A geographic study of West Nile virus in humans, dead corvids and mosquitoes in Ontario using spatial scan statistics with a survival time application.

Surveillance of West Nile virus (WNv) in Ontario has included passive reporting of human cases and testing of trapped mosquitoes and dead birds found by the public. The dead bird surveillance programme was limited to testing within a public health unit (PHU) until a small number of birds test positive. These dead corvid and mosquito surveillance programmes have not been compared for their ability to provide early warning in geographic areas where human cases occur each year. Spatial scan statistics were applied to time-to-event survival data based on first cases of WNv in found dead corvids, mosquitoes and humans. Clusters identified using raw data were compared to clusters based on model-adjusted survival times to evaluate whether geographic and sociodemographic factors influenced their distribution. Statistically significant (p < .05) space-time clusters of PHUs with faster time to detection were found using each surveillance data stream. During 2002-2004, the corvid surveillance programme outperformed the mosquito programme in terms of time to WNv detection, while the clusters of first-positive mosquito pools were more spatially similar to first human cases. In 2006, a cluster of first-positive dead corvids was located in northern PHUs and preceded a cluster of early human cases that was identified after controlling for the influence of geographic region and sociodemographic profile.

AAGBI: Consent for anaesthesia 2017: Association of Anaesthetists of Great Britain and Ireland.

Previous guidelines on consent for anaesthesia were issued by the Association of Anaesthetists of Great Britain and Ireland in 1999 and revised in 2006. The following guidelines have been produced in response to the changing ethical and legal background against which anaesthetists, and also intensivists and pain specialists, currently work, while retaining the key principles of respect for patients' autonomy and the need to provide adequate information. The main points of difference between the relevant legal frameworks in England and Wales and Scotland, Northern Ireland and the Republic of Ireland are also highlighted.

Response to letter regarding article "How far north are migrant birds transporting the tick Ixodes scapularis in Canada? Insights from stable hydrogen isotope analyses of feathers".

In this letter we respond to correspondence and clarify the intent and importance of our article.

How far north are migrant birds transporting the tick Ixodes scapularis in Canada? Insights from stable hydrogen isotope analyses of feathers.

Lyme disease is emerging in Canada because of northward range expansion of the tick vector Ixodes scapularis. It is hypothesised that I. scapularis feeding on passerine birds migrating north in spring are important in founding new I. scapularis populations leading to northward range expansion. However, there are no studies on how far north I. scapularis may be carried, only inferences from passive tick surveillance. We used stable hydrogen isotope (δ(2)H) analysis of rectrices collected from northward migrating, I. scapularis-carrying, passerine birds captured in Canada to estimate how far north I. scapularis may be carried. Rectrices are usually grown close to breeding sites and their δ(2)H values reflect those in the environment, which vary strongly with latitude in North America. Passerines usually return to their breeding or natal sites so δ(2)H values of rectrices of northward migrating birds can identify the likely latitudinal bands of their intended destinations. In 2006 we analysed δ(2)H from rectrices of 73 I. scapularis-carrying birds captured at five migration monitoring stations, mainly from southern Ontario. Values of δ(2)H ranged from -33 to -124‰, suggesting 19/71 (26.7%) birds were destined for latitude band B (the most southerly part of Ontario), 40/71 (56.3%) birds were destined for band C (which extends from southern Ontario, Quebec and the Maritimes to southern James Bay) and 12/71 (16.9%) birds were destined for bands D and E (which extend from northern Ontario and Quebec into the southern Canadian Arctic). This indicates that many I. scapularis-carrying migratory birds in spring have destinations far north in Canada, including some farther north than the current region of climatic suitability for I. scapularis. These findings support the hypothesis that I. scapularis may continue to be spread north by spring migrating passerines. Some thrush species may be particularly implicated in far northward dispersion of I. scapularis.

Solving the Martian meteorite age conundrum using micro-baddeleyite and launch-generated zircon.

