Evaluation of crude and purified Toxocara canis antigens in serodiagnosis of human toxocariasis.

Three serological tests: Immunodiffusion (ID), Counterimmunoelectrophoresis (CIEP) and Enzyme-linked immunosorbent assay (ELISA) were used to study the role of crude adult worm antigen (CAWA) of Toxocara canis and each of its purified fractions in the serodiagnosis of human toxocariasis. Sensitivities of the three tests were lower in the ocular than in the visceral group, using different antigens. Purified fraction 1 showed more sensitive and specific reactions in the three tests, compared to CAWA or purified fraction 2 (P-F2) antigen. The other purified fractions (P-F3, P-F4 and P-F5) gave no positive reactions in any of the three tests. Using P-F1 antigen, ELISA was the most sensitive technique for diagnosis of both visceral and ocular toxocariasis followed by CIEP and then ID and the difference was statistically significant. However, CIEP was the most specific test followed by ELISA and lastly ID test. The ELISA test using Excretory-Secretory (E-S) larval antigen of Toxocara canis was less sensitive than the ELISA test using P-F1, although it was 100% specific. Thus, ELISA test using P-F1 is the test of choice for diagnosis of human toxocariasis, but when the specificity of a reaction is in doubt, CIEP test using the same antigen can be of value.

Serum levels of tumour necrosis factor- alpha in schistosomiasis mansoni and their analogous changes in collagen diseases and schistosomal arthropathy.

Serum levels of TNF-alpha was quantitatively estimated by the use of solid enzyme amplified sensitivity immunoassay (EASIA) in different stages of schistosomiasis mansoni, rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and schistosomal arthropathy. Statistically, significant higher levels were detected in the different groups compared to the normal control group. The level was found highest in hepatosplenic schistosomiasis with ascites (group 1c). The difference was significantly higher compared to cases of early S. mansoni infection (group Ia) and insignificant compared to hepatosplenic schistosomiasis without ascites (group 1b). No significant difference was detected comparing groups 1a and 1b, or groups 2a (RA) and 2b (SLE). Cases of schistosomal arthropathy (group 3) showed significantly higher level compared to groups 1a and 1b, although the level in group 1c was still significantly higher compared to group 3, the level was also significantly higher in group 3 compared to cases of RA but not to cases of SLE.

Effect of immunomodulation on the course of experimental toxocariasis in mice.

Immunosuppressed groups treated with cortisone showed fulmination of Toxocara canis infection in terms of significant increase in brain parasitism, total larval count and significant decrease in the percentage reduction of the total count. Suppression of the host inflammatory responses was detected in the liver, lungs, brain and muscles. Accelerated transit of larvae through the liver was observed when cortisone was given before infection. Whether BCG was given before or after infection, it showed no significant changes regarding all criteria compared to the control group. Induction of diabetes, whether before or after infection, led to persistence of larvae in the liver, insignificant increase in brain and total larval parasitism and insignificant decrease in the percentage reduction of the total count.

Histopathological evidences for the antifibrogenic effect of colchicine in schistosomiasis mansoni in mice.

Colchicine treated mice showed significant decrease in prevalence of fibrocellular and fibrocellular and fibrous granulomas in liver specimens compared to corresponding control groups. Percentage of spindle cell component and red fibrillar (RF) material showed significant reduction compared to control groups. These evidences of the antifibrogenic effect of colchicine were more prominent when treatment was given early after infection. Combined therapy with colchicine and praziquantel gave the same results. Mice treated with praziquantel alone showed no significant change compared to control groups. Colchicine showed also an immunomodulant effect evidenced by a significant decrease in the intensity of small and medium-sized to large cell components compared to control groups.

Effect of immunomodulation on experimental hymenolepiasis nana in mice.

Oral infection of cortisone treated and diabetes induced groups of mice (immunosuppressed) with H. nana eggs, whether before or after infection, showed persistent hyperinfection of the gut with H. nana worms and cysticercoids, dissemination of cysticercoids to the liver and marked degenerative changes in the intestinal mucosa and liver. BCG treated groups (immunostimulated) whether before or after infection, showed no significant changes compared to the control group. Subcutaneous infection of mice resulted in severe localized cellular reaction around and infiltrating the injected H. nana eggs in BCG treated and control groups. BCG did not inhibit larval development, as cysticercoids were found in the injected sites. In cortisone treated and diabetic groups, mild cellular reaction was observed.

Parasitic infections associated with malignancy and leprosy.

Results of parasitic infections, as revealed by urine and stool examination was significant (P less than 0.05) in 43.3% of patients suffering from different malignant diseases and non significant (P greater than 0.05) in 29.3% of leprosy patients compared to 22% in control subjects. The most prevalent parasites were E. histolytica and G. lamblia. Cryptosporidium occysts were not detected. By stool examination and culture, S. stercoralis larvae were detected only in the malignancy group. The most common parasites occurring concomitantly were A. duodenale and S. stercoralis. By the IFAT, strongyloidiasis gave significantly higher positive results in the malignancy group than in the leprosy and control groups. IFAT for toxocariasis, showed highly significant positivity in the leprosy group and significantly positivity in the malignancy group. For toxoplasmosis, it showed highly significant positive results in both leprosy and malignancy groups. Eosinophilia was significantly more prominent among malignancy patients and insignificant among those with leprosy. Parasitic infection detected by urine and stool examination among patients with eosinophilia was found in 76% of the malignancy patients and in 66.7% of the leprosy patients.

A survey for enteroparasites in Menoufia governorate, Egypt with special reference to Strongyloides stercoralis.

The prevalence of Strongyloides stercoralis and other enteroparasites was studied in Menoufia Governorate. 565 stool & 500 serum samples were examined by direct smear, zinc sulphate, stool culture & IFAT using ultrasonicated non digested non fixed filariform larva as antigen. IFAT proved superior than the direct methods since it detected 11.1% of cases while the latter detected only up to 3.4%. The prevalence of enteroparasites was found to be 62.3%. E. histolytica and A. lumbricoides showed the highest incidence while Taenia showed the lowest incidence.