scholarly journals Meteorological and climatic variables predict the phenology of Ixodes ricinus nymphs activity in France, accounting for habitat heterogeneity

2021 ◽  
Author(s):  
Phrutsamon Wongnak ◽  
Maude Jacquot ◽  
Séverine Bord ◽  
Albert Agoulon ◽  
Frédéric Beugnet ◽  
...  
Keyword(s):  
Lyme Borreliosis ◽  
Ixodes Ricinus ◽  
Negative Binomial ◽  
Negative Binomial Regression ◽  
Habitat Characteristics ◽  
Average Temperature ◽  
Minimum Relative Humidity ◽  
Questing Activity ◽  
Ixodes Ricinus Ticks ◽  
Exposure Risks

Abstract Ixodes ricinus ticks (Acari: Ixodidae) are the most important vector for Lyme borreliosis in Europe. As environmental and climate changes might affect the distribution and activity of tick populations, this study aimed to determine the effects of environmental factors, i.e., meteorological, bioclimatic, and habitat characteristics on questing activity of I. ricinus nymphs across diverse climatic types in France over an 8-year period. Questing activity was observed using a repeated removal sampling design with a cloth-dragging technique in 11 sampling sites from 7 tick observatories from 2014 to 2021 at approximately 1-month intervals, involving 631 sampling campaigns. Three phenological patterns were observed, potentially following a climatic gradient. The mixed-effects negative binomial regression revealed that observed nymph counts were driven by different interval-average meteorological variables, including one-month average temperature, previous-season average temperature, and half-year average minimum relative humidity. The interaction effects indicated that the phenology in colder climates peaked differently from that of warmer climates. Also, the land cover characteristics that support the highest baseline abundance were moderate forest fragmentation with transition borders with agricultural areas. Finally, our model could potentially be used to predict seasonal human-tick exposure risks in France that could contribute to mitigating Lyme borreliosis risks.

scholarly journals Variable Strength of Forest Stand Attributes and Weather Conditions on the Questing Activity of Ixodes ricinus Ticks over Years in Managed Forests

PLoS ONE ◽  
2013 ◽  
Vol 8 (1) ◽  
pp. e55365 ◽  
Author(s):  
Ralf Lauterbach ◽  
Konstans Wells ◽  
Robert B. O'Hara ◽  
Elisabeth K. V. Kalko ◽  
Swen C. Renner
Keyword(s):  
Ixodes Ricinus ◽  
Weather Conditions ◽  
Forest Stand ◽  
Managed Forests ◽  
Variable Strength ◽  
Questing Activity ◽  
Ixodes Ricinus Ticks ◽  
Stand Attributes

Effect of environmental conditions on injury rates at a Colorado ski resort

2019 ◽  
Vol 26 (4) ◽  
pp. 324-329
Author(s):  
Lauren A Pierpoint ◽  
Zachary Y Kerr ◽  
Gary Grunwald ◽  
Morteza Khodaee ◽  
Tessa Crume ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Negative Binomial ◽  
Injury Rate ◽  
Negative Binomial Regression ◽  
Injury Rates ◽  
Ski Resort ◽  
Average Temperature ◽  
Binomial Regression ◽  
Rate Ratios ◽  
Packed Powder

ObjectiveTo determine the effect of daily environmental conditions on skiing and snowboarding-related injury rates.MethodsInjury information was collected from a mountainside clinic at a large Colorado ski resort for the 2012/2013 through 2016/2017 seasons. Daily environmental conditions including snowfall, snow base depth, temperature, open terrain and participant visits were obtained from historical resort records. Snowpack and visibility information were obtained for the 2013/2014 through 2014/2015 seasons and included in a subanalysis. Negative binomial regression was used to estimate injury rate ratios (IRRs) and 95% CIs.ResultsThe overall injury rate among skiers and snowboarders was 1.37 per 1000 participant visits during 2012/2013 through 2016/2017. After adjustment for other environmental covariates, injury rates were 22% higher (IRR=1.22, 95% CI 1.14 to 1.29) on days with <2.5 compared with ≥2.5 cm of snowfall, and 14% higher on days with average temperature in the highest quartile (≥−3.1°C) compared with the lowest (<−10.6°C; IRR=1.14, 95% CI 1.03 to 1.26). Rates decreased by 8% for every 25 cm increase in snow base depth (IRR=0.92, 95% CI 0.88 to 0.95). In a subanalysis of the 2013/2014 and 2014/2015 seasons including the same covariates plus snowpack and visibility, only snowpack remained significantly associated with injury rates. Rates were 71% higher on hardpack compared with powder days (IRR=1.71, 95% CI 1.18 to 2.49) and 36% higher on packed powder compared with powder days (IRR 1.36, 95% CI 1.12 to 1.64).ConclusionsEnvironmental conditions, particularly snowfall and snowpack, have a significant impact on injury rates. Injury prevention efforts should consider environmental factors to decrease injury rates in skiers and snowboarders.