Invaluable records of planetary dynamics and evolution can be recovered from the geochemical systematics of single meteorites. However, the interpreted ages of the ejected igneous crust of Mars differ by up to four billion years, a conundrum due in part to the difficulty of using geochemistry alone to distinguish between the ages of formation and the ages of the impact events that launched debris towards Earth. Here we solve the conundrum by combining in situ electron-beam nanostructural analyses and U-Pb (uranium-lead) isotopic measurements of the resistant micromineral baddeleyite (ZrO2) and host igneous minerals in the highly shock-metamorphosed shergottite Northwest Africa 5298 (ref. 8), which is a basaltic Martian meteorite. We establish that the micro-baddeleyite grains pre-date the launch event because they are shocked, cogenetic with host igneous minerals, and preserve primary igneous growth zoning. The grains least affected by shock disturbance, and which are rich in radiogenic Pb, date the basalt crystallization near the Martian surface to 187 ± 33 million years before present. Primitive, non-radiogenic Pb isotope compositions of the host minerals, common to most shergottites, do not help us to date the meteorite, instead indicating a magma source region that was fractionated more than four billion years ago to form a persistent reservoir so far unique to Mars. Local impact melting during ejection from Mars less than 22 ± 2 million years ago caused the growth of unshocked, launch-generated zircon and the partial disturbance of baddeleyite dates. We can thus confirm the presence of ancient, non-convecting mantle beneath young volcanic Mars, place an upper bound on the interplanetary travel time of the ejected Martian crust, and validate a new approach to the geochronology of the inner Solar System.

Single-dose pharmacokinetics of oxytetracycline and penicillin G in tammar wallabies (Macropus eugenii).

The pharmacokinetics of oxytetracycline and penicillin G was investigated in tammar wallabies (Macropus eugenii). Groups of eight healthy tammar wallabies were administered i.v. oxytetracycline hydrochloride (40 mg/kg), i.m. long-acting-oxytetracycline (20 mg/kg), i.v. sodium penicillin G (30 mg/kg), or i.m. procaine/benzathine penicillin G (30 mg/kg). Plasma concentrations of oxytetracycline were determined using high-performance liquid chromatography. Pharmacokinetic parameters were comparable to those reported for eutherians of equivalent size and suggest that the practice of adjusting allometrically scaled doses to account for the lower metabolic rate of marsupials may not be valid. Long-acting oxytetracycline and penicillin G both demonstrated depot effects. However, the plasma concentrations achieved question the therapeutic efficacy of the long-acting preparations.

A. tumefaciens-mediated transient expression as a tool for antigen production for cucurbit yellow stunting disorder virus.

The emerging importance of criniviruses, together with their limited characterisation, necessitates the development of simple tools to enable rapid detection and monitoring in case of an outbreak. While serological tools would be ideal, criniviruses are notoriously difficult to purify and traditional methods of antibody production, requiring purified virus particles, are extremely challenging. The development of a novel molecular strategy for in planta viral antigen preparation to bypass particle purification and allow antibody production are described. An A. tumefaciens-mediated transient expression system, coupled with a green fluorescent protein (GFP) purification method was employed to generate CYSDV coat protein (CP) in whole plant leaves. The CYSDV CP gene was ligated into a GFP construct, transformed into A. tumefaciens and agroinfiltrated into N. benthamiana. Expression levels of the recombinant protein were increased by co-infiltration with the viral gene-silencing suppressor P19 from TBSV. The recombinant protein, purified from plant leaves was used to immunise rats for the preparation of polyclonal antisera.

Role of migratory birds in introduction and range expansion of Ixodes scapularis ticks and of Borrelia burgdorferi and Anaplasma phagocytophilum in Canada.

