On the Origin of Brucellosis in Bison of Yellowstone National Park: A Review

Brucellosis caused by Brucella abortus occurs in the free-ranging bison ( Bison bison ) of Yellowstone and Wood Buffalo National Parks and in elk ( Cervus elaphus ) of the Greater Yellowstone Area. As a result of nationwide bovine brucellosis eradication programs, states and provinces proximate to the national parks are considered free of bovine brucellosis. Thus, increased attention has been focused on the wildlife within these areas as potential reservoirs for transmission to cattle. Because the national parks are mandated as natural areas, the question has been raised as to whether Brucella abortus is endogenous or exogenous to bison, particularly for Yellowstone National Park. We synthesized diverse lines of inquiry, including the evolutionary history of both bison and Brucella , wild animals as Brucella hosts, biochemical and genetic information, behavioral characteristics of host and organism, and area history to develop an evaluation of the question for the National Park Service. All lines of inquiry indicated that the organism was introduced to North America with cattle, and that the introduction into the Yellowstone bison probably was directly from cattle shortly before 1917. Fistulous withers of horses was a less likely possibility. Elk on winter feedgrounds south of Yellowstone National Park apparently acquired the disease directly from cattle. Bison presently using Grand Teton National Park probably acquired brucellosis from feedground elk.     

Comparison of data from two vegetation monitoring methods in semi-natural grasslands

Two vegetation-monitoring methods were compared: subplot frequency analysis (SF) and visual estimation of percentage cover (VE). Two independent observers collected data from two semi-natural, species-rich grasslands on three different occasions during the growth-season. During the last data collection period, survey times were also recorded. The two different data sets from the two methods were compared using partial Redundancy Analyses. The purpose of the comparison was to identify the method that explains most of the relevant variation in biodiversity-monitoring (inter-and intra-site variation), and the variation irrelevant when evaluating data (systematic inter-observer variation and variation due to phenological changes). Compared with VE data, more variation in SF data could be explained by spatial variables, while less variation depended on the observer and time of year surveyed. SF also found more species per plot but took on average five times longer to complete than VE. In conclusion, the different methods are suitable for different purposes: SF is more suitable for purposes demanding high accuracy and high precision, such as long-term biodiversity-monitoring when the identification of small changes has high priority, while VE might be more suitable for a one-time mapping of a large area.     

Seat belt use and fit among drivers aged 75 years and older in their own vehicles

Objective: This article aims to describe seat belt wearing patterns and quality of seat belt fit among drivers aged 75 years and older. A secondary aim is to explore associations between body shape, comfort, and seat belt use patterns.

Methods: This is an observation and survey study of a cohort of 380 drivers aged 75 years and over. During home visits, photographs were taken of the drivers in their vehicles for later analysis of belt fit and a short survey was also administered to collect demographic data and information about seat belt use and comfort. Seat belt fit and use of belt and seat accessories were analyzed from the photographs.

Results: Data from 367 participants with photographs were analyzed. Whereas 97% reported using a seat belt and 90% reported their seat belt to be comfortable, 21% reported repositioning their seat belt to improve comfort. Good sash and lap belt fit were achieved in 53 and 59% of participants, respectively, but only 35% achieved overall good fit. Both poor sash and lap belt fit were observed in 23% of participants. Drivers who were in the obese category had over twice the odds (95% confidence interval [CI], 1.2–4.1) of having a poor lap belt fit than those in the normal body mass index [BMI] range, and drivers who were overweight had 1.8 times the odds (95% CI, 1.1–2.9) of having poor lap belt fit. Older females also had twice the odds (95% CI, 1.3–3.5) of poor lap belt fit compared to older males, regardless of BMI. Sash belt fit did not vary significantly by BMI, stature, or gender. However older drivers who reported that they had not made any adjustments to the D-ring height had 1.7 times the odds of having poor sash belt fit than those who made adjustments (1.2–2.9). Females were 7.3 times more likely to report comfort problems than males (95% CI, 3.2, 16.3) but there was no association between reported comfort and BMI or seat belt fit. Drivers who reported comfort problems had 6 times the odds (3.2–13.6) of also reporting active repositioning of the belt.

Conclusions: The results suggest that older drivers face challenges in achieving comfortable and correct seat belt fit. This may have a negative impact on crash protection. Belt fit problems appear to be associated with body shape, particularly high BMI and gender. There is a need for further investigation of comfort accessories; in the interim, older drivers and occupants should be encouraged to use features such as D-ring adjusters to improve sash belt fit.