Mice across the Northeast appear to be winning their long war with the poisons meant to kill them, according to a new study reported by Eyewitness News. Researchers at Rutgers University found that the rodents have genetically changed and evolved to survive common poisons, a development with clear implications for the region's notorious rat and mouse problem.
The research drew on populations from several major cities. Rutgers examined mice from New York City, Washington D.C., New Jersey and Philadelphia to see how widespread the changes had become across the corridor.
The scale of the finding surprised the researchers. They found that about 70 percent of the mice populations contain mutations, and that the poison simply is not killing them anymore, a much higher mutation frequency than had been assumed before.
The explanation lies in basic natural selection. Some mice and rats that happened to be resistant to the poison lived to see another day, and those survivors then bred, producing offspring that were also poison resistant, locking the trait into the population.
The pace of the change has also drawn attention. Researchers say the mice have been mutating quickly for about five years, a speed that they suggest may not be entirely random and that has prompted closer study of what is driving it.
One factor they point to is a shift in where food waste ends up. As people ordered more takeout, more food garbage moved outside of homes rather than into restaurants, the researchers note, scattering mice and exposing them to more poisons. That heavier exposure, they suggest, may be part of why resistant populations have spread so widely.
For now, the takeaway is that the old tools are losing their edge. Rutgers continues to study the problem, and experts say control methods will have to adapt, noting that even alternative approaches have limits, since a rodent that cannot reproduce can still spread disease.