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PubMed2006

Zoonotic protozoa--food for thought.

Outbreaks of water- and foodborne diseases caused by Cryptosporidium, Giardia and Toxoplasma are well documented. Three features of these zoonotic protozoa ensure a high level of environmental contamination and enhance the likelihood of waterborne transmission. Firstly, they are responsible for disease in a broad range of hosts including man, have a low infectious dose enhancing the possibility of zoonotic transmission, secondly, their transmissive stages are small in size and environmentally robust and thirdly are insensitive to the disinfectants commonly used in the water industry. In addition, there is growing evidence for the role that water and food can play in the transmission of the microsporidia, Balantidium and Blastocystis to humans.

Animals↗
PubMed2006

[Trypanosomatid (Protozoa, Kinetoplastida) parasites of sloths (Mannmalia, Xenarthra)].

Worldwide famous for their slothfulness, sloths are xenarthran mammals living in the tropical forests of the New World. In these highly biodiverse habitats, sloths are implicated in long-term interactions with many organisms. They are especially involved in the parasitic cycles of various trypanosomatids including human parasites. This review describes the different species of the genera Leishmania, Endotrypanum and Trypanosoma that infect sloths. The improvement of the preventive method efficacy against synanthropozoonotic diseases due to several of these protozoa relies on studies on the ecology and biology of wild reservoir hosts such as sloths.

Animals↗
PubMed2006

Intestinal parasites in Dakahlia governorate, with different techniques in diagnosing protozoa.

A total of 3180 patients attending Mansoura University Hospitals' Clinics, were subjected to stool examination by direct wet smear, formol-ether concentration, original formol-tween concentration, modified formol-tween concentration, modified Sheather's sugar floatation, Potassium hydroxide concentration and Gomori's Trichrome stain, and modified Kinyoun's acid-fast stain, and Ryan's Trichrome blue stain for Microsporidia. The intestinal helminthes in a descending order of abundance were: S. mansoni (5.3%), Fasciola sp. (4.8%), H. heterophyes (4.2%), Hymenolepis nana (3.9%), Trichostrongylus sp. (2.6%), A. lumbricoides (1.8%), Strongyloides stercoralis (1.5%), H. diminuta (1.4%), Taenia saginata (1.1%), E. vermicularis (by smear; 1.1 %), T. trichura (0.7%) and lastly A. duodenale (0.1%). The intestinal protozoa in a descending order of abundance were Blastocystis hominis (22.4%), Giardia lamblia (19.6%), Entamoeba histolytica/E.dispar (19%), Iodamoeba butschlii (16%), Cryptosporidium parvum (14.3%), E. coli (9.7%), Isospora hominis (7.7%), Endolimax nana (6.9%), E. hartmani (5.9%), Dientamoeba fragilis (5.1%), Chilomastix mesnili (5.1%), Trichomonas hominis (4.2%), Cyclospora cayetanensis (4.2%), Microsporidia spores (3.2%), Enteromonas hominis (1.9%) and Embadomonas intestinalis (1.3%). The results were discussed.

Animals↗
PubMed1991

[A mathematical model of the growth of a population of Legionella pneumophila in the presence of Tetrahymena pyriformis protozoa].

The mathematical model describing the dynamics of the growth of L. pneumophila in aqueous environment in the presence of protozoa has been worked out. The model has demonstrated considerable heterogeneity of the initial population of virulent L. pneumophila strains. The number of bacteria capable of multiplication in Infusoria is no more than 0.1% of the initial population. The time of the generation of the infective agent inside Tetrahymena pyriformis is 2.8 hours.

Animals↗
PubMed1977

Biochemical and technical considerations regarding the mass production of certain parasitic protozoa.

This article summarizes the most relevant biochemical knowledge about growth factors as specific essential components of culture media, and calls attention to their significance with respect to the mass cultivation of some parasitic protozoa-e.g., Trypanosoma and Leishmania spp. and amoebae. Details of recent developments and techniques of parasite fermentation are reviewed.

Amino Acids↗
PubMed1990

A study of the protozoa associated with some harmful insects in the local environment.

The present study includes finding resulting from examination of three species of harmful insects, Periplaneta americana, Schistocerca gregaria and Anacanthoterms ochraceus, collected from six cities in the Central Region of Saudi Arabia. Two species of septate gregarines of the genus Gregarina Dufor, were found G. blattarum (Siebold) from mid gut of P. americana and G. rigida from gut of S. gregaria, also six species of Mastigophora in gut of white ant A. ochraceus, Trichonympha campanula, Spirotrichonympha sp., Holomastigoides hartmanni, Rostronympha magna Monocercomonas axostylis and an unidentified species. The seasonal intensity of these Protozoa and percentage of infection together with informations about the holotype materials are included. At present the holotype materials are deposited at the department of Zoology, Girls College of Education, Riyadh, Saudi Arabia.

Animals↗
PubMed1989

[The significance of amoebae and other protozoa in water conduit systems in dental units].

