Probabilistic model for estimating field mortality of target and non-target bird populations when simultaneously exposed to avicide bait     

Johnston JJ  Holmes MJ  Hart A  Kohler DJ  Stahl RS 《Pest management science》2005,61(7):649-659

A probabilistic model was developed to estimate target and non-target avian mortality associated with the application of the avicide CPTH (3-chloro-p-toluidine hydrochloride) to minimize sprouting rice damage in the southern USA. CPTH exposures for individual birds were predicted by random sampling from species-specific non-parametric distributions of bait seed consumption and CPTH residues detected on individual bait seeds. Mortality was predicted from the species-specific exposure versus mortality relationship. Individual variations in this response were captured in the model by Monte Carlo sampling from species-specific distributions of slopes and median toxicity values (LD50) for each bird. The model was used to simultaneously predict mortality (percentage of exposed population and number of birds killed/weight of consumed bait) for a target (blackbird) and non-target (mourning dove) species feeding on bait sites for up to five consecutive days.  相似文献   

Risk assessment of dietary exposure to pesticides using a Bayesian method   总被引：2，自引：0，他引：2  

Paulo MJ  van der Voet H  Jansen MJ  ter Braak CJ  van Klaveren JD 《Pest management science》2005,61(8):759-766

Risk assessment of pesticides can be a statistically difficult problem because pesticides occur only occasionally, but they may occur on multiple components in the diet. A Bayesian statistical model is presented which incorporates multivariate modelling of food consumption and modelling of pesticide measurements which are for a large part below a measurement threshold. It is shown that Bayesian modelling is feasible for a limited number of food components, and that in a data-rich situation the model compares well with an empirical Monte Carlo modelling.  相似文献   

Germination of <Emphasis Type="Italic">Plasmodiophora brassicae</Emphasis> resting spores stimulated by a non-host plant     

Hanna?FribergEmail author  Jan?Lagerl?f  Birgitta?R?mert 《European journal of plant pathology / European Foundation for Plant Pathology》2005,113(3):275-281

Plant-induced germination of Plasmodiophora brassicae resting spores was studied in a laboratory experiment. Spore reaction was analysed in nutrient solution with exudates from growing roots of different plant species – one host plant (Brassica rapa var. pekinensis) and four non-host plants (Lolium perenne, Allium porrum, Secale cereale and Trifolium pratense) – and in controls with distilled water and nutrient solution. It was found that root exudates from L. perenne stimulated spore germination more than exudates from the other plants, including those from the host plant. The effect could not be explained by differences in the nutritional composition of the solutions due to differential uptake of the plant species, or by differences in root activity, measured as exudation of soluble sugars. This is the first time such a separation of factors has been done in analysing the influence of plants on P. brassicae germination. Although stimulation of P. brassicae resting spore germination is not restricted to the presence of host plants, it seems to vary depending on the plant species.  相似文献   

<Emphasis Type="Italic">N</Emphasis>-acyl-homoserine lactone-mediated quorum sensing blockage,a novel strategy for attenuating pathogenicity of Gram-negative bacterial plant pathogens     

X.?Cui  R.?HarlingEmail author 《European journal of plant pathology / European Foundation for Plant Pathology》2005,111(4):327-339

Quorum sensing is a bacterial communication mechanism by which bacteria sense their own population size and couple specific gene expression to cell density. In Gram-negative bacteria, the most commonly used quorum sensing signals are N-acyl homoserine lactones (AHLs). It is now apparent that many pathogenic bacteria employ quorum sensing to control premature expression of virulence factors. This control is thought to decrease the likelihood that the plant host would detect the pathogens presence and activate its defense system. Novel strategies that target bacterial quorum sensing systems in order to control plant bacterial diseases are discussed.  相似文献   

