Studying Current 21st Century Patterns of a Spreading Pandemic

World map shows flight routes from the 40 largest U.S. airports.
Image: Christos Nicolaides, Juanes Research Group

Northwestern University developed a computational model, based on transportation data, that determines its source and how quickly a pandemic will spread to a specific location.

A pandemic refers to an epidemic of infectious disease that has spread across a large area or even in global proportions. It occurs when a strain of a virus appears that causes a readily transmissible disease for which most have no immunity. Influenza pandemics are the most common and occurs with little or no warning and infects a large area of population in multiple waves.

In 1918, The Spanish Flu Pandemic infected 500 million worldwide and killed 20 to 30 million. At the time, the death toll equates to about one to three percent of the world's population, making it one of the deadliest natural disasters in human history. The most recent pandemic was the 2009 H1N1 flu pandemic that killed about 300,000 people worldwide.

Recently, scientists are worried about the H5N1 virus, also known as the avian flu virus. Currently it only affects birds but studies have surfaced showing how this virus can be modified to infect mammals. They believe that if this virus carries over to humans, it may cause a pandemic that will overshadow the disaster brought about by the Spanish Flu Pandemic.

Scientists are studying how pandemics can spread worldwide and how this can be contained in the fastest and most effective way. With the advent of air travel and how fast one can travel from one point in the world to another, the dynamics of a spreading disease has changed from how it was centuries ago.

AAAS News: Letter on Resuming Avian Flu Transmission Research

At the start of 2012, the US National Science Advisory Board for Biosecurity recommended restricting the publication of results from research on H5N1 avian influenza virus. This was with regards to previous developments on the H5N1 virus leading to a discovery for the generation of the virus to be made transmissible to mammals.

The experiment involved ferrets who acquired the virus, previously almost exclusive only to birds, through respiratory droplets. There was concern that this discovery may lead to the virus affecting humans.

Based on rare cases of humans contracting H5N1, there is a 59% chance of mortality once the disease is contracted. To put this into perspective, the Spanish Flu in 1918 that killed an estimated 50 to 100 million people the world over, only had a mortality rate of just 2%.

The National Science Advisory Board for Biosecurity is a panel of the United States Department of Health and Human Services. It was decided by the panel that the research behind H5N1 poses a significant health and security threat. They recommended restricting the publication of results from research on H5N1 avian influenza virus, leading to the generation of viruses that are more transmissible in mammals.

In January 2012, influenza researchers from around the world announced a voluntary pause on any research involving H5N1 influenza viruses which may lead to it being more transmissible in mammals.

H5N1 Controversy One Year Later

Correspondence signed by 40 influenza virus researchers and jointly published in Science and Nature this week announces that the voluntary pause on certain types of H5N1 avian influenza research should end in countries where the aims of this moratorium have been met and authorities have reached decisions about how best to conduct such work safely.