Germs on a Plane: The Transmission and Risks of Airplane-Borne Diseases




Sevilla, Nereyda Lucia

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Purpose: This dissertation explores the role of air travel in the spread of diseases, specifically the threat of pneumonic plague as a natural outbreak or after a bioterrorist attack. Introduction/Background: Air travel provides new means for diseases to spread internationally at unprecedented rates. This was evident in the 2003 Severe Acute Respiratory Syndrome (SARS) pandemic that killed over 800 people across 37 countries, the 2009 Influenza H1N1 epidemic which affected over 200 million individuals, and the 2014 Ebola outbreak that killed over 11,000 people. An aircraft has a role in disease spread both as a vector and incubator. Public health interventions including travel restrictions, entry and exit procedures, quarantine and isolation, and risk communication, are some of the current methods used to contain disease outbreaks. An outbreak of pneumonic plague, which has a high mortality rate, is spread from person to person, and is endemic to the United States, may challenge the effectiveness of these public health responses. Methods: This dissertation uses a mixed methods approach to evaluate the impact of aviation on the spread of infectious diseases and the effectiveness of different public health strategies. A compartment method of mathematical modeling is used to compare and contrast the spread of SARS, H1N1, and Ebola. In addition, hypothetical natural pneumonic plague outbreaks are modeled starting with 1 or 10 initial cases as well as bioterrorist attacks with Y. pestis that may infect 1, 10, 50, 100, or 1000 individuals to determine the potential spread over a six-month period. Results: All the graphical and numerical results indicate that SARS and H1N1 have a much greater impact in terms of infections and deaths than Ebola or pneumonic plague regardless of the initial number of infections. Modeling shows that the spread of pneumonic plague is minimal and should not be a major air travel concern if an individual becomes infected. Due to the rapid progression of pneumonic plague and the high likelihood of death, spread of the disease is highly unlikely to progress from the initial victims. Conclusion: This is the first type of research to compare, contrast, and model different diseases to determine the best scientific disease mitigation measures for the common air traveler. The threat of pneumonic plague is not from the disease, but from the potential psychological impact. To contain the outbreak of pneumonic plague, aviation and public health authorities should establish preventative infectious disease measures at airports, streamline contact procedures for ticketed passengers, expand the definition of “close contact,” and conduct widespread educational programs. The measures will put in place a foundation for containing any infectious disease and ensure that a natural or intentional pneumonic plague outbreak cannot be sustained.



Public health, Public policy, Air travel, Biodefense, Infectious diseases, Plague, Spatiotemporal Epidemiological Modeler, Travel health