Further characterization of Leishmania isolates from children with visceral infection in Alexandria area, Egypt.

Two visceral Leishmania isolates from children (aged 1 1/2 and 4 years) living in El Agamy area, Alexandria, Egypt, were compared with 5 marker strains, and 2 other human isolates from Sinai and Sudan, identified on clinical and geographical grounds as cutaneous and visceral leishmaniasis respectively. Isoenzyme variations were assessed on the basis of their electrophoretic profiles on cellulose acetate membranes. The enzymes studied were glucose 6-phosphate dehydrogenase E.C.1.1.1.49, phosphoglucomutase E.C.2.7.5.1, 6-phosphogluconate dehydrogenase E.C.1.1.1.44 (6-PGD), glucose phosphate isomerase E.C.5.3.1.9, malate dehydrogenase E.C.1.1.1.37, mannose phosphate isomerase E.C.5.3.1.8 and nucleoside hydrolase E.C.3.2.2.2. The last 4 enzymes could differentiate between cutaneous and visceral strains. The Alexandria strains proved to belong to the L. donovani complex; however, their 6-PGD pattern was identical to that of L. infantum, which was different from that of the L. donovani marker strain.

Evaluation of enzyme linked immunosorbent assay (ELISA) as a diagnostic tool for schistosomiasis.

The sensitivity and specificity of the ELISA were assessed in the diagnosis of schistosomiasis in two groups of school children, one attending a rural school where schistosomiasis is highly prevalent, the other attending a school in an urban locality where schistosomiasis is absent. The results showed that the ELISA had a sensitivity of 92.2% and 100% in Schistosoma mansoni and mixed infection, respectively. The specificity of the test increased from 92.1% to 98% when a fourth stool examination was done in cases giving false positive results. ELISA positively was significantly increased with the increase in egg count till it reached 100% in cases with 160 eggs per gram stools.

Identification of Trichinella isolates from naturally infected stray dogs in Egypt.

Larvae of Trichinella species recovered from the diaphragms of 2 stray dogs killed during a governmental antirabies campaign in Cairo, Egypt, were fed to white mice for production of adult worms and larvae for morphological and isoenzyme studies. Comparisons were made with reference species of Trichinella spiralis, Trichinella nelsoni, Trichinella nativa, and Trichinella pseudospiralis. Results indicated that the 2 Trichinella specimens from the dogs were morphologically and biochemically identical with T. spiralis.

The possibility of congenital infection with Acanthamoeba culbertsoni.

Acanthamoeba culbertsoni is one of the free-living amoebae which are known to be pathogenic to man, causing granulomatous amoebic encephalitis (GAE). In this study, Acanthamoeba culbertsoni was isolated from a water sample of El-Mahmoudia Canal in Alexandria, in July-1993. This was used to infect mice intranasally to study the histopathological picture of the brain and lungs. The neuropathological features consisted of chronic granulomatous encephalitis in which cysts and trophozoites were found. Associated Acanthamoeba pneumonitis with massive consolidation was also observed. Congenital infection of offsprings was reported for the first time in this study.

Granuloma size in the liver of mice with Schistosoma haematobium infection and Schistosoma mansoni challenge.

Swiss albino mice have been infected with S. haematobium and challenged with S. mansoni. S. haematobium infection in the mouse runs a course more or less parallel to that of S. mansoni infection. Granuloma has reached a maximal size at 135 days post infection and has regressed thereafter. Suppression of S. mansoni granuloma was observed in mice previously infected with S. haematobium. This manifests the presence of cross immunization.

Studies on experimental mixed infection of Schistosoma haematobium and Schistosoma mansoni in the albino mouse.

Swiss albino mice have been infected with S. haematobium and challenged with S. mansoni. No apparent disturbances as regards worm load and oviposition were observed. Yet certain deviations in the egg-distribution sites for both species were found. They were attributed to the possibility of earlier de-development of collateral circulation. Cross-pairing between the two species was met with, which might explain the extra number of S. haematobium eggs found in the small intestine. Although no major effect has been revealed, no conclusion at this stage could be put forward as regards complete absence of cross-immunity.

Schistosoma haematobium (Egyptian strain) transmission microscopy of normal and praziquantel treated worms.

The ultrastructure of the tegument and subtegumental structures of S. haematobium worms was examined by TEM. The effect of praziquantel on residual worms which remained after a curative dose was also studied. The male S. haematobium worms were characterized by deep tortuous pits and sharp apically directed spines. Spherical and elliptical bodies were also observed. The esophageal tegument was described. The effect of praziquantel on the male worms revealed flattening of spines and their disappearance in some regions as well as disruption and vacuolization of the tegument in others.

A comparison between human, crustacean and bivalve isolates of Microsporidia.

Identification of Microsporidia detected in diarrhoeic stool of human and from press preparation of crabs, and bivalves muscles was done by staining with Giemsa, modified trichrome and H & E stains respectively. Positive samples were isolated & used for infection of 3 groups of mice viz group A human isolate, group B crab & group C bivalve isolates. Parasitological and histopathological studies using light and transmission electron microscopy (TEM) were done for samples from each group. The results clarified that human, crab & bivalve Microsporidia isolates showed common features. They were found in the supranuclear region of enterocytes. The stages observed were meronts, sporonts and free spores. Each spore was 1-2 um in length containing a single nucleus, a vacuole and a polar filament. Further genetical and biochemical studies will be undertaken to confirm the similarity or differences between these isolates.

