Head lice infestations (Anoplura: Pediculidae) in Saudi and non-Saudi school-aged children.

The prevalence and human risk factors associated with head lice infestation was studied. A total of 860 children, 474 (55.1%) boys and 386 (44.9%) girls, with ages ranged from 6-13 years were critically examined. They were randomly selected from two schoolchildren (one for boys and one for girls) in Jazan Province. The children or their parents were subjected to questionnaire and physical examination by visual inspections of scalp and hair for the presence of adult lice, nymphs, and/or eggs (nits). A total of 114 children (13.3%) were infested with head lice, 73 (18.9%) girls and 41 (8.6%) boys. The highest infestation rate was recorded in rural area (20.5%). Pediculosis had a negative association with father's education level and frequency of hair washing (p > 0.01). The results indicated that rural residence, sex, long hair, age- group 6- < 8 years old, positive history of previous infestation, sharing of beds and combs, uneducated mother and family overcrowding might be the risk factors for the head lice infestation.

Efficacy of Ixodes ricinus as a vector of zoonotic babesiosis in Sinai Peninsula, Egypt.

Ticks and blood samples were collected every month from March 2009 through April 2010 from different sites in Sinai to detect babesial parasites using PCR assay based on nuclear small subunit rRNA gene. Ticks were found to contain babesial DNA. Sequence determination and analysis of amplified portions of nss-rDNA revealed their identity with B. bovis and a high degree of homology with B. bigemina and B. divergens. The results represent the first genetic evidence of different species of Babesia and identified the role of Ixodes ricinus as a vector of zoonotic B. microti infection. Rodent isolate (HK) and American isolate (GI) were studied in transmission experiments. The present study used in vitro culture of zoonotic Babesia sp. EU1 from blood samples of rodent in Sinai. This study provides an evidence of transovarian and transstadial transmissions of the parasite within I. ricinus, which emphasizes that this tick could be a vector and reservoir of EU1

Electron miscroscopy and histochemical studies on four Egyptian helminthes eggs of medical importance.

By SEM the Fasciola gigantica egg is ovoid with a small knob like operculum, while the egg of Heterophyes heterophytes is broad oval with the operculum more tapering. The egg shell of fertilized Ascaris lumbricoides has interconnected ridges and peak-like projections, while the egg of Enterobius vermicularis is flattened with a thicker margin at the curved side. By TEM, Fasciola egg shell consists of fine reticulum fibrils of three layers. The outer lipoprotein of perivitelline membrane beneath which 2 membranes separated by inclusions, middle of protein globules and inner lipoprotein layer with minute electron-dense granules of melanin or polymer origin, in some parts of the shell giving the egg its brown coloration. The Heterophyes egg shell is more or less similar to that of Fasciola but lacking the minute electron-dense granules. The egg shell of Ascaris has outer ulterine layer with three consecutive layers, basal lipoprotein layer and the inner lipid or ascaroside layer which is the most resistant layer. The Enterobius egg shell consists of five layers, external uterine, internal uterine, vitelline, chitinous and lipid layer. Histochemically, Fasciola egg shell consists of nine amino-acids, and that of Heterophyes consists of ten amino acids. In Ascaris, the lipid layer characteristically consists 25% protein and 75% lipid. The histochemical examination of Enterobius as a detailed example, showed different degrees of reactions with mercuric bromophenol blue, diazotization coupling, Sakaguchi reaction, Sudan black and Mallory's triple stain. Temperature showed marked effect on eggs survival. Eggs of Fasciola and Heterophyes withstand more low temperatures but those of Ascaris and Enterobius withstand more high ones. There are marked correlations between the egg shell constitution, histochemical compositions on one hand and water permeability and egg dryness on the other hand. The results were photographed and discussed.

The histo-pathology of human giardiasis.

In giardiasis symptomatic group (I) the prevalence of diarrhoea was 5/7 (71.43%), 13/13 (100%) in Grade 0, I, II, III and IV pathology respectively which is statistically insignificant in comparison to each other (P > 0.05). The prevalence of abdominal pain is 71.43%, 73.33%, 95%, 91.67% and 100% in Grade 0, I, II, I & IV pathology respectively which is statistically insignificant to each other (P > 0.05). The prevalence of flatulence is 42.86%, 40%, 80%, 83.33% and 100% in Grade 0, I, II, III & IV pathology respectively, was statistically significant in comparison to each other (P < or = 0.05) So, the prevalence of flatulence is more frequent in patients with marked pathological changes in the duodenum. The prevalence of anorexia was 14.29%, 53.33%, 65%, 50% & 100% in Grade 0, I, II, III & IV pathology respectively, statistically significant in comparison to each other (P < or = 0.05). The prevalence of vomiting was 0%, 13.33%, 15%, 16.67 & 85.71% in Grade 0, I, II, III and IV pathology respectively, significant increased in Grade IV and absent in Grade 0 (P < or = 0.001).

Cytogenetics of acute and chronic schistosomiasis mansoni.

Schistosomiasis mansoni patients with acute were examined for genetic damage using the conventional cytogenetic method to assess the frequency of chromosomal aberration (CA) in the cultured blood cells. A non-significant difference was noticed in the frequency of CA between patients (acute & chronic) and control (n = 15), but on treatment of blood cultures with bleomycin (a radiomimetic agent with a DNA alkylating effect), the percentage of induced breakage and fragmentation increased significantly 2 and 3 folds in acute and chronic patients respectively, indicating increased chromosomal fragility. The incidence of rearrangement in the form of translocation increased significantly as compared to control blood cultures treated with bleomycin. The study revealed the antimitotic of schistosomiasis from significant inhibition of mitotic index. Although schistosomiasis did not show a direct clastogenic effect, it can be considered as a comutagen when there is concomitant exposure, especially chronic ones, to radiomimetic agents, schistosomiasis may amplify their cytogenetic damage.

Effect of some chemical agents on the viability of Cysticercus bovis.

The effect of eight chemicals; vinegar, Allium sativum (crude garlic), Acacia auriculiformis, lemon juice, praziquantel, pumpkin, perosan and yomesan on the viability of cysticerci of Taenia saginata in vitro was investigated. The minimum exposure time required for cysticerci to be non-evaginable for the eight chemicals were 5, 10, 25, 40, 55, 75, 90 and 105 minutes respectively. The best one was vinegar and the least effective was yomesan.

Occurrence of nematode larvae in terrestrial hermit crab Coenobita scaevola Forskal from Safaga region, Egypt.

The present work represents a new host, the terrestrial hermit crab, Coenobita scaevola Forskal and a new locality records for the larval nematode, Ascarophis from Safaga city. The results showed a direct relationship between host size (carapace length) and the prevalence rate of infected specimens. Larval nematodes were rarely found in specimens smaller than 17.0 mm in carapace length. Also, the fecundity of infected crabs was less than that of normal ones. Two types of host tissue response to infection were represented by muscular and haemocytic capsules around the larval nematodes.