Giardiasis Pattern among Different Age Categories: Childhood Assemblage B Proclaim Endemicity.

BACKGROUND: Giardiasis is one of the commonest intestinal parasitic diseases that affects wide range of age groups. We aimed to detect the pattern of Giardia intestinalis assemblages among symptomatic patients at the age of 2 up to 40 years. METHODS: Stool samples were collected from 278 patients and examined microscopically and genetically for giardiasis. Giardia was diagnosed using wet mount examination and subjected to molecular assays targeting three genes, glutamate dehydrogenase (gdh) using semi-nested PCR (nPCR), ß-giardin (bg) and triose phosphate isomerase (tpi) using nPCR. Amplified products were subjected to genotyping using PCR-restriction fragment length polymorphism (PCR-RFLP) targeting gdh and bg genes. RESULTS: Among 48 samples positive by microscopy and by a minimum of one of the three used genes, genotyping was successful among 23 samples (47.9%). Assemblage B was more prevalent (16/23, 69.6%), than assemblage A (4/23, 17.4%) and 3 (13%) isolates were identified as assemblage B at gdh locus which later were identified as assemblage A at bg locus. Sub-assemblage AII (3/4, 75%) and sub-assemblage BIII (12/15, 66.7%) were predominate at gdh locus. Age groups was an estimated risk factor for infection with assemblage B with a peak (87.5%) during 6 to 12 years (P< 0.05), diarrhea and abdominal pain (OR (95%CI) = .654 (.094, .963); .201 (.048, 1.009), respectively) were significantly associated with assemblage B. CONCLUSION: It is recommended to suspect infection with giardiasis assemblage B by physicians during late childhood presenting with diarrhea and abdominal pain.

First isolation of a new species of Leishmania responsible for human cutaneous leishmaniasis in Ghana and classification in the Leishmania enriettii complex.

An active case detection approach with PCR diagnosis was used in the Ho District of the Volta Region, Ghana that identified individuals with active cutaneous leishmaniasis. Three isolates were successfully cultured and DNA sequences from these were analysed (ribosomal RNA internal transcribed spacer 1; ribosomal protein L23a intergenic spacer; RNA polymerase II large subunit), showing them to be Leishmania, identical to each other but different from all other known Leishmania spp. Phylogenetic analysis showed the parasites to be new members of the Leishmania enriettii complex, which is emerging as a possible new subgenus of Leishmania parasites containing human pathogens.

Genotypic characterization of cutaneous leishmaniasis at Al Baha and Al Qasim Provinces (Saudi Arabia).

Fifty samples of skin ulcers were collected from the western region of Saudi Arabia Kingdom (Al Baha and Al Qasim) to study genotypic characterization of Cutaneous Leishmaniasis in this area. Thirty-six samples were recorded as Leishmania isolates. The same isolates were subsequently tested with fingerprinting with single arbitrary primers. The primers used derived from the core sequence of the phage M13, and the repeat sequences (GTG)5 and (GACA)4. The 36 isolates were all identified as Leishmania major (n = 25 isolates) or Leishmania tropica (n = 11 isolates). All produced polymorphic patterns, which were grouped depending on the species they belonged to, next to the relevant well-characterized strains of the same species. Within the L. major and L. tropica group the subgroupings formed were mainly related to the geographical origin of the strains. A nested polymerase chain reaction-based schizodeme method for identifying Leishmania kinetoplast minicircle classes was used as a diagnostic tool for L. major and L. tropica.

Diagnosis of clinical samples spotted on FTA cards using PCR-based methods.

