For that super bowl applause. Sensational singer joining a starstudded list of performers belting theore the big game, hoping to hit the high notes as Whitney Houston did 25 years ago. But first the nightline 5. The bold nissan rogue with intuitive allwheel drive. Because winter needs a hero. On that excites. Good evening. Thanks for joining us. The mysterious disease causing international anxiety. Were in brazil, ground zero of the zika outbreak, withives trying to stop the contagion from spreading. The World Health Organization declaring a Global Health emergency. Here in the u. S. With at least 50 cases now confirmedmounting concern. Heres abcs chief medical editor dr. Richard besser. Reporter 3monthold anna like any normal baby but anna was born with microcephaly, an extremely small head, due to abnormal brain development. A devastating condition that doctors suspect is linked to zika virus infection during pregnancy. In brazil the barbosa family is roughly 150 cases of microcephaly occurred in brazil in 2014. Last year, there were more than 4,000. Her bruna tells us her zika infection happened when she was 12 months pregnant. The last in her family to get itck. Fever, headache, rash. Her baby. When during your pregnancy did you know that there wasbeatrice . Translator never. Reporter annas condition wasnt picked up until the sudden silence in the delivery ors told her anna would only live for a day but shes defying the odds. Shes looking at you. Does she recognize you . Translator very case of microcephaly is different but many doctors and Scientists Say the big rise in cases has a common cause. A mosquito carrying the zika of those infected with zika but for those who are pregnant, evidence is growing that it can be a disaster. His outbreak the government is trying to reach 50 million houses across the country every month, sending in the military and Public Health teams, going door to door, looking for could breed. For a country this size, thats a monumental task. Theres no cure. No treatment for zika. So the brazilian government is trying to control thethe only way it can every house in this area is visited at least once a month by the soldiers to look for any place a mosquito could breed. So if a soldier knocks on open up. We follow one soldier on his inspections. Hes even looking to see where the water drainsigerator, the condensation, to make sure theres no pooling water. Thats all it would take for mosquitos to breed. Hes putting a chemical, a larvicide on top which will killully will last and protect this water until the like everyone in brazil these days we apply mosquito repellent us is on the move. More than 50 cases so far reported in the u. S. All travel related. Lizzy morales, a houston mother, contracted zika on a christmas visit to you could see bumps in my lips. My eyes. My ears. You have no strength, no energy. Like to do anything. Not to even sit down. All you want to do is lay down reporter she wasnt pregnant. Her symptoms subsided. Since the virus is believed to leave your blood when you reco should be fine. Today Florida Governor rick scott declared a Public Health emergency in four counties where people have been diagnosed with zika. Red cross is telling donors to hold off giving for 28ve been somewhere that has zika transmission. Yesterday the first confirmed case of zika transmission in the u. S. Spread not by mosquito but through sexual contact with disease scientist, said blood transfusions and sexual contact should be the least of our concerns. The case of sexual of a red herring. Our efforts need to be focused on preventing mosquito bites. Reporter hotez says hes very spreading in areas like this one, the heart of houston city limits. Lots of discarded tires that are thrown out by the side of the road. These a rain will fill with water and fill with leaves and other debris and this makes the perfect mix for mosquito larvae to breed and develop. Ll become adult mosquitos and then theyre going to fly across to all the houses that have no window screens, no air conditioning. So all of these factors come together to create that kind ofstorm. Reporter he says that just like the shanty towns in brazil, impoverished areas here are prime breeding grounds for mosquitos. In many respects this looks likelth movie you students, Public Health students. But its not in a developing country, its right here in the united states. Reporter back in brazil, we toured a place where some scientists are undertaking a radical experiment to reduce the kind of mosquitos that spread diseases likeo create a line of mosquitos that die before they can bite people. We are in a mosquito factory. This building here, it male mosquitos genetically modified every single week. Only female mosquitos bite pe teared so their offspring will die before they can bite anyone. After they reach maturity theyre sprayed out the window of a van. They mate with the females in the community and the offsing e offspring day, reducing the spread of the disease. 25 million mosquitos have been released. The number of mosquitos that can spread disease has gone way theyre all male and male mosquitos dont bite. Theres 245,000 of them. The longterm impact oft yet known. These mosquitos are not approved for use in the u. S. And critics worry that messing with genetics may not be safe. Microcephaly isnncern when it comes to zika virus. A debilitating form of paralysis has been on the rise in places ig question, though, is whether zika is the cause. To answer this, dr. Ashley sachinsky, firstyear detective with cdc, took us with her as n investigation in partnership with the Brazilian Health ministry. Samples. Looking for a possible link rare andn. Doing . Well, its humbling. Because of the significance of the Public Health problem. But its also sort of exciting to be onve side and figure it out in realtime. Reporter the summer olympics many questions remain. Preparations have begun, including fumigating the mainmosquitos. Late last week, rios Olympic Committee said they were confident athletes in brazil will be completely safe. But american wrestler alisa lape, who is in the games, isnt so sure vinita nair she says shes being cautious. Wearing bug spray, i guess. I havent really been outside the hotel. K thats really helping. Yeah. Its kind of scary. Reporter the reality is we are just starting to learn about zika virus, about its effects, and how to fight it. We dont proportion of the children born with microcephaly have it because of zika, and whether there are other conditions besides micro civil cephaly that may be with zika. Reporter as the dancers prepare for carnival, a worried brazil wonders, where do we go from here . Besser, brazil. Xt, the president ial candidate giving Hillary Clinton a run for her money. And later, the superstar joining a chorus of pastnging americas anthem at the super bowl. Dad, you can just drop me off right here. Oh no, ill take you up to the front of the school. Thats where your friends are. Seriously, its, its really fine. You dont want to be seen with your dad . No, its. No. Dad stop, please. Oh, theres tracy. What [ horn honking ] [ tires screech ] bye dad brakes when you dont. Forward collision warning and autonomous emergency braking. Available on the newly redesigned passat. 