children only. So, it can be concluded that IgG avidity ELISA is a valuable method that helps to differentiate early from chronic schistosomiasis mansoni infection in both children and adults.

Variations of direct fluorescent antibody test and serum bile acids levels following praziquantel treatment in Schistosoma mansoni experimentally infected mice.

This study was performed to evaluate the efficiency and use of an immunopathological test viz "Direct Fluorescent Antibody Test (DFAT) for detection of IgG and IgM deposits in liver and kidney biopsies" and a biochemical test viz "estimation of serum bile acids by enzymatic colorimetric technique" for follow up Schistosoma mansoni infection using Swiss albino mice. Test were done during infection and after Praziquantel (PZQ) treatment. Mice were classified according to the duration of infection and post-therapy periods. It was found that both tests should be used together to provide good parameters to demonstrate S. mansoni infection and to test the regression of the disease after treatment.

Immune complexes as monitors of cure in Schistosoma mansoni infected mice.

This study was done to assess the use of immune complexes estimated by micro-ELISA as monitors of cure of schistosomiasis mansoni experimentally infected Swiss albino mice which received praziquantel (PZQ) treatment. They were grouped according to duration of infection (4, 8, 12, 16w) and then subgrouped owing to post-treatment life span (4, 6, 8w). It was found that the changes observed in serum level of immune complexes (IC) would provide a good parameter to demonstrate the severity of infection and being an indication of improvement after treatment. The recorded changes confirmed the relationship between schistosomal hepatic affection and serum levels of IC. The study showed the potent anti-schistosomal effect of PZQ. It cured completely when it was given early after infection or improved moderately when given late.

Effect of praziquantel treatment on hepatic pathology of Schistosoma mansoni experimentally infected mice.

In this study we used Schistosoma mansoni (S. mansoni) infected mice were used to assess the pathological changes in the liver at various stages of the disease as well as the effectiveness of Praziquantel (PZQ) treatment on hepatic pathology also at different stages. The S. mansoni infected mice were divided into 7 groups and subgroups according to post infection and/or post treatment periods. The various hepatic pathological changes were recorded and it was concluded that PZQ is an effective yet, safe non hepatotoxic drug and that the earlier the application of treatment in the course of the disease the better cure we can get with minimal or no insult to the liver tissue.

Evaluation of different serological tests in mansonian schistosomiasis and correlation to hepatitis B virus infection.

A total of 70 bilharzial mansonian patients (Group I: 20 early intestinal mansonian patients, Group II: 20 hepatosplenic mansonian patients without ascites, Group III: 30 hepatosplenic mansonian patients with ascites) and 30 normal controls were studied. Using the circumoval percipitin test (COPT), there was a statistically significant difference between sensitivities in Group I and Group III with higher sensitivity for Group I. Using either the indirect haemagglutination test (IHA) or the indirect fluorescent antibody test (IFAT), there was no statistically significant difference between the sensitivities in the different bilharzial groups. No statistically significant difference was found between the 3 tests in Group I, II respectively. A statistically significant difference was found between the sensitivities of COPT and IHA in Group III. A highly significant difference was found between the sensitivities of COPT and IFAT in Group III also. No statistically significant difference was found between the sensitivities of IFAT and IHA in Group III. There was no statistically significant difference between the percentages of positivity of hepatitis B surface antigen (HBSAg) in the different bilharzial groups while each of the 3 groups showed highly statistically significant difference with the control group. No statistically significant difference was found between the positivities of HBSAg and the different titers of either IHA of IFAT in each group.

Diagnosis of active urinary schistosomiasis using homologous adult Schistosoma haematobium antigen.

The role of antigen prepared from Schistosoma haematobium adult worm (ShAWA, W.H.O. Geneva) in diagnosis of active urinary schistosomiasis, by counterimmunoelectrophoresis (CIEP), was evaluated by comparison with simpler methods as sedmentation of urinary ova and detection of haematuria by chemical reagent strips. Sixty patients (30 school boys and 30 adults) passing living S. haematobium eggs, as detected, by nucleopore filtration technique (NF), and 30 controls were studied. Results showed statistically significantly higher (P < 0.001) egg counts in school boys than adults. Sensitivities of haematuria detection, ova sedimentation and CIEP were 93.3%, 80%, 50%, 70%, 73.3%, 33.3% in school boys and adults respectively. It was concluded that direct parasitological examination of urine samples is more superior than CIEP using homologous ShAWA to detect active urinary schistosomiasis both qualitatively and quantitatively. Haematuria detected by chemical reagent strips can identify a high proportion of active urinary schistosomiasis in epidemiological surveys in endemic areas. Nucleopore filtration is more superior than ova sedimentation method for detection of active urinary schistosomiasis.

Naturally occurring toxoplasma antibodies in serum and milk of lactating women.

Serum and milk of lactating women were tested for toxoplasmosis using specific-IgG IFAT. Apparently healthy 70 women were selected: 54 from rural and 16 from urban areas. Serum and milk were simultaneously collected from each one. Sera were positive in 22 (31.4%) of the total 70; including 16 (29.6%) and 6 (37.5%) of rural and urban groups respectively. No statistical significant difference was found for positivity and titre levels between the two groups (P greater than 0.05). Milk was positive in 12 (17.1%) of the 70 women; including 10 (18.5%) and 2 (12.5%) from rural and urban groups respectively, having no statistical significant difference (P greater than 0.05). Comparing serum and milk for positivity and titre levels, also there was no statistical significant difference (P greater than 0.05). It is concluded that relatively low antibody levels in serum could be excreted in milk and may be protective for suckling babies. Occurrence of antibodies in serum and milk are homogeneously distributed between rural and urban inhabitants.

Detrusor morphology and pathology in relation to bladder outflow obstruction in bilharzial patients.

The light and electron microscopic structure of detrusor muscle of trabeculated urinary bladder from patients with urodynamically proved bilharzial outflow obstruction had been compared with normal detrusor muscle. In bilharzial outflow obstruction, the detrusor muscle bundles were formed of relatively smaller smooth muscle cells widely separated by dense connective tissue, fatty infiltration, bilharzial ova, inflammatory cells and hyalinosis. No evidence of smooth muscle hyperplasia, mitosis, or fibroblastic proliferation. At the level of electron microscopy. The connective tissue infiltration was proved to be microfibriles apparently in continuity of the basal lamina of the smooth muscle. These pathological changes can explain both the morphological and urodynamic changes in bilharzial urinary bladder outflow obstruction.

Specificity of crude and purified Fasciola antigens in immunodiagnosis of human fascioliasis.

A study has been done to find the effect of purification of crude antigens extracted from adult F. gigantica and F. hepatica on the cross reactions encountered in C.I.E.P., I.H.A. and E.L.I.S.A. serological techniques with sera o other parasitic and non-parasitic diseases. It was performed on 75 patients and 20 healthy controls. It was found that sera of many diseases may cross-react with crude Fasciola antigen in serological diagnosis. These diseases include schistosomiasis, hydatidosis, amoebic liver abscess, heterophyiasis, trichinosis, non parasitic liver diseases (liver neoplasms, pyogenic liver abscess, viral hepatitis and acute leukaemic) and rheumatoid arthritis. Partial purification of crude Fasciola antigens is a suitable method to avoid cross reactivity when using C.I.E.P. or to diminish them when using E.L.I.S.A. No need for this purification when using I.H.A. So using partially purified adult Fasciola antigens C.I.E.P. was the most specific test (100%) of followed by C.L.I.S.A. then I.H.A.