of the first half of the forecast. cool turning warmer by next weekend. >> nbc "nightly news" is next. >> see you at 6:00. on this sunday night -- deadly virus. for the first time mers spreads from one person to another in the u.s. dr. nancy snyderman tonight with what you need to know. stranded. the growing catastrophe is the worst flooding in a century, triggers landslides, kills dozens, and forces tens of thousands from their homes. texts to 911. in case of an emergency, the new way to alert you're in trouble. tonight who can use it and how it works. and play of the night. but it turns out there was more than the eye could see when a boy at the game did such a seemingly nice thing. >> announcer: from nbc news world headquarters in new york,

this is "nbc nightly news with lester holt." good evening. the level of concern here in the united states over the deadly mers virus has been raised a notch with word late yesterday that the disease has for the first time in this country been passed from one person to another. there have been hundreds of confirmed cases of mers overseas since 2012, with almost a third of the cases proving fatal. but it showed up here just three weeks ago when a person who had arrived by air from the middle east. now health officials say that patient has passed it along to someone else, raising new questions about how it's transmitted and how big a threat the virus could turn out to be. we've asked our chief medical editor, dr. nancy snyderman, to put it all in perspective for us. >> reporter: the illinois man who tested positive for mers antibodies became infected after coming in contact with a health care worker who traveled to

saudi arabia for a business. >> had two business meetings, somewhere around 35, 40 minutes, repeat exposure, two back-to-back days. it would be considered not a close contact, but not a passerby. >> reporter: this recent patient whose closest contact was shaking hands reported to have mild cold symptoms. but officials say he is no longer sick and has been asked to isolate himself from contact. yet u.s. health officials worry. >> we are concerned because it does -- it does lead to the hypothesis that you can actually get it, in some cases easier than we thought. so that is of concern. >> reporter: and since 20% of patients are asymptomatic, the number of those infected may increase as we learn more about the virus. what we do know is that it can take up to 14 days for someone to show any symptoms. those infected developed severe acute respiratory illness with fever, cough, and shortness of breath. 30% of those in the middle east who have gotten the virus have died. still, cdc guidelines maintain it's not easily transmitted. >> we have to be very careful

about just giving people this false sense of security. but at the same time right now we have to also state that the problem is largely limited to the middle east. >> worldwide, there have been 572 confirmed cases in 15 countries. 173 people have died. officials have posted warnings in nearly a dozen airports in the u.s., reminding people to be alert of sick passengers. health care workers who are on the front lines have been told to be extra careful when treating anyone suspected of carrying the virus. middle east respiratory syndrome is not as infectious as influenza. but because there is no treatment and no way to prevent the illness other than catching it directly, no vaccine, doctors want to remind everyone if you get influenza-type symptoms, fever, cough, shortness of breath, it's not flu season. make sure your doctor knows so the appropriate testing can be done. lester? >> all right, dr. nancy snyderman, thank you. tonight there is

unprecedented flooding in parts of europe, specifically bosnia, croatia and serbia, where thousands of landslides have caused wide destruction and where dozens of people have died. we get the latest from nbc's duncan golestani. >> reporter: it's a rescue as dangerous as it is daring. no safety rope, just one man scrambling on to a military helicopter, desperate to escape the floodwater. across the balkans, help comes by air and boats because roads have become rivers. a state of emergency has been declared, water stretching as far as the eye can see, trapping people in their homes. this has never happened before, he says. for those staying behind, much needed supplies, bread in a bucket. the woman asking rescuers to return when they can. it's not just people stranded here, animals too. vast areas of farmland have been

destroyed, crops ruined and animals lost when the river burst its banks. in bosnia, more than a million people live in the flood zone. roads, houses, and entire villages have been lost to landslides. for the rescued, there is still uncertainty. i lost everything, this woman says. the home that i lived in, my house, everything is destroyed. her home, like so many in bosnia had only recently been rebuilt after the country's devastating war. and now there is the risk of land mines being disturbed. more than 100,000 remain live and dangerous. downriver in neighboring serbia, 24,000 people have been evacuated as water levels keep rising, now threatening the country's biggest power plant. the race is on to build up defenses before another wave of destruction. duncan golestani, nbc news, london. here in this country, the worst is over tonight in southern california after almost a week of destructive wildfires in the san diego area. but with severe and prolonged