During the spring in 2005 and 2006, 39,095 northward-migrating land birds were captured at 12 bird observatories in eastern Canada to investigate the role of migratory birds in northward range expansion of Lyme borreliosis, human granulocytic anaplasmosis, and their tick vector, Ixodes scapularis. The prevalence of birds carrying I. scapularis ticks (mostly nymphs) was 0.35% (95% confidence interval [CI] = 0.30 to 0.42), but a nested study by experienced observers suggested a more realistic infestation prevalence of 2.2% (95% CI = 1.18 to 3.73). The mean infestation intensity was 1.66 per bird. Overall, 15.4% of I. scapularis nymphs (95% CI = 10.7 to 20.9) were PCR positive for Borrelia burgdorferi, but only 8% (95% CI = 3.8 to 15.1) were positive when excluding nymphs collected at Long Point, Ontario, where B. burgdorferi is endemic. A wide range of ospC and rrs-rrl intergenic spacer alleles of B. burgdorferi were identified in infected ticks, including those associated with disseminated Lyme disease and alleles that are rare in the northeastern United States. Overall, 1.4[corrected]% (95% CI = 0.3 [corrected] to 0.41) of I. scapularis nymphs were PCR positive for Anaplasma phagocytophilum. We estimate that migratory birds disperse 50 million to 175 million I. scapularis ticks across Canada each spring, implicating migratory birds as possibly significant in I. scapularis range expansion in Canada. However, infrequent larvae and the low infection prevalence in ticks carried by the birds raise questions as to how B. burgdorferi and A. phagocytophilum become endemic in any tick populations established by bird-transported ticks.

Awareness and memory function during paediatric anaesthesia.

BACKGROUND: Previous research indicates a much higher incidence of awareness during anaesthesia in children than in adults. The present study is the first large-scale, intraoperative assessment of awareness during paediatric anaesthesia using the isolated forearm technique, and the first large-scale study of memory function during paediatric anaesthesia. METHODS: One hundred and eighty-four children, 5-18 yr, underwent the isolated forearm technique during the first 17 min of surgery while receiving volatile anaesthesia. The isolated forearm technique was modified to accommodate brief or no paralysis. Bispectral index was monitored in a subset of 54 patients. Sixteen neutral words were played 20 times during surgery and, on recovery, implicit memory for these words was tested with a word identification task. Explicit memory for the surgical period was tested with a structured interview. Behavioural changes were assessed with age-appropriate questionnaires. RESULTS: No child had explicit recall of intraoperative events on recovery, and there was no evidence of implicit memory for words presented during anaesthesia. Two of 184 children made unambiguous and verified responses on the modified isolated forearm technique, an incidence of intraoperative awareness of 1.1%. One of these children reported that he was uncomfortable and not completely unconscious during surgery. Neither child had implicit memory for the neutral words, or adverse behaviour change. CONCLUSIONS: The incidence of awareness during surgery in children is approximately eight times that measured in adults by postoperative recall. In contrast to adults, there is no evidence for preserved memory priming during anaesthesia.

Faster, simpler, more-specific methods for improved molecular detection of Phytophthora ramorum in the field.

Phytophthora ramorum is the causal agent of sudden oak death. The pathogen also affects a wide range of tree, shrub, and herbaceous species in natural and landscaped environments as well as plants in the nursery industry. A TaqMan real-time PCR method for the detection of this pathogen in the field has been described previously; this paper describes the development of a number of assays based on this method which have various advantages for use in the field. A scorpion real-time PCR assay that is twice as fast as TaqMan was developed, allowing the detection of P. ramorum in less than 30 min. Also designed was a loop-mediated isothermal amplification (LAMP) assay, which allowed sensitive and specific detection of P. ramorum in 45 min using only a heated block. A positive reaction was identified by the detection of the LAMP product by color change visible to the naked eye.

A comparison of intubating conditions in children following induction of anaesthesia with propofol and suxamethonium or propofol and remifentanil.

Sixty ASA 1 and 2 children aged between 2 and 16 years who required tracheal intubation as part of anaesthesia for elective surgery were studied. We evaluated intubating conditions, haemodynamic responses and duration of apnoea following propofol 4 mg.kg-1 combined with either remifentanil 1.25 microg.kg-1 (group R), or suxamethonium 1 mg.kg-1 (group S). Tracheal intubation was graded as excellent, good or poor according to ease of laryngoscopy, vocal cord position, coughing, and jaw relaxation and limb movement. Thirty of group S and 28 of group R children were successfully intubated on the first attempt. Overall, intubation conditions were excellent or good in 26/30 (87%) patients in group S and 20/30 (67%) in group R (p<0.05). Mean apnoea time was 190 s in group S, and 362 s in group R (p<0.001). Heart rate increased in response to suxamethonium (p<0.01) and both systolic and diastolic blood pressure decreased in the remifentanil group (p<0.01).

