Study of factors affecting growth of Leishmania in cultures.

The rate of growth of Leishmania major and L. infantum in El-On's culture media supplemented with human, dog, rat and avian blood was studied in vitro. Rabbit blood was used as a control. The effect of culture with these types of blood on the infectivity of both Leishmania strains to albino mice was also studied. The results showed that a good yield of both L. major and L. infantum parasites can be obtained in culture by using avian blood as substitute for rabbit blood in El-ON's medium. In addition, rat blood gave good results with L. infantum. The morphological forms of L. major and L. infantum on all types of blood supplemented media: elongated promastigotes, spindle promastigotes, paramastigotes and amastigoes were present all through the culture period with variable percentages. The infectivity to experimental animals was not affected by culture of both Leishmania strains on rabbit, human, rat, dog as well as avian blood supplemented media.

Evaluation of an indirect immunofluorescence assay for the detection of Leishmania promastigotes and amastigotes in sand flies and lesion fluid aspirates.

Rabbit monospecific antibody Leishmania major surface glycoprotein (gp63) was used in an indirect immunofluorescence assay (IFA) to identify promastigotes and amastigotes from sandflies and lesion fluid aspirates, respectively. Anti-gp63 fluoresced the entire periphery and flagella of promastigotes of different Leishmania species at dilutions to 1:50. Promastigotes were distinctively demonstrated in whole infected sandfly homogenate for 17 days post-infection. Amastigotes from lesion aspirates of infected BALB/c mice and from a human cutaneous leishmaniasis case were also fluoresced by the antibody. This technique could prove to be especially useful in arthropod vector surveillance efforts in which detection of the pathogen is as important as speciation of the sand fly vector.

Amebiasis in schistosomiasis endemic and non-endemic areas in Egypt.

Stool and blood specimens were collected from each of 404 and 576 individuals at Sindbis village (Qualiubia Governorate) in the Nile Delta where schistosomiasis is endemic and El-Rashda village (New Valley Governorate) in the Western Desert of Egypt where there is no schistosomiasis; respectively. Based on the microscopical examination of stool specimens, the prevalence of infection with Entamoeba (E. histolytica and/or E. dispar which are morphologically indistinguishable) was higher at Sindbis than at El Rashda village (29.3% and 20%, respectively). At Sindbis, the prevalence of Entamoeba (both species) was 35.2% (50/142) in S. mansoni infected individuals versus 26.3% (69/262) in S. mansoni negative individuals. Serum antibodies develop only against E. histolytica but not against E. dispar infection. When serological results were considered, the prevalence of E. histolytica was 4.7% in Sindbis and 3.4% at El Rashda based on those who were positive microscopically and serologically in the two villages, respectively. In other words, only 16-17% of those who were positive microscopically can be considered infected with E. histolytica as determined serologically. However, the prevalence of E. histolytica (present or past) based on those who were positive serologically whether positive or negative microscopically was 13.4% and 12.7% at the two villages, respectively. At Sindbis, the prevalence of E. histolytica infection was lower in S. mansoni negative (8.5%) than in S. mansoni positive (16.0%) individuals. These epidemiologic data suggest that: (1) S. mansoni infection may suppress the immune response of the host and therefore, the prevalence of E. histolytica based on serological testing is probably underestimated in the S. mansoni infected people and it may be higher than in the S. mansoni negative people. (2) Serological examinations can be used in determining the true prevalence of E. histolytica (present or past infections) until a routine test for detecting E. histolytica specific antigen in stool becomes available to differentiate E. histolytica from E. dispar infections.

Identification of a misleading trypanosomatid parasite from Gerbillus pyramidum and G. andersoni in a Leishmania major endemic area in north Sinai.

During an epidemiologic investigation of cutaneous leishmaniasis at a focus in north Sinai, Egypt, between June 1989 and December 1991, 897 desert rodents were trapped and examined to identify reservoir hosts for Leishmania major. Mixed forms of epimastigotes and promastigotes were isolated in Tanabe's medium from 4 Gerbillus pyramidum and 1 Gerbillus andersoni. The 2 forms were later grown and separated as distinct cultures in Schneider's medium. The isoenzyme profile of the gerbils' promastigotes was identical to Leishmania tropica but differed from those of L. major and the gerbils' epimastigotes. The protein pattern by sodium dodecyl sulfate poly acrylamide gel electrophoresis gave no conclusive results. The Hae III restriction endonuclease analysis of kinetoplast DNA of both morphological forms confirmed their similarity and distinguished them from L. tropica and L. major. The gerbils' promastigotes were 30% broader, with a smaller nucleus than those of L. tropica. Following several subcultures, epimastigotes were found to transform to promastigotes. These observations suggest that the 2 forms belong to the genus Trypanosoma. Further studies are in progress to classify this putative Trypanosoma species whose promastigote stages display isoenzyme patterns identical to L. tropica, and which can be misidentified microscopically as Leishmania promastigotes.

Leishmania major: amastigote formation in cell-free media.

