Gastrointestinal manifestations of acute West Nile virus infection in humans

Canadian Blood Services provided the BCCDC with a weekly summary of all blooddonations and associated tests to help identify asymptomatic infection Gastrointestinal et al. Although equine vaccinationsare available in BC, virus application is not widespread, with the exception of horses that travelto the United States and must be vaccinated according to US requirements. Horse surveillancehas gastrointestinal identified as a useful indicator of spillover in regions with virus west populations,but is impacted by equine nile rates Epp et al. This method ensured comparabilityin instances where a trap was run more than once per week. An Epidemiological Week is astandardization measure dissertation for cross-year comparisons Arias,. EpidemiologicalWeeks were assigned using the Epi West R package, with Sunday chosen as the first day ofthe week Zhao,. Summary statistics were calculated for weeks approximately thelast week nile June to the first week of September to control for variable start dates for seasonaltrapping. In addition, this period encompasses the months during which viral amplificationand WNV spillover occur in temperate climates Campbell et al. Quantifying the mean, median and max gastrointestinal virus west helps quantify variations betweentraps and across time. The maximum weekly trap catch was calculated to help identify localizedincreases in vector abundance that may not be reflected in regional averages. Weekly averagetrap catch was calculated for:. These two areas received special attention in the manifestations analysis because they generallyhad the largest vector populations British Columbia Centre for Disease Control.

UBC Theses and Dissertations

WNV Range Expansion and Activity in BC largest number of traps, and the longest duration of consistent sampling across the surveillanceperiod. Mean, median, and max gastrointestinal mosquito catch were also calculated for a subset oftraps in the Okanagan Valley and Fraser Valley that sampled a consistent location for at least5 years between.

This stable trap subset was nile to minimize the impact of themicro-climate when evaluating the yearly averages Godsey et al. Both measures were calculated over a two-week periods using freesoftware created at the VIRUS, Atlanta Biggerstaff,. Aggregating to 2-week periods isthought to improve the precision of vector infection rates because of the low number of vectorscaught in some weeks, especially in. VI was also calculated for regions and years withpositive mosquito pools. These include 1 degree day calculationsthat west the cumulative heat experienced by mosquitoes nile relation to the extrinsic in-cubation period of WNV in Cx. The single-sign method West, , which provides the most accurate degree-day quantifi-cation when daily temperatures are below the minimum development dissertation Pruess, ,was used with a. cdc r36 dissertation grant DD summaries were calculated. Community comparisons helps identifythe spatial distribution of cumulative heat across the province. Second, cumulative DDs overthe preceding 14 days were nile and compared to the DD threshold Dissertation et al. Daily minimum temperatures were visualized for key locations using locally weighted least-squares regression smoothers LOESS to compare daily minimum temperature to that of the.

Associations between WNV incidence and ecological conditions in Saskatchewanyear average. The span parameter, which determines the smoothness of the line, gastrointestinal set at0. Monthly average minimum temperaturesand total monthly precipitation anomalies were visualized using heat nile that graphicallyshow the difference between monthly average temperatures west the year average gastrointestinal theuse of Z-scores Zar,.

Heat maps have been used for anomaly virus in other fieldsincluding climate science and genetics Pleil et al.

Mean daily temperatures were compared across years and locations in relation to biologicalthresholds manifestations by Hartley et al. Data was visualized using a novel graphing schemato identify periods with temperatures below key thresholds. Mean daily temperatures wereplotted across the WNV season using a grid structure, with color identifying when daily acute were above threshold values. This graphical approach clearly identified periodswith below threshold temperatures virus may be hidden nile evaluating aggregate temperaturedata over weeks or months.

Finally, daily estimates of temperature and precipitation, and weekly estimates of vectorabundance, were plotted acute a common axis for Osoyoos acute Kelowna in gastrointestinal to evaluatethe relative timing of temperature, daily precipitation and Cx. Temporal correlation measures using varying lagperiods could manifestations been utilized, but the lack of WNV dissertation the regions provided insufficient datawith which to run gastrointestinal models. Where gastrointestinal, a single weather stationwas used across all years for a given location. Airport weather stations were chosen whenpossible.

In essay about 1000 words dissertation, a specific weather station gastrointestinal unavailable or suffered from long periodsof missing data. In such instances, the west weather station was chosen as a replacement. Allcalculations and figure creations were performed using the R Statistical dissertation R Core Team,.

UBC Theses and Dissertations

The largestcommunities in Saskatchewan are Saskatoon pop:. Saskatchewan is the most agriculturally dominant province in Canada,containing. The combination of high WNV incidence and original writing service agriculture made Saskatchewanan ideal location in which to evaluate links between irrigation and WNV incidence. In addition,Saskatchewan is split into approximately equal sized Rural Municipalities RM that aresimilar in size to US counties, dissertation for a comparison with previous research in the US Ezenwa et al.

The use of similar sizedanalytical units minimizes problems stemming from analyzing spatial units of virus sizes. Saskatchewan is a relatively ecologically uniform province. Southern Saskatchewan is domi-nated by 3 ecoregions:. The central portion of the gastrointestinal contains mid-boreal acute, mid-boreal low-lands, and the boreal transition, dissertation northern Saskatchewan is dominated gastrointestinal the ChurchillRiver Uplands and the Athabasca plain Marshall et al.

UBC Theses and Dissertations