Risk Factors for Lamb Mortality in Sahelian Sheep on a Breeding Station in Ghana     

Turkson PK  Sualisu M 《Tropical animal health and production》2005,37(1):49-64

A retrospective cohort study was designed to examine the effect of sex, season of birth, type and year of birth, and birth weight on lamb mortality. The method used involved analysis of breeding records for Sahelian sheep kept on a breeding station at Pong-Tamale in northern Ghana from 1994 to 2000. The pre-weaning and post-weaning mortalities were 10% (n = 505) and 19% (n = 453), respectively, while the overall mortality from birth up to 12 months of age was 28% (n = 505). Compared to the pre-weaning period, the post-weaning period recorded significantly higher proportions of deaths in male, single-born, lambs born in the rainy or dry seasons, and in lambs with low (<3 kg) or high (> or =3 kg) birth weight. The odds and risks of death for male lambs were about one and a half times those for females at post-weaning. Lambs born in the dry season had significantly higher mortality than those born in the rainy season. Lambs that died by the time of weaning were not significantly different in weight at birth from those that survived. The mean birth and weaning weights of single-born lambs were significantly higher than those for twins. The mean pre-weaning ADG was significantly higher in lambs born as singles compared to that for twins. The season of birth had influence on mean birth weight, with those born in the rainy season having significantly higher weights than those born in the dry season. The year of birth significantly affected birth weight, weaning weight, weight at 12 months and ADG at all stages of the lambs' life. The study concluded that the most significant risk factors for lamb mortality included sex of the lamb, season of birth and birth weight. The last two could be manipulated, to some extent, to reduce lamb mortality.  相似文献   

Risk factors for outbreaks of infectious salmon anemia in farmed Atlantic salmon, Salmo salar   总被引：1，自引：0，他引：1  

McClure CA  Hammell KL  Dohoo IR 《Preventive veterinary medicine》2005,72(3-4):263-280

Infectious salmon anemia (ISA) is a viral disease occurring in farmed Atlantic salmon (Salmo salar) that is characterized by lethargy, anorexia, anemia and death. To control the disease in New Brunswick, Canada, 7.5 million fish from outbreak cages have been destroyed since 1997. Despite changes made by farmers, 2002 was the worst year ever for ISA losses in the region.

We evaluated the associations between potential risk factors and ISA outbreaks in the Atlantic-salmon sites in New Brunswick. This was a multilevel study in which the site-level design was a retrospective cohort study while the cage-level design was a modified case-cohort study. The questionnaire was divided into site-level questions, cage-level questions and hatchery information.

The important factors identified by this study can be categorized as environmental, farmer controlled or industry controlled according to the capacity to change or eliminate them. Environmental risk factors such as increasing the depth of the net (if nets were ≤9 m, odds ratio (OR) = 3.34) and decreasing the depth of water underneath the net (if depth of water underneath the net >3 m, OR = 3.34) are for the most part dictated by site location. Wild pollock (Pollachius virens) in the cage reflects the number of wild pollock that live in the site location. If there were ≥1000 pollock in the cage, the odds of disease in the cage increased 4.43-fold. Risk factors that are under farm control include increasing the number of times that the salmon are treated for sea lice (OR = 3.31 if lice treatments are ≤2 times), transferring small smolts into seawater (OR = 2.40 if smolts weighed >99 g) and improving on the adaptation of smolts to seawater to reduce post-transfer mortalities (OR = 4.52 if there was at least one cage with post-transfer mortalities >5%). The industry-controlled factors need to be addressed by the industry as a whole. Organizing boat travel to minimize the time and frequency of boats travelling to or by sites currently is being reviewed. This will be extremely important because the OR = 9.43 if processing boats travel within 1 km of the site and the OR = 4.03 if the site has dry feed delivered by the feed company. Because the hazard ratio increased stepwise from 1 if the nearest neighbor with ISA was ≥5 km up to 5.5 if the nearest site with ISA was within 0.5 km, increasing the distance between sites might be necessary for effective control.  相似文献   

Herd-level factors associated with isolation of Salmonella in a multi-state study of conventional and organic dairy farms II. Salmonella shedding in calves     

Fossler CP  Wells SJ  Kaneene JB  Ruegg PL  Warnick LD  Bender JB  Eberly LE  Godden SM  Halbert LW 《Preventive veterinary medicine》2005,70(3-4):279-291