In a longitudinal study over a period of ten weeks, the water conduit systems of seven dental surgeries with a total of 20 dental units in which legionellae had been detected in an earlier study (3) were investigated as a complement to extended microbiological tests (4) for the occurrence of free-living amebae and other protozoa. In 96% of all water samples, one or several ameba species were detected. These included 14 strains of the genus Naegleria, but no acanthamoebae. The naeglerias isolated were not thermophilic and thus belong to the N. gruberi complex, which does not contain any pathogenic strains. In two water samples, two different species of small freeliving nematodes were demonstrated. The simultaneous investigation of samples from the warm water supply in the individual dental surgeries revealed an ameba contamination in 24.9% of the samples. A nonpathogenic strain of the genus Protacanthamoeba was demonstrated once. The possible role of the trophozoites of various ameba species as hosts for an intracellular proliferation of the legionella strains demonstrated at the same time (cf. 4) is discussed. The occasional protective intracellular inclusion of legionellae in trophozoites of various species and in cysts of acanthamoebae might be an explanation for the resistance of legionellae to disinfection measures which has been repeatedly observed. This observation will have to be taken into consideration in sterilization and disinfection projects.

Amoeba↗
PubMed1989

Gastrointestinal helminths and protozoa from two raccoon populations in Kansas.

A survey in Kansas compared the prevalence of gastrointestinal helminths and protozoa in 2 raccoon (Procyon lotor) populations; a population in a typical rural setting and a relatively undisturbed population on a military reservation. Gastrointestinal tracts of 128 raccoons were examined. Freeze storage of alimentary tracts prevented collection of data on trematode prevalence. Helminth infections other than trematodes included 1 acanthocephalan, 2 cestodes, and 3 nematodes. Helminths were found in all raccoons from the population on the military installation and 96% of those from the rural population. Prevalence of helminths was generally greater in raccoons from the population living in the rural setting. Eimeria spp. and Sarcocystis sp. were also found, whereas Giardia spp. and Cryptosporidium parvum were not.

Animals↗
PubMedDate not supplied

[A modified method of preserving feces for the detection of intestinal protozoa].

Methylene blue is excluded from the original preservative in the modified conservation method elaborated by Safaraliev. The conserved material is examined in humid smear or, still better, after enrichment by falling out in the formol-ether solution or staining the smears by Lugol's solution or 0.25% solution of methylene blue. Intestinal Protozoa may be kept conserved for no less than a year. In case of enrichment the technique becomes 2--3-fold more effective than the original one, enabling to save the reagents, laboratory vessels, time (for microscopy), as well as to evade the odour of acetic acid and phenol from the preparations under study.

Animals↗
PubMed1989

Pathogenic protozoa: an overview of in vitro cultivation and susceptibility to chemotherapeutic agents.

Chemotherapeutic management of many of the important protozoal diseases relies upon a relatively small number of compounds, many of which are quite toxic to the host. The increasing appearance of organisms resistant to standard therapy confounds this problem. The development of new efficacious therapies depends on the evaluation of drug activities both in vitro and in vivo. The use of axenic cultivation methods and cell culture techniques has greatly aided efforts to study drug effects on protozoa in vitro, although standardization of susceptibility tests is lacking.

Animals↗
PubMed1977

Heat-labile enterotoxigenic Escherichia coli and intestinal protozoa in asymptomatic travellers.

Thirty-two asymptomatic travellers who had recently journeyed in the Near, Middle, and Far East and had experienced a high incidence of diarrhoeal disease were screened for heat-labile enterotoxigenic Escherichia coli (ent+ E. coli) and other bacterial and parasitic pathogens. Six percent were colonized with ent+ E. coli and while other bacterial pathogens were not found, the intestinal protozoa Giardia lamblia (13%), Entamoeba histolytica (6%), Entamoeba coli (6%), Endolimax nana (6%), and Entamoeba hartmanni (3%) were detected in the stools. Ent+ E. coli, G. lamblia and E. histolytica should be considered in the differential diagnosis of gastrointestinal disease in travellers returning from the Orient. Furthermore, these travellers may be a potential source for the introduction of ent+ E. coli into communities where such organisms are relatively rare.

Adult↗
PubMed1978

[Effect of lipid preparations isolated from protozoa on experimental leishmaniasis in golden hamsters].

The effect of lipid preparations Nos. 59 and 60 isolated from Protozoa on experimental leishmaniosis of golden hamsters was studied. Preparations Nos. 59 and 60 are water-soluble derivatives of fatty acids isolated from Trypanosoma lewisi and Astasia longa respectively. It was found that both preparations administered to the animals simultaneously with the causative agent or after formation of the leishmaniosis infiltrates inhibited the development of the disease clinical signs. Such an effect of the preparations was observed only during the period of the animals exposure to them. After discontinuation of the treatment the development of the clinical process proceeded the same as in the control animals. The lipid preparation No. 60 differing from preparation No. 59 by high content of C20-poly-unsaturated fatty acids was more active and induced a significant decrease in the size of the leishmaniosis infiltrates formed. Preparation No. 60 was more effective in the treatment of the animals infected with L. tropica major than in the animals infected with L. tropica minor. Preparation No. 59 had no significant effect on multiplication and morphology of the parazites.

