Air Travel and Disease: Airborne

Air travel has skyrocketed since the first commercial flight took off in 1914. Internationally there were almost 10 million flights last year alone1, carrying over 800 million passengers all over the world3. This massive flow of human traffic has facilitated an unprecedented level of global interconnectedness and made a huge impact on global health.

Health in a globalized world

The new accessibility of the planet has increased the reach of humanitarian relief organizations and scientists. The availability of flights spanning the globe has enhanced the ability of international health organizations, such as Doctors Without Borders and the Red Cross, to respond to health crises, offering on the ground emergency care. Outbreaks receive nearly immediate attention, both from public health officials and scientists. Samples can be shipped within hours, expediting the process of pathogen identification and vaccine development.

There is a downside to the ease of international transport. Like the ships of the great explorers, airplanes provide a means for disease transmission, both as sites for direct transmission and as vectors for foreign pathogens. However, while airplanes do offer a unique opportunity for people (and microbes) from around the world to mingle, they are relatively free from epidemics. In fact, the most common illness contracted on airplanes is food poisoning. A great deal of study and engineering has gone into the development of airplane ventilation and air filtration systems in an effort to reduce infectious disease spread. Unfortunately filters are not mandated on all airplanes, and some amount of transmission will remain despite our best efforts. Nonetheless, the risk of contracting something from a co-passenger is roughly the same as in other confined spaces2.

air travel
Think of this as a mosquito.

Touchdown

More worrying than on-flight transmission is what happens after the airplane lands. It has been speculated that several disease outbreaks, including West Nile Virus in the United States, can be traced back to air travel, either by infected passengers, animals, or insects. Insect vectors (insects that transmit a disease between human or animal hosts), such as mosquitoes, can be unwelcome stowaways on flights from warmer climes. This has led to a phenomenon called airport malaria, a rare occurrence when a traveler who has not been to an affected region gets sick with the disease2.

In a world growing smaller by the day, you may not even need to travel to risk exposure. Western cultural exportation may be spreading the mental illnesses of the West around the world. Mental illness, unlike physical illness, expresses itself in a way that is culturally acceptable. With the dissemination of a western view of mental illness and the Diagnostic and Statistical Manual of Mental Disorders (the DSM, a catalogue of mental illnesses), western illnesses have risen in occurrence globally. At the same time western illnesses are increasing, mental illnesses originating in other cultures are disappearing as they lose visibility4.

Air travel and the globalization that accompanies it has changed the face of global health, shifting the spread of diseases and they way we treat them. It gives us the ability to explore the four corners of the earth, but that opportunity has its risks. This tradeoff highlights one of the scariest realities of disease; its dangers are often hidden until it’s too late.

References

1. Flights, All Carriers-All Flights. Bureau of Transportation Statistics. Web. Accessed 30 September 2013. http://www.transtats.bts.gov/Data_Elements.aspx?Data=2

2. Mangili, A & MA Gendreau. (2005). Transmission of infectious diseases during commercial air travel. Lancet. 365:989-996.

3. Passengers, All Carriers-All Airports. Bureau of Transportation Statistics. Web. Accessed 30 September 2013. http://www.transtats.bts.gov/Data_Elements.aspx?Data=1

4. Watters, E. The Americanization of Mental Illness. The New York Times. 10 January 2010.

Image credit: Creative Commons, http://www.freestockphotos.biz/stockphoto/9260

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Suzi Claflin

I am a postdoctoral fellow studying chronic disease epidemiology.

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