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91.
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Influenza A viruses (IAVs) have both zoonotic and anthroponotic potential and are of public and veterinary importance. Swine are intermediate hosts and ‘mixing vessels’ for generating reassortants, progenies of which may harbour pandemic propensity. Swine handlers are at the highest risk of becoming infected with IAVs from swine but there is little information on the ecology of IAVs at the human–animal interface in Africa. We analysed and characterized nasal and throat swabs from swine and farmers respectively, for IAVs using RT‐qPCR, from swine farms in the Ashanti region, Ghana. Sera were also analysed for IAVs antibodies and serotyped using ELISA and HI assays. IAV was detected in 1.4% (n = 17/1,200) and 2.0% (n = 2/99) of swine and farmers samples, respectively. Viral subtypes H3N2 and H1N1pdm09 were found in human samples. All virus‐positive swine samples were subtyped as H1N1pdm09 phylogenetically clustering closely with H1N1pdm09 that circulated among humans during the study period. Phenotypic markers that confer sensitivity to Oseltamivir were found. Serological prevalence of IAVs in swine and farmers by ELISA was 3.2% (n = 38/1,200) and 18.2% (n = 18/99), respectively. Human H1N1pdm09 and H3N2 antibodies were found in both swine and farmers sera. Indigenous swine influenza A viruses and/or antibodies were not detected in swine or farmers samples. Majority (98%, n = 147/150) of farmers reported of not wearing surgical mask and few (4%, n = 6) reported to wear gloves when working. Most (n = 74, 87.7%) farmers reported of working on the farm when experiencing influenza‐like illness. Poor husbandry and biosafety practices of farmers could facilitate virus transmission across the human–swine interface. Farmers should be educated on the importance of good farm practices to mitigate influenza transmission at the human–animal interface.  相似文献   
94.
The effective use of manure nutrients requires an accurate assessment of their availability to the specific crops being grown. A fertilizer equivalence approach was used to evaluate the availability of nitrogen (N) and phosphorus (P) from liquid dairy manure to potatoes in field experiments conducted in northeast Wisconsin in 2000, 2001, and 2002. Crop responses to moderate and high rates of liquid dairy manure (93,500 and 187,000 L ha?1) were compared to results obtained from N or P fertilizer applied at five rates (0 to 269 kg ha?1). Availability estimates were made using the fertilizer equivalence method based on tuber yield, harvested tuber N or P concentration and uptake, petiole nitrate or total P concentration, and soil nitrate or extractable P phosphate levels. Results showed an apparent availability of manurial N from 10% to 40%, with an overall average across all 3 years and all parameters of 28.6% for the lower rate and 24.6% for the high rate. These values are slightly less than average availability measured where corn has been used as the test crop. Although all parameters did not show responses to P fertilizer additions in these trials, where estimates were possible, P availability ranged from 20% to 90% with an overall average across all 3 years of 55.4% for the low and 50.5% for the high manure rates. Despite potato being more shallow-rooted and somewhat less efficient in N and P use compared to corn, it appears that only minor adjustments to manurial nutrient availability estimates are warranted when potatoes are grown.  相似文献   
95.
Four of five major cultivars of the potato (Solanum tuberosum L. ssp.tuberosum) from different sources were found to vary genetically. This variability was detected by an electrophoretic study of enzymatic activity for alkaline phosphatase and glucosephosphate isomerase. An examination of red cultivars from Beltsville, Md. suggests that the apparent intracultivar variability observed for Red Pontiac may be due to cultivar mislabeling rather than mutation or mitotic recombination. The results of this study raise concerns about potato cultivar certification and interpretations of some of the previous cultivar work. We suggest that a more extensive survey of intracultivar variability be carried out. Further, we suggest that these genetic markers and others could be used in cultivar identification.  相似文献   
96.
The effect of pea canopy structure on epidemics of Mycosphaerella pinodes was investigated in four spring pea cultivars (Bridge, Obelisque, Solara and Athos) in two field experiments. These cultivars had similar levels of susceptibility to ascochyta blight and presented different architectural features (branching, standing ability and stem height). Stem height ranged from 77 to 95 cm in 1999 and from 72 to 92 cm in 2000, while leaf area index (LAI) ranged from 3·8 to 5·1 in 1999 and from 3·8 to 4·7 in 2000. Internode lengths varied from 4·6 to 6·0 in 1999 and from 3·8 to 4·7 in 2000. Mean distance between nodes in the canopy (MDN) ranged from 12·2 to 15·3 cm in 1999 and from 11·2 to 13·9 cm in 2000. Canopies with different architecture differed in disease progression on stipules and mainly on pods. The levels of disease on stipules and pods were strongly correlated. Moreover, if disease was considered as a function of stipule height up the stem, large differences in vertical disease distribution were observed between cultivars. Three architectural features acted on disease development: cumulative LAI above the node on which disease was assessed (LAIcum) and large MDN favouring disease development, and large internode length reducing disease severity. Modifying LAI distribution and plant organization could be one way to reduce the impact of ascochyta blight, by direct or indirect effects on environmental and dispersal conditions.  相似文献   
97.