Animals↗
PubMed1979

[A study of the frequency of protozoa and yeasts isolated from the parodontium of 509 subjects (author's transl)].

The protozoa Entamoeba gingivalis and Trichomonas tenax together with yeasts of the genus Candida were investigated in the mouth (gums or neck of tooth) of 509 healthy or diabetic subjects. A study of the possible correlation between presence of these parasites and various local or general factors, showed that neither the sex, maxillo-facial anomalies nor smoking had any influence on parasite incidence. Entamoeba gingivalis was encountered in 85 per cent of subjects free from parodontopathy. Numerous factors influenced the presence of Trichomonas tenax: age, social status, alcohol consumption, dental condition and gingival pathology. Presence of Candida was associated with diabetes, poor buccal hygiene and dental condition.

Adolescent↗
PubMedDate not supplied

Induction of interferon by bacteria, protozoa, and viruses: defensive role.

Interferon is established as one of the natural defenses against virus infection. The evidence that interferon may serve a defensive role against certain protozoa is less complete and consists mainly of induction of interferon during protozoal infection, as well as interferon protection of mice against malarial infection. The evidence that interferon may function as a defense against certain bacterial infections is extended with data indicating that a wide variety of bacteria can induce interferon in the mouse and in cultured human peripheral lymphoid cells. This induction of interferon by bacteria and the ability of interferon under many conditions to activate neutrophils and macrophages raises the possibility that interferon may serve a defensive role against some bacteria.

Animals↗
PubMed1982

Pretreatment with phorbol myristate acetate inhibits macrophage activity against intracellular protozoa.

To further document the role of toxic oxygen intermediates in mononuclear phagocyte antiprotozoal activity, microbicidal macrophages were depleted of the capacity to generate superoxide anion (O-2) and hydrogen peroxide (H2O2) by pretreatment with phorbol myristate acetate (PMA), a soluble agent which triggers the macrophage respiratory burst. Treating cells for 90 min with 200 ng/ml of PMA inhibited the extracellular release of both O-2 and H2O2 by 90% upon subsequent restimulation with either PMA or opsonized zymosan. This effect persisted for 48 h, and could not be reversed by the addition of lymphokine. Intracellular nitro-blue tetrazolium reduction by PMA-treated cells was also inhibited by 66-95% upon rechallenge with either PMA or inert or viable particulate agents. In parallel, PMA pretreatment abolished or markedly impaired the ability of normal, lymphokine-stimulated, and in vivo activated macrophages to kill three diverse protozoa--Toxoplasma gondii, Leishmania donovani, and Trypanosoma cruzi. These studies illustrate an additional technique for investigating the antiprotozoal effects of macrophage-derived O-2 and H2O2 and reemphasize the importance of an intact respiratory burst mechanism in killing of intracellular parasites.

Animals↗
PubMed1983

The nonpathogenic intestinal protozoa.

Nonpathogenic intestinal protozoa are frequently reported in fecal specimens sent to laboratories for parasitologic examination. Family physicians should be familiar with the most commonly encountered species.

Entamoeba↗
PubMed1980

Diagnostic clinical parasitology: II. Identification of the intestinal protozoa.

This article (the second in a series of four papers on clinical diagnostic parasitology) presents information on the diagnostic morphology of the protozoa which infect humans. The description of morphological characteristics includes information on atypical morphology as well as the classic descriptions. Because these organisms are the most difficult to identify, extensive detail is included to illustrate the morphological variability.

Amoeba↗
PubMed1981

Stereo-electron microscopy of nuclear structure and replication in ciliated protozoa (Hypotricha).

Employing stereo-electron microscopy on sections (ca. 0.1 micrometer thick) of the ciliated protozoa Stylonychia, Oxytricha and Euplotes, we have examined the ultrastructure of macronuclear replication bands (RB) and micronuclei. The macronuclear RB is composed of two zones: a "forward zone" showing a special chromatin organization consisting of regular 40 to 50 nm diameter fibers with an indication of nucleosomal substructure; and a "rear zone", the site of DNA replication, consisting of a mesh of 10 nm chromatin fibers. Micronuclei exhibit chromatin strands of 60 to 70 nm diameter. Employing the Bernhard staining procedure, we have observed that the chromatin fibers of the RB and of the micronuclei remain unbleached, whereas macronuclear condensed chromatin is bleached of stain, indicating that the replication band and the micronuclei contain chromatin in a configuration different from that of other forms of densely packed chromatin. The regularity of the chromatin fibers within the forward zone is of particular interest since it is comparable to the regularity of chromatin seen in the transcriptionally-inactive chromatin of other nuclei such as avain erythrocytes and sea urchin spermatozoa. It is likely that the forward zone chromatin fibers consist of highly ordered arrangements of nucleosomes, associated with additional nonhistone proteins.

Animals↗