cough or sneezing, should not be wearing any type of mask. >> yeah, they're really concerned about this. they want folks who are actually sick to wear the masks instead. and will carr joins us now from outside that hospital tonight. and will, we know some of those hospital workers who came in contact with this patient have also been quarantined? >> reporter: that's right. a number have been asked to self-quarantine, to stay at home, check their own temperatures and report in if they show any symptoms. everyone else across this region is considered low risk tonight. david? >> all right, will carr leading us off tonight. will, thank you. this new case, of course, brings a whole new set of questions. why did it take so long for the patient to be tested for coronavirus? so, let's get right back to abc's chief medical editor dr. jen ashton, who is with us here tonight. and jen, first of all, that new patient in california. particularly because she's in the county where they brought americans back from china who are being quarantined. was it alarming to you that it took four days? >> reporter: well, that's alarming, but this case is significant, because it represents the first case of human-to-human transmission in