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PubMed1996

Eosinophilic colitis and hepatitis in a horse with colonic intramucosal ciliated protozoa.

Tissues from a 9-year-old American Standardbred gelding with a history of anorexia, mild colic, and unexpected death were submitted to the Laboratories of Veterinary Diagnostic Medicine at the University of Illinois for histopathologic examination. Microscopic diagnoses were severe subacute, diffuse eosinophilic colitis with intralesional protozoa and a subacute to chronic eosinophilic portal hepatitis with granuloma formation. Two tissue-invading, ciliated protozoa were identified in large numbers within the colonic mucosa. The ciliates were Polymorphella ampulla and Cycloposthium sp., Phylum:Ciliophora. The eosinophilic colitis and portal hepatitis in association with the overpopulation and invasion by the ciliated protozoa suggests a causal etiology.

Animals↗
PubMed2003

Comparison of the 5.8S rRNA gene and internal transcribed spacer regions of trichomonadid protozoa recovered from the bovine preputial cavity.

Sequence analysis of the 5.8S rRNA gene and the internal transcribed spacer regions (ITSRs) was used to compare trichomonadid protozoa (n = 39) of varying morphologies isolated from the bovine preputial cavity. A multiple sequence alignment was performed with bovine isolate sequences and other trichomonadid protozoa sequences available in GenBank. As a group, Tritrichomonasfoetus isolates (n = 7) had nearly complete homology. A similarity matrix showed low homology between the T. foetus isolates and other trichomonads recovered from cattle (<70%). Two clusters of trichomonads other than T. foetus were identified. Eighteen isolates comprised 1 group. These isolates shared >99% homology among themselves and with Pentatrichomonas hominis. The other non-T. foetus cluster (n = 14) did not exhibit a high degree of homology (<87%) with other bovine isolates or any of the trichomonad sequences available in GenBank. The sequence homology among isolates in that cluster was >99%, except for 1 isolate that varied from the others in both ITSRs (approximately 2% dissimilarity). Sequence analysis of the 5.8S rRNA gene and ITSRs was useful for comparing trichomonadid protozoa isolated from the bovine preputial cavity and demonstrated that 2 distinct types of trichomonads constituted the non-T. foetus isolates recovered from the bovine preputial cavity.

Animals↗
PubMed1999

Intestinal protozoa in HIV-infected patients: effect of rifaximin in Cryptosporidium parvum and Blastocystis hominis infections.

In HIV-1 infected patients severe enteritis and chronic diarrhea are often documented as a consequence of multiple opportunistic infections. We analyzed 48 HIV-1 positive patients for the presence of intestinal pathogenic protozoa. Patients with CD4 > or = 200/mm3 showed a higher prevalence of a single pathogenic protozoa than patients with CD4 < or =200/mm3, who showed the presence of multiple protozoal infections. Patients who proved positive for only a single protozoa, Cryptosporidium or Blastocystis, were also positive, by stool culture, for the presence of Proteus mirabilis (3 samples), Citrobacter freundii (3 samples), Escherichia coli (one sample) or Enterobacter cloacae (one sample). Treatment with rifaximin (600 mg, 3 times a day, for 14 days) was efficacious in resolving the clinical symptoms and clearing protozoan infections in HIV-1 infected patients with CD4 > or = 200/mm3, who presented enteric and systemic symptoms due to Criptosporidium or Blastocystis associated with enteropathogenic bacteria.

AIDS-Related Opportunistic Infections↗
PubMed2005

Phylogenetic positions of several amitochondriate protozoa--evidence from phylogenetic analysis of DNA topoisomerase II.

