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The British Journal of Nutrition May 19881. The dynamics of protozoa were studied in two groups of rumen-fistulated cattle fed on a basal diet of molasses ad lib., with oaten chaff given at 6 or 18 g/kg live...
1. The dynamics of protozoa were studied in two groups of rumen-fistulated cattle fed on a basal diet of molasses ad lib., with oaten chaff given at 6 or 18 g/kg live weight. This diet resulted in different mixtures of protozoal species in the populations in the rumen. 2. The rumen protozoa were studied by intrarumen injections of protozoa labelled in vitro with [14CH3]choline. An indication of protozoal death and fermentation of protozoal cell residues was obtained by measuring 14C loss via the methane pool. 3. After a single injection of labelled protozoa, the decline in the specific radioactivity (microCi/g nitrogen) of the protozoal pool in the rumen indicated that first-order kinetic processes applied. Conversely the specific radioactivity of protozoa, incubated in rumen fluid, remained constant indicating no growth in vitro, presumably owing to a rapid exhaustion of essential nutrients. 4. The protozoal populations in the rumen of cattle fed on the diet with the low level of oaten chaff were mainly small ciliates; but on the higher level of chaff in the diet, the large ciliates were a higher proportion of the total protozoal population present. 5. The mean pool size of protozoa in the rumen was significantly larger and the protozoal half-life tended to be longer for cattle fed on the higher level of chaff in the diet. The apparent production rate of protozoa in cattle fed on each diet was not significantly different and there were no differences in the production rate of methane. The percentage losses of label from protozoa in the rumen via the methane pool were not significantly different on the two diets and indicated that 74% of the protozoa that were apparently irreversibly lost from the rumen could be accounted for by death and lysis in the rumen and therefore only 26% of protozoa apparently entered the lower digestive tract.
Topics: Ammonia; Animals; Cattle; Choline; Dietary Fiber; Eukaryota; Half-Life; Male; Methane; Rumen
PubMed: 2840114
DOI: 10.1079/bjn19880051 -
International Journal of STD & AIDS Dec 1999Our objective was to determine the prevalence of intestinal protozoa in homosexual men attending a sexually transmitted diseases (STD) clinic, to compare it with the...
Our objective was to determine the prevalence of intestinal protozoa in homosexual men attending a sexually transmitted diseases (STD) clinic, to compare it with the prevalence in a previous study from the same clinic, and to examine the relationship, if any, between the presence of protozoa and sexual practices. Men who consecutively attended the clinic and who gave a history of having had recent sexual contact with another male were invited to provide a stool sample for protozoological examination. Diarrhoeal samples were examined by direct microscopy for trophozoites and cysts and, after staining, for Cryptosporidium spp. In all cases, a modified formol-ether method was used to concentrate protozoal cysts before microscopy. One hundred and seventy-five of the 257 men invited to participate in the study provided a stool sample. At least one species of protozoan was found in 99 (57%) men. Giardia intestinalis was identified in only 5 (3%) men. Blastocystis hominis was found in 46 (26%) men, but the presence of this protozoan was not associated with diarrhoea. Other than the prevalence of Entamoeba dispar/histolytica and G. intestinalis, which remained unchanged, the proportion of men who harboured the non-pathogenic protozoa was significantly increased from 1981/82. A correlation between oral-anal sex or peno-insertive or peno-receptive anal intercourse and the prevalence of protozoa was not found. There was also no correlation between the number of species of protozoa carried and these sexual practices. The presence of protozoa was not associated with a history of foreign travel or sexual contact with a man who had recently travelled outside the UK. The study showed that, although the prevalence of infection is low, giardiasis is still transmissible amongst homosexual men. A correlation between individual sexual practices and the prevalence of intestinal protozoa was not found.
Topics: Animals; Contact Tracing; Diarrhea; Disease Transmission, Infectious; Eukaryota; Feces; Giardia lamblia; Homosexuality; Humans; Intestinal Diseases, Parasitic; Longitudinal Studies; Male; Scotland; Sexual Behavior; Sexually Transmitted Diseases
PubMed: 10639057
DOI: 10.1258/0956462991913547 -
Animal : An International Journal of... Nov 2014A meta-analysis was conducted to evaluate the effects of protozoa concentration on methane emission from ruminants. A database was built from 59 publications reporting... (Meta-Analysis)
Meta-Analysis
A meta-analysis was conducted to evaluate the effects of protozoa concentration on methane emission from ruminants. A database was built from 59 publications reporting data from 76 in vivo experiments. The experiments included in the database recorded methane production and rumen protozoa concentration measured on the same groups of animals. Quantitative data such as diet chemical composition, rumen fermentation and microbial parameters, and qualitative information such as methane mitigation strategies were also collected. In the database, 31% of the experiments reported a concomitant reduction of both protozoa concentration and methane emission (g/kg dry matter intake). Nearly all of these experiments tested lipids as methane mitigation strategies. By contrast, 21% of the experiments reported a variation in methane emission without changes in protozoa numbers, indicating that methanogenesis is also regulated by other mechanisms not involving protozoa. Experiments that used chemical compounds as an antimethanogenic treatment belonged to this group. The relationship between methane emission and protozoa concentration was studied with a variance-covariance model, with experiment as a fixed effect. The experiments included in the analysis had a within-experiment variation of protozoa concentration higher than 5.3 log10 cells/ml corresponding to the average s.e.m. of the database for this variable. To detect potential interfering factors for the relationship, the influence of several qualitative and quantitative secondary factors was tested. This meta-analysis showed a significant linear relationship between methane emission and protozoa concentration: methane (g/kg dry matter intake)=-30.7+8.14×protozoa (log10 cells/ml) with 28 experiments (91 treatments), residual mean square error=1.94 and adjusted R 2=0.90. The proportion of butyrate in the rumen positively influenced the least square means of this relationship.
