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Hoang Thi Thanh Thuy Nguyen Nhu Ha Vy Tu Thi Cam Loan 《Water, air, and soil pollution》2007,182(1-4):73-81
The aquatic system of Hochiminh City comprises two main rivers: the Sai Gon and Nha Be rivers. Five canals discharge into these two rivers: NhieuLoc-ThiNghe, TauHu-BenNghe, TanHoa-LoGom, ThamLuong-BenCat and Doi-Te. The rivers and these canals collect effluent water from domestic and industrial sources. Most of these flows are not treated or at most are only primarily treated. A total of 33 sediment cores were taken from these rivers and canals. Chemical composition of these aquatic sediments has very high concentrations of several “urban” metals such as Cd, Cr, Cu and Zn. Most of the samples have exceeded the US EPA’s toxicity reference values for Cu, Zn and Cr (82, 82 and 70%, respectively). The highest concentrations of these metals appear to be associated with the uncontrolled and untreated industrial runoff to the discharge canals. These concentrations in fluvial sediment are relatively low, which indicates the dilution process of the contaminants. This finding indicates that the anthropogenic inputs play an important role in the elevation of heavy metals in the aquatic system and organic matter seems to exert a strong geochemical control on the amount of heavy metals. The Pearson correlation coefficients calculated for Cd, Cr, Cu and Zn, are 0.89; 0.72; 0.93 and 0.87, respectively. 相似文献
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Barley cultivars show various patterns of resistance against isolates of Magnaporthe oryzae and M. grisea. Genetic mechanisms of the resistance of five representative barley cultivars were examined using a highly susceptible barley cultivar, 'Nigrate', as a common parent of genetic crosses. The resistance of the five cultivars against Setaria, Oryza, Eleusine, and Triticum isolates of M. oryzae was all attributed to a single locus, designated as Rmo2. Nevertheless, the Rmo2 locus in each cultivar was effective against a different range of isolates. Genetic analyses of pathogenicity suggested that each cultivar carries an allele at the Rmo2 locus that recognizes a different range of avirulence genes. One allele, Rmo2.a, corresponded to PWT1, which conditioned the avirulence of Setaria and Oryza isolates on wheat, in a gene-for-gene manner. The other alleles, Rmo2.b, Rmo2.c, and Rmo2.d, corresponded to more than one avirulence gene. On the other hand, the resistance of those cultivars to another species, M. grisea, was conditioned by another locus, designated as Rmo3. These results suggest that Rmo2 is effective against a broad range of blast isolates but is specific to M. oryzae. Molecular mapping revealed that Rmo2 is located on the 7H chromosome. 相似文献
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Hepatitis E in southern Vietnam: Seroepidemiology in humans and molecular epidemiology in pigs 
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下载免费PDF全文 A. Berto H. A. Pham T. T. N. Thao N. H. T. Vy S. L. Caddy R. Hiraide N. T. Tue I. Goodfellow J. J. Carrique‐Mas G. E. Thwaites S. Baker M. F. Boni the VIZIONS consortium 《Zoonoses and public health》2018,65(1):43-50
Viral pathogens account for a significant proportion of the burden of emerging infectious diseases in humans. The Wellcome Trust‐Vietnamese Initiative on Zoonotic Infections (WT‐VIZIONS) is aiming to understand the circulation of viral zoonotic pathogens in animals that pose a potential risk to human health. Evidence suggests that human exposure and infections with hepatitis E virus (HEV) genotypes (GT) 3 and 4 results from zoonotic transmission. Hypothesising that HEV GT3 and GT4 are circulating in the Vietnamese pig population and can be transmitted to humans, we aimed to estimate the seroprevalence of HEV exposure in a population of farmers and the general population. We additionally performed sequence analysis of HEV in pig populations in the same region to address knowledge gaps regarding HEV circulation and to evaluate if pigs were a potential source of HEV exposure. We found a high prevalence of HEV GT3 viral RNA in pigs (19.1% in faecal samples and 8.2% in rectal swabs) and a high HEV seroprevalence in pig farmers (16.0%) and a hospital‐attending population (31.7%) in southern Vietnam. The hospital population was recruited as a general‐population proxy even though this particular population subgroup may introduce bias. The detection of HEV RNA in pigs indicates that HEV may be a zoonotic disease risk in this location, although a larger sample size is required to infer an association between HEV positivity in pigs and seroprevalence in humans. 相似文献
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Nguyen ST Honma H Geurden T Ikarash M Fukuda Y Huynh VV Nguyen DT Nakai Y 《Research in veterinary science》2012,93(2):848-852
We investigated the prevalence and risk factors associated with Cryptosporidium oocysts shedding in pigs in Central Vietnam. A total of 740 single fecal samples collected from diarrheic and non-diarrheic pigs on 89 farms were screened by the modified Ziehl-Neelsen staining method. Prevalence at the animal and the farm levels were 18.1% (134/740) and 71.9% (64/89), respectively. Risk factors for the infection were identified using univariate and multivariate logistic regression analysis. The results revealed that age, sanitary condition and topography were significantly associated with oocyst shedding (P<0.05). Pre-weaned piglets were at the highest risk for infection, followed by post-weaners, sows and finishing pigs. Good sanitary conditions showed positive effects in decreasing oocysts shedding. Topographically, Cryptosporidium was more common in mountainous zone than that in coastal delta zone. There was an association between the occurrence of diarrhea and the level of Cryptosporidium oocyst excretion within infected pigs. This is the first epidemiological investigation of prevalence and risk factors of Cryptosporidium in pigs in Vietnam. 相似文献
