Уточнить поиск
Результаты 1-10 из 11
Cryptosporidium: Detection in water and food Полный текст
2010
Smith, H. V. (Huw V) | Nichols, Rosely A.B.
Water and food are major environmental transmission routes for Cryptosporidium, but our ability to identify the spectrum of oocyst contributions in current performance-based methods is limited. Determining risks in water and foodstuffs, and the importance of zoonotic transmission, requires the use of molecular methods, which add value to performance-based morphologic methods. Multi-locus approaches increase the accuracy of identification, as many signatures detected in water originate from species/genotypes that are not infectious to humans. Method optimisation is necessary for detecting small numbers of oocysts in environmental samples consistently, and further work is required to (i) optimise IMS recovery efficiency, (ii) quality assure performance-based methods, (iii) maximise DNA extraction and purification, (iv) adopt standardised and validated loci and primers, (v) determine the species and subspecies range in samples containing mixtures, and standardising storage and transport matrices for validating genetic loci, primer sets and DNA sequences.
Показать больше [+] Меньше [-][Overfertilized water - underfertilized fields: approach to cycling and sustainable food supply [Bohuslaen]]
1996
Schoenbeck, A.
The food and feeding behaviour of water monitor, Varanus salvator, in Malaysia
1994
Traeholt, C. (Copenhagen Univ., Copenhagen (Denmark). Institute of Population Biology)
Faecal pellets of Varanus salvator collected in Pulau Tulai in the South China Sea revealed that individuals there mainly feed on crabs and tourists' leftovers. The stomach contents of monitor lizards living in an oil palm estate in Peninsular Malaysia show that the main diet in that habitat consisted of various types of insects and occasionally small rodents. Hatchlings were strictly insectivorous. Both groups of lizards exhibited area-concentrated foraging behaviour and their preferred hunting technique was "open pursuit"
Показать больше [+] Меньше [-]Food selection by adult red foxes Vulpes vulpes during a water vole decline Полный текст
1996
Food selection by adult red foxes Vulpes vulpes was studied in a mountainous environment characterised by fluctuating populations of water voles. According to optimal foraging theory, the diets of adults and cubs should be similar during vole highs, with voles as staple prey. On the other hand, a difference should occur when water voles become scarce. Adults should then bring larger alternative prey to their cubs, and consume smaller prey at the capture site. Adult and cub scats were collected around breeding dens during a 6‐year period, from the peak to a near‐extinction phase of the water vole population, and analysed. As predicted by the optimal foraging theory, no significant difference was found between the diets of cubs and adults when voles were abundant. Furthermore, cubs consumed a higher proportion of large alternative prey, i.e. lagomorphs, than adults in the first year of low vole density. Unexpectedly, this difference did not persist the following years despite the water vole scarcity. The consumption of large alternative prey at the den decreased significantly, whereas the consumption of small alternative prey, i.e. invertebrates, increased. Consequently, the composition of prey brought to the den was similar to that consumed at the capture site. Food selection was probably affected by the unpredictability of large prey availability and accessibility. It is suggested that if small alternative prey proves less profitable to the cubs than large prey, a long‐lasting shortage of water voles could possibly become a factor regulating fox numbers in the area studied.
Показать больше [+] Меньше [-]Replacing wheat bran by corn gluten feed without steep water in complete dog food Полный текст
2018
Pires, Juliana de Melo | Ferreira, Lívia Geraldi | Saad, Flávia Maria de Oliveira Borges | Zangeronimo, Márcio Gilberto | Bueno, Ives Cláudio da Silva | Carneiro, Aline Duarte de Souza | Corrêa, Graziane Ferrer | Parisi, Giuliana | Brandi, Roberta Ariboni
Twenty-four adult Beagles were utilised to evaluate the partial replacement of wheat bran with corn gluten feed without steep water on digestibility and characteristics of faeces. The treatments were 0 (no substitution), 30, 60 or 90 g/kg of corn gluten without steep water. There was no effect (p > .05) on the digestibility coefficients (g/kg) of dry matter (0.771), organic matter (0.806), crude protein (0.813), ether extract (0.798), crude fibre (0.393), neutral detergent fibre (0.425), acid detergent fibre (0.286) and crude energy (0.812), whilst there was effect (p < .05) on the digestible and metabolisable energy. There were effects (p < .05) for dry matter and pH of faeces but no effect (p > .05) was found on the remaining faecal characteristics: excretion for 100 g of food (56.77 g), excretion (129.6 g/day and 49.0 g dry matter/day), score (3.90), dry matter excretion for 100 g of food (22.86 g), buffering capacity (BC) at pH 5 (57.81), ammonia nitrogen (1.46 g/kg of faecal dry matter) and water balance (333.25 mL/day), in vivo and in situ gas production (p > .05). Corn gluten feed without steep water can be utilised to replace up to 90 g/kg of wheat bran without causing negative effect on the digestibility and characteristics of faeces.
