Seasonal variation in spatial distribution and pathogen prevalence of Borrelia burgdorferi in blacklegged ticks (Ixodes scapularis) influences human population risk of Lyme disease in peri-urban built environments. Parks, gardens, playgrounds, school campuses and neighborhoods represent a significant risk for Lyme disease transmission. From June 2012 through May 2014, ticks were collected using 1 m2 corduroy cloths dragged over low-lying vegetation parallel to walkways with high human foot traffic. DNA was extracted from ticks, purified and presence of B. burgdorferi assessed by polymerase chain reaction amplification. Summer is reported as the time of highest risk for Lyme disease transmission in the United States and our results indicate a higher tick density of 26.0/1000 m2 in summer vs. 0.2/1000 m2 to 10.5/1000 m2 in spring and fall. However, our findings suggest that tick infection rate is proportionally higher during the fall and spring than summer (30.0–54.7% in fall and 36.8–65.6% in spring vs. 20.0–28.2% in summer). Seasonal variation in infected tick density has significant implications for Lyme disease transmission as people are less likely to be aware of ticks in built environments, and unaware of increased infection in ticks in spring and fall. These factors may lead to more tick bites resulting in Lyme infection.
There is a public perception that the white-tailed deer Odocoileus virginianus (Artiodactyla: Cervidae) is the main reservoir supporting the maintenance and spread of the causative agent of Lyme disease, Borrelia burgdorferi. This study examines the pathogen prevalence rate of Borrelia in adult Ixodes scapularis (Ixodida: Ixodidae), the black-legged tick, collected from white-tailed deer and compares it with pathogen prevalence rates in adult ticks gathered by dragging vegetation in two contiguous counties west of the Hudson Valley in upstate New York. In both Broome and Chenango Counties, attached and unattached ticks harvested from white-tailed deer had significantly lower prevalences of B. burgdorferi than those collected from vegetation. No attached ticks on deer (n = 148) in either county, and only 2.4 and 7.3% of unattached ticks (n = 389) in Broome and Chenango Counties, respectively, were harbouring the pathogen. This contrasts with the finding that 40.8% of ticks in Broome County and 46.8% of ticks in Chenango County collected from vegetation harboured the pathogen. These data suggest that a mechanism in white-tailed deer may aid in clearing the pathogen from attached deer ticks, although white-tailed deer do contribute to the spatial distribution of deer tick populations and also serve as deadend host breeding sites for ticks.
Objectives As daily environments change, behavior and activity also change and since blood pressure (BP) and heart rate (HR) are allostatically tied to these factors, one might expect that environments that elicit the greatest behavioral/activity variation should also evince the highest BP and HR variability (standard deviation (SD) or coefficient of variation (CV)). The purpose of this study was to evaluate this premise. Methods Two hundred and six women (age=37.6±9.1 years) wore an ambulatory BP monitor on a midweek workday. All worked in clerical, technical, or professional positions. Ambulatory BP and HR Means, SDs and CVs at work (11AM–3PM), home (approx. 6PM–10PM) and during sleep (approx. 10PM–6AM) were compared using repeated measures ANCOVA. Results Mean BP and HR decreased from work and home to sleep (121±11, 120±11 vs 107±12 systolic; 82±10, 80±11 vs 66±11 diastolic; 79±12, 80±12 vs 68±11 heart rate (all p<0.001)), while the CV of systolic and diastolic BP increased (0.06±0.02, 0.07±0.02 vs 0.08±0.03 systolic; 0.09±0.03, 0.10±0.04 vs 0.12±0.05 (p<0.001)). The HR SD decreased during sleep (8.1±3.8, 8.2±3.8 vs 6.9±3.2 (p<0.001)). Conclusions HR variability follows the expected variability pattern with behavior and activity, whereas BP does not.
Objectives The purpose of this study was to compare the daily inter- and intra-situational ambulatory blood pressure (BP) variation by ethnicity in women. Methods The African-American (N=82; Age=39.7+8.9), Hispanic-American (N=25; age=37.5+9.4), Asian-American (N=22; Age=35.2+8.6), and European-American (N=122; Age=37.2+ 9.4) women in this study all worked in similar positions at two major medical centers in NYC. Each wore an ambulatory monitor during the course of one mid-week workday. Proportional BP changes from work or home to sleep, intra-situational BP variation (standard deviation (SD)) and mean situational BP levels were compared among the groups using ANOVA models. Results African-American and Asian-American women had significantly smaller proportional work-sleep systolic changes than either European- (p<.05) or Hispanic-American (p<.05) women, but the Asian-American women’s changes tended to be smallest. The variability (SD) of diastolic BP at work was significantly greater among African- and Hispanic-American women compared to Asian- and European-American women (all p<.05). African-American women had greater sleep variability than European-American women (p<.05). Asian-American women had the highest level of sleep diastolic pressure (all comparisons p<.05). Conclusions African-American and Asian-American women have an attenuated proportional BP decline from waking environments to sleep compared to European-American and Hispanic-American women. Asian-American nocturnal BP may be elevated relative to all other groups.
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