Vector seasonality, host infection dynamics and fitness of pathogens transmitted by the tick Ixodes scapularis.

Fitness of tick-borne pathogens may be determined by the degree to which their infection dynamics in vertebrate hosts permits transmission cycles if infective and uninfected tick stages are active at different times of the year. To investigate this hypothesis we developed a simulation model that integrates the transmission pattern imposed by seasonally asynchronous nymphal and larval Ixodes scapularis ticks in northeastern North America, with a model of infection in white-footed mice (Peromyscus leucopus) reservoir hosts, using the bacteria Borrelia burgdorferi and Anaplasma phagocytophilum as examples. In simulations, survival of microparasites, their sensitivity to reduced rodent and tick abundance, and to 'dilution' by a reservoir-incompetent host depended on traits that allowed (i) highly efficient transmission from acutely-infected hosts, (ii) long-lived acute or 'carrier' host infections, and/or (iii) transmission amongst co-feeding ticks. Minimum values for transmission efficiency to ticks, and duration of host infectivity, necessary for microparasite persistence, were always higher when nymphal and larval ticks were seasonally asynchronous than when these instars were synchronous. Thus, traits influencing duration of host infectivity, transmission efficiency to ticks and co-feeding transmission are likely to be dominant determinants of fitness in I. scapularis-borne microparasites in northeastern North America due to abiotic forcings influencing I. scapularis seasonality.

Ixodes scapularis ticks collected by passive surveillance in Canada: analysis of geographic distribution and infection with Lyme borreliosis agent Borrelia burgdorferi.

Passive surveillance for the occurrence of the tick Ixodes scapularis Say (1821) and their infection with the Lyme borreliosis spirochaetes Borrelia burgdorferi s.l. has taken place in Canada since early 1990. Ticks have been submitted from members of the public, veterinarians, and medical practitioners to provincial, federal, and university laboratories for identification, and the data have been collated and B. burgdorferi detected at the National Microbiology Laboratory. The locations of collection of 2,319 submitted I. scapularis were mapped, and we investigated potential risk factors for I. scapularis occurrence (in Quebec as a case study) by using regression analysis and spatial statistics. Ticks were submitted from all provinces east of Alberta, most from areas where resident I. scapularis populations are unknown. Most were adult ticks and were collected in spring and autumn. In southern Québec, risk factors for tick occurrence were lower latitude and remote-sensed indices for land cover with woodland. B. burgdorferi infection, identified by conventional and molecular methods, was detected in 12.5% of 1,816 ticks, including 10.1% of the 256 ticks that were collected from humans and tested. Our study suggests that B. burgdorferi-infected I. scapularis can be found over a wide geographic range in Canada, although most may be adventitious ticks carried from endemic areas in the United States and Canada by migrating birds. The risk of Lyme borreliosis in Canada may therefore be mostly low but more geographically widespread than previously suspected.

Renal tubular-cell neoplasms in black-footed ferrets (Mustela nigripes)--38 cases.

Thirty-eight cases of renal tubular cell neoplasms were diagnosed in 184 captive, adult (>1-year-old), black-footed ferrets (Mustela nigripes) examined from 1985 to 1996. This prevalence (20.7%) is one of the highest reported for this neoplasm in a population of animals. These tumors rarely metastasized (1/38), and usually were incidental postmortem findings, associated clinical disease being present in only 3 (8%) of the 38 cases. The prevalence of renal tubular cell neoplasms found at postmortem examination increased linearly with age, up to 67% in ferrets >8 years old. Both males (prevalence = 19%) and females (prevalence = 24%) were affected. Multiple renal tumors were common, and seven ferrets (18.4% of affected animals) had bilateral tumors. The cause of this neoplastic syndrome could not be determined. Since most of the animals affected by this condition were in their postreproductive years of life, the impact of this neoplastic syndrome on the captive propagation of this species is negligible.

