« Prev Next »
Humans have been playing defense against viruses for much of history. Think about it, -people mainly take action against a virus once it has already become a threat. Just recently, researchers have switched tactics and taken the offensive. A team of scientists lead by Simon Anthony of Columbia University released a study this month in the journal mBio estimating the number of novel viruses in all mammalian species to be 320,000. Anthony and his colleagues' estimate of mammalian viruses is the first ever to be statistically supported. With this information scientists may discover potentially dangerous viruses before they transition from wildlife to humans.
To clarify, 320,000 viruses is a very rough estimate. The scientists assumed that every mammal carries 58 viruses based on their findings with flying foxes. The problem with this figure is that flying foxes, and bats in general, are virus friendly animals. The lifestyle factors that predispose bats to be good viral carriers are living in large communities, long distance travel and dispersal throughout the world. It is unlikely that the remaining 5,485 other mammals also carry exactly 58 viruses. Scientists are not sure by what factor the estimate could be off. Dr. Anthony explains "it is very likely that 320,000 viruses under-estimates the actual number of viruses, but we have no way of knowing by how much. It is for this very reason that we need to expand and repeat these systematic studies, and only then will we be able to refine our estimations with greater confidence."
This study is significant because it presents the first statistically supported estimate of mammalian viruses.
One purpose of cataloguing all mammalian viruses is to establish an "early warning system." Scientists could be on the lookout for viruses with the potential to bind to human cells. If one is identified, then it can be closely monitored in the hopes of nipping an outbreak in the bud. Just imagine what the world might be like now if HIV/AIDS was found before it morphed into a full-fledged epidemic. Some scientists have even begun to implement this new preventative method of tracking down the viruses. While studying the flying foxes, Dr. Anthony and his colleagues discovered a new virus known as GBV-D. It turns out that GBV-D is related to the virus causing hepatitis in humans. The scientists are now looking for signs of GBV-D in human populations near where the bats live. Evidence of GBV-D in people would suggest that the virus has jumped into the human population. Plans are also in the works to repeat the study performed on flying foxes using primates from Bangladesh and bats from Mexico.
Although the estimate is subject to change, it is an important step in preventative measures. Not only has it defined the number of viruses that exist, but it has also brought about a new method for early prevention. Really, the only major roadblock that stands in the way of cataloguing all mammalian viruses is funding. I personally have no doubt that funding will be granted eventually, especially after people realize the potential to save a lot of money and prevent a lot of human misery. As the old saying goes, in order to defeat your enemies one has to know them, and the first step to knowing a virus is finding it.
References:
Anthony, S. J. et al. A strategy to estimate unknown viral diversity in mammals. mBio, 5 (2013).
Healthfinder.gov. Scientists Tally Viruses Living in Mammals. (2013).
Morelle, R. "Mammals harbour 'at least 320,000 new viruses'." BBC News. September 2, 2013.
Simon Anthony. Personal communication.
Simthsonian.com. "A minimum of 320,000 viruses awaits discovery." Simthsonian.com. (September 3, 2013).
Yong, E. "How Many Mammalian Viruses?" The Scientist. September 3, 2013.
Images:
Ryan Poplin (via Wikimedia Commons).
Microbe World (via Flickr)