The Otherworldly Infection Story that Started with a Virus Reincarnation is a Manga/Manhwa/Manhua in english language, Fantasy series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

I was supposed to be dead, but when I woke up, I was a rat! …or, more accurately, I became a virus-infested rat!! The more I infect, the more bodies and skills I get! I’m going to cause a pandemic in this other world!