'If you look sick, you're not boarding': Russia plague fears put aviation health screening to the test

Workers spray disinfectant inside an Asiana Airlines aircraft at Incheon Airport in South Korea in 2021. [Getty Images]

Just before takeoff, infectious disease expert David Freedman noticed something alarming a few rows ahead: a man drenched in sweat, visibly ill. Whether it was the flu, COVID-19 or something worse, Freedman could not tell. A flight attendant spoke briefly with the passenger, then returned with the captain. The captain decided the man was too sick to fly.

"The captain took one look at this sweaty patient and said, 'You're in no condition to fly — you need to get off,'" Freedman recalled. An emeritus professor at the University of Alabama at Birmingham, Freedman helped build a global network for tracking infectious diseases among travelers.

The scene illustrates how US authorities rely on airlines as an informal first line of defense against infectious disease outbreaks, the Washington Post reported Wednesday (local time). That system has grown steadily stronger through successive global health crises — SARS, Ebola and COVID-19.

Now it faces a new test. The death of a laboratory technician at a plague research institute in Russia, possibly linked to pneumonic plague, has put the world on edge.

Russian authorities have said little about what exactly happened to the worker at the Siberia and Far East Plague Research Institute in Irkutsk. But after COVID-19, the idea that a single rare illness in a remote region could escalate into a global catastrophe no longer sounds far-fetched.

Aviation health screening has not always worked perfectly. Yet the global air network's dual role — as both a conduit for disease and an early-warning system — makes it increasingly important. "We're much better than we used to be at responding to rare events that could be the harbinger of a large outbreak," Freedman said.

Flight crews do not diagnose illness. Instead, they practice what is known as passive surveillance — watching for passengers who appear unwell. Alongside that, a project is underway to screen aircraft wastewater for emerging disease threats, and plans are being developed to sample air at major international airport hubs. The United States also retains the authority to restrict or deny entry on public health grounds.

A passenger wearing a mask stows luggage in an overhead bin before a flight. [123RF]

The United States has already shown it will act. In April, after a deadly Andes hantavirus outbreak aboard a Dutch cruise ship, US authorities ordered 42 days of quarantine for 18 American passengers who had been on board — far exceeding the post-exposure guidelines for most infectious diseases. Some completed their quarantine at the University of Nebraska Medical Center.

A month later, in May, the Donald Trump administration barred foreign nationals and some non-citizens who had recently traveled to the Democratic Republic of Congo, where Ebola was spreading, from entering the United States. Two months after that, it took the unusual step of restricting flights for American citizens returning from Congo, requiring them to spend 21 days in a third country before boarding. The measure is known as a "Do Not Board" order.

Some US citizens and nationals who had departed Uganda or South Sudan within 21 days were required to enter the United States only through airports equipped with public health quarantine facilities. The 21-day window reflects the maximum incubation period for Ebola, a highly lethal hemorrhagic fever. The travel restrictions are renewed every 30 days and remain in effect.

Freedman said that if Russia's suspected case were to grow into a larger outbreak, US authorities could issue "Do Not Board" orders targeting recent travelers from specific regions of Russia.

There is at least one reassuring aspect of plague, however. Most infections do not spread silently. "Plague doesn't transmit until someone is very, very visibly ill," Freedman said.

The US Centers for Disease Control and Prevention has expanded aircraft wastewater testing since the COVID-19 pandemic. It launched a pilot program on select international flights at New York's John F. Kennedy International Airport in 2022 and has since extended it to several domestic airports. The system, however, is not yet designed to detect plague.

A research team from Australia's Qantas Airways and the University of Queensland has proposed a global genomic surveillance system using aircraft wastewater — designed, they say, "to provide early warning of future pandemics." The team also developed a device to collect samples more easily without clogging pipes, moving away from the old method of "holding a bucket under the waste truck."

But researchers caution that the approach may have limits when it comes to fast-moving pathogens. Vicki Hertzberg, founding director of the Center for Data Science at Emory University, who has studied disease transmission aboard aircraft, said wastewater testing could yield useful information — but perhaps too late. "You might learn something from wastewater, but by the time you get results, if someone flew from Kazakhstan through Atlanta to Austin, who knows where they are?" she said.

mokiya@heraldcorp.com