The objective of this study was to evaluate associations between herd-level factors and the isolation of Salmonella in calves from dairy farms in Minnesota, Wisconsin, Michigan and New York. Study farms were 129 conventional and organic farms enrolled without regard to previous history of Salmonella infection. Herds were sampled at 2-month intervals over a 1-year period. Salmonella was isolated in fecal samples from 176 (3.8%) of 4673 preweaned calves with 40 (31.0%) of 129 farms having at least one positive calf sample over the course of the study. Multivariable logistic regression using the generalized estimating equations approach was used to evaluate risk factors for Salmonella shedding after adjustment for effects of herd size, season, state of origin and the multiple sampling occasions per herd. Factors retained in the final model that were associated with an increased odds for Salmonella shedding were lack of routine feeding of milk replacer containing antimicrobials to preweaned calves (OR = 2.8, 95% CI: 1.4, 5.8), use of maternity housing as a hospital area for sick cows more than once a month (OR = 2.1, 95% CI: 1.1, 4.0), and cow prevalence level by visit, categorized into the following four-levels: ≥20% (OR = 11.6, 95% CI: 5.7, 23.7), 10–19.9% (OR = 4.7, 95% CI: 2.0, 11.5), 0.1–9.9% (OR = 3.6, 95% CI: 1.5, 8.7) and 0% (reference level). Herd size was not associated with Salmonella shedding in the final multivariable model.  相似文献   

松材线虫对湖南林业和生态环境影响的风险性分析   总被引：12，自引：0，他引：12  

王明旭  陈良昌  宋玉双 《中国森林病虫》2001,20(2):42-45

遵循国际植物保护公约（IPPC）制定的有害生物分析准则，结合森林植物检疫对象的特点，从地理和管理标准、传入、定殖、定殖后扩散的可能性、潜在的经济和环境重要性在对松材线虫传入湖南进行了风险分析。证明松材线虫完全符合检疫性有害生物地理和管理标准，随松类植物及产品的调运从国内外疫区传入的可能性极大，在湖南完全能够定殖，定殖后能迅速扩散并暴发成灾，不仅对全省林业生产影响极大，而且严重威胁世界自然遗产武陵源风景区的安全,提出了3种降低风险的管理措施。  相似文献   

Effects of NF-κB "decoy" oligodeoxynucleotides on TNF-α and IL-6 expression in LPS-induced mouse macrophages     

WANG Jian  DENG Xiao-ming  REN Xu-yi  LI Jin-bao  CAO Jin-mei 《园艺学报》2004,20(5):741-744

AIM: To study the effect of NF-κB "decoy" oligodeoxynucleotides on TNF-α and IL-6 expression in LPS-induced mouse macrophages. METHODS: Mouse macrophage cell line J774.1 cells were cultured with LPS and liposome-mediated oligodeoxynucleotides, and the levels of TNF-α and IL-6 measured in the different culture supernatant by enzyme linked immunosorbent assay. RNA was extracted from macrophages, and the mRNA expression of TNF-α and IL-6 in macrophages was observed by RT-PCR. RESULTS: NF-κB "decoy" oligodeoxynucleotides decreased the expression of TNF-α and IL-6 in LPS-induced macrophages and inhibited generation of TNF-α and IL-6. The level of TNF-α and IL-6 did not change in control group. CONCLUSIONS: NF-κB "decoy" oligodeoxynucleotides inhibit the expression of TNF-α and IL-6 in LPS-induced macrophages, which is probably due to the specific inhibition of activated NF-κB binding sites .  相似文献   

Exposure to sulfosulfuron in agricultural drainage ditches: field monitoring and scenario-based modelling     

Brown CD  Dubus IG  Fogg P  Spirlet M  Gustin C 《Pest management science》2004,60(8):765-776

Field monitoring and scenario-based modelling were used to assess exposure of small ditches in the UK to the herbicide sulfosulfuron following transport via field drains. A site in central England on a high pH, clay soil was treated with sulfosulfuron, and concentrations were monitored in the single drain outfall and in the receiving ditch 1 km downstream. Drainflow in the nine months following application totalled 283 mm. Pesticide lost in the first 12.5 mm of flow was 99% of the total loading to drains (0.5% of applied). Significant dilution was observed in the receiving ditch and quantifiable residues were only detected in one sample (0.06 microg litre(-1)). The MACRO model was evaluated against the field data with minimal calibration. The parameterisation over-estimated the importance of macropore flow at the site. As a consequence, the maximum concentration in drainflow (2.3 microg litre(-1)) and the total loading to drains (0.76 g) were over-estimated by factors of 2.4 and 5, respectively. MACRO was then used to simulate long-term fate of the herbicide for each of 20 environmental scenarios. Resulting estimates for concentrations of sulfosulfuron in a receiving ditch were weighted according to the prevalence of each scenario to produce a probability distribution of daily exposure.  相似文献