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Expert medicine works here. Find out why at cancer center. Com. Cancer treatment with his thick brooklyn accent and his quirky professorial manner, bernie revolution. The stage set in New Hampshire for an intense battle between the vermont senator and the political heavyweight, hillary bcs david wright. You say you want a revolution reporter at the stage door of the old colonial theater inmpshire, the fans are gathering. You cant buy bernie reporter here as they would put it to feel the reporter Bernie Sanders campaign is on fire right now. Frontrunner to win thery if you want a government that represents all of the people and not just a few, come onrevolution reporter and but for the he came awfully close to winning the Iowa Caucuses too. Tails. Virtual tie. Rep junior senator from vermont, the only democratic socialist in congress, now giving Hillary Clinton a serious run his campaign raised 3 million in 24 hours after iowa. Integrity and authenticity are words his supporters use. O have somebody around that feels worth getting passionate about. There are a lot of conversations that hes presenting that we need to be having in this country. Bernie talks aboutorrupt campaign finances, he talks about raising the minimum wage to a living wage, he talks about bringing back manufacturing, he talks about r a political rise nobody but bernie saw coming. When i first met him a year ago, he was just considering whether to throw his hat into the ring. Would you be in it to win it or in it to articulate that i know the answer to. If i ran, i would run to win. I know if i do this, i start off 70 of the American People dont is. The word snowballs chance comes to mind. No offense. Reporter hes out there raising fundamental questions about the americanem and the u. S. Economy. A system he says is rigged in favor of billionaires and bankers. We the people are g have a government that represents all of us, not just a handful of billionaires. Reporter he rails against the 1 and the politicians they keep in their pocket. Hisght out of occupy wall street. College education freeforall americans. Health care free for all hed break up the big banks, raise the minimum wage, and fund all this by raising taxes on the rich and on corporations. Are you tilting at wind mills . Is a minutable fight . I dont want to tilt at wind mills. There are so many people who are hurting, working longer hours for low wages, and the ng richer. Reporter Bernie Sanders has given them a voice. And hes put his money where his mouth is. Theres no super pac aligned with his campaign. Instead, hes funding itcord numbers of small donations. 3. 25 million of them. Average amount 27 apiece, according to his campaign. Hes an unlikely easily parodied by snl the other candidates are taking millions from the coke brothers and exxonmobil. But not me. I only accept coins. Alking about fancy coins like dimes and quarters. I just want nickels and pennies. Reporter his Main Campaign ad features a golden oldie. Or america reporter simon and garfunkel with an upbeat message. His events you find plenty of folks from the woodstock y i am feeling the bern reporter also legions of feel the bern reporter among registered and younger, nationally sanders outpolls clinton nearly 41. I just like his ideas for wall street and what hes going to do with our futures already been incredibly impressive for him. Reporter digital journalist mary alice parks has been traveling with the months. It has been huge since the beginning. The biggest crowds were over the summer in a west coast swing, 28,000 people in portland, almost 25,000 in l. A. Of obama. Big change, high hopes, high dreams. Reporter sanders has pledged to fight a clean campaign, even refusing to attack clintons use of a private email the American People are sick and tired of hearing about your damn emails. Thank you. Me too. Me too. Reporter now hes drawing. Hitting her hardest on her ties to wall street and her dependance on campaign contributions. Do you think Hillary Clinton some days, she announces that she is a proud moderate. Then i guess shes not a progressive. It was kind of a low ay here in New Hampshire, clinton fired back. It was a good day for progressives when i helped to get 8 care under the Childrens Health insurance program. Reporter the lowest polls show clinton trailing sanders by more than 20 points here. Clinton and others chalk that up to the fact he has the homege as the senator from a neighboring state. Tonight he reminded voters at a cnn town hall that Hillary Clinton voted for the iraq he didnt. The Progressive Community was pretty united in saying, dont listen to bush, dont go to war. War. Reporter obviously you still havent gotten the memo, this was supposed to be a coronation, right . No, we didnt get that memo. Ot yet is a new and improved version yes, we can thank you, New Hampshire he force that came out of nowhere back in 2008 to take away hillarys crown. Eight years ago barack obama wasabout, yes, we can. Yep. Lets be honest on a lot of things he just couldnt. What makes you think you can . People are tired of a rigged economy and a finance system. They want real change. Thats why were doing well. Reporter back outside the colonial theater, theres no question theyre feeling the the bern whoo reporter im david wright for nightline in keene, New Hampshire. As for the do not want to miss the last Republican Debate before the New Hampshire primary saturday night right here on abc. Up next, how will lady gaga Gold Standard lincoln mkx for 399 a month only at your lincoln dealer. C each morning because you cant beat zero heartburn ahhh the sweet taste of victory pill each morning. Whether youre the president of ther not, there is no denying her career is on fire. Shes adding one more notch to her belt, kicking off sundays super bowl by honoring a longstanding football and nonfootball fans alike. She got plenty of applause as a pop star. But latelyeen showing the world a very different side. When the dog bites last year masterfully performingsound of music medley. Climb every mountain teaming up with tony bennett to record an albulleting fans know anything goes. On americas anthem at its biggest game, singing the starspangled banner at the super bowl. And the rockets red glare the stakes are 25 years ago Whitney Houston belted out what many still consider to be the best pregame performance. Brave securing her place as a legend. F singers have fallen flat. At super bowl xlv, Christina Aguilera forgot the words. What so proudly we watched tyler delivered this yeah who cane barrs performance. Last gleaming something tells us lady gaga is on the edge of football glory. Ge of glory thanks for watching. Tune into gma tomorrow. 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