University of Iowa professor has studied coronavirus
There's now a second-confirmed case of coronavirus in the U.S.
The Centers for Disease Control and Prevention says the patient is in isolation at a Chicago hospital. They've only identified her as a woman in her sixties who flew from Wuhan to Chicago on Jan. 13.
The woman was not ill while traveling and health authorities don't think she spread the virus during that time. They say she's had limited contact with others since returning to Chicago.
So far, health officials say sixty-three people from 22 states are under investigation for the virus.
A man in his 30s in the Seattle area was confirmed to have coronavirus earlier in the week.
"It's certainly a confirmation of something we worried about," Dr. Stanley Perlman, a professor of microbiology and immunology at the University of Iowa who has done research on SARS and MERS, told ABC News of the human-to-human transmission cases.
Perlman told ABC News while it made sense that the outbreak started in a Chinese fish market, if there was no person-to-person transmission, it should have ended quickly, once the market was closed and fumigated.
Perlman cautioned that experts don't yet have a good read on how severe the virus is.
"It's a concerning development, but we don't know the level of contagiousness or the number of cases," he said to ABC News.