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How City Planning Can Affect How Diseases Spread

There are many ways that city planning and urban design can mitigate, or exacerbate, the spread of public health risks.
Kayla Matthews | @KaylaEMatthews | June 10, 2018, 1pm PDT
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The 164 Cholera Map of London, by John Snow.
John Snow

Long before they had the data to prove it, doctors suspected city amenities, layouts, population counts, and sanitation measures impacted how diseases spread and, in turn, the severity of epidemics.

Numerous attempts at disease mapping failed, until 1864, when a physician named John Snow successfully mapped a cholera outbreak in London and forever changed how people in the public health sector approached epidemiology.

City planners must think about how to minimize the spread of disease and take that need as seriously as any other aspect of a well-managed city.

Sanitation Measures Are Essential

Statistics indicate about 4 billion people around the world live in urban areas, and that number is on the rise. As inhabitants increasingly cram into cities, potential infectious diseases could spread faster due to people living in close quarters.

People living in slums or other underdeveloped areas often don’t have appropriate access to water supplies and sewage systems. Plus, contaminated water harbors bacteria, putting people at higher risk for infections.

Problems get worse when contamination occurs at health care facilities. The Michigan Department of Health recently concluded the state’s McLaren Flint Hospital was primarily responsible for the spread of Legionnaires’ disease. Its report mentioned 94 percent of people with hospital exposures to the illness were associated with that facility.

“Legionella is a naturally occurring organism, so preventing the bacteria entirely is difficult,” says Brett Colburn, Legionella Control Consultant for Chardon Laboratories. “But there are many steps you can take to control the growth to prevent an outbreak of Legionnaire’s disease.”

“How a water system is designed is crucial to limit bacterial growth,” Colburn says. “Piping areas with little or no water flow (stagnation) become a big risk for Legionella, so designing piping to have consistent flow is important.”

“Having an effective biocide program also helps control bacterial growth,” he says. “Whether the city is using a chlorine disinfectant or any other kind of biocide, proper feed rates and dosages of these chemicals needs to be entered into the system, otherwise Legionella is likely to grow freely. Routinely testing and monitoring systems for dead piping/stagnation, chlorine and biocide levels, and keeping pipes corrosion-free are all great steps in controlling Legionella growth.”

Analysts recognize it is not always feasible to perform an overhaul of a city’s sanitation system, and especially not in a short time. And research shows 700 million people still lack access to safe water. Some suggest using an all-encompassing early warning system that alerts as many residents as possible following the discovery of potential issues.

Public Habits and Poorly Ventilated Areas Increase Contagion Exposure

People emit liquid droplets containing germs when they sneeze or cough. When they have a cold or flu, that ease of transmission makes those around them more likely to get sick.

That’s why health experts recommend people sneeze or cough into the creases of their elbows instead of covering their mouths with their hands. If individuals do the latter, they can easily transfer those droplets onto hard surfaces like doorknobs or telephones.

Unfortunately, a study of 154 people found only one individual took the recommended action of sneezing into their arm. Researchers say more often than not, people don’t take any preventive measures to stop their germs from going out into the open air.

An organization called ARCHIVE Global seeks to draw attention to how the ventilation in a building can affect disease spread, especially regarding tuberculosis and other respiratory-based infectious diseases.

During the height of the 2010 swine flu outbreak, researchers from Stanford University used wireless sensors to determine how often 788 people at a school came within 10 feet of each other, which is the distance at which infections can spread via sneezes and coughs. The researchers found in only one day, there were 762,868 instances of such close contact.

Cross-ventilation, which allows air to move entirely through a defined area, is one method that can prevent germs from lingering. Architects can also use techniques that take advantage of the fact that hot air rises.

Failing to Accommodate the Homeless Can Promote Diseases

A Hepatitis A outbreak in San Diego shed light on how it’s crucial to figure out how to reduce the homeless population during city planning efforts. Officials created the city’s first legal homeless camp and installed public toilets. However, if those facilities had been in place from the start, it might not have been necessary to take so many reactive measures.

Advocates for the homeless also bring up how a lack of housing can exacerbate mental health problems and other chronic issues. Vulnerable members of the community often do not have access to ongoing care for those problems and must go to their nearest emergency rooms, but usually only when the conditions are already out of control.

Supportive housing — which gives people places to live and helps them avail themselves of community services — could be integrated into city plans to reduce the size of the homeless population and ensure those with infectious or chronic illnesses do not wait too long to get treatment.

Designing Cities to Reduce Chronic Illness

It’s well-documented that people with sedentary lifestyles are at a higher-than-average risk of chronic ailments like obesity, heart disease and diabetes. Officials associated with European cities are aiming to design those destinations in ways that encourage people to walk or bike to get where they need to go, instead of relying on cars.

Data indicates 80 percent of Europeans will live in urban areas by 2030, meaning now is an excellent time to begin increasing the number of pedestrian paths, bike lanes, and other characteristics that encourage people to stay active.

Without those interventions, people will likely continue primarily using cars or public transportation, and neither of those options urges people to exercise.

Moreover, residents who cannot afford cars or bus fare may remain largely homebound. That could mean they don’t get lifesaving medications refilled on time and they suffer the mental and emotional distress caused by too much solitude, in addition to the issues associated with sedentary lifestyles.

Wellness Must Be a Constant Concern

History tells the tales of what can happen when people don’t have access to proper plumbing or other sanitation measures. The risk of issues goes up as areas become more populated, too. City planners cannot afford to overlook the well-being of current or future residents. Failing to keep it in mind — at least as much as is realistic based on resources — could prove fatal.

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