The broad clinical presentation of Leishmaniasis makes the diagnosis of current and past cases of this disease rather difficult. Differential diagnosis is important because diseases caused by other aetiologies and a clinical spectrum similar to that of leishmaniasis (e.g. leprosy, skin cancers and tuberculosis for CL; malaria and schistosomiasis for VL) are often present in endemic areas of endemicity. Presently, a variety of methods have been developed and tested to aid the identification and diagnosis of Leishmania. The advent of the PCR technology has opened new channels for the diagnosis of leishmaniasis in a variety of clinical materials. PCR is a simple, rapid procedure that has been adapted for diagnosis of leishmaniasis. A range of tools is currently available for the diagnosis and identification of leishmaniasis and Leishmania species, respectively. However, none of these diagnostic tools are examined and tested using samples spotted on FTA cards. Three different PCR-based approaches were examined including: kDNA minicircle, Leishmania 18S rRNA gene and PCR-RFLP of Intergenic region of ribosomal protein. PCR primers were designed that sit within the coding sequences of genes (relatively well conserved) but which amplify across the intervening intergenic sequence (relatively variable). These were used in PCR-RFLP on reference isolates of 10 of the most important Leishmania species: L. donovani, L. infantum, L. major & L. tropica. Digestion of PCR products with restriction enzymes produced species-specific restriction patterns allowed discrimination of reference isolates. The kDNA minicircle primers are highly sensitive in diagnosis of both bone marrow and skin smears from FTA cards. Leishmania 18S rRNA gene conserved region is sensitive in identification of bone marrow smear but less sensitive in diagnosing skin smears. The intergenic nested PCR-RFLP using P5 & P6 as well as P1 & P2 newly designed primers showed high level of reproducibility and sensitivity. Though, it was less sensitive than kDNA minicircle primers, but easily discriminated between Leishmania species.

PCR assay in malaria diagnosis using filter paper samples from Jazan region, Saudi Arabia.

PCR assay using designed primers was evaluated in detecting human malaria infection from whole blood and/or on Whatman filter-paper compared to conventional microscopy. Two DNA extraction methods were used for dried blood-spots; QIAamp mini kit and methanol-fixation/heat-extraction. A total of 118 cases were collected from 4 hospitals at Jazan district. Microscopic examination showed positivity in 66/118 samples (56%). Thin films showed parasitaemia from 1+ to 4+. In PCR assay, 79 samples (70%) were positive for the genus Plasmodium given 153 base pair PCR product. All microscopy positive samples were PCR positive but PCR detected 13 cases missed by microscopy. As for filter-paper spot samples, 68 samples (57.6%) were PCR positive when DNA was extracted by QIAamp mini kit whereas 49 (41.5%) by methanol-fixation/heat-extracion method. PCR sensitivity decreased by using DNA extracted from filter-paper compared to microscopy and whole blood PCR. But the DNA isolated from filter paper detected parasites in many microscopy negative samples.

Preliminary study of the prevalence of intestinal parasites among diarrheic inhabitants in Makkah Al-Mukarramah.

Darrheic disease is one of the greatest causes of morbidity and mortality worldwide. Intestinal parasites contribute to the disease and the well being of humans. This study was undertaken in the Holly City of Makkah Al-Mukarramah. A total of 166 diarrheic stool samples were collected. A wet smear from each specimen in normal saline and Lugol's iodine solution was examined microscopically for the trophozoites and cysts of protozoan parasites. Stools were also examined using ethyl acetate formalin concentration technique to confirm the diagnosed parasites. All stool specimens were stained by Ziehl-Neelsen stain to detect the oocysts of Cryptosporidium spp. One way ANOVA was used to analyze data. 128 persons were found to be infected, with an overall prevalence of 77.1%. 46.99% of the samples were females, and 53.01% were males. The prevalence of infection in females was 36.1%, and 40.9% in males. 16.9% of infected females were living near the Holy Masjid (down town), while 19.3% were living away from the Holy Masjid (up town). 18.7% of infected males were living down town, while 22.3% were living up town. The majority of cases fall into the young age groups (< 30 years old). There is no significant difference between the prevalence of infection down town and up town (P = 0.22), whereas the prevalence of infection between the patients over or under 30 years old was significance (P = 0.036). The rates of infection were higher in those living up town than those living down town. The results were critically discussed.

Review on electron microscopy in taxonomy and biology of parasitic Nemathelminthes.

