“It does look like a gargantuan powder keg for infectious disease."
That’s how one health official describes the situation in Lagos, Nigeria, Africa’s largest city, where new infections of the Ebola virus have recently been detected. “[Lagos] is massive—21 million people with a massive population density,” says Dr. J. Stephen Morrison from the Global Health Policy Center at the Center for Strategic and International Studies.
Nigeria’s coastal metropolis has a much different geography from the rural settings in which past Ebola crises have played out. Never before has a megacity like Lagos played host to the virus. Keeping potentially infected individuals isolated and under surveillance—vital during an outbreak—is nearly impossible. It’s feared that living conditions in crowded areas without the benefit of reliable sanitation could help spread the disease at rapid pace (click here for an interactive map that shows how Ebola has spread).
A similar situation once unfolded in a U.S. metropolis—New York City. And that the lessons we learned from reining in that epidemic could offer some guidance for Lagos. Over a 14-year span during the 1980s and early 1990s, New York City battled its own pandemic of infectious disease: tuberculosis. According to The New England Journal of Medicine, the number of TB patients in NYC over the course of those years nearly tripled. By 1991, the city's infections accounted for 61 percent of all TB cases in America—despite the fact that NYC represented only 4 percent of the country’s population at the time. Several strains of the disease even became drug resistant, hindering the ability of health workers to treat the infected. Ultimately, the epidemic cost the city over $1 billion.
How did a modern megacity like New York become paralyzed by an illness found most commonly in the developing world? It infiltrated through holes in the city’s most vulnerable communities. According to the same report from The New England Journal of Medicine, minorities, the poor, and people living with HIV/AIDS were most susceptible to contracting TB during the outbreak. In central Harlem, where 41 percent of residents were living below the poverty line in 1980, there were 222 TB cases per 100,000 residents. According to the World Health Organization, that’s a higher prevalence than rates found in present-day Haiti, Afghanistan, and Sudan. Thirty-three percent of TB carriers in NYC in 1993 were already battling HIV/AIDS. Those with the fewest resources were the most susceptible to contracting and spreading the disease.
There are differences, of course, in the transmission of these diseases. TB is an airborne disease, while Ebola is contracted through person-to-person contact. Nonetheless, there's an important lesson to be drawn from New York’s experience with TB: Make it a priority to protect low-income areas and people whose immune systems are already compromised.
“If [the Ebola virus] does trickle down to a population that sleeps three to a bed, it’s likely to spread much quicker,” says Dr. Dan Bausch of Tulane University, a tropical disease specialist that recently returned from West Africa. Right now, almost every individual infected or suspected of infection in Lagos has been a hospital worker. That’s a good thing, says Bausch: Those people are likely to be middle-class workers with formal housing who can be easily isolated. It’s estimated, however, that 70 percent of Lagos residents live in slums, packed into small spaces. If Ebola hits these communities, the scenario becomes much more problematic, Bausch says. “This is when the issue of population density does come into play. Then you have a really bad situation.”
To mitigate this risk, Lagos needs to double down on preventative health measures for low-income populations. In the midst of New York’s crisis, the city increased TB funding tenfold, from $4 million in 1988 to $40 million by 1994. That funding supported TB screening for the homeless and expanded single-person housing for those infected with HIV. Two new clinics and 300 additional health practitioners were also put on the city’s payroll to specifically treat the disease.
Nigeria’s megacity is facing a unique situation and a distinctly separate disease from the one that struck New York. But a crucial parallel can be drawn: Resources must be expanded for those most vulnerable to infection. Hopefully, it can happen more quickly in Lagos than it did in New York.