In recent decades, the ability—and correspondingly, the propensity—of people to travel long distances quickly has increased dramatically; more than one billion people are transported by plane every year (Pavia 2007). Humans can traverse the globe in hours, and so can their pathogenic hosts. While humans have changed how we move around the Earth, viruses infect us in the same way, and with the same effectiveness, as they always have. This presents us with the unsettling possibility that deadly diseases can be transported all over the globe using human hosts as vectors, spreading rapidly, and causing huge disease outbreaks. Since there are no plans to reverse our travelling technology, and we cannot rid the world of viruses, what are we supposed to do about this problem?
First, we need to understand where viruses come from, and how they spread. And while their mechanisms of transmission are varied and complex (Baron et al. 1996), many recent massive disease outbreaks have arisen from a specific problem: cross-species transmission. The Zika virus, HIV, and the Dengue virus can be attributed to primate-human transmission (Pike et al. 2012), while SARS, H1N1, H5N, Chicken Pox, and Cow Pox—all diseases caused by viruses—result from prolonged human exposure to livestock (Graham and Baric 2010). Viruses are crafty, they sometimes mutate in such a way that allows them to infect more than one species. When that other species is humans, the prolonged, unhygienic contact with animals that is typical in less economically developed countries (LEDCs) can have devastating consequences (Parrish et al. 2008). This phenomenon, known as disease emergence, can be addressed. Removing viral vectors in rural communities, keeping livestock healthy and clean, and providing basic hygiene in very poor areas will help to prevent disease emergence. Unfortunately, this problem will never entirely disappear, since there is always a chance that a well-adapted (mutated) virus will change species, and hosts.
However, just because we cannot bring the evolution of viruses to a halt, does not mean that the human race will inevitably be destroyed by an epidemic. In fact, there are a number of relatively simple steps we can take that will allow us to limit the spread of viruses. Firstly, great advances are being made in disease detection. Rather than relying upon traditional culturing methods, new, rapid diagnostic assays can analyze blood samples from suspected virus hosts, and quickly determine whether or not that person is infected. These assays may be handheld, and able to detect evidence of infection in less than 15 minutes (they do this by detecting proteins and other macromolecules associated with viruses in order to make a diagnosis). These tests are not perfect, but they are more convenient (sometimes hand-held), faster, and cheaper than traditional methods, and are constantly improving (Peruski P and Peruski A 2003). Technology like this may allow us to prevent the spread of disease simply by refusing passage to infected persons.
Finally, there is one relatively easy solution to many of the problems posed by virus transmission on airplanes: basic hygiene. Standardizing hand-washing, and high efficiency particulate air (HEPA) filters (air filters used on planes that trap tiny particles), should reduce the risk of germ transmission for passengers. Additionally, if aircraft companies would standardize better cleaning procedures on their aircraft, hygiene risks could be avoided. In a personal interview with a former flight attendant, a member of our team learned about some disturbing, unhygienic standard practice in the air-transport industry. On some airlines, pillows and blankets are re-used throughout the day by different people (without being cleaned); employees are often discouraged and dissuaded from using hand-sanitizer and rubber gloves, and often come to work sick; and there are major risks of cross-contamination of surfaces due to using the same cleaning equipment for different parts of the plane (2016 personal interview with SP).
In conclusion, viruses are cunning and crafty: constantly adapting, and impossible to control completely. This, in combination with the ability for people to traverse long distances by using modern air travel, can result in the rapid spread of viral disease. It is a difficult, complicated problem, but there are steps we can take to mitigate the risk of disease outbreaks. By identifying and eliminating unhygienic contact with animals, improving disease-detection technology, and standardizing basic hygiene on aircraft, we may be able to prevent future epidemics and pandemics.