Topics: Animals; Diet; Eukaryota; Fermentation; Methane; Models, Biological; Rumen; Ruminants; Symbiosis
PubMed: 25075950
DOI: 10.1017/S1751731114001852 -
Journal of Environmental Management Jul 2022Waterborne parasitic protozoa (WPP) infections have a worldwide distribution and are a source for epidemic and endemic human diseases. Although a variety of protozoa are...
Waterborne parasitic protozoa (WPP) infections have a worldwide distribution and are a source for epidemic and endemic human diseases. Although a variety of protozoa are commonly detected in wastewater and cited as causative agents of outbreaks, effluents from wastewater treatment plants (WWTPs) used for irrigation can contain other pathogenic protozoa that are not currently being controlled. The lack of control on a routine basis using rapid and sensitive methods to detect these parasites in water may keep them under-recognized. This study focused on using molecular tools, 18 S rRNA amplicon-based sequencing and qPCR, to characterize WPP distribution in wastewater samples from urban WWTPs used for irrigation. A total of eight wastewater samples (from secondary and tertiary disinfection treatment effluents) were collected. Potentially pathogenic protozoa identified by 18 S rRNA sequencing and/or qPCR in the analyzed samples included Acanthamoeba spp., Blastocystis sp., Entamoeba coli, Entamoeba dispar, Entamoeba hartmanni, Giardia intestinalis assemblage A and Toxoplasma gondii Positive results by qPCR were in non-quantifiable levels. Blastocystis sp. was the most represented protozoa among the sequences retrieved from the amplicon sequencing. Blastocystis ST1 and ST2 were the most abundant subtypes among the obtained OTUs. Moreover, Blastocystis sp. ST3, ST4, ST6 and ST8 were also detected, although in lower abundances. Results of this study showed that WWTP effluents used for irrigation can provide a source of WPP.
Topics: Animals; Blastocystis; Feces; Giardia lamblia; Humans; Parasites; Wastewater
PubMed: 35430514
DOI: 10.1016/j.jenvman.2022.115029 -
The Journal of Protozoology Feb 1975Large numbers of birds, until recently, were brought into the United States each year. Countries of origin were varied, and included those of Australasia, Africa, South...
Large numbers of birds, until recently, were brought into the United States each year. Countries of origin were varied, and included those of Australasia, Africa, South America, and the Caribbean islands, as well as other places. With them of course come their parasites, some of which may be potential pathogens to domestic avifauna. In part for this reason, a survey was undertaken of blood parasites of birds from pet shops and importers. So far a total of 1234 birds belonging to 186 species has been examined. Several new species and subspecies of avian Plasmodium have been found in the course of this study, including P. octamerium Manwell, 1968 in a Pintail Whydah, Vidua macoura, from Africa; P paranucleophilum Manwell & Sessler, 1971 in a South American tanager, Tachyphonus sp; and P. nucleophilum toucani Manwell & Sessler 1971 in a Swainson's Toucan, Ramphastos s. swainsonii. Plasmodium huffi Muniz, Soares & Battista is undoubtedly a synonym pro parte for the last. Plasmodium tenue Laveran & Maruliaz, long thought to be a synonym of Plasmodium vaughani Novy & MacNeal, was rediscovered and found to be a valid species. Plasmodium nucleophilum, infrequently seen in the New World, occurred in many Asian and African birds, and especially in starlings. Infections with other species of Plasmodium were common. Haemoproteus was the commonest blood parasite; Leucocytozoon was very rare as was Atoxoplasma (Lankesterella). The 2 families of birds best represented were the Fringillidae and the Psittacidae, but no blood parasites were seen in the latter. It is clear that imported birds are often infected with blood protozoa, some of which are unknown from native birds.
Topics: Animals; Apicomplexa; Bird Diseases; Birds; Blood; Malaria, Avian; Plasmodium; Protozoan Infections; Protozoan Infections, Animal
PubMed: 804038
DOI: 10.1111/j.1550-7408.1975.tb00956.x -
Minerva Stomatologica Oct 2005The importance of a good knowledge in microbiology of the oral cavity is every day more and more indispensable in order to propose proper therapeutic treatments. In this... (Review)
Review
The importance of a good knowledge in microbiology of the oral cavity is every day more and more indispensable in order to propose proper therapeutic treatments. In this study, the most frequent protozoa and mycetes present in the oral cavity are described, distinguishing the different species and their pathologies.
