The British science journal New Scientist reports that a scientist funded by the US government has deliberately created an extremely deadly form of mousepox, a relative of the smallpox virus, through genetic engineering. The new virus kills all mice even if they have been given antiviral drugs as well as a vaccine that would normally protect them. According to New Scientist the work has not stopped there.
But the research brings closer the prospect of pox viruses that cause only mild infections in humans being turned into diseases lethal even to people who have been vaccinated. And vaccines are currently our main defence against smallpox and its relatives, such as the monkeypox that reached the US this year.
Some researchers think the latest research is risky and unnecessary. “I have great concern about doing this in a pox virus that can cross species,” said Ian Ramshaw of the Australian National University in Canberra on being told of Buller’s work.
Ramshaw was a member of the team that accidentally discovered how to make mousepox more deadly (New Scientist, 13 January 2001, p 4). But the modified mousepox his team created was not as deadly as Buller’s.
Since then, Ramshaw told New Scientist, his team has also created more deadly forms of mousepox, and has used the same method to engineer a more deadly rabbitpox virus.
But this research revealed that the modified pox viruses are not contagious, he says. That is good news in the sense that these viruses could not cause ecological havoc by wiping out mouse or rabbit populations around the world if they escaped from a lab.
However, this discovery also means some bioterrorists might be more tempted to use the same trick to modify a pox virus that infects humans. Such a disease, like anthrax, would infect only those directly exposed to it.
It would not spread around the world and rebound on the attackers. But there is no guarantee that other pox viruses modified in a similar way would also be non-contagious. Ramshaw’s team made its initial discovery while developing contraceptive vaccines for sterilising mice and rabbits without killing them.