As President Trump sought to reassure the nation that the coronavirus is under control in the U.S., officials on Wednesday confirmed a first-of-its kind case near Sacramento, California.
Experts have been able to trace how every other patient in the U.S. became infected, but not this one.
The CDC says this means the virus could be spreading locally, person-to-person.
This comes as some eight-thousand people in California are currently being monitored for coronavirus.
In the Commonwealth, health officials say the best way to make sure that the virus does not spread is to self-quarantine.
231 people in Massachusetts are still being monitored including a woman in Pittsfield.
She had returned from China last weekend and is being monitored daily while in isolation.
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