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At least 271 records · Page 15Linked to original sources
PubMed2002

Ciliated protozoa and organic load at low temperatures in an aerated biofilter.

Ciliated protozoa have been widely used as water quality indicators because their main morphological characteristics are relatively simple to identify microscopically. The species and individual numbers in wastewater treatment systems are a consequence of the operational and environmental conditions of the process. The main objective of this research was to relate the effluent quality of a pilot aerated biofilter with the presence and relative abundance of ciliated protozoa when operated under different organic loading rates. The experimental work was done in a pilot aerated biofilter using 12 mm volcanic porous stones as filtering media and it was fed with municipal wastewater adjusting the experiments to 3 organic loading rates (3, 7, and 9 gCOD/m2 x d). Temperature in the filter varied from 11 to 14 degrees C during the experimental work. COD and BOD removal rates do not change significantly with the different organic loads. Nitrification improves inversely to the organic load and it does not show dependence on the slight temperature changes observed. Eighteen species were identified as typical residents in wastewater systems. Free swimming species prefer higher organic loads. Crawling and attached species did not show significant changes with the organic load. According to the saprobity index of Pantle and Buck, the system, independently of the organic load, presented typical alpha-mesosaprobe level.

Animals↗
PubMedDate not supplied

[Persistent properties of protozoa-associated bacteria].

The species structure and persistent properties (antilysozyme and antihistone activity) of bacteria forming associations with protozoa is revealed. Among them, 68.9% of the isolates were enterobacteria, the remaining organisms belonged to the families Aeromonas, Alcaligenes, Pseudomonas, Vibrio, etc. Within the family Enterobacteriaceae bacteria of the Escherichia group prevailed. 50.4% of the isolates were found to have antilysozyme activity and 97%--antihistone activity. The level of persistent properties in the representatives of allochthonous microflora was higher than that in the representatives of autochthonous microflora. In addition to antilysozyme activity antihistone activity was noted in protozoa-associated bacteria, which could be of importance for the formation of symbiotic links in natural associations. These data may be used in sanitary and hygienic practice for microecological monitoring of the environment.

Aeromonas↗
PubMed1992

[Pseudomonads as parasites of protozoa].

The experimental study of the interaction of Tetrahymena pyriformis with different microorganisms of the genus Pseudomonas, isolated from the soil, was made. The study revealed that T. pyriformis phagocytosed some Pseudomonas pigment-forming species (P. cepacia, P. putida, P. fluorescens, P. pirkettii). The most pronounced cytopathogenic effect was produced by P. cepacia. The dynamic observations of the ultrastructural features of interaction between P. cepacia and protozoa were made. Even at early stages of this interaction some types of parasitiferous phagosomes containing both intact bacteria capable of multiplication by binary division and Pseudomonas cells exhibiting different degrees of destruction were registered. In several phagosomes morphologically intact bacteria differing in their cell-wall profiles and the density of their cytoplasm and nucleotide were present simultaneously. More dense cells with sinuous cell-wall membranes were more virulent. By hour 18 one giant parasitiferous vacuole was formed by fusion of smaller phagosomes, which subsequently broke up, liberating a new generation of bacteria. In infected cells disturbances in the structure of their mitochondria and macronucleus appeared. During the first 2 days of the joint cultivation of P. cepacia and T. pyriformis the accumulation of bacteria occurred due to the selection and multiplication of digestion-resistant bacterial cells, which ensured the resistance of this Pseudomonas population in association with protozoa.

Animals↗
PubMed2004

[Infections with helminths and/or protozoa in cats in animal shelters in the Netherlands].

To determine the prevalence of infections with helminths and protozoa in cats in animal shelters, faecal samples from 305 cats from 22 animal shelters in the Netherlands were examined, using a centrifugation-sedimentation-flotation-technique. The association between potential risk factors and the occurrence of an infection was also tested. Infections with helminths and/or protozoa were found in 160 samples (52.5%). Toxocara cati was found in 86 cats (28.2%), Cystoisospora felis in 59 cats (19.3%), Cystoïsospora rivolta in 43 cats (14.1%), Capillaria spp. in 34 cats (11.2%), Ancylostoma tubaeforma in 9 cats (3.0%), Taenia taeniaeformis in 9 cats (3.0%), Aelurostrongylus abstrusus in 8 cats (2.6%), Giardia intestinalis in 3 cats (1.0%), Dipylidium caninum in 2 cats (0.7%) and Toxoplasma gondii in 1 cat (0.3%). The highest prevalence was seen in kittens and stray cats. The main preventive factor against infection was a short stay in a shelter.

