Image courtesy of the CDC via Wikimedia Commons.
The spread of infectious disease is a subject of intense paranoia whenever it hits, and 2014’s Ebola outbreak is no exception.
This fear of disease and subsequent paranoia around air travel are tied, as airplanes have aided the spread of the hemorrhagic fever Ebola, creating a combined tension point around travel and health risk.
But are these fears justified? As it turns out, while the risks of flight-powered intercontinental contagion exist, on-board transmission is surprisingly infrequent. But that doesn’t mean that the consequences of infrequent mishaps can’t be dire.
Ebola on the wings
According to a technical report (pdf) by the European Centre for Disease Prevention and Control (ECDC) assessing the risk of infectious disease by aircraft, the increasing passage of millions of people by air globally and on-board conditions give rise to new threats of infection.
- On June 26, 2014, Ebola – a dangerous fever that kills nearly half of those infected – was brought by plane from Liberia to Lagos, Nigeria, Africa’s largest city with a population of over 21 million.
- In August, several infected U.S. missionaries were flown to Atlanta for treatment — both recovered and were released.
- On September 20th, the first man diagnosed with Ebola outside of Africa was diagnosed after flying from Liberia to Texas. The man, who has since died, also infected two American healthcare workers.
- One of the infected nurses took a plane before her diagnosis; no other passengers appear to have been infected.
- A Spanish nurse was diagnosed in Madrid after flying from Liberia, and fully recovered on October 19. No one on her flight has been reported as infected.
The fact that any infected person could board an international flight without notice is a cause for understandable discomfort: with symptoms similar to other diseases, and a silent incubation period of 2 – 21 days, no amount of health screening is fool-proof.
Already having claimed about 4,493 lives across West Africa in the largest known outbreak, Ebola has spread from Guinea to Sierra Leone and Liberia before turning up in Senegal and Nigeria (it’s been eliminated in the latter two).
Spread beyond Africa
Disease has spread by air before: In 2003, SARS traveled from southern China to Hong Kong, an air hub from which it then spread it to Vietnam and Thailand, then Canada and the United States followed by a spattering of European countries. 8,000 were infected.
But there are some key differences that make Ebola unlikely spread widely in other nations, infectious disease specialist Kamran Khan told NPR.
Ebola requires very close and long exposure between blood or body fluid to transfer, whereas SARS can be spread by a cough or sneeze — and even that infected a low rate of .8% of passengers identified as contacts.
So even if infected persons make it to the U.S. and other countries, they (for the most part) will be safely isolated, with the chance of contagion low.
Catching infection by plane is no more common than catching it on ground, the ECDC says. In fact, according to the World Health Organization (WHO), ventilation systems on airplanes recirculate and filter air similarly to hospitals, actively preventing such spread.
The real trouble is not international contagion, or planes in general: air travel is safer than ever in spite of a recent anomaly of incident. The greater issue is Ebola’s spread in African communities, which are lacking in resources and have poor understanding of the epidemic, hindering treatment.
That aside, just as the rest of the world should be equipped to handle rare crises like plane accidents, it doesn’t bode well that many hospitals, African, American, and otherwise, are ill-prepared to handle a large influx of patients should the improbable become a reality.