How long is the time-space cross infection?

Spatio-temporal infection refers to mutual infection between patients in a certain time and space through different channels. A cross pathogen is a disease, or a different type or strain of another disease. For example, an infected person has been to a place in 14 days, and someone's trajectory has crossed with him in this 14 day, then he may be considered as a space-time companion. Screening "time-space partners" can find potential infected people to the greatest extent. If infected, it is also called space-time infection.