Age Factors↗
PubMedDate not supplied

[A preliminary investigation on the occurrence of protozoa in swimming pools in Italy].

In Italy controls on the hygienic quality of swimming pools are fixed by the Accordo tra il Ministero della Salute, le regioni e le province autonome di Trento e di Bolzano, come into force in 2003. In the present study swimming pools were investigated from the microbiological point of view on the basis of the new legislation. Contemporaneously, for the first time in Italy, analytical controls on the occurrence of the protozoa Cryptosporidium and Giardia were performed with both techniques of immunofluorescence and polymerase chain reaction. Results evidenced a good water quality when the bacterial parameters stated by law were considered. However in some swimming pools, the protozoa were also recovered. Factors affecting the use of molecular techniques on the analysis of environmental samples are also put into evidence.

Animals↗
PubMed2005

Amphizoic amoebae: pathogenic free-living protozoa; review of the literature and review of cases in Thailand.

A large variety of species of free-living amoebae (FLA) caused an indefinite form of these protozoa. Non-fixed form, as indicated by amoeboid movement and possed the bacteria to survive in nature. Two species of pathogenic FLA: Naegleria fowleri and Acanthamoeba spp. were identified as the causative agents of Primary Amoebic Meningoencephalitis (PAM) and Granulomatous Amoebic Encephalitis (GAE) respectively. They were suggested to amphizoic protozoa, capable of living as parasites or as free-living and they were also considered to be distributed worldwide. These amoebae were detected in lakes, rivers and ponds. The first case of meningoencephalitis was observed in 1961 by Fowler Many cases were reported later on and the pathogenicity was tested by nasal inoculation of mice. In fact, quite a number of FLA were isolated but only a few species were pathogenic to humans. The three typical features which allow recognition of Naegleria spp. flagellate stage, round cyst and promitotic trophozoite. This promitosis distinguishes the Naegleria genus from Acanthamoeba spp. The disease caused by PAM usually occurs with acute onset, whereas chronic for GAE. The GAE cases mentioned are mostly in debilitated patients, chronic alcoholics or patients under treatment with immunosuppressive methods. About 6 cases of PAM were reported in Thailand during 1982-1997. Four cases of GAE were reported in 1994 and two isolated cases ofAcanthamoebafrom keratitis patients were reported in 2000. Finally one case of PAM and one case of GAE were reported in 2001. The surveys of FLA were set up to study the distribution of these pathogenic amoebae and determine the prevalence of amoebae in aquatic habitats of human environments. About 40% were identified as Acanthamoeba spp., 30% were Naegleria spp., 20% were Hartmanella and 10% were Vahlkampfia. Only 10% of Naegleria spp. belonged to Naegleria fowleri.

Acanthamoeba↗
PubMedDate not supplied

[Importance of Trichomonas tenax and Entamoeba gingivalis protozoa in the human oral cavity].

Trichomonas tenax and Entamoeba gingivalis are protozoa found in the human oral cavity. Morphological and ultrastructural characteristics of those parasites were reviewed and then studied with the scanning electron microscope in this paper. Based on previous epidemiological studies, the relationship between periodontal disease and those protozoa was analysed. Evaluation of the pathogenicity of Trichomonas tenax and Entamoeba gingivalis was also part of the discussion of this study.

Adolescent↗
PubMed1988

[Effects of addition of palmitostearin or soybean oil on the protozoa in the rumen of dairy cows and sheep].

Addition of unprotected palmitostearin (P; 10.6% DM intake) or soybean oil (SO; 8.7% DMI) to a hay/diet concentrate (50/50) led to no significant differences in the total number of protozoa in rumen liquid of dairy cows and sheep, and in the distribution and postprandial variations of protozoan species. Chemical analysis of purified protozoa revealed no significant effects of lipid supplementation on their total N, RNA and lipid contents. However, there was a specific incorporation (P less than 0.05) of C16:0 and C18:2 acids in the free fatty acid fraction with the P and SO diets respectively.

Animals↗
PubMed1986

Effect of lasalocid, monensin and thiopeptin on rumen protozoa.