Several groups of parasitic protozoa, as represented by Giardia, Trichomonas, Entamoeba and Microsporida, were once widely considered to be the most primitive extant eukaryotic group--Archezoa. The main evidence for this is their 'lacking mitochondria' and possessing some other primitive features between prokaryotes and eukaryotes, and being basal to all eukaryotes with mitochondria in phylogenies inferred from many molecules. Some authors even proposed that these organisms diverged before the endosymbiotic origin of mitochondria within eukaryotes. This view was once considered to be very significant to the study of origin and evolution of eukaryotic cells (eukaryotes). However, in recent years this has been challenged by accumulating evidence from new studies. Here the sequences of DNA topoisomerase II in G lamblia, T. vaginalis and E. histolytica were identified first by PCR and sequencing, then combining with the sequence data of the microsporidia Encephalitozoon cunicul and other eukaryotic groups of different evolutionary positions from GenBank, phylogenetic trees were constructed by various methods to investigate the evolutionary positions of these amitochondriate protozoa. Our results showed that since the characteristics of DNA topoisomerase II make it avoid the defect of 'long-branch attraction' appearing in the previous phylogenetic analyses, our trees can not only reflect effectively the relationship of different major eukaryotic groups, which is widely accepted, but also reveal phylogenetic positions for these amitochondriate protozoa, which is different from the previous phylogenetic trees. They are not the earliest-branching eukaryotes, but diverged after some mitochondriate organisms such as kinetoplastids and mycetozoan; they are not a united group but occupy different phylogenetic positions. Combining with the recent cytological findings of mitochondria-like organelles in them, we think that though some of them (e.g. diplomonads, as represented by Giardia) may occupy a very low evolutionary position, generally these organisms are not as extremely primitive as was thought before; they should be polyphyletic groups diverging after the endosymbiotic origin of mitochondrion to adapt themselves to anaerobic parasitic life.

Animals↗
PubMed2003

Spermidine metabolism in parasitic protozoa--a comparison to the situation in prokaryotes, viruses, plants and fungi.

Targeting polyamines of parasitic protozoa in chemotherapy has attracted attention because polyamines might reveal novel drug targets for antiparasite therapies (Müller et al. 2001). The biological function of the triamine spermidine in parasitic protozoa has not been studied in great detail although the results obtained mainly imply three different functions, i.e., cell proliferation, cell differentiation, and biosynthesis of macromolecules. Sequence information from the malaria genome project databases and inhibitor studies provide evidence that the current status of spermidine research has to be extended since enzymes of spermidine metabolism are present in the parasite (Kaiser et al. 2001). Isolation and characterisation of these enzymes, i.e., deoxyhypusine synthase (EC 1.1.1.249) (DHS) and homospermidine synthase (EC 2.5.1.44) (HSS) might lead to valuable new targets in drug therapy. Currently research on spermidine metabolism is based on the deposition of the deoxyhypusine synthase nucleic acid sequence in GenBank while the activity of homospermidine synthase was deduced from inhibitor studies. Spermidine biosynthesis is catalyzed by spermidine synthase (EC 2.5.1.16) which transfers an aminopropyl moiety from decarboxylated S-adenosylmethionine to putrescine. Spermidine is also an important precursor in the biosynthesis of the unusual amino acid hypusine (Wolff et al. 1995) and the uncommon triamine homospermidine in eukaryotes, in particular in pyrrolizidine alkaloid-producing plants (Ober and Hartmann 2000). Hypusine is formed by a two-step enzymatic mechanism starting with the transfer of an aminobutyl moiety from spermidine to the epsilon-amino group of one of the lysine residues in the precursor protein of eukaryotic initiation factor eIF5A by DHS (Lee and Park 2000). The second step of hypusinylation is completed by deoxyhypusine hydroxylase (EC 1.14.9929) (Abbruzzese et al. 1985). Homospermidine formation in eukaryotes parallels deoxyhypusine formation in the way that in an NAD(+)-dependent reaction an aminobutyl moiety is transferred from spermidine. In the case of homospermidine synthase, however the acceptor is putrescine. Thus the triamine homospermidine consists of two symmetric aminobutyl moieties while there is one aminobutyl and one aminopropyl moiety present in spermidine. Here, we review the metabolism of the triamine spermidine with particular focus on the biosynthesis of hypusine and homospermidine in parasitic protozoa, i.e., Plasmodium, Trypanosoma and Leishmania, compared to that in prokaryotes i.e., Escherichia coli, a phytopathogenic virus and pyrrolizidine alkaloid-producing plants (Asteraceae) and fungi.

Animals↗
PubMed2004

Ruminal fermentation and degradation patterns, protozoa population, and urinary purine derivatives excretion in goats and wethers fed diets based on two-stage olive cake: effect of PEG supply.

