Health officials have confirmed the first transmission of the zika virus in the United States. A person in dallas was infected after sex with a partner who had been in venezuela where zika is epidemic. It is usually transmitted by mosquitoes and suspected of causingevastating birth defects. Hardest hit is brazil where we find dr. Jon lapook. Reporter it is a search and destroy mission by government workers. Each morning, teams of army and Health Workers target neighborhoods in the city looking to kill mosquitoes that may carry the zika virus. The epicenter of an explosion of microcephaly, an abnormally small head at birth linked to the infection. Each is a notified case of microcephaly. Reporter the doctor heads up the city health department. Of mow skieesquito to see less zika and hopefully less microcephaly cases later on. Reporter there are 272,000 homes in this district alone. Officials follow up every two months. 30yearold is pregnant with her fourth child. A worker added chemical to kill mosquito larvae. The breeding of this species of mosquitoes occurs in peoples homes. What are you doing at home to loper your chance of getting bitten by a mosquito. Borgess told me, tries to keep her home clean, eliminates standing water and occasionally uses bug spray. Still gets mosquito bites once a week. She has had no obvious symptoms of zika, but 80 of the time those infected dont feel sick. What do you worry about . Prejudice exists and is serious. As a mom, i would give all of my love, but i would worry about scott, i asked the Health Commissioner about todays report of sexual transmission of zika virus in the United States the he said that has not been reported yet in brazil, but that after today, Health Officials here are certain to take a closer look. Dr. Jon lapook, reporting for us, jon, thank you. What are the chances of a large outbreak of zika in this country . We put the question to dr. Thomas frieden who runs the centers for disease control. Everything we see so far doesnt suggest there will be a widespread outbreak of zika in the u. S. We have two things going for us. First, the mosquitoes are not present at all in most of the country. And theyre present in much lower numbers where they are present. Second, because people have air conditioning, are inside, legislation crowded than some of the places where zika is spreading so rapidly, we arere much less likely to have the despread transmission even in the places where are the dr. Thomas frieden of the cdc. Turning overseas there was a bang and suddenly a gaping hole in a jetliner over war torn somalia today. Margaret brennan has the that. Reporter cell phone video shot on the plane while still in flight shows oxygen masks fwloeg in the wind near the hole in the airbus 321. Some passenger toward the back of the plane can be seen wearing oxygen masks. On the ground the damage to the plane was clearly visible with pieces of the fuselage curled out from the body of the plane. All 74 passengers and crew were evacuated. Aviation Officials Say two people were injured. The somali owned airline was on the way from mogadishu to and the diplomat was on the flight and said on facebook he heard a loud noise and couldnt see after the smoke cleared he realized quite a chunk of the plane was missing. U. S. Intelligence officials are aware of reports there may have been an explosion. It is unclear from structural failure. And a terror group controlsart of the country and isis is expanding its footprint. Megan brennan, thank you. Five days ahead of super bowl 50, the nfl is studying how to deal with a 58 increase in concussions. From 115 during the 2014 season to 182 in 2015. This after the League Already cracked down on helmet to helmet hits. John blackstone is looking into this. After former new york giant tyler sash died at age of 27, doctors were shocked to discover he had a degenerative brain some one so young. His mother, varnetta, blames football. They could have all the money back if i could have my son back. You know . Nothing else matters. And you cant compensate anybody enough for that. If you continue to deny my work. Reporter in concussion will smith plays the pathologist who first identified the brain disease chronic traumatic encephalopothy or cte. He battled the football establishment to have it recognized. Nobody is denying cte any longer. The doctor studied the brains of dozens of deceased nfl players. How many of the players on the field, on super bowl sunday, will already be suffering from brain damage . I believe that 90 to 100 of, of professional players will i think that is a bift hyperbole, honestly. I cant imagine that being the case. Reporter dr. Mitch berger, is chair of the committee that monitors head injuries for the nfl. Over the past decade the league made dozens of rule changes to reduce the risk. An athletic trainer, dubbed eye in the sky watches for injuries from a stadium box and independent Neurological Consultant monitors from the side lines. Concussions are up. I think primarily because the of the vigilance, the consultant, spotter in the media box there were twice as many evaluations or screenings for concussions this year. Reporter the doctor believes it takes less than a concussion to damage the brain. By the time you reach a professional level, you must have received thousands, if not not hundreds of thousands of blows to your head. Reporter the doctor has a foundation to research the be causing. Scott, the nfl is looking at equipment changes and even new kinds of turf that could reduce head injuries. John blackstone reporting for us. John, thank you. A mother remembers her murdered daughter. Was the killer online . And snowplows overwhelmed by a severe storm. 