2005年褐飞虱大暴发原因及其应对策略

对2005年褐飞虱Nilaparvata lugens Stal在浙江省仙居县大暴发的原因进行分析,认为害虫暴发主要由于以下几方面的因素而引起:(1)当时的气候很适宜于褐飞虱的繁育;(2)滥用农药、大量杀伤天敌和环境被严重破坏。为减轻褐飞虱的对水稻的危害,提出了相应的策略。     

Genome analysis of Campylobacter jejuni strains isolated from a waterborne outbreak

Background

Waterborne Campylobacter jejuni outbreaks are common in the Nordic countries, and PFGE (pulsed field gel electrophoresis) remains the genotyping method of choice in outbreak investigations. However, PFGE cannot assess the clonal relationship between isolates, leading to difficulties in molecular epidemiological investigations. Here, we explored the applicability of whole genome sequencing to outbreak investigation by re-analysing three C. jejuni strains (one isolated from water and two from patients) from an earlier resolved Finnish waterborne outbreak from the year 2000.

Results

One of the patient strains had the same PFGE profile, as well as an identical overall gene synteny and three polymorphisms in comparison with the water strain. However, the other patient isolate, which showed only minor differences in the PFGE pattern relative to the water strain, harboured several polymorphisms as well as rearrangements in the integrated element CJIE2. We reconstructed the genealogy of these strains with ClonalFrame including in the analysis four C. jejuni isolated from chicken in 2012 having the same PFGE profile and sequence type as the outbreak strains. The three outbreak strains exhibited a paraphyletic relationship, implying that the drinking water from 2000 was probably contaminated with at least two different, but related, C. jejuni strains.

Conclusions

Our results emphasize the capability of whole genome sequencing to unambiguously resolve the clonal relationship between isolates of C. jejuni in an outbreak situation and evaluate the diversity of the C. jejuni population.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-768) contains supplementary material, which is available to authorized users.     

Dengue in China: not a passing problem

<正>China is experiencing the most severe dengue outbreak since the 1980s.Till 31 October 2014,a total of 44497 laboratory-confirmed dengue cases with six deaths have been reported in mainland China,among which 43031 cases were from Guangdong.Although dengue fever is classified as a notifiable infectious disease according to Chinese Ministry of Health,the public and health care system has not fully     

主动监测培养对于控制院内MRSA感染的效果

目的探讨主动监测培养对于住院患者耐甲氧西林金黄色葡萄球菌（MRSA）感染控制情况的效果。方法统计沈阳军区总医院2011-2013年MRSA培养阳性率、感染率等相关数据,以6个月为单位,对实施主动监测培养前后各时间段情况进行比较。结果实施监测培养后MRSA培养阳性人数一度增加,由原平均每月不足10人,增至2012年下半年的平均约12人/月。后逐渐下降,2013年下半年降至约平均9人/月,与2012年上半年相比,差异有统计学意义（P〈0.05）。MRSA感染发病率在实施监测培养后呈下降趋势,由最初1.3‰-1.4‰降至2013年下半年的0.49‰,该数值与2013年上半年相比差异有统计学意义（P〈0.05）。抗MRSA抗生素使用量在引入监测培养后减少。2013年下半年用量降至约平均65支/月,与2013年上半年相比,差异有统计学意义（P〈0.05）。结论主动检测培养为院内原有MRSA感染检测的重要补充。若MRSA筛查培养阳性可早期采取相应干预手段,有效防止院内感染发生,促进了抗生素的合理应用。     

The medical and veterinary role of Ornithodoros erraticus complex ticks (Acari: Ixodida) on the Iberian Peninsula

Argasid ticks of the Ornithodoros erraticus complex are associated with traditional pig‐farming practices on the Iberian Peninsula and are also found elsewhere in North Africa, West Africa, and western Asia. The ticks associated with pig farming on the Iberian Peninsula are the only biological vectors of African swine fever virus (ASFV) known to occur in Europe, and their ecology makes them an extremely effective reservoir of both ASFV and the Borrelia species which cause tick‐borne relapsing fever (TBRF) in humans. The recent reappearance of ASFV in the European Union, coupled with evidence that Portuguese tick populations continue to harbor Borrelia despite a lack of confirmed human infections, suggest that these populations merit closer attention. In Portugal, a series of surveys over the last twenty‐five years indicates that the number of farm sites with tick infestations has declined and suggest that populations are sensitive to changes in farm management, particularly the use of modern pig housing. Various technologies have been suggested for the control of farm‐associated Ornithodoros ticks and related species but, in our opinion, farm management changes are still the most effective strategy for population control. Furthermore, we suggest that this species could probably be eradicated from Iberian pig farms.     

Local outbreaks of Operophtera brumata and Operophtera fagata cannot be explained by low vulnerability to pupal predation

• 1 One of the unresolved questions in studies on population dynamics of forest Lepidoptera is why some populations at times reach outbreak densities, whereas others never do. Resolving this question is especially challenging if populations of the same species in different areas or of closely‐related species in the same area are considered.
• 2 The present study focused on three closely‐related geometrid moth species, autumnal Epirrita autumnata, winter Operophtera brumata and northern winter moths Operophtera fagata, in southern Finland. There, winter and northern winter moth populations can reach outbreak densities, whereas autumnal moth densities stay relatively low.
• 3 We tested the hypothesis that a lower vulnerability to pupal predation may explain the observed differences in population dynamics. The results obtained do not support this hypothesis because pupal predation probabilities were not significantly different between the two genera within or without the Operophtera outbreak area or in years with or without a current Operophtera outbreak.
• 4 Overall, pupal predation was even higher in winter and northern winter moths than in autumnal moths. Differences in larval predation and parasitism, as well as in the reproductive capacities of the species, might be other candidates.