Three experiments were conducted in Granadina goats and Segureña wethers fed at maintenance level to evaluate the effect of including a mixture of barley and a new by-product derived from olive oil extraction (two-stage dried olive cake) on ruminal degradation and passage kinetics (Exp. 1), fermentation pattern and protozoa population (Exp. 2), and urinary purine derivatives excretion (Exp. 3). Polyethylene glycol was supplied to the animals to evaluate the effects of tannins contained in the by-product. The experimental diets were as follows: alfalfa hay and alfalfa hay plus a concentrate, formulated with two-stage dried olive cake, barley, and a mineral-vitamin mixture either with or without the addition of polyethylene glycol to the drinking water. The inclusion of two-stage dried olive cake in the diet resulted in an increase of condensed tannins. Ruminal VFA concentration in goats and wethers increased (P < 0.05) and ammonia N (NH3-N) concentration decreased (P < 0.05). The inclusion of two-stage dried olive cake decreased (P < 0.001) urinary allantoin excretion only in wethers. Ruminal degradation profiles and fractional passage rates were similar in goats and wethers. The polyethylene glycol supply increased (P < 0.001) DM and N degradation rates in both animal species but did not modify the fractional passage rate. Ruminal fermentation patterns were also similar in goats and wethers and were affected by polyethylene glycol supply. In general, Entodiniomorphida and Holotricha protozoa counts were higher (P < 0.05) in the rumen of goats than of wethers. Protozoa count in wethers responded more to polyethylene glycol supply than in goats. The present work presents the first data obtained from a comparative study with sheep and goats concerning urinary excretion of purine derivatives. The excretion was similar in both animal species when fed alfalfa hay; however, polyethylene glycol affected only urinary allantoin excretion in wethers. Results suggest a greater sensitivity of wethers than of goats to two-stage olive cake condensed tannins.

Ammonia↗
PubMed1983

Rumen ciliate protozoa: effects on digestion in the stomach of sheep.

Six wethers, each fitted with a rumen cannula and duodenal reentrant cannula, were used to study effects of ciliate protozoa on rumen digestion and metabolism. A corn: corn silage (1:1) diet was fed for two periods. During the first period, defaunation was attempted with nonyl phenol ethylene oxide. Defaunation was complete in three sheep and partial in the other three sheep in which a reduced population of a small Entodinium sp. was observed. During the second period the sheep were inoculated with ciliate protozoa, which established a large population in all animals. Apparent digestion in the stomach of organic matter and starch was higher when a large protozoal population was present. Amino acid flow through the duodenum was greater in defaunated animals. A large population of ciliates was associated with increases in both rumen ammonia and plasma urea but had a stabilizing effect on ruminal pH. Volatile fatty acids were higher in the defaunation period, but there were only small differences of molar proportions of the acids between the two periods. Effects of ciliate protozoa are related to animal performance.

Amino Acids↗
PubMed1996

Understanding intestinal spore-forming protozoa: cryptosporidia, microsporidia, isospora, and cyclospora.

OBJECTIVES: To summarize recent information about the "new" gastrointestinal protozoal pathogens (cryptosporidia, microsporidia, isospora, and cyclospora) and to help practicing clinicians integrate this information into their clinical databases by emphasizing the similarities among these organisms. DATA SOURCES: Relevant English-language articles published between 1988 and 1995 were identified through a MEDLINE search done using the names of the intestinal spore-forming protozoa. Articles cited in the bibliographies of these and other articles were searched manually. STUDY SELECTION: Studies that contained information on the history, taxonomy, life cycle, epidemiology, pathogenesis, clinical manifestations, diagnosis, and treatment of the pathogens were reviewed. DATA EXTRACTION: Cryptosporidium parvum, Isospora belli, Cyclospora cayetanensis, Enterocytozoon bieneusi, and Septata intestinalis are intestinal spore-forming protozoa that cause intracellular infections, predominantly in the epithelial cells of the intestine. They are transmitted either by stool from person to person or through contaminated water or food by an infectious particle called a spore or oocyst. Asymptomatic infections occur; the most common symptom of infection is diarrhea. Infections have been associated with intestinal inflammation, disordered architecture (such as villus blunting), and abnormal function (for example, malabsorption). Mild to moderate, self-limited diarrhea is common in healthy persons, but patients with immune dysfunction can have severe intestinal injury and prolonged diarrhea. Diagnosis is made by a microscopic examination of the stool and the use of appropriate staining techniques. Effective antibiotic treatment for prolonged infection in immunocompromised patients is available for most of these infections. CONCLUSIONS: The intestinal spore-forming protozoa are four frequently identified gastrointestinal pathogens that have important similarities in epidemiology, disease pathogenesis, clinical manifestations, diagnosis, and treatment.