Investigation of ground level and remote-sensed data for habitat classification and prediction of survival of Ixodes scapularis in habitats of southeastern Canada.

In southeastern Canada, most populations of Ixodes scapularis Say, the Lyme disease vector, occur in Carolinian forests. Climate change projections suggest a northward range expansion of I. scapularis this century, but it is unclear whether more northerly habitats are suitable for I. scapularis survival. In this study, we assessed the suitability of woodlands of the Lower Great Lakes/St. Lawrence Plain region for I. scapularis by comparing tick egg survival in four different woodlands. Woodlands where I. scapularis are established, and sand dune where I. scapularis do not survive, served as positive and negative control sites, respectively. At two woodland sites, egg survival was the same as at the positive control site, but at two of the sites survival was significantly less than either the positive control site, or one of the other test sites. Egg survival in all woodland sites was significantly higher than in the sand dune site. Ground level habitat classification discriminated among woodlands in which tick survival differed. The likelihood that I. scapularis populations could persist in the different habitats, as deduced using a population model of I. scapularis, was significantly associated with variations in Landsat 7 ETM+ data (normalized difference vegetation index [NDVI] and Tasselled Cap indices). The NDVI index predicted habitat suitability at Long Point, Ontario, with high sensitivity but moderate specificity. Our study suggests that I. scapularis populations could establish in more northerly woodland types than those in which they currently exist. Suitable habitats may be detected by ground-level habitat classification, and remote-sensed data may assist this process.

Climate change and the potential for range expansion of the Lyme disease vector Ixodes scapularis in Canada.

We used an Ixodes scapularis population model to investigate potential northward spread of the tick associated with climate change. Annual degree-days >0 degrees C limits for I. scapularis establishment, obtained from tick population model simulations, were mapped using temperatures projected for the 2020s, 2050s and 2080s by two Global Climate Models (the Canadian CGCM2 and the UK HadCM3) for two greenhouse gas emission scenario enforcings 'A2'and 'B2' of the Intergovernmental Panel on Climate Change. Under scenario 'A2' using either climate model, the theoretical range for I. scapularis establishment moved northwards by approximately 200 km by the 2020s and 1000 km by the 2080s. Reductions in emissions (scenario 'B2') had little effect on projected range expansion up to the 2050s, but the range expansion projected to occur between the 2050s and 2080s was less than that under scenario 'A2'. When the tick population model was driven by projected annual temperature cycles (obtained using CGCM2 under scenario 'A2'), tick abundance almost doubled by the 2020s at the current northern limit of I. scapularis, suggesting that the threshold numbers of immigrating ticks needed to establish new populations will fall during the coming decades. The projected degrees of theoretical range expansion and increased tick survival by the 2020s, suggest that actual range expansion of I. scapularis may be detectable within the next two decades. Seasonal tick activity under climate change scenarios was consistent with maintenance of endemic cycles of the Lyme disease agent in newly established tick populations. The geographic range of I. scapularis-borne zoonoses may, therefore, expand significantly northwards as a consequence of climate change this century.

On-site DNA extraction and real-time PCR for detection of Phytophthora ramorum in the field.

Phytophthora ramorum is a recently described pathogen causing oak mortality (sudden oak death) in forests in coastal areas of California and southern Oregon and dieback and leaf blight in a range of tree, shrub, and herbaceous species in the United States and Europe. Due to the threat posed by this organism, stringent quarantine regulations are in place, which restrict the movement of a number of hosts. Fast and accurate diagnostic tests are required in order to characterize the distribution of P. ramorum, prevent its introduction into pathogen-free areas, and minimize its spread within affected areas. However, sending samples to a laboratory for testing can cause a substantial delay between sampling and diagnosis. A rapid and simple DNA extraction method was developed for use at the point of sampling and used to extract DNAs from symptomatic foliage and stems in the field. A sensitive and specific single-round real-time PCR (TaqMan) assay for P. ramorum was performed using a portable real-time PCR platform (Cepheid SmartCycler II), and a cost-effective method for stabilizing PCR reagents was developed to allow their storage and transportation at room temperature. To our knowledge, this is the first description of a method for DNA extraction and molecular testing for a plant pathogen carried out entirely in the field, independent of any laboratory facilities.