Показать больше [+] Меньше [-]Effect of Oral Administration of Sodium Fluoride on Food and Water Utilisation in Silkworm, Bombyx mori L Полный текст
1999
The effect of fluoride on the food and dietary water intake and utilisation were studied in final instars of silkworm, Bombyx mori L. race NB₄D₂ fed ad libitum with mulberry leaves treated with sodium fluoride at concentrations of 25 ppm, 50 ppm and 75 ppm. The larval duration increased by two days while food consumption, assimilation rate, assimilation efficiency, feeding and metabolic rates increased significantly in all the treated larvae. On the other hand, the amount of faeces produced, food conversion, conversion rate and conversion efficiencies decreased significantly in all the treated batches when compared to controls. The water intake and utilisation parameters increased significantly while rate of water loss through faeces, water retained in the body and retention efficiency decreased in all the fluoride-treated silkworms. The factors responsible for these changes in treated batches are discussed in relation to the effect of fluoride on cocoon and shell weights.
Показать больше [+] Меньше [-]Micro-organisms used as indicators of fecal contamination of water and food | Les micro-organismes indicateurs de contamination fecale de l'eau et des aliments
1998
Bornert, G. (Commissariat de l'Armee de Terre, Saint Cloud (France). Service Central d'Etudes et de Realisations)
Les iidicateurs de contamination fecale sont des micro-organismes dont la presence dans une eau ou un aliment est le signe d'ume contamination par des matieres fecales. En France, quatre flores bacteriennes sont habituellement recherchees au laboratoire: les coliformes, les coliformes thermotolerants, les Escherichia coli et les enterocoques. Leur denombrement, effectue selon des methodes normalisees simples et sensibles, se substitue a la recherche des micro-organismes pathogenes, souvent fastidieuse. Les connaissances acquises recemment dans le domaine de l'ecologie des coliformes et des enterocoques conduisent cependant a interpreter avec prudence les resultats d'analyses: l'origine fecale des indicateurs usuels n'est pas toujours certaine. Pour assurer plus efficacement la protection de la Sante Publique, il est imperatif de disposer d'indicateurs plus fiables. Les recherches actuelles s'orientent vers les bacteriophages a ARN F-specifiques et vers les bacteries du genre Bifidobacterium
Показать больше [+] Меньше [-]Enteroaggregative Escherichia coli is the predominant diarrheagenic E. coli pathotype among irrigation water and food sources in South Africa Полный текст
2018
Aijuka, Matthew | Santiago, Araceli E. | Girón, Jorge A. | Nataro, James P. | Buys, Elna M.
Diarrheagenic E. coli (DEC) has been implicated in foodborne outbreaks worldwide and have been associated with childhood stunting in the absence of diarrhoea. Infection is extraordinarily common, but the routes of transmission have not been determined. Therefore, determining the most prevalent pathotypes in food and environmental sources may help provide better guidance to various stakeholders in ensuring food safety and public health and advancing understanding of the epidemiology of enteric disease. We characterized 205 E. coli strains previously isolated from producer distributor bulk milk (PDBM)(118), irrigation water (48), irrigated lettuce (29) and street vendor coleslaw (10) in South Africa. Enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enteroaggregative E. coli (EAEC) and diffusely adherent E. coli (DAEC) were sought. We used PCR and partial gene sequencing for all 205 strains while 46 out of 205 that showed poor resolution were subsequently characterized using cell adherence (HeLa cells).PCR and partial gene sequencing of aatA and/or aaiC genes confirmed EAEC (2%, 5 out of 205) as the only pathotype. Phylogenetic analysis of sequenced EAEC strains with E. coli strains in GenBank showing ≥80% nucleotide sequence similarity based on possession of aaiC and aatA generated distinct clusters of strains separated predominantly based on their source of isolation (food source or human stool) suggesting a potential role of virulence genes in source tracking. EAEC 24%, 11 out of 46 strains (PDBM = 15%, irrigation water = 7%, irrigated lettuce = 2%) was similarly the predominant pathotype followed by strains showing invasiveness to HeLa cells, 4%, 2 out of 46 (PDBM = 2%, irrigated lettuce = 2%), among stains characterized using cell adherence.Therefore, EAEC may be the leading cause of DEC associated food and water-borne enteric infection in South Africa. Additionally, solely using molecular based methods targeting virulence gene determinants may underestimate prevalence, especially among heterogeneous pathogens such as EAEC.
