Diagnosis of toxoplasmosis in immunosuppressed mice using the polymerase chain reaction (PCR) and the enzyme linked immuno-sorbent assay (ELISA) techniques.

In the present study, Toxoplasma infection with the virulent and avirulent strains in both immunocompetent and immunosuppressed mice was diagnosed using the MDS ELISA for detection of CA in sera and the PCR for demonstration of DNA in livers, brains and mononuclear cells of blood. Both techniques proved to be convenient, especially in immunosuppressed mice.

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.

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.

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.

A study on patients with eosinophilia of suspected parasitic origin.

A study of 53 patients with eosinophilia of suspected parasitic origin was conducted. Investigations done for each case included, stool and urine examinations, absolute eosinophilic count and countercurrent immunoelectrophoresis (CIEP) using crude antigens of Fasciola hepatica, Schistosoma mansoni worms, Trichinella spiralis and Toxocara canis larvae, and hydatid fluid. Stool examination revealed six cases with Fasciola eggs, two with Ascaris lumbricoides and one with S. mansoni eggs. The eosinophilic count ranged from 682 to 10560 cell/mm3. 26 cases showed mild eosinophilia, 24 moderate and three marked eosinophilia. Out of the 53 cases examined by the CIEPT, 30 were positive with Fasciola antigen. Their eosinophilic count ranged from 770 to 10560 cell/mm3. Six cases were positive with hydatid antigen and had an eosinophilic count ranging from 825 to 2970 cell/mm3. Only one case was positive with S. mansoni antigen and its eosinophilic count was 935 cell/mm3. 16 cases were negative with the different antigens used and their eosinophilic count ranged from 682 to 2200 cell/mm3.

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.

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.

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.

Evaluation of enzyme-linked immunosorbent assay and counter-current immunoelectrophoresis in diagnosis of experimental trichinosis.

Definite diagnosis of trichinosisis mainly by direct demonstration of larvae, however, these methods are neither feasible nor sensitive. Thus, confirmation relies mainly on positive serology. In this study, enzyme-linked immunosorbent assay (ELISA) and counter-current immunoelectrophoresis (CIEP) using crude larval antigen were assessed as a tool in the diagnosis of trichinosis. Sera were tested one, two, five, eight, and twelve weeks post-infection. It was found that ELISA was positive in all tested sera from the second till the 12th week (100% sensitivity). As regards CIEF, 36% of the sera were positive two weeks post-infection, while all sera were positive at 5 and 8 weeks. Ninety per cent of the tested sera gave positive results at the 12th week post-infection. ELISA proved to be more sensitive in diagnosing trichinosis both early and late in infection, while CIEP test was more specific since no false positive results were noticed.

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.

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.