The effects of lasalocid, monensin and thiopeptin on the total number and the generic composition of rumen protozoa were determined in vivo and in vitro. Feeding lasalocid or monensin to cattle on either high grain or high roughage diets reduced total protozoal counts. Addition of lasalocid or monensin (6 to 48 micrograms ml-1) to the in vitro rumen fermentation resulted in marked reduction in protozoal numbers. The inhibition was dose dependent. Thiopeptin had no effect on rumen protozoa either in vivo or in vitro. Among the protozoal types, holotrichs (Dasytricha, Isotricha and Charonina) were unaffected by either lasalocid or monensin. Among the entodiniomorphs, Entodinium, Diplodinium and Ophryoscolex were more sensitive than the other types. Ophryoscolex purkynei was more sensitive to monensin than to lasalocid. Protozoal inhibition by lasalocid and monensin was transient because prolonged antibiotic feeding resulted in the selection of a resistant population in the rumen of cattle.

Animals↗
PubMed1977

The prevalence of human intestinal protozoa in Ibadan, Nigeria.

This study shows that the two intestinal protozoa, Giardia lamblia, Balantidium coli in addition to Entamoeba histolytica are prevalent in the Ibadan population and are responsible for many of the non-bacterial diarrhoea seen in patients. A high seasonal prevalence of the intestinal protozoa in the dry months of the year was associated with the use of contaminated water. Both the high infection rates recorded in adults and children under five years old, and the high frequency of association involving Trichomonas hominis, Entamoeba histolytica and Giardia lamblia were discussed.

Adolescent↗
PubMedDate not supplied

[Prevalence of infection by intestinal helminths and protozoa in school children from a coastal locality in the province of Valdivia, Chile].

During July-August 1989, 219 coprological samples from primary school children from Niebla and Los Molinos localities (39 degrees 52'S, 73 degrees 26'W) in the coast of province of Valdivia, Chile, were analysed. Prevalence % (in parentheses) of infection by intestinal protozoa and helminths were the followings: Entamoeba histolytica: (18.0), Entamoeba coli (34.0), Endolimax nana (34.4), Iodamoeba buetschlii (7.4), Blastocystis hominis (64.3), Giardia intestinalis (27.9) Chilomastix mesnili (0.8), Ascaris lumbricoides (12.7), Trichuris trichiura (32.0), Trichostronqylidea gen. sp. (0.8), Enterobius vermicularis (1.6), Hymenolepis nana (0.4) Diphyllobothrium sp. (0.4). No sanitary conditions, water, faeces and garbage disposal were detected in the 55.5%, 86.4% and 52.7% of 110 houses from the sector, respectively. The high prevalence of protozoa and helminths intestinal infections in the sector are related to no sanitary conditions of houses and fecal contamination of the estuary of the Valdivia river.

Adolescent↗
PubMedDate not supplied

[The role of opportunistic protozoa in human pathology today].

The paper deals with opportunistic protozoa, their common properties distinctions from commensals and obligate parasites, and the specific features of their caused opportunistic infections. It also provides evidence for the increasing contribution of opportunistic protozoa to human pathology today and for paramount necessity for researchers and practitioners of various disciplines to lay a special emphasis on them.

AIDS-Related Opportunistic Infections↗
PubMed1994

[Fixation and immunological reactivity of parasitic protozoa in sol-gel matrices].

Parasitic protozoa have been entrapped within sol-gel silica matrices. Stationary phase promastigote cells of Leishmania donovani infantum are mixed with a silicon alkoxide solution. They remain trapped within the growing oxide network formed upon hydrolysis and condensation of the alkoxide. Electron microscopy shows the preservation of the cellular organization and the integrity of the plasma membrane of entrapped parasites. Specific antigen-antibody reactions have been performed within the sol-gel matrix via enzyme-linked immunosorbent assays (ELISA) currently used for the diagnostic of visceral leishmaniasis. A clear-cut difference in optical density was measured between positive and negative sera from dogs. Entrapped protozoa antigens are still able to react with specific antibodies through the open porosity of the silica network. These results suggest that sol-gel matrices could be used for the development of immunodiagnostic assays requiring whole cell parasites as antigens.

Animals↗
PubMed1994

The prevalence of intestinal protozoa in wild and domestic pigs.

We examined faecal samples from 842 domestic and 91 wild pigs in order to record the prevalence of intestinal protozoa. We used staining of faecal smears by Noller-Westphal-Gönnert method, cultivation in modified LES broth and microscopical examination of native preparations using small magnification (for detection of Balantidium coli). Moreover, the faeces from wild pigs were examined by flotation in Sheather's sugar solution for detection of coccidia. We found 8 coccidian species in the wild pigs. Except sucking piglets, high prevalence of B. coli, Entamoeba polecki, lodamoeba sp. and Tritrichomonas suis was noticed in all categories of animals. On the other hand, only sporadic occurrence of Chilomastix sp. was recorded. The intensity of infections by different protozoa was variable in all categories of animals. It is not sure whether Chilomastix sp. and Iodamoeba sp. are identical with the species known from the intestine of humans and that is why their epidemiological importance is not clear.

