人畜共存，那就宠物一起做核酸。或者宠物不允许离开不就好了。没错吧？还是说这个病毒也能感染昆虫？
至于老鼠，我突然想起鼠疫。 难道说动物传人人类就给灭亡？还是闹鼠疫的时候我们不消灭老鼠而是与鼠疫共存？？ 
另外我觉得你可能对于选择压力有误解，就以现在科技我们还做不到确保出现的结果是我们想要的。 具体你可以看看下面
Nature is analogue. It is not a binary system. In the living world there are no explicit switches that discreetly turn systems on or off. Rather, nature adjusts systems through analogue dials, like an old radio — gradually changing variables to achieve balance and equilibrium to ensure that life is sustainable and carries on.
Evolution proceeds in this way, with new life forms appearing and some disappearing over millennia — or, in the case of microbial pathogens (viruses, bacteria and parasites) over days or weeks.
Evolutionary change results from two opposing forces: Positive selection reproduces beneficial genetic variations that enable the virus to survive, while negative selection pressure hinders the virus’s survival and ability to reproduce.
Evolution can be studied at the molecular level. For many years, my research was focused on the African trypanosome, the parasite responsible for African sleeping sickness.
源：https://theconversation.com/how-new-covid-19-variants-emerge-natural-selection-and-the-evolution-of-sars-cov-2-176030