I never did any research about the causes of the Covid-19 and other viruses but if you read what I said earlier, I said it is always a product of human mistakes but when it happens it will come out of the blue and there's always something that triggers it.
Covid-19 can be because of research mistake in China, but no one knows, it can also be because of natural changes in Corona virus that makes it more deadly than before. Everything can not be because of human mistakes, some just evolved naturally. One thing about microbes is that they can naturally and genetically modified within short period of time.
There's no smoke without fire they say. Most of the disease we saw these days is either invented or caused through research mistakes.
I followed the covid-19 news a lot when it first happened in Wuhan and I read some statements of Dr. Li Wenliang. Aside from that, if the issue evolved naturally there's still something that triggers through human activities.