Bat flu genes pose low risk

Bats are well-known carriers of human viruses, such as rabies and the headline-grabbing Ebola. But could they be harbouring other infections too? Researchers recently discovered flu virus-like genes in bats raising concerns that these nocturnal creatures might carry flu viruses, and could transmit them to people. Fortunately, a new study from US researchers published in the journal PloS Pathogens suggests that bats may be in the clear for now. Because they couldn't find any trace of live flu virus particles in the animals, the researchers looked at the flu-like genes in depth, to find out if they came from active, infectious viruses or were merely relics of defunct ancestors.

Next, they synthesised the entire DNA of one of the bat viruses, called Bat09, and put it into human cells growing in the lab. Surprisingly, the virus DNA led to the creation of flu-like virus particles, but these were unable to infect any other types of cells, including human, dog, monkey, pig or bats themselves. This is because the virus DNA doesn't encode crucial proteins in the virus coat that enables it to get into cells. And the scientists think that the bat viruses are unlikely to be able to pick up this ability by recombining with other flu viruses inside bats, due to genetic incompatibility. So for now we only have to worry about rabies and ebola...