Detection of G1 genotype of human cystic echinococcosis in Egypt.

The first trial to detect G1 genotype in Egyptian human isolates of hydatid cysts (HC) and serum samples to approach diagnosis of cystic echinococcosis (CE) using human sera by PCR. Using strain specific primers, 27/36 confirmed CE patients (75%) showed G1 specific band in their sera at 254 bp. Specificity was 100% without detecting bands for either other parasitosis, or mass occupying lesions. Using PCR, G1 genotype was detected in 83.3% of HC samples, without significant difference between types of human isolates (pulmonary, hepatic, or multi-organ). G1 genotype detection in human sera was in 75% of CE patients compared to 83.3% in HC samples of the same group of patients proved satisfactory, simple and safer than HCF sampling. IHAT gave sensitivity of 58.3% compared to histopathological examination of surgically removed cysts or examination of hydatid cyst fluid (HCF) for protoscolices (gold standards). The specificity was 70% with false positive reactions with other parasitic infections and mass occupying lesions. PCR detection of G1 genotype in Egyptian animal hydatid cysts showed 90% in camel isolates and 80% in sheep isolates, but pig isolates were negative. The presence of this genotype in a high percentage in camel isolates incriminated sheep strain as the source of CE camel infection. The results may give an explanation to the contradicting results of other studies that did not relay upon molecular aspects.

Growth patterns and antigenic analysis of Egyptian Trichomonas vaginalis isolates.

The vaginal washouts from symptomatic and asymptomatic patients were examined by wet mount examination and culture on modified TYM medium. Among the 320 cases examined, 10 were positive for T. vaginalis trophozoites by wet mount examination and culture. Modified TYM medium proved very satisfactory for isolation as well as maintenance of the 10 T. vaginalis isolates. Comparison between the growth patterns of all isolates, by counting the number of viable organisms every 24 hours for 7 days, showed that there is a wide variability in the growth characteristics, as regards lengths of log phase, growth peaks reached, generation times, division rate and number of divisions. Antigenic differentiation of the 10 T. vaginalis isolates through SDS-PAGE demonstrated a total of 34 bands using 10% resolution gel. The bands ranged in molecular weight from 12 to 189 KDa. Most of the bands were common among several isolates while isolate 2 appeared different than other isolates with two characteristic bands; one at 136 KDa and the other at 25 KDa. Also, isolates 4 and 8 had characteristic bands at 163 KDa and 189 KDa respectively.

Genotyping of human giardiasis in relation to anti-Giardia secretory IgA and mucosal histopathology.

Comparative study between the prevalence of pathological grading and Giardia genotypes revealed that, in patients infected with Giardia group I and II, out of patients having Giardia genotype I the prevalence of grade 0 was 13.16%, grade I was 21.05%, grade II was 47.37%, grade III was 13.16% and grade IV was 2.26% in comparison to 0%, 30.77%, 46.15%, 7.69% and 15.38% in genotype II (13 patients) and 10%, 40%, 20%, 20% and 10% in group III (10 patients) also in relation to 25%, 43.75%, 18.75%, 6.25% and 6.25% in mixed genotype infections group (16 patients) and 25%, 25%, 35.71%, 10.71% and 3.57% in undetermined infection group (28 patients) for grade 0, I, II, III & IV pathology respectively. There was no statistically significant difference regarding the prevalence of pathological grading in different Giardia genotypes in Gs I & II (P > 0.05). The mean OD of anti-Giardia secretory IgA in relation to Giardia genotypes in patients infected with Giardia Gs I & II was significantly different in the mean OD values of anti-Giardia secretory IgA in patients with different Giardia genotypes which were 1.091 +/- 0.377, 1.079 +/- 0.474, 1.524 +/- 0.503, 1.292 +/- 0.472 & 1.004 +/- 0.31 groups of genotype I, II, III, mixed genotypes infection and undetermined infection group respecttively (P > 0.05), being more increased in patients infected with Giardia genotype III and in mixed genotype infection.

Laboratory evaluation of Bacillus sphaericus recycling in mosquito larvae.

After ingestion by Culex pipiens and Anopheles pharoensis 4th instar larvae, spores of Bacillus sphaericus strain faiyoum rapidly germinated inside live mosquito midgut. Bacterial counts and electron microscopic observations on intoxicated larvae revealed that the number of viable spores rapidly decreased during the first 12 h, with a maximum between 12 and 24 h. In cadavers, the number of heat-resistant spores quickly increased between the first and second day post-feeding. After one week, the number of spores inside dead larvae reached approximately 20 times the number of ingested spores for both mosquito species (4 x 16(5) spores/larva). Ultrathin sections of recycled spores showed the presence of a crystalline inclusion identical to that initially present in spores before ingestion. Bioassay on Cx pipiens 4th instar larvae showed a similar toxicity between in vivo recycled spores (LC50 = 1.1 +/- 0.3 x 10(5) spores/ml after 24h exposure) and culture-medium-grown spores of B. sphaericus strain faiyoum (LC50 = 1.7 +/- 10(5) spores/ml).