Animals↗
PubMedDate not supplied

[Is not plague a "protonosis"? (the role of Protozoa in the epizootiology of plague)].

The author expounds the idea that soil protozoa, whose vegetative forms and cysts can harbor the plague agent for fairly prolonged periods of time, can be a major player in the epizootiology of plague. It is also postulated that the symbiotic protozoa of the digestive tract of rodents and lagomorpha can also be a reservoir of the plague agent. If this is so, among apparent epizootic cycles in mammalians in wild plague foci one should look for Yersinia pestis in the protozoa from the burrows of their primary and secondary carriers. Because parasitism of bacteria in one-celled animals is essentially epizootic, plague epizootics are presumed to be a permanent process.

Amoeba↗
PubMed2000

Intestinal spore-forming protozoa among patients suffering from chronic renal failure.

Cryptosporidium parvum, Isospora belli, Cyclospora cayetanensis and Microsporidia are four intestinal spore-forming protozoa that cause diarrhoea in immuno-competent individuals and immuno-suppressed patients. Fresh stool samples were obtained from 120 patients suffering from CRF and attending the Dialysis Unit of Zagazig University Hospital. Also, stool samples were obtained from 40 immuno-competent individuals complaining of diarrhoea (control group). The stool samples were examined by direct smear and formol-ether concentration methods then stained by Giemsa, Modified Ziehl Neelsen (MZN) and Aniline carbol methyl violet stains. The four intestinal spore-forming protozoa were detected in 40/120 (33.3%) of patients with CRF and in 2/40 (5.0%) of the control group with a statistically highly significant difference (P < 0.001). C. parvum, Microsporidia, C. cayetanensis and I. belli were detected in 18/120 (15%), 10/120 (8.3%), 9/120 (7.5%) and 3/120 (2.5%), respectively. The four protozoa were found as mixed infections with other pathogens or as single infections confirming their role alone as a cause of diarrhoea. MZN stain was the most efficient simple, and not expensive.

Adult↗
PubMed2001

Effect of ozone on the viability of some protozoa in drinking water.

Water samples from household tanks in several districts of Alexandria, were examined for protozoa contamination and study to the effect of ozone and chlorine on their viability. The parasitic protozoa encountered were Giardia (56%), Cryptosporidia (50%), Blastocystis (12%), Cyclospora (9%) and Microsporidia (3%). Distilled water was treated by ozone or chlorine. Ozonated-water samples were prepared at a concentration of 1 ppm after contact times with ozone of three, five, seven and nine minutes. Chlorine concentrations were 4 and 8 ppm. Parasites were incubated overnight at room temperature with the treated distilled water. Viability of the parasites was assessed by examining intestinal sections of infected animals. The best results were obtained by using ozonated water after a contact time of nine minutes. Giardia, Cryptosporidia and Microsporidia were completely inactivated, while infectivity of Cyclospora and Blastocystis was markedly reduced. It is suggested that ozone at an appropriate concentration inactivate pathogenic protozoa in water.

Animals↗
PubMed2003

Predation of Cryptosporidium oocysts by protozoa and rotifers: implications for water quality and public health.