drought conditions, no one expects much of a break before the next battle. nbc's joe fryer is just north of san diego in escondido, california, for us tonight. joe? >> reporter: good evening, lester. all evacuation orders have now been lifted and crews are making good progress fighting the four fires still burning, three of them at camp pendleton. the final firefight is being waged on a military base. nbc news rode along on a marine helicopter that was attacking flames still burning at camp pendleton. >> target's under the nose. >> roger, perfect. >> reporter: the pilot was already battling a fire on the base last week when he was called to the cocos fire which was threatening his own neighborhood. >> and so the whole night i just wanted to go say i want to save my city, i want to go save my neighborhood. and we got that opportunity to do that. >> reporter: today more evacuated residents are returning home. >> when did you guys come back? >> just about a half hour. >> reporter: the hocky family left wednesday as the cocos fire started rolling down the hill

toward their house. it stopped right across the street. >> we had no idea what the condition of our home was until we got here. and we're pleased it's still standing. >> reporter: despite cooler temps and calmer winds, a small brushfire popped up this weekend outside of san diego, proof california is still ripe for more action. >> this whole area burnt down in 2003 so i'm always prepared to leave. >> reporter: right now half of the country is experiencing some level of drought. and for the first time, all of california is in a serious drought or worse. >> it's unfortunately going to get worse before it gets any better. so i still think, you know, we've got to turn our eyes to the winter of 2014-15. >> today governor jerry brown blamed climate change. >> we get heat and we get fires and we get what we're seeing. >> reporter: this year california already approved $700 million for drought relief and hired 300 firefighters for which homeowners are grateful.

>> they saved our house. and all the work and the hours they put in, it's unbelievable. >> reporter: officials are still assessing the damage, but so far about 50 structures were destroyed, plus an 18-unit condo complex. investigators are still looking into how these fires started. lester? >> all right, joe, thank you. the global cries to rescue the nigerian schoolgirls abducted by the boko haram terrorist group continue to grow louder. at the cannes film festival in france while on the red carpet, actress salma hayek raised the issue in a visible display. meanwhile, across the border from nigeria in cameroon, the military is trying to do what it can to help find the girls. nbc's stephanie gosk is there. >> reporter: the cameroon military is asking this border village for any information they might have about either the schoolgirls or boko haram. but relying on local intelligence can be tricky here. there are people that support boko haram. this is a very poor village. they also distrust their central

government. the other problem is fear. the people that are against boko haram might be afraid to speak out. a local expert told us that in the last year, 20 people have been assassinated just because they spoke to the police. so boko haram uses fear and support. and with both of those, they have plenty of places to hide. stephanie gosk, nbc news, on the border of cameroon and nigeria. in north africa, a dangerous and chaotic situation is unfolding tonight in libya, where forces loyal to a rogue general attacked parliament today in the capital tripoli. this assault has been going on for a few days now and began in benghazi. nbc's ayman mohyeldin who has covered the region extensively joins us tonight with more. ayman? >> reporter: good evening, lester. there was heavy fighting today on the streets of the libyan capital. armed gunmen attacked the capital in tripoli and heavy gunfights and explosions were heard across the city in fighting that has now killed at

least 70 people since it started on friday. the fighting is between sources loyal to a former libyan general who now commands his own military and the central government army. former general khalifa haftar says he wants to purge the libyan government of islamic extremists and wants a strong and decisive central government. libya is calling the attack an attempted coup. they have declared a no-fly zone over libya as the violence continues. sings libya's backed up revolution, the country has been in constant turmoil. it has failed to draw up constitution and has seen several leaders resign. large parts of the country are controlled by militias, and the presence of al qaeda-linked militants is on the rise. now, this rebellion by the renegade general is going to further challenge the government and its ability to control the country. it's also going to create one more crisis for the obama administration in an already troubled region. lester? >> ayman mohyeldin tonight, thank you.