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A little touch is all it takes. Battled illness, bullying and lived much of her short life on line. Saturday in virginia she was found murdered. Two freshmen are under arrest and don dahler is following this. At a press conference, tammy weeks tried to describe the daughter. She couldnt finish. She had a passion for pandas, dreamed of being on american idol. Idol. Nicole touched many people throughout her short life. Yeah, i cant do that part. Reporter prosecutored charged David Eisenhower with first degree murder and Virginia Tech engineering student, natalie keepers charged with helping him commit the crime. Pettitte. A very preliminary determination of the cause of death is stabbing. Eisenhauer, a former track star. According to documents he said i believe the truth can set me free. Lovell, was last seen at her mothers blacksburg, Virginia Home wednesday. Her body was discovered saturday, lying on a road in north carolina. Lovells father david and stepmother terry stayed in touch with the teen through social media but were concerned about her activities on web sites where the family believes she ultimately met her accused killer. Are you aware she was active on these teen flirt sites . We know that there were some issues at one time with her on these sites. And we addressed them. And i guess, we didnt do enough. Reporter t t suspects are being held at this jail without bond. They have not yet entered a nicole lovell, her funeral will be held thursday. Don, thank you. Next. The candidates got out of iowa just one step ahead of a storm that could still spawn tornados. Heres david begnaud. Tonight a blizzard sweeping Middle America from colorado to wisconsin. More than 13 Million People are under the threat of winter weather. Nearly a foot of snow has fallen in colorado alone in just 24 hours. In kansas, vehicles had to be dug out. Blowing snow has made driving treacherous, with little visibility. Big rigs have become stranded. Some sedans didnt have a chance. Even snowplows were struggling. The snow cut power to at least 1,600 customers in lincoln, nebraska where monie and lee a moment where you go back to where people didnt have power. You have to learn how to adapt. Reporter elsewhere today unusually warm from chicago to new orleans. Nashville set a record, 75 degrees. That warmth combined with strong winds will cause severe thunderstorms and a looming threat of tornados for nearly 9 Million People from the gulf coast to illinois. Tonight, we are in mississippi and right now the National Weather service out of jackson confirms there is a tornado on the ground in mississippi. And scott, people there are being urged to take cover right now. Well check with you tomorrow. Thank you very much. Millions of people will be in the path of the flood of super next. The super bowl is coming sunday here on cbs. But first, a word from the sponsors. Heres demarco morgan. Each morning i get up i die a little cant bear to stand on my feet take a look at your self reporter these singing sheep hope to have football fans flocking to the honda dealer. Whether you are an animal lover or one with a sweet tooth and move to go an octave higher. Be ready to be flooded. Knocked over and entertained by this years super bowl ads. Its hard to reapsist great taste. What does the super bowl mean to advertisers . The super bowl for advertisers one of the last big things for them to put their people in america. Reporter companies are shelling out 4. 8 million on average for a 30second spot. Thats 160,000 per second. Over here we have their alphabet. It was called emoji. Reporter during last years super bowl, smaller brands, avocados from mexico spent 10 of their budget for an ad. I mean, double dipped. Reporter the Company President , alvare luce. Giving an example to brand that could participate, or compete, share the stage with huge brands. Reporter the brand grew 33 . The lesson, the ad that wins has a message that resonates. Budwiseer. And a brand that sticks for years to come. Just one look demarco morgan, cbs news. Thats the overnight news for this wednesday. For others check back with us later for the morning news and cbs this morning. From the Broadcast Center in new york city, im scott pelley. Announcer this is the cbs welcome to the overnight news. The devastating z za avirus continues to spread. The first known cases reported in ireland, chile and nicaragua. Zika is moving like wildfire through latin america and caribbean. The World Health Organization declared it a Public Health emergency. Skaerd carried by mosquitoes. For pregnant mothers the virus can be devastating, some times causing miscarriage and birth defects. Brazil is ground zero. The Health Officials are warning pregnant women not to attend this summers olympic games. Dr. Jon lapook has more. Reporter i left 30 soldiers with Health Workers going house to house here in places like this looking to identify and destroy mosquitoes and to educate the local population about prevention. Health workers are spraying their way through part of south hoping to eliminate mosquitoes, the carrier of the zika virus. Doctors in brazil are seeing a spike in infants with microcephaly. Were y y sec atick at all . No. Reporter the birth defect which results in a small head is suspected to belinged to the zika virus. Dr. Angela rocha has been a pediatric diseases specialist for four decades. A huge generation of babies with problems, rocha told me, a huge, social, economic and Public Health problem. She said she had never seen anything like it. Of the 28 countries and territories where the virus has been transmitted brazil has seen the largest outbreak w wh estimated 1. 