Only circumstantial evidence: Monkeypox, a rare tropical disease has suddenly appeared in; UK, Australia, Spain, Germany, US, Israel, (all countries supporting Ukraine). Putin is losing his war in Ukraine and blames the west. Putin is a sneaky little ... who is well known for using poison against his enemies. He has used polonium and novochic in the past. Russia has already threatened the west with nuclear war and other unspecified attacks. There have been occasional outbreaks in the past but the current cases have happened at the same time in 8 different countries on three different continents; Europe, America, Asia. This is just the sort of thing the cowardly little .... would do.