tuesday marks one year since a huge and devastating tornado swept through moore, oklahoma, killing 24 people and injuring hundreds. since then, engineers have been studying the damage to determine how buildings might be constructed differently to better protect them and those inside. we get more on this tonight from nbc's gabe gutierrez. >> that day was the most terrifying day of my life. >> reporter: a year ago this week, briarwood elementary was torn apart, and amanda mccalister's three kids somehow survived. >> you have to prepare yourself, because you don't know -- hold on. what you're going to see. so that was the hardest for me. >> reporter: since then, researchers have been analyzing the damage in moore, looking for clues to see if structures can be better protected from future tornadoes. an engineer at the university of oklahoma, chris ramseyer presented initial findings to the state legislature, citing possible construction flaws at briarwood, which had been built about 30 years ago.

he said the steel rebar in the school's cinder block walls was inadequate, only overlapping 6 to 8 inches in some spots when it should have overlapped at least 24. >> this wall should not have been able to come apart. >> reporter: he also found one support beam was not properly connected to the wall. the findings are now being peer reviewed by the american society of civil engineers, which has not issued its final report on its investigation and would not comment. was briarwood built up to code? >> absolutely. >> reporter: jamie flemming is the spokesman for moore public schools. >> it was built to the standards of that day. >> reporter: after decades of focusing on hurricane-prone regions, researchers are pushing to strengthen building codes throughout tornado alley to withstand low-level twisters. among the suggestions, metal straps holding a building's roof to its walls and the walls to the foundation. >> i think it's going to catch on across the country in tornado-prone areas. >> reporter: just last month, moore became the first city in the country to pass new stronger

residential building codes to withstand tornadoes with winds of up to 135 miles per hour. the change did not include schools, but briarwood and nearby plaza towers elementary, where seven children died, are both being rebuilt with storm shelters. amanda mccalister who is still rebuilding her home hopes her kids will never have to use them. >> you're never really i think goings to fully understand weather. you can't, really. it's unpredictable. but i still think it all needs to be investigated so maybe it can prepare us for the future. >> reporter: gabe gutierrez, nbc news, moore, oklahoma. when "nbc nightly news" continues on this sunday, the new option for getting help when there is an emergency. and later, he is two out of three, but there may be an obstacle ahead for california chrome as he pursues the triple crown.

we're back now with a huge deal just announced tonight in the tv and broad band industries. at&t has agreed to buy directv for about $48 billion. the boards of both companies

approved the deal today. the merger is subject to government review. it would give at&t a larger base of video subscribers and increase its ability to compete against comcast and time warner cable, which agreed to merge earlier this year. comcast is the parent of nbcuniversal. that brings us to another idea whose time has come, moving 911 more fully into the digital age by allowing people to text for emergency help with their mobile phones. some states are set up for it already with more on the way. we get more on this tonight from nbc's kristen dahlgren. >> reporter: during the mass shooting at virginia tech in 2007, many students trapped, terrified and trying to stay quiet could only text 911. their pleas for help never received. emergency centers weren't set up for text messages. now the nation's four largest carriers have agreed to offer texts to 911. >> it will benefit those who are in situations where it's simply safer to text than it is to talk. >> it has been long overdue, particularly within the deaf, deaf/blind and speech disability community. >> reporter: richard ray knows from experience. a few years ago, he had chest pains while driving. luckily, he had a friend with him to call 911. >> if there was nobody around, i don't know where i would be. it may have been that i had died. >> durham 911, where is your emergency? >> reporter: in durham, north carolina, emergency operators are now trained to respond to texts. but officials say text isn't a substitute for calling in every case.

>> if you can call us, we still want you to call us. you know, that's the quickest way and the most efficient way to get the help you need. >> reporter: there is no law mandating 911 texting service. the agreement is voluntary. and how it's implemented may vary. right now 911 texting is only available in iowa, maine, vermont, and select counties in 13 other states. >> i would hope that the 911 community across the country would be able to have this done within a couple of years nationwide. >> reporter: a hope shared by many. >> nobody gets up in the morning thinking that they will need to call 911. >> reporter: even if they hope they'll never need it. kristen dahlgren, nbc news, new york. and up next here tonight, such a nice gesture, until you see just what he had up his sleeve. >> ah, aren't you so sweet?