scholarly journals Prevalence of Borrelia burgdorferi Sensu Lato and Anaplasmataceae Members in Ixodes ricinus Ticks in Alsace, a Focus of Lyme Borreliosis Endemicity in France

2006 ◽  
Vol 72 (4) ◽  
pp. 3074-3078 ◽  
Author(s):  
Elisabeth Ferquel ◽  
Martine Garnier ◽  
Jérôme Marie ◽  
Claire Bernède-Bauduin ◽  
Guy Baranton ◽  
...  
Keyword(s):  
Borrelia Burgdorferi ◽  
Lyme Borreliosis ◽  
Ixodes Ricinus ◽  
Disease Incidence ◽  
Borrelia Burgdorferi Sensu Lato ◽  
Borrelia Garinii ◽  
Peak Density ◽  
Tick Infection ◽  
Ixodes Ricinus Ticks ◽  
Northeastern France

ABSTRACT Due to the high Lyme borreliosis incidence in Alsace, in northeastern France, we investigated in 2003-2004 three cantons in this region in order to determine the density of Ixodes ricinus ticks infected by Borrelia burgdorferi sensu lato and Anaplasmataceae. The peak density of nymphs infected by B. burgdorferi sensu lato at Munster and Guebwiller, where the disease incidence was high, was among the highest reported in Europe (105 and 114 per 100 m2, respectively). In contrast, the peak density of infected nymphs was low in the canton of Dannemarie (5/100 m2), where the disease incidence was low. The two main species detected in ticks were Borrelia afzelii, more frequent in nymphs, and Borrelia garinii, more frequent in adult ticks. The rates of tick infection by Anaplasma phagocytophilum were 0.4% and 1.2% in nymphs and adults, respectively.

A Density Map of the Tick-Borne Encephalitis and Lyme Borreliosis Vector Ixodes ricinus (Acari: Ixodidae) for Germany

2016 ◽  
Vol 53 (6) ◽  
pp. 1292-1302 ◽  
Author(s):  
Katharina Brugger ◽  
Denise Boehnke ◽  
Trevor Petney ◽  
Gerhard Dobler ◽  
Martin Pfeffer ◽  
...  
Keyword(s):  
High Resolution ◽  
Ixodes Ricinus ◽  
Negative Binomial ◽  
Regional Scale ◽  
Negative Binomial Regression ◽  
Information Criterion ◽  
Public Health Issue ◽  
Bioclimatic Variables ◽  
Density Map ◽  
Mean Square Errors

Abstract The castor bean tick Ixodes ricinus (L.) is the principal vector for a variety of viral, bacterial, and protozoan pathogens causing a growing public-health issue over the past decades. However, a national density map of I. ricinus is still missing. Here, I. ricinus nymphs in Germany were investigated by compiling a high-resolution map depicting the mean annually accumulated nymphal density, as observed by monthly flagging an area of 100 m2. Input data comprise ticks collected at 69 sampling sites. The model domain covers an area of about 357,000 km2 (regional scale). Two negative binomial regression models were fitted to the data to interpolate the tick densities to unsampled locations using bioclimatic variables and land cover, which were selected according to their significance by the Akaike information criterion (AIC). The default model was fitted to the complete dataset resulting in AIC = 842. An optimized model resulted in a significantly better value of AIC = 732. Tick densities are very low in urban (green) areas. Maximum annual densities up to 1,000 nymphs per 100 m2 are observed in broad-leaved forests. The tick maps were verified by leave-one-out cross-validation. Root mean square errors of RMSE = 137 and RMSE = 126 nymphs per 100 m2 were estimated for the two models, respectively. These errors are of the order of the interannual variation of the tick densities. The compilation of a high-resolution density map of unfed nymphal I. ricinus for Germany provides a novel, nationwide insight into the distribution of an important disease vector.

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