Predation by free-living protozoa and rotifers was investigated as a possible mechanism for the removal of Cryptosporidium parvum oocysts in aquatic ecosystems including wastewater treatment plants. Free-living ciliated protozoa (Stylonychia mytilus, Paramecium caudatum and an unidentified wastewater wetland ciliate), an amoeba (Acanthamoeba culbertsoni) and rotifers, all commonly found in aquatic ecosystems, were exposed to varying doses of C. parvum oocysts. All organisms investigated ingested oocysts. Predation activity and rates of ingestion varied with predator species and prey density. Ciliated protozoa demonstrated greater predation activity than A. culbertsoni or rotifers when exposed to 2 x 10(5) oocyst/mL for up to 3 h. Greatest predation after 1 h exposure was observed in P. caudatum, the largest ciliate, with on average 1.9 oocysts/cell (range 0-9 oocysts/cell). Stylonychia mytilus and the wetland ciliate had a similar mean ingestion of around 0.3 oocysts/cell, with numbers internalised ranging from 0-3 oocysts/cell. Rotifers ingested on average 1.6 oocysts/individual (range 0-7 oocysts/individual) whilst amoebae ingested on average 1.8 oocysts/cell after 2 h exposure (up to 3 oocysts/cell). Grazing activity by P. caudatum was demonstrated at a variety of prey levels ranging from 9 to 9,000 oocysts. Numbers of oocysts internalised by Paramecium frequently exceeded the reported human infective dose of 30 oocysts. In general, numbers of internalised oocysts increased with incubation time of up to 20-30 min although the rate of accumulation was slower at lower dose levels. The significance of predation on the fate of Cryptosporidium oocysts in the environment is discussed.

Animals↗
PubMed2003

Human pathogenic protozoa in bivalves collected from local markets in Alexandria.

Bivalves are filter feeders concentrating pathogens from waters and are often eaten raw. Two species, Caelatura Iaronia pruneri and Donax trunculus limiacus commonly known as Gandofli and Om el Kholool respectively were examined. Shellfish were collected from markets in Alexandria to detect any human pathogenic protozoa in them. The infectivity of the detected protozoa was studied by experimental animal inoculation. The results revealed the presence of infectious Cryptosporidia oocysts and Microsporidia spores in both bivalves. Cyclospora sp. was detected only in Gandofli but was non-infectious to mice. There is a potential risk of acquiring protozoa infections if shellfish are eaten raw or insufficiently cooked.

Animals↗
PubMed2004

[New drugs for the treatment of human parasitic protozoa].

Whereas parasitic diseases are always a heavy burden for humanity, few are the new antiparasitic molecules marketed during the last 25 years. Thus on the 1393 new molecules marketed between 1975 and 1999, only 7 have antiprotozoan properties. This talk will detail the progress made in the treatment of the intestinal protozoa, malaria, visceral leishmaniasis and toxoplasmosis, problems with which are especially confronted the European parasitologists. The treatment of Giardia and intestinal amoebas is based on 5-nitro-imidazoles derivatives. Single-dose treatments can be used with tinidazole or secnidazole. Resistance to these compounds of Giardia were described and in these cases, treatment by quinacrine or nitazoxanide are possible alternatives. Nitazoxanide is marketed in the United States and in Australia. It seems to be a well tolerated antiparasitic agent with a broad spectrum because it is active on a lot of intestinal protozoa and helminths. It acts on the same metabolic way as the 5-nitro-imidazoles (inhibition of the ferredoxine reductase) but without synthesis of free radicals and DNA deterioration of the target cell. It is thus neither teratogenic nor mutagenic. Artemisinin derivatives allowed considerable progress in the treatment of malaria. They have short half-lifes, allowing a fast parasitic clearance and these derivatives do no provoke resistance. They are first line drugs for the treatment of malaria in areas of drug resistance. The arthemeter-lumefantrine association (Riamet, Coartem) ensures a rapid disappearance of the circulating parasites and is well tolerated. Atovaquone-proguanil (Malarone) is usable in the treatment of acute malaria but also in disease prevention with the advantage of continuing drug intake for only 7 days after having left the infected area. The treatment of leishmaniasis is always delicate and is characterized by the worrying development of antimony resistances, probably related in the European zones to the treatment of dogs. Liposomal amphotricin is an alternative of choice but remains very expensive. The heating of amphotericin to 70 degrees C during 20 minutes gives it experimental properties and efficacies comparable with that of liposomal amphotericin, but at a less cost. Miltefosine, an alkyl-phospholipide antimetabolite, is very active on visceral leishmaniasis resistant to antimonial treatment. However, its long half-life could induce the emergence of resistances. Miltefosine induces much less side effects than conventional amphotericin B. The commonly used anti-toxoplasmic drugs (sulphadiazine and pyrimethamine) were marketed some 50 years ago and are only active on the rapid forms in multiplication. No drug is really efficient on the cysts although preliminary tests with atovaquone are encouraging to treat ophthalmologic forms in immunocompetent patients. To conclude, it is important to continue to search for new antiprotozoan molecules because, for some parasites, drug resistance is an important problem. Moreover, the treatment of the pregnant women, particularly during the first trimester, is often impossible and there is a lack of galenic forms easily usable in children. A better knowledge of the metabolic pathways of protozoa (particularly the apicoplast of Apicomplexa parasites) would certainly open the posssibility to identify new drugs. To reduce and delay the appearance of resistances, mass-treatments of mass should be avoided and targeted treatments prefered as well as the use of associations of molecules having different modes of action.

