Influenza A Virus in Rodents

Rats and mice are living in our proximity and they are often closer than you might think. These rodents can get though the tiniest of openings to get to discarded food. Often their droppings are the only clue to their presence. Most people will regard a rat or a mouse as a pest that should be exterminated.

We know that rats can be the carrier of several deadly diseases, like the flea-borne bubonic plague that killed a third the population of Medieval Europe. A lesser known fact is that both rats and mice can become infected with the Influenza A Virus and the most troubling thing is that the virus doesn’t need to adapt itself before it infects these animals. Depending on the subtype of the Influenza A Virus, clinical signs of illness, included weight loss, ruffled fur and hunching.

Mice (Mus musculus)[1] and rats (Rattus norwegicus)[2] could contribute to avian influenza virus transmission on and among farms in a number of ways. They could contribute to viral spread by becoming infected via scavenging on infected poultry carcasses or by contact with contaminated water sources and subsequently transmitting virus if they are scavenged or predated. Mice are a very common prey species for a variety of carnivores, like cats.

Scientists[3] remain worried because the high concentrations of viral RNA detected in the lungs of experimentally infected house mice indicate that wild mice may have the potential to replicate sufficient virus for transmission to other species, humans among them.

[1] Gillim-Ross et al: Avian influenza H6 viruses productively infect and cause illness in mice and ferrets in Journal of Virology - 2008
[2] Shortridge et al: Characterization of avian H5N1 influenza viruses from poultry in Hong Kong in Virology - 1998
[3] Shriner et al: Low-Pathogenic Avian Influenza Viruses in Wild House Mice in PLoS One - 2012