5 million cases. The situation meets the reporter World Health Organization says it will take coordinated International Response to gain control over the virus. The Organization Says zika may infect 4 Million People in the americas over the next year. So far, there have the been at least 31 reported cases in the United States from travelers returning to the u. S. All those cases were felt to be from imported infection from other countries. European union haggles over ways to stop mass might raegsration of people. 50,000 through greece. The netherlands floated an idea to have an armada of ships off the greek island. Migrants get off the boats and be taken back to turkey. Denmark going one step closer, confiscating migrants valuables to help pay for their stay. Reporter when zarif abdella and her four small children we used to have everything, she said, house, cars, jewelry. We had to sell it all before she left raqqa, syria. Now under the new law, the Danish Government can seize any cash and valuables worth more than 1,500 to help pay for her family upkeep. She left her husband behind in turkey and it makes seeing him much harder. It blocks migrants from bringing immediate family members to denmark for at least three years. Nicola bendixon said delaying a Family Reunion is just cruel. Making a law like this is so cynical and so evil. It is, i dont really, i dont know how you can do things like that. Reporter denmark is struggling to cope with an influx of more than 20,000 refugees last year. One of the highest per capita in europe. Politician marcus knute. You could put it that way. It sound very tough. Alternative is that we simply dont have enough empty beds, we dont have enough space, we cant look after the people who come here. Reporter the government says making migrants help pay for their stay is only fair. Danish citizens on welfare also have to give up their cash to qualify. But bendixon said it is not about the money. The cost of an Asylum Seeker in denmark is so much bigger than whatever people are carrying on them. It is really ridiculous. It is symbolic way of scaring people away. Thats the purpose of it. Zarifa told us the new laws have not scared her away. When you have nothing left, there its nothing left to lose. A british mother who took her young son with her to syria to join the Islamic State has been sentenced to six years in jail. Arrested after she returned home, claiming it was all a mistake. Allen pizzey reports. She told her family she was taking her 1yearold son on holiday in turkey and ended up in an Islamic State in syria. The 26yearold claimed it was all accidental. But according to a Police Statement, she self radicalized by viewing extremist material on the internet. She was not naive. She had absolutely clear intentions before leaving. Images recovered from her own, show her posing, holding a gun, and several showed her 1yearold son doing the same. She sent a message to her sister, hey, babe we crossed the border today, we are now in syria living there. It was never my intention to enter into syria. She told British Police the love affair was shortlived. I didnt want to be in syria. Immediately we were there. The other women were like this place its hell. This place is hell. She was kept in a large house with single women. Raqqa blefd to be guarded by up to 5,000 is fighters. She told counterterrorist officers picked up on her return, after three months in raqqa managed to get a taxi. Half a mile from the turkish border. I said, stop the car. Stop the car, i threw 9,000 syrian dollars at him. 50. Grabbed my pampers and everything. Ran, ran, ran. Her son is in state care. Allen pizzey. Small towns across the country are feeling the pinch after walmart closed 154 stores last week. Most of the closed were smaller walmart express stores. Some open for a few months. Many communities had come to rely on them. David begnaud has the the story from texas. They chose to come here. Then when they put the other they want to close. Talk about pettitts, a mom and pop, mainstay in the small town for 60 years. Larry deeds was coowner. What made you close . Business. They just quit coming. Reporter when walmart moved in last year, whiterights mayor, allen west said competition from wal marlt was a good thing. Now it is leaving. Awe off the it will hurt the city financially. It will hurt the citizens economically. Communities are finally getting a look at not only the effects when walmart comes into town, but also when they leave. I think that is a double blow for a lot of people. Reporter now that walmart has closed. Aretha thompson will have to drive half an hour to the closest Grocery Store. Where will you buy your groceries now . I dont know. Wont be walmart. 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