Prevalence and genotyping of Cryptosporidium in stool samples collected from children in Taif City (Saudi Arabia).

This study was conducted to estimate the frequency of Cryptosporidium infections in Taif (Saudi Arabia). Stool samples from children under 10 years by modified Ziehl-Neelson staining and two PCR techniques were used for genotyping experiments. The microscopic examination showed that, eleven samples were positive for presence of Cryptosporidium. With 11 of 100 samples, DNA extraction and subsequent genotyping was successful. By means of RAPD technique, the genetic similarity among the collected isolates was 55%. The 18S rRNA gene sequences confirmed that all Cryptosporidium-isolates belonged to Cryptosporidium parvum. In comparison with reference strains from different species of Cryptosporidium species from GenBank, all collected isolates belonged to Cryptosporidium hominis and C. parvum clade. The fact that only human genotypes were detected suggests that cryptosporidiosis must primarily be considered as a non zoonotic disease in Taif region.

Leishmania donovani is the only cause of visceral leishmaniasis in East Africa; previous descriptions of L. infantum and "L. archibaldi" from this region are a consequence of convergent evolution in the isoenzyme data.

Isoenzyme-based studies have identified 3 taxa/species/'phylogenetic complexes' as agents of visceral leishmaniasis in Sudan: L. donovani, L. infantum and "L. archibaldi". However, these observations remain controversial. A new chitinase gene phylogeny was constructed in which stocks of all 3 putative species isolated in Sudan formed a monophyletic clade. In order to construct a more robust classification of the L. donovani complex, a panel of 16 microsatellite markers was used to describe 39 stocks of these 3 species. All "L. donovani complex" stocks from Sudan were again found to form a single monophyletic clade. L. donovani ss stocks from India and Kenya were found to form 2 region-specific clades. The partial sequence of the glutamate oxaloacetate transaminase (GOT) gene of 17 L. donovani complex stocks was obtained. A single nucleotide polymorphism in the GOT gene appeared to underlie the isoenzyme classification. It was concluded that isoenzyme-based identification is unsafe for stocks isolated in L. donovani endemic areas and identified as L. infantum. It was also concluded that the name L. archibaldi is invalid and that only a single visceralizing species, Leishmania donovani, is found in East Africa.

Towards a standard battery of microsatellite markers for the analysis of the Leishmania donovani complex.

The investigation of microsatellite markers has recently superseded that of isoenzymes for many population-biology applications. Microsatellites have the advantages of being dominant, neutral, highly polymorphic and easily scored by high-throughput methods. However, it is necessary to develop a new panel of markers for each group of organisms of interest. Previously, only about 5% of the markers that amplify Leishmania major microsatellite loci were also found to amplify L. donovani loci. A panel of 20 microsatellite markers that are polymorphic in L. donovani and L. infantum has now been developed, using a rapid-enrichment method that will be suitable for developing libraries of markers for other trypanosomatid species. This is the first panel of polymorphic microsatellite markers, to be isolated de novo from any species of Leishmania, that is large enough for population-biology applications.

Dental treatment under general anaesthesia at a hospital in Jeddah, Saudi Arabia.

UNLABELLED: Dental General Anaesthesia (DGA) has been shown to be of value in providing both restorative treatment and extractions in children who are unable to accept this using other methods of management. AIMS: The aims of this retrospective study were to determine the characteristics of patients attending for treatment under DGA at a centre in Saudi Arabia, to describe the type of dental treatment carried out using DGA and in the subsequent 3-year period. SAMPLE AND METHOD: Data were collected from hospital records of 555 patients who received treatment under DGA at King Fahad Hospital in Jeddah, Saudi Arabia, between 1995 and 1997. RESULTS: Ninety three percent of the patients were aged 8 or younger at the time of DGA, with 43% being under 5 years of age. The main indications for use of DGA in the youngest age group were dental management of rampant caries (77% of the youngest age group) and inability to accept treatment under local anaesthesia (49% of those aged 5-8 years). Seventy percent of patients had treatment involving both extractions and restorative care, and the majority, 81%, had one tooth or more restored with preformed metal crowns. Sixty-three percent of patients attended for recall after 6 months but only 10% did so after a 3-year interval. Only one of the 555 patients received a second DGA at the same centre during the 3 years following treatment. CONCLUSIONS: The service studied provides dental treatment primarily for children with extensive disease. Failure to attend for recall was common, suggesting that preventive methods which rely on regular attendance may not be successful in this group of children.

Ultrastructure of spermiogenesis of Saudian reptiles. 6. The sperm head differentiation in Agama adramitana.

In addition to the common features of spermiogenesis in Reptilia, new structures are seen in Agama adramitana that have not been described in previous studies. Two acrosomal granules are observed in the acrosomal vesicle. The posterior acrosomal granule differentiates as an anterior electron-dense material in the acrosome, and the anterior one forms a posterior translucent component of the acrosome. Also, the subacrosomal granule spreads in the subacrosomal space as a subacrosomal nuclear cap.