The life cycle of Leishmania consists of two distinct developmental stages: the amastigote, which is the ovoid non-flagellated form found in the vertebrate host, and the promastigote, which is an elongated flagellated form found in the gut of an infected sandfly. Following its injection into the vertebrate host by the sandfly vector, the promastigote transforms into an amastigote after entering the host macrophage. The environmental cues inducing this transformation are not fully understood. Attempts to axenically develop and cultivate amastigotes from different Leishmania species have indicated that species and sometimes even strains of the same species vary in their requirements for this process (Pan et al., 1993). The majority of the available published data on transformation pertains to New World Leishmania and provides evidence that elevation in the incubation temperature and/or acidic pH can in some cases induce amastigote formation from promastigotes.

Leishmania tropica in Egypt: an undesirable import.

Cutaneous as well as visceral leishmaniasis has been previously reported in Egypt. The former clinical manifestation is attributed to Leishmania major, the latter to L. infantum. In this study, L. tropica was isolated from an Egyptian labourer returning from Saudi Arabia. Amastigotes were detected by both Giemsa staining and indirect immunofluorescence using rabbit anti-gp63. Promastigotes from Schneider's medium were typed isoenzymatically as L. tropica. In view of the emerging threat of visceralization of L. tropica, the potential risk for its transmission in Egypt is discussed.

Biochemical characterisation of human isolates of Blastocystis hominis.

SDS-PAGE and iso-enzyme analysis of 11 human isolates of Blastocystis hominis revealed at least two variants with different polypeptide patterns and two zymodemes, respectively. This is the first iso-enzyme and the second protein analysis to indicate strain differences in B. hominis.

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.

Incorporation of simulated waste raffinates containing 134Cs into cement-clay matrices.

Simulated waste solutions containing 134Cs were incorporated into cement matrices at varying compositions and in the presence and absence of various additive materials. Montmorillonite and kaolinite clay minerals, in addition to sand, were added for improving the properties of the cement composites. The leachability of 134Cs was measured for different cement-clay mixtures. The effect of the presence of ions, such as borates, sulphate, and nitrates commonly found in waste raffinates, was also investigated. The results for compressive strength and leachability were explained in light of the effect of the presence of clay additives on cement matrices.

Intestinal capillariasis in Egypt: a case report.

Capillaria philippinensis eggs, larvae, and adults were identified in the stool of a 41-year-old female physician from Cairo, Egypt, who had never traveled abroad. She had eaten local and imported fish. She suffered from borborygmi, abdominal pain, severe diarrhea, vomiting, and loss of weight for greater than 3 months. Treatment with Flubendazole (R17889-Janssen) 200 mg twice daily for 30 days resulted in clinical and parasitological cure.

Treatment of intestinal E. histolytica and G. lamblia with metronidazole, tinidazole and ornidazole: a comparative study.

Metronidazole, tinidazole and ornidazole were compared in patients treated for Entamoeba histolytica or Giardia lamblia intestinal infections. Only patients with three positive stool specimens for trophozoites and/or cysts of E. histolytica or G. lamblia by the merthiolate iodine formaldehyde (MIFC) technique were included. Criteria for cure were at least 10 negative stool specimens over 3 weeks after completing therapy. Fifty-three male patients (aged 9-65 years) had E. histolytica infection. Seventeen received metronidazole (1.5 g daily for 10 days), 18 tinidazole (1.5 g daily for 10 days) and 18 ornidazole (1 g daily for 10 days). Metronidazole yielded 88%, tinidazole 67% and ornidazole 94% cure rates. Side reactions were minor. Eighty patients had G. lamblia infection, of whom 20 received metronidazole (0.5 g daily for 10 days), 30 tinidazole (single 2 g dose) and 30 ornidazole (single 1 g dose). Cure rates were 95% for metronidazole, 90% for tinidazole and 97% for ornidazole with no side reactions.

Use of a partially purified Fasciola gigantica worm antigen in the serological diagnosis of human fascioliasis in Egypt.

Crude extracts of Fasciola gigantica adult worms, when used as an antigen in indirect hemagglutination (IHA) and counterimmunoelectrophoresis (CIEP) tests, detected all independently diagnosed human F. gigantica and F. hepatica infections but cross-reacted with sera of patients with schistosomiasis and amebiasis. Fractionation of this crude worm extract using Sephadex G-200 chromatography demonstrated four major protein peaks. Antigen from the crest and descending portion of peak II (mol. wt. approximately 20 x 10(3)) and all of peak III (mol. wt. approximately 6 x 10(3)) were pooled and used as a source of partially purified antigen. This partially purified fraction, when used in the CIEP test, reacted with sera from patients with fascioliasis but not those from schistosomiasis or amebiasis patients, whether undiluted or concentrated fivefold, but failed to react by IHA with fascioliasis sera. It reacted with undiluted sera from all individuals passing F. gigantica eggs except one, a possibly spurious infection, and with eight of 20 sera from individuals passing F. hepatica eggs, while the remaining 12 sera became positive after fivefold concentration. It also reacted with two sera from individuals passing eggs of both Fasciola species and with five of 11 sera from individuals negative microscopically but positive serologically with the crude antigen.