this is "nightline." tonight, medical mystery. how did a california covid-19 patient get infected? doctors now detectives. >> this is a more severely-affected patient. >> the new coronavirus concerns. potential pandemic? separating facts from fears, and for the lucky few, life after quarantine. >> i'm negative! we're going home! plus, power player, two-time west wing right hand man, rough and tumble party chief. >> you're not bothered by having enemies. >> look, what garnered the enemies?

>> roots of rahm emmanuel, the chicago son, but first the "nightline" five. a former army medic, made of the we maflexibility to handle members like kate. whatever monday has in store and tackle four things at once. so when her car got hit, she didn't worry. she simply filed a claim on her usaa app and said... i got this. usaa insurance is made the way kate needs it - easy. she can even pick her payment plan so it's easy on her budget and her life. usaa. what you're made of, we're made for.

usaa good evening, thank you for joining us. tonight the global health emergency in effect for the coronavirus, the number of cases exploding, health officials scrambling to contain the

mysterious disease. the u.s. bracing for possible outbreak here at home. >> good to get back into the city, because the flights were canceled. there's quite a large line here. >> isolated, stranded, under surveillance. >> there's no people on the streets. >> about five times a day. >> reporter: hundreds of thousands of people in quarantine, the mysterious coronavirus spreading from country to country. >> i have to tell you now we're becoming quite afraid. >> reporter: the world preparing for a pandemic. so far there are more than 80,000 cases of the virus now known as covid-19, spreading to at least 49 countries. the death count surpassing 2,800. and now the u.s. is dealing with a dangerous new development. >> we begin tonight with the new and concerning case of the coronavirus here in the united states. >> a woman from northern california tested positive for the virus. officials say she's believed to be the first case of community spread, meaning she had not

travelled to a hot zone, and doesn't appear to have been in contact with anyone known to be infected. she had been placed on a ventilator at a local hospital and tested positive for covid-19 four days after symptoms first appeared. >> they're contacting any individuals who might have been exposed and isolating them. >> this latest case putting the u.s. total at 60. experts are bracing for likely outbreaks. >> what we should expect is similar to what we're seeing in china. currently, there are no counter measures for the coronavirus disease. that's a worst-case scenario, and that's how we should prepare for it. >> symptoms are common to illnesses like the cold or flu. at mt. sinai hospital in new york, radiologists like dr. michael chung now have access to scans of infected patients. >> this patient tested positive and was symptomatic with fever and cough. >> but within days the scans change. >> the rounded appearance as

well as how it's in the outer portion of the lungs. in the chest wall. this is a more severe case. >> reporter: they hope this will help identify and treat covid-19. >> it's going to be instrumental in not only finding a cure but creating prompt isolation protocols for health care systems. >> reporter: meantime, governments are quarantining anyone who may have come in contact with an infected person. >> they are feeling a little robbed i guess. >> reporter: like the retired couple who had been in quarantine for weeks. they were on the "diamond princess" cruise ship when an outbreak forced it to dock in japan. that's when we first started skyping with them. >> this is the first time we've been outside in the sun. and it's beautiful. >> today's day six. and we're almost over the hump. >> reporter: but then john came down with the fever, had to be moved to a japanese hospital. melanie is in quarantine at a

military base in california. they still aren't sure exactly when they will see each other again. it's been less than two months since the chinese government confirmed this new virus. >> now to that new mystery virus sparking concern around the globe. china reporting dozens of new cases of the deadly new coronavirus. >> reporter: on january 11th, state media reported the first death. nine days later, the first confirmed cases outside china, including the u.s. by the end of the month, the world health organization declared a global health emergency. >> cases of the coronavirus now surpass sars. >> reporter: on february 10th, an alarming milestone. death toll from covid-19 passed the sars epidemic in 2002 and 2003. but doctors say the vast majority of cases are mild, and there's no reason to panic. >> i think the public should be well-informed about coronavirus. i do not think there should be extreme worry or hysteria. >> u.s. airlines are suspending some flights and offering waivers for italy. >> reporter: in italy, we found

a 23-year-old, a young woman living with her parents in a town outside milan. >> now i'm going to show you how we've been dealing with everything. >> reporter: italy saw a sudden spike. confirming more than 500 case so far. many of them in or around milan. >> oh, look at this. we've got so many medicines in here. >> reporter: rosella's family isn't sick, but they can't leave the city limits. the usually busy town was put on lockdown. >> oh, there are people queueing over there. that's a pharmacy. a cafe. i go there with my friends. then you can see it really, really looks like a ghost town. >> reporter: italy's government is trying to clamp down on the spread of coronavirus. models walked the armani fashion show in front of just cameras. and soccer teams competing in