Topics: Animals; Eukaryota; Humans; Mitosporic Fungi; Mouth; Yeasts
PubMed: 16224377
DOI: No ID Found -
Memorias Do Instituto Oswaldo Cruz 2000Protozoa are among the most important pathogens that can cause infection in immunocompromised patients. They infect particularly individuals with impaired cell immunity,...
Protozoa are among the most important pathogens that can cause infection in immunocompromised patients. They infect particularly individuals with impaired cell immunity, such as those with hematologic neoplasias, those submitted to transplant of solid organs, those under high-dose corticosteroid therapy, and carriers of the human immunodeficiency virus. Among the protozoa that most commonly cause disease in immunocompromised individuals are Toxoplasma gondii, Trypanosoma cruzi, Cryptosporidium parvum, Isospora belli, Cyclospora cayetanensis and microsporidia; the former two cause severe encephalitis and myocarditis, and the others cause gastrointestinal infections. Early diagnosis and prompt institution of specific therapy for each of these organisms are basic measures to decrease morbidity and mortality associated with these infections.
Topics: AIDS-Related Opportunistic Infections; Animals; Humans; Immunocompromised Host; Protozoan Infections
PubMed: 11142706
DOI: 10.1590/s0074-02762000000700026 -
Respiratory Medicine Jun 2011Atypical infectious agents have been proposed as potential contributors to asthma. A novel set of morphological and staining criteria permit the identification of...
BACKGROUND
Atypical infectious agents have been proposed as potential contributors to asthma. A novel set of morphological and staining criteria permit the identification of flagellated protozoa in sputum. This case-control study was designed to use this novel method and to assess: (1) are protozoa more common in asthmatics than in non-asthmatics; (2) is the presence of protozoa associated with the use of steroid inhalers; and (3) is the presence of protozoa associated with living in damp housing?
METHODS
Induced sputum samples were collected from asthma patients and local non-atopic, non-smoking controls. Questionnaires assessed asthma severity and housing conditions. Sputum was examined for flagellated protozoa using a previously described staining technique.
RESULTS
96 participants were recruited for this study; 54 asthma patients and 42 controls, age range 21-62 years, 70% female participants. Limiting results to those who were clearly positive or negative for flagellated protozoa, 66.7% (20/30) of asthmatics and 30.8% (4/13) of controls had protozoa (p = 0.046). Among the asthma patients, prevalence of protozoa was not significantly different between those who had (10/18), and those who had not (10/12), used steroid inhaler in the preceding two weeks (p = 0.11). Similarly, the prevalence of protozoa was not significantly different between those who did (6/11) and those who did not (18/32), live in damp homes (p = 0.92).
CONCLUSIONS
This case-control study demonstrates an association between flagellated protozoa in sputum and asthma. It is now necessary to confirm and characterise the protozoa using genetic techniques based on 18S ribosomal RNA. Once tis is established it would be worthwhile to determine if asthma symptoms improve when treated by anti-protozoal agents.
Topics: Adult; Animals; Asthma; Bronchial Provocation Tests; Case-Control Studies; Female; Housing; Humans; Male; Middle Aged; Protozoan Infections; Sputum; Surveys and Questionnaires
PubMed: 21138788
DOI: 10.1016/j.rmed.2010.11.016 -
Frontiers in Immunology 2020
Topics: Animals; Host-Parasite Interactions; Humans; Infection Control; Infections; Parasites
PubMed: 32457761
DOI: 10.3389/fimmu.2020.00880 -
Canadian Journal of Microbiology Jun 1983Methanogenic bacteria superficially associated with rumen entodiniomorphid protozoa were observed by fluorescence microscopy. A protozoal suspension separated from...
Methanogenic bacteria superficially associated with rumen entodiniomorphid protozoa were observed by fluorescence microscopy. A protozoal suspension separated from strained rumen fluid (SRF) by gravity sedimentation exhibited a rate of methane production six times greater (per millilitre) than SRF. The number of protozoa (per millilitre) in the protozoal suspension was three times greater than that of SRF; however, the urease activity of this fraction was half that of SRF. The methanogenic activity of SRF and the discrete fractions obtained by sedimentation of protozoa correlated with the numbers of protozoa per millilitre in each fraction. Gravity-sedimented protozoa, washed four times with cell-free rumen fluid, retained 67-71% of the recoverable methanogenic activity. Thus it is evident from our observations that many methanogens adhere to protozoa and that the protozoa support methanogenic activity of the attached methanogens. When protozoa-free sheep were inoculated with rumen contents containing a complex population of protozoa, methanogenic activity of the microflora in SRF samples was not significantly enhanced.
Topics: Animals; Bacteria; Carbon Dioxide; Cattle; Eukaryota; Female; Hydrogen; Male; Methane; Rumen; Symbiosis
PubMed: 6411316
DOI: 10.1139/m83-110