Animals↗
PubMed1993

Amebiasis and "nonpathogenic" intestinal protozoa.

Infection with single or multiple species of intestinal protozoa is common in humans and can result in either asymptomatic colonization or symptoms of intestinal disease. Entamoeba histolytica serves as a paradigm for invasive colonic protozoal infection. The key to diagnosis and treatment of amebiasis is knowledge of the epidemiologic risk factors and clinical manifestations, a rational approach to diagnosis, and an understanding of the sites of action and uses of anti-amebic drugs. This knowledge of treatment provides a context for consideration of intestinal infection with less common protozoan pathogens such as Dientamoeba fragilis and Balantidium coli and 'nonpathogenic' protozoa such as Blastocystis hominis and Entamoeba coli.

AIDS-Related Opportunistic Infections↗
PubMed1995

Immunochemical characterization of carbohydrate antigens from fungi, protozoa and mammals by monoclonal antibodies directed to glycan epitopes.

Cell surface carbohydrates constitute the major antigenic determinants of fungi and protozoa. Glycoconjugates also represent a large variety of antigens or markers present in mammals such as histo-blood groups ABO, differentiation and heterophile antigens, among others. This article focuses on the general properties of glycoconjugate antigens and production and characterization of the anti-carbohydrate monoclonal antibodies (MoAbs). It describes the specificity and some properties of monoclonal antibodies directed against carbohydrate epitopes present in tumor-associated glycoproteins, in glycosaminoglycans of higher eukaryotes and in glycolipid antigens of protozoa and fungi. The epitopes recognized by the anti-carbohydrate MoAbs range from one sugar unit up to ten sugar units. Although most anti-carbohydrate MoAbs are directed predominantly toward terminal sugar residues, a few MoAbs are also reactive with internal sugar residues. The fine structure of the carbohydrate epitopes has been chemically defined by [1H] NMR, GC/MS of alditol acetates of partially permethylated compounds, -FAB/MS, degradation with exoglycosidases and inhibition with different methyl-glycosides and oligosaccharides.

Animals↗
PubMed1996

Intestinal protozoa.

Giardia is the best known cause of protozoal gastrointestinal disease in North America, producing significant but not life-threatening gastrointestinal distress and diarrhea. Although diagnosis of giardiasis may be challenging, treatment is usually successful. Entamoeba histolytica poses a rarer but far more difficult clinical challenge. Dysentery caused by E. histolytica may be the most feared intestinal protozoal infection, although Cryptosporidium parvum, Balantidium coli, Isospora belli, Sarcocystis species and other newly described protozoa also may cause diarrhea in healthy individuals and may result in intractable, life-threatening illness in patients with acquired immunodeficiency syndrome or other immunosuppressive diseases. Certain protozoa once considered relatively unimportant, such as Cryptosporidium, are now recognized as significant causes of morbidity even in the United States, since transmission readily occurs through contaminated water.

Balantidiasis↗
PubMedDate not supplied

[Prevalence of protozoa infections in synanthropic rodents in Valdivia City, Chile].

In order to determine the prevalence of infection by blood and intestinal protozoa in 57 synanthropic rodents from Valdivia city, a study was carried out in the period march-september 1986. The group of rodents studied was constituted by 31 Mus musculus, 19 Rattus rattus and 7 Oryzomys longicaudattus, being 42 males and 15 females. Diagnostic forms of protozoa were found in 70.2% of the investigated animals. The presence of five species of enteroprotozoa and one species of hemoflagelate was detected. The number and the corresponding percentages of infected animals were the following: Giardia muris, 21 (36.8%), Hexamita muris, 22 (38.6%), Trichomonas muris, 27 (47.4%), Entamoeba muris 9 (15.8%), Eimeria sp. 15 (26.3%) and Trypanosoma lewisi 9 (15.8%). Not significant differences were observed when considering host or sex of the species found infected. Furthermore, the yielding of fecal examination considering direct examination, sugar solution flotation and SAFS were compared. The sugar solution flotation technique showed the highest percentage diagnosis of coccidia, whereas SAFS was more efficient for detecting G. muris and E. muris.

Animals↗