Like People, Diseases Travel Fast These Days

Coauthored by Sam Sternin

Like People, Diseases Travel Fast These Days

Since the 1918 flu pandemic that wiped out about five percent of the world’s population there have been strides toward eradicating most communicable diseases, yet the vulnerability of certain parts of the world affects everyone. 

On the 100th anniversary of the 1918 flu pandemic that killed 50 to 100 million people, the world still suffers some of the conditions that made the pandemic possible, even after a century of progress in medicine and public health.

In 1918 only one in ten people lived in cities, and the first transatlantic flight was still five years away. Yet issues like poor hygiene in hospitals, and undernourishment caused the flu to spread rapidly, and worldwide, killing approximately five percent of the global population. Today’s public health, immunization, and surveillance systems are stronger, but major gaps persist around the globe, and the world is both more urban and more interconnected than ever before.

A broader approach to urban resilience can better incorporate communicable disease control into ongoing investments to reduce the risk of urban epidemics and decrease the cost of containing them. With dedicated effort, there are approaches cities worldwide can take to improve outcomes for all.

While wealthy cities have contained most infectious diseases, they are still the leading causes of death in low-income countries, and continue to threaten major economic losses for all cities, rich and poor. Despite this, communicable diseases were not even mentioned once in the program of the most recent World Urban Forum. That’s pretty shocking in a century whose first 18 years have already featured major urban outbreaks of both familiar and new diseases--SARS and Yellow Fever, Zika and Cholera, Ebola and even the Plague. These outbreaks have cost billions of dollars and thousands of lives, and as cities are increasingly interconnected, the potential for international disruption is immense.

The public health world is working on a number of innovative tools to improve pandemic response, but these methods are not integrated with urban development and are mostly reactive, with little investment in prevention. There are, however, a number of promising interventions that could be integrated into existing resilience programs by ministries of urban development, mayors, city councils, urban planners, civic organizations, and urban philanthropists:

Water, sanitation, and solid waste management investments often aim to reduce the environmental impacts of poor water, sanitation and hygiene and solid waste management. But done right, these programs can have a major impact on public health, such as when Brazil’s Salvador, a city of 2.5 million, decreased diarrheal diseases by 22 percent, by improving sewer coverage. Where sewers are not practical (they are both water- and energy-intensive) there are non-piped alternatives, as illustrated by Durban’s trailblazing approach. For just 10 percent of the cost of the Ebola response, the Durban model could have covered the entire populations of Ebola-hit Conakry, Freetown, and Monrovia. Similarly, applying a communicable disease lens to solid waste management and drainage would lead to more emphasis on prioritized investments that target mosquitoes and rats in lower-income, higher risk zones.

Urban primary health services can reduce epidemics by reducing susceptibility through preventative services, including immunization. Yet, millions of people living in informal settlements and peri-urban areas lack access to basic care. In countries as diverse as Pakistan and Madagascar, the districts with the largest numbers of unvaccinated children are not rural or mountainous areas – they’re the primary and secondary cities. Increasing the coverage and quality of urban primary health care also builds trust in the public health system, an invaluable resource when confronting disease outbreaks. Potential solutions range from construction and staffing of clinics based on population (rather than administrative boundaries or legal status) and investing in (unglamourous) primary clinics instead of tertiary hospitals catering to local and international elites; use of outreach or mobile clinics in urban areas lacking fixed infrastructure; and strengthened partnerships with the formal and informal private health providers from which many urban residents receive care. These urban primary health investments also provide the platform for behavior change campaigns, aimed at both controlling communicable diseases and promoting other positive health, nutrition, and social behaviors.

Urban planning and architecture, or the lack thereof, influences the shape and structure of our cities, which influences disease transmission. Climate-focused resilience experts promote density to improve transit and walkability, and reduce environmental footprints. But millions of slum residents can testify what “density” means without associated investments in quality infrastructure and affordable housing: overcrowded homes, schools, and workplaces. Scientists linked the recent spread of tuberculosis in Cape Town to close contact in cramped and poorly ventilated minibuses, highlighting the potential contribution of transportation investments on reducing infectious disease transmission.

Monitoring and surveillance has the power to predict outbreaks for enhanced prevention. A Swedish computer model based on weather patterns accurately predicted a Dengue outbreak in 2011, but no systematic disease-surveillance programs were in place for the 2014 Ebola outbreak. Programs like Humanitarian OpenStreetMap and Dar Ramani Huria are mapping informal settlements, including the location of clinics. The growing field of digital epidemiology can leverage investments in big data—a common feature of the urban resilience agenda—for communicable disease early warning systems. Beyond early warning, more mayors need to have targets and indicators linked with communicable disease risk factors (water, sanitation, primary health coverage, disease vectors, etc.) in their management dashboards.

The examples above are not a comprehensive solution, but they’re a start. Additional analysis is needed to understand which interventions (or packages of measures) would be most cost-effective in different contexts. A stand-alone framework for control of communicable diseases in cities would be extremely costly: A more effective path is to integrate epidemic prevention into existing and future urban planning, management, budgets, programs, and strategies to avoid the next deadly pandemic.

Historically, hygiene was at the core of the urban agenda. The famous John Snow map of London’s Cholera outbreak is cited as the beginning of both epidemiology and urban design. It demonstrated that health is reliant on the built environment. The task of controlling communicable diseases cannot be left to the health sector alone: It requires action by urban development and management actors.

In the 21st century, truly resilient cities will be those that protect their citizens from both non-communicable and communicable diseases.

2022-02-09 (created sometime in 2018)