School Notes: School of Public Health
March/April 2010

Lyme disease spread by birds

The range of Lyme disease is spreading in North America, and it appears that birds play a significant role by transporting the Lyme disease bacterium over long distances, a new study by the Yale School of Public Health has found. Researchers analyzed published records and concluded that at least 70 species of North American birds are susceptible to infection by black-legged ticks, the principal vector of the Lyme disease bacterium. The evidence also suggests that these bird species are dispersing infected ticks into areas previously free of the disease, such as Canada. What remains to be seen is whether the bacterium that can infect birds can also cause disease in humans. If so, the role of birds in the epidemiology of Lyme disease could be profound. “Birds are often overlooked in Lyme disease studies,” said Robert Brinkerhoff, a postdoctoral student in Maria A. Diuk-Wasser’s lab, “but they may be playing a key role in its rapid expansion.”

Current soda taxes not enough to curb obesity

Current state taxes and levies on soft drinks are slowing consumption and resulting in slimmer waistlines, but the effect is generally small in magnitude. Jason Fletcher, an assistant professor at the Yale School of Public Health, analyzed the effectiveness of various forms of soda taxation on body mass index (BMI) over a 16-year period and found that an individual’s weight does respond to changes in taxation—a 1 percent tax increase resulted in a BMI decrease of 0.003 points, which is less than a tenth of a pound for a man of average height. “Our results suggest that the current low, hidden rates of soft-drink taxation in most states are not effective in substantially changing adult consumption,” Fletcher said. One reason that soda taxation may have limited results on BMI is that there are so many alternative beverages with similar calorie content available to consumers.

Stemming chronic disease in New Haven

In the second stage of a long-term effort to reverse worsening rates of chronic disease in New Haven, residents of six city neighborhoods have been surveyed about their current health and health habits in a program spearheaded by CARE: Community Alliance for Research and Engagement at Yale. CARE is part of the Yale Center for Clinical Investigation. Approximately 1,400 adults in the city’s Dixwell, West River/Dwight, Fair Haven, Hill North, Newhallville, and West Rock neighborhoods were interviewed last fall about their health issues, diet, exercise, tobacco use, access to health care, and neighborhood environment. The information gathered is being combined with data from health maps completed last summer of the same six neighborhoods, and the findings will be used to develop policy proposals and health programs to curb the onset of chronic disease.