Adult↗
PubMed2005

[Joint acute toxicity of fipronil and bata-cypermethrin to protozoa community].

Compared with the toxicity test on single organism, the effects of toxic pollutants on organisms at community level are more reliable. The acute single and joint toxic effects of Fipronil and Bata-cypermethrin on freshwater protozoa community are studied in this paper. The results show that the 48h-LC50 of Fipronil and Bata-cypermethrin to the microbial community was 35.83mg x L(- 1), 1.92mg x L(-1), the joint toxicity of Bata-cypermethrin and Fipronil was antagonism in 48h with toxicity 1: 1 to freshwater protozoa community, and Additive Index was -0.08. The structure of protozoa community would change in a low concentration of Bata-cypermethrin and Fipronil mixture; the species and population of Algivores(A) and Predators Raptors (P) would reduce but Bactivoresdetrivores(B) would become predominant relatively.

Animals↗
PubMedDate not supplied

[New biologically active substances from protozoa and an evaluation of their action].

Novel biologically active substances were obtained from nonpathogenic for humans and free-living protozoa: Crithidia oncopelti, Trypanosoma lewisi, and Astasia longa. There were studied conditions of biosynthesis, composition and biological activity of the total lipid fraction from the protozoa species, sucrose ethers and fatty acids, the latter were isolated from A. longa--(astazilide preparation), reserve beta-1,3 glucan from A. longa (astazian preparation), and fraction of surface glycophospholipids and peptides from Crithidia oncopelti (GLP preparation). Two of three preparations studied (astazilide and GLP) are the complexes of natural substances with certain composition. Conditions of the protozoa cultivation were developed to provide standardization of the complex composition. Division of the complexes into separate components decreased or abolished the biological activity. It was established that the substances studied modify biological reactions, that is exert a systemic effect. They may be used for inhibiting the growth of experimental tumors and preventing the metastatic spreading in tumor-carrier animals. The substances obtained belong to the group of nonspecific stimulators for cellular immunity which can be used in medicine, veterinary medicine, food industry, pharmacologic industry and cosmetology.

Adjuvants, Immunologic↗
PubMed1989

[The occurrence of protozoa in the intestinal microflora of laboratory mice].

The intestinal content of 216 white SPF laboratory mice was examined for the presence of protozoa. 153 (70.8%) were found to be positive. The following protozoa species were determined: Trichomonas muris in 31.5%, Trichomonas sp. in 29.6%, Chilomastix becentourti in 18.5%, Octomitus intestinalis in 7.8%, Giardia muris in 6.9%, Spironucleus muris in 4.1%, and Entamoeba muris in 14.8%. The given species occurred in the mice either individually or, in the majority of cases, combined infections involving 2-5 species were recorded. Young mice transferred from the breeding station were but rarely colonized, and that only by a small number of protozoa. They contract infection from older animals in the animal room. (Tab. 3, Ref. 11.).

Animals↗
PubMed1985

Frequency, multiplicity and repertoire of intestinal protozoa in healthy homosexual men and in patients with gastrointestinal symptoms.

Various conventional parasitological methods were used to study three faecal samples from 153 homosexual men and 119 patients with abdominal symptoms. In 59.5% of the homosexual men 198 protozoa were identified, and in 31.9% of the patients the number of protozoa was 51. Cryptosporidium and Giardia lamblia were more frequent in the patients, while various amoebae were more frequent in the homosexual men. The frequency, multiplicity and repertoire of intestinal protozoa in the homosexual men were very similar to those reported from other parts of the world, but quite different from those associated with gastrointestinal illness in the local general population.

Carrier State↗