this scene in texas last night as the rangers-blue jays game as a fouled ball was picked up by toronto's third base and tossed into the crowd. without missing a beat, a nice young man shows what he is made of when he hands off the ball to the woman behind him. generous, isn't he? but looks are deceiving. it turns out the ball was one he had apparently brought to the stadium. nice move, slick. you would have to call that the play of the game. winning the triple crown is one of the biggest achievements in all of sports. and tonight california chrome is a big step closer to that goal after going all the way in the preakness yesterday in

baltimore. but now as nbc's craig melvin reports, there could be an unforeseen obstacle in the way. >> reporter: as california chrome rounded the final turn, the odds on favorite thundered to victory to keep his triple crown bid alive. >> california chrome has won the preakness! >> reporter: only 11 horses have claimed the coveted triple crown, winning the derby, preakness and belmont stakes. the last to take the title, affirmed in 1978. but this morning california chrome awakened to controversy. what if he is not allowed to wear the nasal strips that she has worn in his last six victories? with belmont just three weeks away, trainer art sherman raised the possibility. "i don't know why they would ban you from wearing one," he said, "but we'll have to cross that bridge when we get there, i guess." new york racing officials would not allow i'll have another to wear them in 2012. that horse had already won the first two legs of the triple crown. he dropped out before belmont with a beg injury. expert veterinarians think the strips make little difference. >> i would say that the odds of it making a difference if the horse ran with that strip or without is pretty low. >> reporter: california chrome has already countered skeptics who questioned his speed and humble pedigree. >> i was so excited i win the race, i didn't even know who i was talking to. >> reporter: getting two-thirds of the way to history reduced the colt's owner steve coburn to tears. >> when i saw this colt, i saw

this baby when he was a day old, i told my wife, carolyn, this horse is going to do something big. >> reporter: he and partner perry martin were ridiculed for spending just $8,000 on the mare that produced chrome. >> he's not the millionaire in this field. he is truly the blue collar guy that has been turning in millionaire-like performances. >> reporter: now many are hoping for just one more. craig melvin, nbc news, new york. when we come back, finding strength and hope in what remains of a day they'll never forget.

finally tonight, one more note from moore, oklahoma, a community this week that is marking the anniversary of last may's powerful and deadly tornado. from the shattered remains of a great school, young survivors have found a way to remember the classmates they lost that day and to build a pathway to renewal, one brick at a time. >> this was the shirt i wore on may 20th. it's like my survivor shirt. >> reporter: cade newton is one of hundreds of children who rode out the ef5 tornado that tore through moore, oklahoma last may. 24 were killed, including seven children at plaza towers elementary school. soon after, many families found comfort by taking actual pieces of the school, bricks, and turning them into tributes to

the victims. >> i wrote "nick" on it. and "he'll always be remembered in my heart." and it has legos for him because he loved to play with legos. >> since the paw was our logo. so i just decided i wanted to draw that on it. >> this is the plaza towers. and it says "i survived an ef5 tornado in my school on may 20th, 2013." >> reporter: the idea of painting the bricks of plaza towers came from sixth grader zoe tennyson who was trapped at the school on that terrifying day. >> my friend sat by me in the bathroom and buried me. >> reporter: she said she wanted to remember her classroom and asked if i would go over and get it.

a lot of the fathers were out there busting them up into individual blocks so kids or anybody who wanted them could get them. >> reporter: with hope, the brick project has become a building block in moore's emotional recovery. >> we were all there together, and we were all feeling the same thing. and it was a safe place. >> plaza towers, moore strong. >> reporter: nearly a year later, xavier delgado still has the physical and mental scars, but his mom says he is doing better each day. >> and they just, you know, helped us with all our anxiety and stuff that we were having, and they gave us hope that things would be better. >> reporter: what had once been rubble and remnants of despair now framing a foundation of hope and renewal. that's "nbc nightly news" for this sunday. brian williams will be here tomorrow. i'm lester holt reporting from new york. for all of us here at nbc news, good night.

governor brown sounding the alarm on fire danger across california. he's warning of a long and dangerous season. we're going to show you how local fire departments are re e preparing. plus, gunshots in the south bay. who police are looking for tonight. and mnow police are saying dozens arrested at the beta breaker race. we're live with the sights and sounds after tens of thousands filled the streets. good evening, earn. i'm terry mcsweeny. >> and i'm diane dwyer. well, fire departments are