     

Effect of CO2 concentration on mosquito collection rate using odor‐baited suction traps

Carbon dioxide (CO₂) has been used for decades to enhance capture of host‐seeking mosquitoes when released in association with traps commonly used by mosquito and vector control agencies. However, there is little published work evaluating the effect of altering CO₂ release rates relative to the number of mosquitoes captured in these traps. This study investigated how varying CO₂ concentration altered the mosquito collection rate at a freshwater wetlands in southern California. Host‐seeking mosquitoes were captured in CDC‐style traps baited with one of six CO₂ release rates ranging from 0–1,495 ml/min from gas cylinders. Species captured were Aedes vexans, Anopheles franciscanus, An. hermsi, Culex erythrothorax, and Cx. tarsalis. A biting midge, Culicoides sonorensis, was also captured. For all species, increasing CO₂ release rates resulted in increasing numbers of individual females captured, with the relative magnitude of this increase associated to some extent with known feeding preferences of these species. We found that variation in CO₂ release rate can significantly alter mosquito capture rates, potentially leading to imprecise estimates of vector activity if the relationship of CO₂ release rate to mosquito capture rate is not considered.     

The influence of environmental management and animal shelters in vector control of Culicoides (Diptera,Ceratopogonidae) in northeastern Brazil

We investigated whether biting midges in peridomestic environments are affected by environmental management practices and the presence of domestic animals. We used CDC light traps to collect midges in 112 residences across 24 locations along tourism routes of Maranhão, Brazil. The collection areas were characterized as follows: i) peridomestic area with domestic animals and without management (dirty); ii) peridomestic with domestic animals and management (clean); iii) peridomestic without animals and with management (clean); iv) peridomestic without animals and without management (dirty). The first two treatments had higher biting midge species richness and abundance, respectively. Generalized linear models indicated a positive correlation between the presence of domestic animals and midge abundance, with an approximate four‐fold increase in Culicoides (Diptera: Ceratopogonidae) abundance in peridomestic areas with animals. The same model showed that domestic animals have no influence on richness. Environmental management does not appear to influence species richness or abundance of biting midges.     

A review on microbiological decontamination of fresh produce with nonthermal plasma

Food safety is a critical public health issue for consumers and the food industry because microbiological contamination of food causes considerable social and economic burdens on health care. Most foodborne illness comes from animal production, but as of the mid‐1990s in the United States and more recently in the European Union, the contribution of fresh produce to foodborne outbreaks has rapidly increased. Recent studies have suggested that sterilization with nonthermal plasma could be a viable alternative to the traditional methods for the decontamination of heat‐sensitive materials or food because this technique proves capable of eliminating micro‐organisms on surfaces without altering the substrate. In the last 10 years, researchers have used nonthermal plasma in a variety of food inoculated with many bacterial species. All of these experiments were conducted exclusively in a laboratory and, to our knowledge, this technique has not been used in an industrial setting. Thus, the purpose of this review is to understand whether this technology could be used at the industrial level. The latest researches using nonthermal plasma on fresh produce were analysed. These evaluations have focused on the log reduction of micro‐organisms and the treatment time.     

Ecological consequences of an unusual simultaneous masting of Araucaria araucana and Chusquea culeou in North‐West Patagonia,Argentina

A simultaneous masting of two abundant species in the temperate forests of North‐West Argentinean Patagonia occurred in 2013 for the first time ever recorded: the semelparous bamboo grass Chusquea culeou (colihue), dominating the understory, flowered and set seed across 1100 km² while pehuén (Araucaria araucana), an endemic conifer co‐dominating the tree layer had the highest regionally synchronized mast event in the last 30 years. Strong trophic effects were expected as a consequence of this extraordinary amount of seed, such as rodent outbreaks (ratadas) that followed previous Chusquea spp. mast events and included Oligoryzomys longicaudatus, the main reservoir of the Andes virus causing the Hantavirus Pulmonar Syndrome. From March 2013 to May 2014, we sampled relative abundance and activity of seed‐eaters and carnivores at four study sites with different proportions of both masting species. Surprisingly, total rodent capture rates never exceeded 14% in wild habitats and 8% in peridomestic areas showing low overall density in spite of some heavy O. longicaudatus males extending their reproductive activity into winter. Total abundance and relative proportion of granivorous birds peaked at the four sites in winter or spring, when they are usually scarce. Other surveyed organisms (native and exotic seed‐eaters, ungulates and carnivores) showed moderate responses at most, probably through aggregation from surrounding areas rather than reproduction. Seed removal from experimental seed stations varied in time and space though never peaked. The clearest pattern of community responses, though much subtler than expected, occurred at the site where colihue was abundant and pehuén scarce. This is the first systematic study that reports such a simultaneous double masting and our surveys revealed no widespread community consequences. We propose that either contingent events, such as an unprecedented drought, or permanent environmental features or contextual characteristics may explain the lack of a rodent outbreak in this area.