Editing Serial passage (section)

===Influenza===
The [[H5N1]] virus is a particularly lethal strain of [[influenza]]. Currently, it can infect humans, but it is not [[contagious disease|contagious]] between humans. Still, over 600 people worldwide are known to have died from animal-transmitted H5N1 virus,<ref name="zimmer" /> so the transmissibility of the virus is of major concern to scientists.

Several serial passage experiments have been conducted to determine the feasibility of the virus becoming transmissible in humans. In particular, Ron Fouchier and his colleagues did a 10-step serial passage experiment in ferrets.<ref name="zimmer" /> In doing so, they created a strain of influenza that not only infected ferrets, but was transmissible between ferrets.<ref name="zimmer" /> Notably, this strain was very similar to the original strain with which they had infected the first ferret—in other words, only a few mutations were necessary for the virus to become transmissible between ferrets.<ref name="zimmer" /><ref name="puiu">{{Cite web |date=3 May 2012 |title=H5N1 controversial paper shows that bird flu is only a genetic mutation away from mammal flu. |url=http://www.zmescience.com/research/h5n1-bird-flu-paper-genetic-mutation-human-transmission-05032/ |access-date=26 April 2014 |website=ZME Science |vauthors=Puiu T}}</ref>  Similarly, researcher Yoshihiro Kawaoka found that a single mutation is necessary to make the virus transmissible in ferrets.<ref name="puiu" />

Both Fouchier's research and Kawaoka's research were initially censored, per implications for [[bioterrorism]].<ref name="puiu" /> The research was later published, but remained controversial.<ref name="puiu" />

Serial passage is an artificial technique that is used in a laboratory setting, rather than a natural process.  Accordingly, the likelihood that the H5N1 virus would actually mutate to become transmissible in humans is unknown; however, researcher Derek Smith created an evolutionary model to show that this is possible.<ref name="zimmer" />