empty stadiums. >> we feel like we're in prison. so please, please try to understand the situation we're in. because you could be in this situation. >> reporter: meanwhile, flights from italy continue to arrive in the united states. mauricio landed in new york on a direct flight from milan. he says when he arrived in lael there were screenings. but when he arrived at jfk. >> nobody asked me. >> reporter: nothing special. >> i was surprised that there wasn't nay control. especially because we fly from milan. >> reporter: he sailed through customs and right to his cab. >> something like that happens i go immediately to the hospital. >> reporter: it's a different experience for asian travelers. many flights have been suspended. passengers who do make it out face multiple obstacles. >> we've seen videos of chinese people getting attacked, getting hit, getting punched.

>> so it's very important to put things into context and understand that it's virus that we should be concerned about, not, you know, for example asians. >> reporter: fear of covid-19 feeding fear on wall street as well. sending the markets diving. >> we need ar-6. >> reporter: for jeffrey norwood and small business owners like him that fear is real. about 90% of his inventory comes from china and he's running low. >> there is no american source. so it's not likeki go somewhere else. >> reporter: chinese companies are telling him products should arrive soon, but he's nervous. >> i'm trying to hold it together. so that they don't turn to me and say cancel the orders. financially, it wouldn't put us out of business, but it would hurt business. >> reporter: experts say there are simple things americans should be doing to be ready. >> we need to make sure we are prepared and able to respond fast, efficiently to protect as many lives as possible. if you take medications, make

sure you have at least a 30 day or 90-day supply of these items, non-perishable food items, documentation, things that you need every single day many. >> reporter: all measures john and melanie herring will have to take into account when they finally get back to their utah home. >> i'm negative! and i am so thrilled! so honey, we're goin' home! i love you! ooh! >> reporter: the couple sharing the video messages when they found out they will be out of quarantine soon. >> well, babe, the happy day is here. i am free to go. they gave me my release. and i am going to be coming back to the usa! so thrilled and so happy and i can't wait to put my arms around you. >> reporter: john tested negative for covid-19 but has pneumonia. it is getting better, so the couple has decided to spend the next month at home, just in

case. >> i'm comin' home. >> i'm so happy my husband's going home. grateful for u i'm really grateful for the journey, actually. if you don't love what is in front of you, there's just no other choice anyway. you just try to make the best of it. >> gma will have the latest on the coronavirus in the morning. up next, the chicago son who became the powerful west wing man to two presidents. (whistling)

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vomike bloomberg has a recordgue of doing something. as mayor, he protected women's reproductive rights. expanded health coverage to 700,000 new yorkers. and decreased infant-mortality rates to historic lows. as president, he'll build on obamacare, cap medical costs, and will always protect a woman's right to choose. mike bloomberg: a record on health care nobody can argue about. mike: i'm mike bloomberg and i approve this message.

he first made his mark in ballet, then as a power broker in d.c. now he has a new mark, author. i spoke to him where we sometimes got a surprising reaction. >> you can see down town from here. >> reporter: for rahm emmanuel, the former mayor of chicago, this library. >> how you doin', more important. >> nice to see you. lookin' good. >> reporter: these people in chicago's little italy neighborhood. >> miss you, miss you. >> reporter: all part of his legacy. i take it you enjoy it. >> yeah,'s people. >> reporter: he's had a long career in politics, probablyoba. he's lass also served as six years in congress. >> to me, it's home. when you know you've found home, and you can't let go, that's where you always come back. >> reporter: he served two terms

and was the city's first jewish mayor. his grandfather was known as big banga. what would your grandfather say about this time running this city that you both love. >> i try to not cry while talking about grandpa. one is that i put myself out there. you believe in something, put it on the table. >> reporter: what would he be disappointed by? >> he'd be disappointed about poverty that we didn't get all those done. >> reporter: he muses on grandfather's impact and his time in politics in his new book titled "the nation city, why mayors are now running the world", especially now as national politics both home and abroad have become so contentious. >> i had no idea that by 2020 the prime minister of england would be the former mayor of london. bloomberg, buttigieg, sanders, all mayors, more now running than anytime in 100 years. anything you think about