Scanning electron microscopy of normal and praziquantel treated S. haematobium worms (Egyptian strain).

The ultrastructure of the tegument of S. haematobium was examined before and after treatment with Praziquantel using scanning electron microscopy. The surface of the adult male worms prior to treatment showed numerous tubercles with apically directed spines and the lateral border showed highly pitted folds. The oral and ventral suckers showed well developed spines. Praziquantel administration caused various structural changes in the various groups studied. Blebs and spine deformities appeared as early as half an hr. after administration. Changes were also observed when the drug was administered prior to worm maturation resulting in generalized deformities in the worms which survived treatment, loss of spines and tegumental swellings.

Aminosidine sulphate in experimental giardiasis.

Giardia lamblia infection may be asymptomatic or may produce diarrhea with or without malabsorption. Many drugs were used for treatment of giardiasis, but none proved to be ideal since all have potential troublesome side effects as they are absorbed from the intestine. In this study, a locally acting drug aminosidine-sulphate (gabbroral) has been tried in treatment of experimental giardiasis in a rat model under different conditions of gastric acidity which is one of the main local factors affecting the pathogenicity of the organism. The best results were obtained in the group with hyperacidity which was induced by indomethacin (indocid) with significant improvement in the pathological picture and parasitic count. While in experimental animals with normal acidity there was only partial eradication of the parasite. However, in the group with hypoacidity induced by cimetidine (cimetex), the drug showed no beneficial effects since most organisms invaded the deeper layers of the intestine escaping the local action of the drug.

Isolation and identification of free-living amoebae from some water sources in Alexandria.

Samples from different water sources of Alexandria, and from nasal passages of 500 healthy children inhabiting areas nearby these sources were examined for the presence of free-living amoebae. These samples were cultured on 1.5% non nutrient agar streaked with bacteria. Amoebae were isolated and identified by means of their morphological characters and ability to produce flagellated forms. Characteristics of the cystic stages and pattern of excystation also aided in the identification of the various species. Nine species, Naegleria gruberi, N. fowleri, Acanthamoeba rhysodes, A. glebae, A. culbertsoni, A. astronyxis, A. palestinensis, V. avara and V. inornata were isolated from the water of canals and drains. N. gruberi and A. rhysodes were found in the nasal passages of six healthy children living near the contaminated canals. No amoebae were encountered in the drinking water, swimming pools, sea and lake water included in this study.

Detection of Microsporidia by different staining techniques.

Previous detection of Microsporidia relied mainly on electron microscopy and histopathology. Recently, non invasive methods were able to recognize this microorganism. In the present study, different stains were used as a means of diagnosing spores of Microsporidia in stool samples of immunosuppressed patients. The original modified trichrome stain (MTS) was used as a standard screening technique for all stool samples. Positive samples for Microsporidia were then stained with the trichrome blue stain, Didier's trichrome blue stain, acid-fast trichrome stain (AFT), modified Ziehl-Neelsen stain, giemsa stain and calcofluor white M2R stain. Both calcofluor and the AFT stains were most efficient. They could simultaneously detect coccidial oocysts and microsporidial spores. This is beneficial and time-saving in the diagnosis of stool samples of immunosuppressed patients, which usually contain more than one opportunistic protozoon. Both stains are easy to perform and require the least amount of staining and examination.

Preliminary identification of an intestinal coccidian parasite in man.

An unidentified coccidian parasite was observed in saline faecal smears of five immunocompromised patients. Very few of these organisms were observed in the oocystic stage. They were oval in shape with rounded edges and contained two sporulated sporocysts, 7.5-9.5 um in diameter with a nipple like projection. They are smaller than sporocysts of Sarcocystis hominis and suihominis. For further identification, the modified Ziehl-Neelsen stain was used. The sporocysts showed variability in staining. Most of them were unstained while those stained were more or less rounded with well defined four crescent shape sporozoites and a residual body but with an unstained cyst wall. Sporocysts were positively stained by phenol auramine which had the advantage of staining the cyst wall. Other coccidial parasites encountered in this study were Cryptosporidium parvum (18.2%), Cyclospora cayetanensis (1.8%) and Isospora belli (0.9%) they were differentiated from this organism. SEM showed oval sporocysts with thickened ridges on its surface dividing it into plates which is a characteristic feature of the family Sarcocystidae. From the above characters, the features of this parasite is suggested to be a Sarcocystis like Protozoa.

Diagnosis of bilharziasis (S. haematobium and S. mansoni) by the ELISA using the homologous antigen.

Sera of subjects with S. haematobium, S. mansoni and mixed infection were studied by the ELISA by means of homologous antigens. The extinction values for S. haematobium and S. mansoni cases were higher with the homologous antigen. Generally, S. haematobium cases were less reactive than S. mansoni or mixed infection.

Schistosoma haematobium infection in the white mouse--histopathological and histochemical studies.

Mice were infected with 1000 Schistosoma haematobium cercariae (Egyptian strain). Histopathological and histochemical studies were performed on the different organs, during the first four weeks after infection and on the fourth week after oviposition. Pathological changes during early prepatency matched with those in S. mansoni infection. Eggs were laid in aggregates in the colon and liver. They initiated the development of typical granulomatous lesions. Abundant bilharzial pigment and areas of sclerosis were present in both liver and spleen. The heart, kidneys and urinary bladder were pathologically free. Disturbed succinic dehydrogenase and acid phosphatase enzyme levels were detected which point to a derangement in the functions of the cell organelles.