"Many may be quick to assume that just because someone is Asian or from China that somehow they are more likely to be carriers of the virus," said Robin Toma, executive director of the LA County Human Relations Commission.
A Los Angeles Asian-American schoolboy accused by bullies of having the virus was taken to the hospital after being beaten.
"He went to the hospital originally and went to the emergency room," Mr Toma said. "They were taking MRIs to ensure he didn't have a concussion or other harm."
In the Los Angeles area, flyers with counterfeit seals for the World Health Organization (WHO) have been posted.
They advised residents to avoid Asian-American businesses like Panda Express because of the coronavirus.
And in a now-deleted Instagram post on "managing fears and anxiety", the University of California, Berkeley health services department listed xenophobia as a "normal" reaction amid a virus outbreak.