A dynamic population model to investigate effects of climate on geographic range and seasonality of the tick Ixodes scapularis.

A dynamic population model of Ixodes scapularis, the vector of a number of tick-borne zoonoses in North America, was developed to simulate effects of temperature on tick survival and seasonality. Tick development rates were modelled as temperature-dependent time delays, calculated using mean monthly normal temperature data from specific meteorological stations. Temperature also influenced host-finding success in the model. Using data from stations near endemic populations of I. scapularis, the model reached repeatable, stable, cyclical equilibria with seasonal activity of different instars being very close to that observed in the field. In simulations run using data from meteorological stations in central and eastern Canada, the maximum equilibrium numbers of ticks declined the further north was the station location, and simulated populations died out at more northerly stations. Tick die-out at northern latitudes was due to a steady increase in mortality of all life stages with decreasing temperature rather than a specific threshold event in phenology of one life stage. By linear regression we investigated mean annual numbers of degree-days >0 degrees C (DD>0 degrees C) as a readily mapped index of the temperature conditions at the meteorological stations providing temperature data for the model. Maximum numbers of ticks at equilibrium were strongly associated with the mean DD>0 degrees C (r2>0.96, P<0.001), when the Province of origin of the meteorological station was accounted for (Quebec>Ontario, beta=103, P<0.001). The intercepts of the regression models provided theoretical limits for the establishment of I. scapularis in Canada. Maps of these limits suggested that the range of southeast Canada where temperature conditions are currently suitable for the tick, is much wider than the existing distribution of I. scapularis, implying that there is potential for spread. Future applications of the model in investigating climate change effects on I. scapularis are discussed.

Use of quantitative molecular diagnostic assays to investigate fusarium dry rot in potato stocks and soil.

ABSTRACT Specific and sensitive quantitative diagnostics, based on real-time (TaqMan) polymerase chain reaction (PCR) and PCR enzyme-linked immunosorbent assay, were developed to detect dry-rot-causing Fusarium spp. (F. avenaceum, F. coeruleum, F. culmorum, and F. sulphureum). Each assay detected Fusarium spp. on potato seed stocks with equal efficiency. Four potato stocks, sampled over two seed generations from Scottish stores, were contaminated with F. avenaceum, F. sulphureum, F. culmorum, F. coeruleum or a combination of species, and there was a general trend towards increased Fusarium spp. contamination in the second generation of seed sampled. F. sulphureum and F. coeruleum caused significantly (P < 0.05) more disease in storage than the other species when disease-free tubers of potato cvs. Spunta and Morene were inoculated at a range of inoculum concentrations (0, 10(4), 10(5), and 10(6) conidia/ml). Increased DNA levels were correlated with increased disease severity between 8 and 12 weeks of storage. The threshold inoculum levels resulting in significant disease development on both cultivars were estimated to be 10(4) conidia/ml for F. sulphureum and 10(5) conidia/ml for F. coeruleum. To study the effect of soil infestation and harvest date on disease incidence, seed tubers of cvs. Morene and Spunta were planted in a field plot artificially infested with the four Fusarium spp. F. culmorum and F. sulphureum were detected in soil taken from these plots at harvest, and F. sulphureum DNA levels increased significantly (P < 0.05) at the final harvest. All four Fusarium spp. were detected in progeny tubers. There was a trend toward higher levels of F. culmorum detected in progeny tubers at the earliest harvest date, and higher levels of F. sulphureum at the final harvest. The use of diagnostic assays to detect fungal storage rot pathogens and implications for disease control strategies are discussed.