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Sam Thi Nguyen Duc Tan Nguyen Thoai Van Nguyen Vu Vy Huynh Duc Quyet Le Yasuhiro Fukuda Yutaka Nakai 《Tropical animal health and production》2012,44(8):1847-1853
The aims of this study were to investigate the prevalence of natural Fasciola infections in both the definitive hosts (cattle) and the intermediate hosts (Lymnaea snails) in central Vietnam. A total of 1,075 fecal samples, randomly collected from cattle in Binh Dinh, Khanh Hoa, and Phu Yen provinces, were examined for Fasciola eggs by a sedimentation method. The overall prevalence of Fasciola was 45.3?%. A subset of the animals (235) was also screened for antibodies against Fasciola by an enzyme-linked immunosorbent assay. Overall, 46.3?% of these animals were shedding Fasciola eggs while 87.2?% were Fasciola seropositive. A lower prevalence of Fasciola was observed in calves ??2?years of age (37.6?%) compared to that in cattle >2?years of age (53.7?%) (p?<?0.05). The prevalence in the rainy season (50.8?%) was significantly different to that in the dry season (38.1?%) (p?<?0.05). Of the 3.269 Lymnaea viridis and 1.128 Lymnaea swinhoei examined, 31 (0.95?%) and seven (0.62?%), respectively, were found to be infected with Fasciola. This appears to be the first epidemiological survey of the prevalence of Fasciola in cattle and snails in these three provinces in central Vietnam. 相似文献
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CA Meza‐Herrera TT Ross DM Hallford DE Hawkins A Gonzalez‐Bulnes 《Reproduction in domestic animals》2010,45(4):723-728
The effects of supplemented protein level (PL) during the periconceptional period and their interaction with body condition were evaluated in sheep. Multiparous Rambouillet ewes (n = 12) received two PL of rumen undegradable protein (UIP) during a 30‐day pre‐mating and 15‐day post‐mating period: low [LPL, 24% crude protein (CP), 14 g UIP and 36 g/CP animal/day] and high [HPL, 44% CP, 30 g UIP and 50 g/CP animal/day]. While ovulation rate (OR) did not differ between treatments (1.6 ± 0.5, mean ± SEM), a lower fertility rate, a decreased embryo number and a reduced uterine pH (UpH) was observed in the HPL group (p < 0.05), irrespective of BC. Luteal tissue weight, volume and progesterone secretion did not differ among treatments. Sheep with lower UpH also had lower conceptus weight (Cwt; p < 0.05, r = 0.65) and conceptuses with lower mass tended to secrete less INF‐τ and IGF‐1, and the correspondent endometrial explants had a higher basal PGF2α release. Current study indicates that high protein diets during the periconceptional period in sheep modify uterine and embryonic relationships, increasing early pregnancy losses and inducing embryo growth retardation. Surviving embryos were affected by weight reductions, which could compromise later foetal growth and birth weight. Results evidence the key role of a balanced diet in reproductive success and indicate that the quality and nutrient composition of the maternal diet are essential for an adequate establishment of pregnancy, having paramount effects on the interplay of the embryo and the uterus. 相似文献
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Soil condition is commonly assessed by using soil organic carbon (SOC) as an indicator; however, a large proportion of the world's soils can contain charcoal, a biologically‐inert form of organic carbon. We investigated whether the presence of charcoal in soil could lead to an inaccurate assessment of soil condition when using SOC as an indicator. We sampled topsoil in a south‐east Australian catchment affected by severe fires in 2003. Samples (n = 100) were analysed for two SOC fractions: (i) total SOC (t‐SOC, loss on ignition), which included charcoal, and (ii) biologically‐active SOC (a‐SOC, persulphate‐oxidation), which did not contain charcoal. Using novel (boosted regression trees) and traditional (linear regression) modelling methods we compared the relative importance of abiotic (slope, aspect, elevation and soil texture) and biotic (land use and vegetation structure) factors as predictors of t‐SOC and a‐SOC concentration. A major difference between the two response variables was less relative importance of land use as a predictor when using t‐SOC as a response variable. Therefore, ignoring the presence of charcoal would have led to an under‐estimation of the effect of land‐use conversion on the biologically‐available SOC fraction. The presence of charcoal has important ramifications for routine assessments of soil condition given that (i) SOC is a commonly used indicator and charcoal and biologically‐active SOC differ in their effects on soil properties, (ii) fires historically occur on a large area of land, (iii) charcoal is a long‐lasting consequence of fires and (iv) charcoal can account for a large proportion of SOC and yet be unnoticed during sample preparation. 相似文献