Показать больше [+] Меньше [-]Fecal Indicator Bacteria along Multiple Environmental Transmission Pathways (Water, Hands, Food, Soil, Flies) and Subsequent Child Diarrhea in Rural Bangladesh Полный текст
2018
Pickering, Amy J. | Ercumen, Ayse | Arnold, Benjamin F. | Kwong, Laura H. | Parvez, Sarker Masud | Alam, Mahfuja | Sen, Debashis | Islam, Sharmin | Kullmann, Craig | Chase, Claire | Ahmed, Rokeya | Unicomb, Leanne | Colford, John M. | Luby, Stephen P.
Enteric pathogens can be transmitted through multiple environmental pathways, yet little is known about the relative contribution of each pathway to diarrhea risk among children. We aimed to identify fecal transmission pathways in the household environment associated with prospectively measured child diarrhea in rural Bangladesh. We measured the presence and levels of Escherichia coli in tube wells, stored drinking water, pond water, child hand rinses, courtyard soil, flies, and food in 1843 households. Gastrointestinal symptoms among children ages 0–60 months were recorded concurrently at the time of environmental sample collection and again a median of 6 days later. Incident diarrhea (3 or more loose stools in a 24-h period) was positively associated with the concentration of E. coli on child hands measured on the first visit (incidence rate ratio [IRR] = 1.23, 95% CI 1.06, 1.43 for a log₁₀ increase), while other pathways were not associated. In cross-sectional analysis, there were no associations between concurrently measured environmental contamination and diarrhea. Our findings suggest higher levels of E. coli on child hands are strongly associated with subsequent diarrheal illness rates among children in rural Bangladesh.
Показать больше [+] Меньше [-]Animal Feces Contribute to Domestic Fecal Contamination: Evidence from E. coli Measured in Water, Hands, Food, Flies, and Soil in Bangladesh Полный текст
2017
Ercumen, Ayse | Pickering, Amy J. | Kwong, Laura H. | Arnold, Benjamin F. | Parvez, Sarker Masud | Alam, Mahfuja | Sen, Debashis | Islam, Sharmin | Kullmann, Craig | Chase, Claire | Ahmed, Rokeya | Unicomb, Leanne | Luby, Stephen P. | Colford, John M.
Fecal-oral pathogens are transmitted through complex, environmentally mediated pathways. Sanitation interventions that isolate human feces from the environment may reduce transmission but have shown limited impact on environmental contamination. We conducted a study in rural Bangladesh to (1) quantify domestic fecal contamination in settings with high on-site sanitation coverage; (2) determine how domestic animals affect fecal contamination; and (3) assess how each environmental pathway affects others. We collected water, hand rinse, food, soil, and fly samples from 608 households. We analyzed samples with IDEXX Quantitray for the most probable number (MPN) of E. coli. We detected E. coli in source water (25%), stored water (77%), child hands (43%), food (58%), flies (50%), ponds (97%), and soil (95%). Soil had >120 000 mean MPN E. coli per gram. In compounds with vs without animals, E. coli was higher by 0.54 log₁₀ in soil, 0.40 log₁₀ in stored water and 0.61 log₁₀ in food (p < 0.05). E. coli in stored water and food increased with increasing E. coli in soil, ponds, source water and hands. We provide empirical evidence of fecal transmission in the domestic environment despite on-site sanitation. Animal feces contribute to fecal contamination, and fecal indicator bacteria do not strictly indicate human fecal contamination when animals are present.
Показать больше [+] Меньше [-]