Airlines and airports could play a significant role in detecting and containing a potential outbreak of pneumonic plague linked to a lab technician’s death in Russia, drawing on public-health measures developed during previous outbreaks of SARS, Ebola and Covid-19.
The possibility comes after the reported death of a worker at the Irkutsk Antiplague Research Institute of Siberia and the Far East. Russian authorities have provided limited information about what happened. The case has nevertheless renewed attention on systems that use commercial aviation not only as a potential route for disease transmission but also as a means of identifying emerging outbreaks.
David O. Freedman, a professor emeritus at the University of Alabama at Birmingham who helped establish a global network for monitoring infectious diseases among travellers, said airlines now form an important informal layer of disease surveillance. He recalled an incident in which a visibly ill passenger was removed from a flight after a flight attendant alerted the pilot. “Basically, the pilot took one look at this sweating patient and said, ‘you look like hell, and you’re out of here,’” Freedman said.
Flight crews are not expected to diagnose illnesses. Instead, they can conduct what public-health officials call passive surveillance by watching for passengers showing obvious signs of sickness. Other measures have expanded since successive international outbreaks, including projects to test aircraft wastewater for emerging pathogens and plans for air sampling at major international airport hubs.
US authorities have also used restrictions on air travel and entry during outbreaks. In April, 18 American passengers who had been aboard a Dutch cruise ship affected by a deadly Andes hantavirus outbreak were placed under a 42-day quarantine. Some completed the isolation at the University of Nebraska Medical Center.
The Trump administration subsequently restricted entry by foreigners and certain non-citizens who had recently travelled to the Democratic Republic of Congo during an Ebola outbreak. Two months later, it barred American citizens returning from Congo from travelling directly to the United States by air until they had first spent 21 days in a third country. Such measures are known as “Do Not Board” orders.
Certain American citizens and US nationals travelling from Uganda or South Sudan within the previous 21 days were also required to arrive through US airports equipped with public-health entry screening. The 21-day period corresponds to the maximum incubation period for Ebola. The travel restrictions remain in effect and are renewed every 30 days.
There are no direct flights between Russia and the United States because of sanctions and the suspension of services following Russia’s 2022 invasion of Ukraine. Travellers can, however, legally reach the US through hubs including Istanbul. If the reported Russian plague case develops into a wider outbreak, Freedman said the United States could consider “Do Not Board” orders for people who had recently travelled to affected areas of Russia.
Plague presents a particular surveillance challenge but also has one characteristic that could help containment. Asymptomatic transmission is considered rare. “Plague is not contagious until somebody is very, very sick and obviously sick,” Freedman said.
Aircraft wastewater surveillance has expanded since Covid-19. The US Centers for Disease Control and Prevention began a pilot programme at New York’s John F. Kennedy International Airport in 2022, sampling some international flights, and later extended the programme to several domestic airports. The existing systems, however, are not designed specifically to detect plague.
Researchers from Qantas and the University of Queensland have proposed a global genomic surveillance system using aircraft wastewater as an early-warning mechanism for future pandemics. But Vicki Hertzberg, founding director of the Center for Data Science at Emory University, warned that wastewater surveillance could lag behind a rapidly spreading infection.
“It will tell you something, but it may be too late,” Hertzberg said. “If they flew from Kazakhstan to Atlanta and then to Austin — by the time they figure it out, who knows where you are?” She said aviation precautions could improve safety, but passengers remained vulnerable during prolonged close contact. “If you’re sitting next to someone on a long flight and they have something, you’re still in big trouble.”
