Identification of a Cyclospora cayetanensis Oocyst Antigens and Their Validity in the Detection of Immunogenic Patterns of Cyclosporiasis Patients.

INTRODUCTION: The diagnosis of cyclosporiasis is currently based on the microscopic detection of oocysts, which may provide invalid results. The availability of simple, objective immunological screening tests would facilitate epidemiological studies of cyclosporiasis. Therefore, the present study aimed to identify the antigens of Cyclospora cayetanensis oocysts and their validity in serodiagnosis. METHODS: According to parasitological and molecular diagnoses, three study groups were specified. Group (G) I included 30 patients with cyclosporiasis, GII included 12 patients with other parasitic infections, and GIII included 16 healthy subjects. SDS-PAGE was used to analyse C. cayetanensis antigens, and the validity of western blotting and enzyme-linked immunosorbent assays (ELISAs) was then assessed amongst the sera of all study groups. RESULTS: The C. cayetanensis antigenic profile showed eight characteristic bands with molecular weights ranging from 14 to 175 kDa. Western blot analysis of sera revealed 93.3% (28/30 of GI) and 92.8% (26/28 of GII and III) sensitivity and specificity, respectively, dividing the patients in GI into four subgroups. The most frequent diagnostic bands (71.4% of GI sera) showed weights of 26-28 kDa, followed by 71 kDa (53.6%). ELISA sensitivity was 90% (27/30), and specificity was 78.6%. Validation showed perfect agreement between the PCR and western blot results, and ELISA presented substantial agreement with both the PCR and western blot results. CONCLUSIONS: Our findings suggest the existence of high immunogenic diversity in C. cayetanensis and indicate that the 26-28 kDa immunogenic groups may potentially be used as a diagnostic marker of cyclosporiasis. Due to the high validity of ELISA, it might be the test of choice for the routine serodiagnosis of cyclosporiasis.

Nested PCR targeting intergenic spacer (IGS) in genotyping of Giardia duodenalis isolated from symptomatic and asymptomatic infected Egyptian school children.

Distinct sequences of Giardia duodenalis assemblages raised the hypothesis that certain assemblages may contribute to its clinical outcome. However, sequences analysis is time consuming, expensive, and needs many manual operations. Nested PCR targeting intergenic spacer (IGS) region was applied successfully to genotype G. duodenalis. This study aimed to identify the prevalence of G. duodenalis assemblages among giardiasis school children and its relation to the presence of symptoms using nested IGS/PCR. Of 65 microscopically confirmed Giardia-positive samples, 65 samples were genotyped proving high sensitivity (92.3%) of IGS/PCR. Negative IGS/PCR samples were also negative for ß-giardin gene. Subassemblage AI was the commonest with 66.6% (20/30) among asymptomatic children compared to 53.3% (16/30) of symptomatic, while assemblage B was found in 40% (12/30) of symptomatic compared to 20% (6/30) of asymptomatic. The difference was significant. AII was only found in asymptomatic with 13.4% (4/30), while mixed infections (AI&B) were recorded only in 6.6% (2/30) of symptomatic group. A significant relation was found between younger children susceptibility for AI and B infections as presented in 77.7 (12/16) and 83.3% (10/12) of symptomatic, respectively, and 80 (16/80) and 33.4% (2/4) of asymptomatic, respectively. Significant relations were found between AI with intermittent diarrhea and B with chronic. A significant relation was found between assemblage distributions and heavy infection intensity. In conclusion, higher incidence of assemblage B among symptomatic children compared to asymptomatic could denote its possible pathogenic potential.

Prevalence and clinical features of Dientamoeba fragilis infections in patients suspected to have intestinal parasitic infection.

The present study was conducted to determine the prevalence and clinical features of dientamoebiasis in patients presumed to be infected with intestinal parasites. A total of 168 patients were examined for D. fragilis using microscopy (after Wheatley's trichrome staining) and culture (using modified Boeck and Drbohlav's medium). D. fragilis trophozoites were detected in 15 samples (8.9%) examined using trichrome staining and in 50 samples (29.8%) by culture method. Other enteric parasites were common in the study population as 48.8% of patients (82/168) were found harboring intestinal parasites. Blastocystis hominis was the most common, identified in 33.3% (56/168) of the samples. Giardia lamblia was detected in 17.9% (30/168) and E. histolytica/E. dispar in 11.9% (20/168). The symptoms most frequently encountered were diarrhea, abdominal pain and weight loss and fatigue. Diarrhea and abdominal pain were significantly more frequent in patients with dientamoebiasis compared to non pathogenic cases (P < 0.05). Diarrhea was 38.5% of patients infected with D. fragilis compared to 50% of patients infected with G. lamblia, while abdominal pain was encountered with D. fragilis in 41% compared to 33.3% with G. lamblia. These differences were insignificant (P > 0.05).