THE “CONTAGION” SCENARIO
The movie ‘Contagion’, released this September and October, showed an alarming sequence of events in which a Western business woman visits China, acquires a virus at a restaurant, and dies a horrible death after spreading the virus to friends and family. The GVN published a press re-lease on this movie at (http://www.marketwatch.com/story/the-contagion-scenario-fact-or-fiction-2011-09-09). A Chilean journalist, Marcelo Cordova, came to the GVN with the following questions which were answered as follows:
1. How high is the threat from a new virus to man kind? Are labs around the world ready to deal with this threat?
The question of new virus threats is not if they can occur, but when they will occur. The possibility of a new virus causing a worldwide epidemic is high and many of the first deaths would be among health care workers and physicians who are trying to respond. Imagine the early days of HIV in central Africa where so many people died that entire countries were on the verge of being destabilized. The GVN has been formed to help prepare for such an event.
2. According to the CDC, scientists discover a new infectious disease every year. Is there any estimation about how many viruses are found each year? In your opinion: Which are the most dangerous threats right now in terms of new viruses?
New virus discovery is a tribute to advances in biomedicine and tells us that the viral world is much larger and more diverse than we imagined before. If we knew which viruses are the greatest threats, we would have strategies to stop them. However, it is false to assume that only unknown viruses pose threats to mankind. The most infectious virus ever known is probably measles virus (3-5 times more contagious than the virus described in this movie) and it remains a deadly killer of children. When people choose to stop vaccination against measles, they increase the odds of a new measles epidemic which would be terrifying beyond what most of us can imagine.
- Several universities have teams of virus hunters who travel the world searching for new threats. Which is the usual procedure with a new virus: to inform all the labs in the world or study it first to decode things like genome? Is it accurate to say Africa and Asia are the most common birth places for new viruses?
Crowding and close human contact with animal viruses are common incubators of new outbreaks. Virus hunting is much like fossil hunting. Finding a fragment of something might cause a press release but rarely makes a significant difference in our understanding or ability to exploit the information. Understanding the relationships between viruses and disease is the crucial question. There are many human viruses which infect nearly everyone in the population but never cause disease. Unless you can establish the disease link, all you will do is continue to discover the great abundance of non-threatening viruses.
4. In the movie, the deadly virus is a combination of influenza and a virus called Nipah, which causes inflammation of the brain and respiratory disease. Is it true that influenza and Nipah have incompatible genomes that are not capable of recombination in nature? Is it true that currently there is no effective treatment for Nipah?
Nipah virus was probably selected for the movie because it is highly contagious among pigs. It cannot recombine with influenza and acute encephalitis of Nipah has been treated with ribavirin.
5. The virus in the movie is so transmissible it spreads to new locations around the globe within days. Is this a regular propagation rate for a new virus? Which are the main factors behind the propagation of a new virus?
Measles is even more transmissible than the virus depicted in the movie, so it has an even faster propagation rate, though it is not as lethal. Virus spread is determined by the route for infection, virus stability in the environment and number of virus particles in an infectious dose. Viruses spread by the aerosol route like influenza and measles, tend to be most contagious. Influenza virus has medium stability in the environment and the number of particles in a dose (one sneeze for example) is very high.
6. As the disease rages on, quick work by scientists leads to a vaccine being developed within about four months. Is this a realistic scenario?
Normally it is unrealistic to produce a vaccine in 4 months. In an emergency, it could be done but there would be many deaths and other problems from vaccination in addition to the epidemic virus itself.
7. The fictional virus reaches humans through a series of animal encounters: a bat eats some fruit then drops it in a pig pen, the pig eats it, then is butchered and handled by a chef who comes in contact with Gwenyth Paltrow. Would you agree that poor disease surveillance in animals and bad animal health care capacities in Africa, Asia and other developing countries deserve much more investment?
Most viruses that cause disease in animals will not cause disease in humans. The ability to cause animal disease means the virus has a specific advantage in that species. The main worry is that a virus silent in animals will cause disease in humans. Consequently, animal health surveillance is important, for food quality and animal husbandry, but not so critical for new viruses.
8. From that same perspective: What more should be done to prevent pandemics?
Prevention of pandemics requires a clear recognition of the prob-lem at the earliest possible time, with appropriate steps toward diagnosis, containment and development of treatments or vac-cines.
- What would be the reaction of an organization like GVN if a "Contagion"-like virus arises in the world?
GVN enters the problem when a new virus (or a familiar virus causing a new outbreak) is beyond the normal capacity of surveillance and public health organizations. GVN is a storehouse of virology experts ready to address complex problems in understanding virus disease and designing treatments of vaccines. We work in the gap between virus surveillance and public health implementation. Our international membership, global coverage with Centers of Excellence in Virology and rapid communications network are key to GVN playing a crucial role in converting a potential epidemic into a manageable public health problem.
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