Electron microscopy (EM) proved a very helpful means that solved a lot of information in different scientific aspects. EM is a very good tool in the hospitals and research centers. It was aimed to pile up available information on the biology in the descriptive morphology of nematodes and their immature stages by scanning (SEM) and transmission (TEM) electron microscopy. Watson (1965a, b) studied Euchromadora vulgaris and Ascaris sp. by using TEM respectively. Lee (1969) investigated the ultra-structure of Nippostrongylus brasiliensis by SEM & TEM, as well as some nematodes by TEM (Lee, 1972). The topography of the adult Baylisascaris procyonis caudal end was illustrated by Snyder (1989). Male tail relatively long, smoothly attenuated, with a small button-like or mucronate termination. Pre-anal papillae situated ventrally in 2 slightly divergent and somewhat irregularly spaced rows. Anterior and posterior to anus 2 slightly raised roughened patches consisting of several rows of small spines. Just anterior to anus along outer margin of pre-anal roughened patch, a large double medio-ventral papilla. Five pairs of post-anal papillae with first pair just posterior to anus doubled and 4 pairs more closely associated in a group near tail end. Second pair with doubled papillae; but, in a few specimens fused as if 2 single closely associated papillae. Three pair single. Fourth pair of caudal papillae phasmids and in centers of each a ringed pore-like opening. Male spicules with a highly sculptured surface with a pincher-like terminal end.

Enteroparasitic occurrence in stools from residents in Southwestern region of Saudi Arabia before and during Umrah season.

OBJECTIVE: Study of the prevalence of human gastro-intestinal parasitic infections among patients living in Makkah Al-Mukkarmah city before and during Umrah season. METHODS: One hundred eighty three stool samples were collected from patients living in Makkah, between the months of March and November 2005. Eighty were collected before the Umrah season began and 103 were collected during the Umrah season. Age, sex, and address were also recorded. Samples were preserved in 10% formol saline. They were examined using the direct smear technique and the formol ether concentration method. RESULTS: The results suggest a higher prevalence of intestinal parasitic infections (70.5%) among the patients under study. Entamoeba histolytica/E. dispar and Giardia lamblia were found to be the most common intestinal parasites among patients before and during Umrah. The infection rate was higher in the under 30 age group (74.8%) and in persons living away from the Holy Masjid (77.7%). The prevalence of intestinal parasitoses during Umrah (73.8%) was higher than that before Umrah (66.3%). CONCLUSION: The present study suggests that the group of people may underline the significant increase in the prevalence of intestinal parasitic infections during Umrah season. This highly significant increase of parasitic infection rate (p=0.018) was elicited when results were compared by one-way analysis of variance (ANOVA). The present data were discussed with previous studies.

Contribution of electron microscopic studies to the biology and classification of parasitic cestodes (review article).

Members of phylum Platyhelminthes are leaf-like or tape-like worms. Class Cestoidea are exclusively parasitic organisms; covered with a nonciliated integument; ciliated epithelium, when present, confined to embryos (onchospheres) hatched from eggs; scolex provided with suckers and frequently hooks for attachment to host tissue; body in most species divided into separate, sexually complete proglottids. Class: Cestoidea: comprises two subclasses: Cestodaria body undivided; only one set of reproductive organs; oncosphere hatching from egg has 10 hooklets. Cestoda: body typically with scolex and series of proglottids, each with one set (rarely 2 sets) of male and female organs; oncosphere typically has 6 hooklets (Beaver et al., 1984).

Detection of malaria in Saudi Arabia by real-time PCR.

Malaria transmission occurs in Saudi Arabia and mainly endemic in the lowlands of Asir region, the Southwester Province. Imported cases have been reported. Sensitive routine laboratory techniques for rapid and accurate malaria diagnosis are therefore desirable to facilitate the identification of individuals infected with the malarial parasites and to follow up the progress of treatment of such cases with appropriate drugs. Traditional diagnosis, based on the microscopic examination of Giemsa-stained thick and thin films remains the main standard method of diagnosis used for malaria diagnosis in Saudi Arabia. Molecular diagnostic techniques based on the detection of nucleic acids (as PCR; Real-time PCR) are now highly considered. Real time-PCR a new methodology has been recently applied to detect human malaria. In this study a total of forty four samples, using whole-blood, dried blood and thick smears were examined by PCR and Real-time PCR. Both techniques showed a higher sensitivity than the microscopy. Parasites were detected in twenty nine samples out of forty four, compared to twenty six of thirty nine were positive with thin blood film. The real-time PCR assay offers a practical and positive alternative for rapid and accurate diagnosis for malaria infection. The application of such technique will be significantly valuable especially for screening for malaria infection in endemic areas.