How do they know that she infected the others?

At one point Governor Cuomo had South Dakota on the "no travel list" to NY because of infections in our state.

From the CDC about the 1918 flu pandemic: "It is estimated that about 500 million people or one-third of the world’s population became infected with this virus.

@James DenonThanks for the Yahoo Finance article which lays out numbers in a very clear manner in terms of infection, death as well as financial fall out.

Perhaps have them sign a hold harmless document towards others that may infect them when they enter.

Geographical location (high virus infection rate/low virus infection rate), did the majority of their tenants have essential jobs with no loss of income or vise versa, were the tenants that didn't pay have issues paying rent prior to Covid-19, did the landlord not show enough compassion or did they show too much compassion, was there a lack of communication, etc.  

There also could be malicious attachments or links that work to steal your login information or infect your computer.Here are some ways that you can protect yourself and your clients.Stay up-to-date on IRS Communications: If you receive any communication from the IRS, ensure it is coming through a verifiable channel.

Be careful when you are sniffing that COVID covered disease infected money.

How about if they install spyware, and infect other devices on the network?

Leather gloves and proper work boots will also save you much grief and potential infections.