98.
Tropical fish medicine. Necropsy examination of fish   总被引:1,自引:0,他引:1  
Necropsy examination of moribund or dead specimens is an essential step in diagnosing fish diseases. This article discusses basic anatomy and necropsy procedures. A large part of the article has been devoted to methods of procuring samples for laboratory analysis and histologic examination. To determine which findings are responsible for the mortalities, the entire case history and gross necropsy findings must be reviewed. Careful observations made during the necropsy examination provide valuable information immediately, as well as later on in the interpretation of laboratory data.  相似文献   
99.
We used DNA probes to study dietary effects on the prokaryotic population in the rumen. Procedures used to isolate and quantify prokaryotic 16S ribosomal RNA (rRNA) from the rumen using universal and species-specific DNA probes were evaluated. In this experiment, three ruminally fistulated steers were fed orchard-grass hay, and ruminal digesta were collected at 0, 3, and 9 h after offering hay (0800). Samples of ruminal digesta were taken from the interior portion of the digesta mat and from the fluid below the mat in the dorsal rumen. Freezing (-65 degrees C) and blending samples both increased (P less than .07) the yield of 16S rRNA from ruminal digesta. Extraction of prokaryotic rRNA was greater (P less than .04) when phenol buffered with sodium acetate was used than when it was buffered with hydroxymethyl-amino-methane. Prokaryotic 16S rRNA concentration of the fluid phase was similar (P greater than .10) at 0, 3, and 9 h after offering hay. Prokaryotic 16S rRNA concentration of the mat phase increased up to the 9 h after feeding. The proportion of Fibrobacter succinogenes remained constant in both digesta phases at all times measured. From these data we concluded that DNA probes can be used to monitor bacterial population shifts in the rumen.  相似文献   
100.
Inhalt: Die Phänomene der gonadalen Dysgenese weisen eine erhebliche Bandbreite au Die hier vorgestellte XY-Kalbin hatte ein geringgradig hypoplastisches, weibliches Genitale, in den dysgenetischen Gonaden lagen 2 Primordialrestfollikel vor. Ihre inter-stitiellen Zellen waren hyperplastisch, doch gab es keine Anzeichen für eine tumoröse Entartung, in Art eines Gonadenblastoms oder Dysgerminoms. Das Tier hatte zur Behandlung der bestehenden primären Amenorrhoe keine Hormonbehandlung erfahren. Die Konzentrationen uon Sexualsteroiden (Testosteron, Epitestosteron, Dehydroepian-drosteron) glichen solchen, wie sie im Zyklus des Rindes auftreten, ein Konzentrations-anstieg nach Pregnylapplikation war nichtzu erzielen. Nucleare Rezeptoren für Dihydro-testosteron waren nicht nachzuweisen. Die Persistenz von einzelnen Follikeln und von Keimzellen in den postpartalen resp. postpubertären Gonaden wurde in den letzten Jahren beim Menschen gelegentlich beschrieben, ist jedoch fur die reine gonadale Dysgenese nicht charakteristisch. Contents: Dysgenesis atypica ovarii in a XY-heifer The phenomena of gonadal dysgenesis show a wide range of variations. The XY-heifer described in this article showed low grade of hypoplasia of the inner female genital organes. Two primordial residual follicles were detected in serial sections of the dysgenetic gonads. The interstitial cells were hyperplastic, but there was no indication of tumorous degeneration, such as gonadoblastoma or dysgerminoma. No hormones had been given to treat primary amenorrhoe. Levels of sexual steroids (testosterone, epitestosterone, dehydroepiandrosterone were similar to those occurring in normal bovine cycle; Pregnyl failed to produce any rise in the concentration of sexual steroids. No evidence was found of nuclear receptors for dihydrotestosterone. Persistence of singular follicles and germinal cells in the postpartal and postpubertary gonads resp. of XY females has been sometimes observed (Cussen & Mac Mahon, 1979; Russel et al., 1980; Warner et al., 1985), but this is — by no means —characteristic for pure gonadal dysgenesis.  相似文献   
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