A new study finds that the design of cities has public health implications in the way it influences residents’ travel habits and in turn affects their risk of exposure to infectious diseases like influenza and COVID-19.
Noel Brizuela, a graduate student at Scripps Institution of Oceanography at the University of California San Diego, and colleagues find that the spatial distribution of commerce, worksites, and schools can strongly influence the spread of flu-like diseases.
In particular, the agglomeration of economic activities causes the risk of contagion to be unevenly distributed within any metropolitan area. The chances of someone getting a flu-like disease can change because of where they live, said Brizuela, with those living closer to city centers risking greater exposure. Urban designers implementing mixed-use zoning policies should enable people to work and shop close to home instead of having everyone commute to a central economic hub, Brizuela said.
“Many older, medium-sized European cities allow people to work and shop near to home, partly because they were built when people had to commute by foot,” said Brizuela. “Downtowns with big skyscrapers are the complete opposite, because a single building can hold economic opportunities for hundreds or thousands of people and this ultimately funnels people from all across the city into a single place.”
To study spatial patterns in the spread of disease, Brizuela and co-authors used census and economic data for Guadalajara, Mexico to infer the mobility habits of residents in each neighborhood. They compared it with hospitalization data collected during the 2009 H1N1 influenza pandemic. This allowed the researchers to resolve neighborhood-level features smaller in spatial scale than city or county data that epidemiologists typically use.
“Neighborhood-scale differences in infection rates like the ones we predict won’t show up in most datasets,” said Brizuela. Advances in tracking technology have helped observe fine-scale patterns in the spread of COVID-19, but Brizuela points out that “the theoretical foundations needed to understand such datasets have yet to be settled.”
“In this case, we borrowed concepts from statistical physics to incorporate people's daily commutes into our disease transmission scheme,” he said. Based on this approach, Brizuela and collaborators propose that despite their apparent similarities, cities of equal size can face vastly different challenges during an infectious outbreak. “At the end of the day, cities are incredibly complex ecosystems, and they're as much a part of Earth as forests, deserts or oceans are; they just happened to be shaped by centuries of human decisions.”
The research, supported by CONACYT, the Mexican Council for Science and Technology, appears Jan. 13 in the journal Proceedings of the Royal Society A. Besides Brizuela, researchers from Universidad de Guadalajara and Georgia State University contributed to the study.
About Scripps Oceanography
Scripps Institution of Oceanography at the University of California San Diego is one of the world’s most important centers for global earth science research and education. In its second century of discovery, Scripps scientists work to understand and protect the planet, and investigate our oceans, Earth, and atmosphere to find solutions to our greatest environmental challenges. Scripps offers unparalleled education and training for the next generation of scientific and environmental leaders through its undergraduate, master’s and doctoral programs. The institution also operates a fleet of four oceanographic research vessels, and is home to Birch Aquarium at Scripps, the public exploration center that welcomes 500,000 visitors each year.
About UC San Diego
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