The first involving a woman, identified only as a U.S. citizen, who flew out of San Francisco International Airport on May 7 to French Polynesia.
After staying there over the weekend, French Polynesian authorities say they learned the woman had been a contact with a positive hantavirus case.
They then quarantined her on another island nearby despite her not showing any symptoms.
Details of the incident seemingly unknown to many Bay Area officials.
"This is the first time I heard this. This is something I want to look into," said San Mateo County Supervisor David Canepa.
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Canepa says while he doesn't have many details, he's asking local health authorities to look into the incident.
He tells ABC7 Eyewitness News it appears the woman was passing through SFO and not necessarily a Bay Area resident.
"If someone has this, we have to make sure they're not able to leave and then go to another country," he said.
The second instance involves a San Mateo County resident who was exposed onboard the now infamous MV Hondius cruise ship.
That's according to county communications reviewed by ABC7 Eyewitness News.
They add that person is currently in quarantine with a handful of other Americans in a specialty facility in Nebraska.
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"As a public health person, it would have been better to keep them isolated on the ship," said Dr. Monica Gandhi.
Gandhi is an infectious disease expert at UCSF.
She believes letting the passengers onboard the MV Hondius leave before the 42-day incubation period was over was a mistake as it opens up more people to possible exposure.
Gandhi cautions though that the risk to the public remains low, mainly because of the way the virus spreads.
She tells ABC7 Eyewitness News people need to have symptoms and be in close contact to others to spread the virus.
"Not passing someone. Not standing next to someone with a runny nose in line but close, personal contact," said Dr. Gandhi.