government as how it really impacts the way you go about live, work and play, is it washington? it's pretty much local government. >> reporter: emmanuel's own term as mayor was filled with highs and lows. by the numbers, you had many successes as mayor. but the chicago sun times op ed gave you an f for collaboration. why did that happen? >> because when i locked and loaded on something and i thought it was important, and then basically pursued it to get it done. >> reporter: you're not bothered by having enemies. >> what garnered the enemies? >> reporter: a little more than a year into his first term as mayor, chicago public teachers staged a strike, the first in nearly 25 years. eventually, emmanuel achieved his objective of lengthening the school day. >> there have been 500 homicides this year. >> reporter: while in office, chicago witnessed two of the bloodiest years in its history, the murder rate eventually going back down. but it was the 2014 police shooting of la kwan mcdonald that took the biggest toll on

his mayorship. with accusations of a coverup by his administration and police department, after emmanuel's office initially resisted releasing video of the shooting. >> i said all along, and i want to repeat, the reforms are to be effective and lasting, it needs to be done with police and not to police. >> reporter: an inspector general report did not implicate his office in the coverup. why did you fight to have the video kept private? >> every city, entity, state, when they're investigating something they hold all the investigation material until it's done. chicago's no different. a long practice, but it illustrates all the levels of distrust. >> reporter: did you make a ms s mistake? >> oh, yeah. >> reporter: 2018 memmanuel announced he would not serve

another term. your successor said it was because you couldn't win. >> that's all hypothetical. i've never lost an election. >> i will never forget the honor it has been to serve alongside you, the people of chicago. >> reporter: though his chapter as mayor is over, his transition to author and pundit swift. since july of 2019, a contributor here at abc news. he's never been afraid to lend his opinion on the race for the white house >> i'll say one thing about bernie sanders. his playbook is no different than donald trump's. >> reporter: on this day, he shut the pundit image and wants to show us his hometown his way. >> when bloomberg was in our town -- >> reporter: while rahm emmanuel earned his combatant, hardscrabble reputati wh people throughsc's doing well.ar

>> reporter: spearheading a partnership with chicago local schools to build a trade facility. >> we can see kids that can see all the buildings going up. it represents power, opportunity, the future. you keep the cubs hat. how long have you been in this session? >> in is the third week right now. >> what made you decide? >> the jobs are here. >> the training. if they work it right. >> if imtee a'm to ask, what's hourly wage? >> five years from now, you'll be making $45 an hour. >> reporter: next stop, marianos. >> what are you running for? >> nothing. i ain't runnin' for nothing! >> reporter: a grocery store built in the side of the ida b. wells. >> this was an inequity. is it different today? are there eight grocers in

neighborhoods that didn't exist before? >> reporter: and off to the train. one of the things critics say about you is they call you mayor 1%. >> mm-hm. >> reporter: that you cared more about what happened downtown, and oh, by the way, to the other communities. >> nobody in the 1% cared about raing um wage. i understand the criticism. i'm proud of the fact that we kept the revenue growing so i could invest it. >> reporter: when i read your book, it reminded me of every book i had read by someone mo was planning to run for president. >> then i'd be the first one to ever run with a second wife. so no. here's the deal. i've gone to work for two great presidents. i have no interest in running for that job. i have a very good interest in making sure there's a democratic president but no interest in running for president. >> reporter: from his immigrant grandparents, today rahm emmanuel, his family, his city, manifestation of what's

possible. complicated, combative, some may question portions of his record but not his love for his city or his efforts to make his ancestors proud and his hometown bert. >> chicago has a pull on my heart, my soul. it's where my family start. i really do. i think it's the best city. >> and next, bringing black history to life. abc news "nightline," sponsored by mercedes benz. you met on an app. delete it. why? he's the one. awww. gesundheit. i see something else... a star... with three points. you're in a... mercedes. yeah, we wish. wish granted. with four models starting under 37 thousand, there could be a mercedes-benz in your near future. lease the a 220 sedan for just $349 a month at your local mercedes-benz dealer.

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grand now we have to deal withed us this.rs. climate change is an emergency. that's why i wrote the nation's most progressive climate law. and that's why i'm endorsing tom steyer. because when big oil tried to stop our clean air laws, he led us to victory. same with the keystone pipeline. when tom says we can save the world and do it together believe him. i'm tom steyer and i approve this message.

and finally tonight, a teacher breathing life into black history month. first grade teacher latoya mcgriff in suffolk, virginia, dressing up as a different historical figure each week. dressed to the nines as ella fitzgerald and with tennis rack et cete racket in hand, arthur ashe. good for you.

you can always catch our full episodes on hulu. thanks for the company, america, goodnight.