Centers for Disease Control and Prevention

A CDC scientist harvests H7N9 virus that has been grown for sharing with partner laboratories for research purposes.

More than 50 travelers just back in the United States from China who had flu-like symptoms have been tested for the H7N9 bird flu virus, federal health officials say. So far, none has tested positive.

But the fact that they’re being tested at all shows just how worried the U.S. government is about this new strain of bird flu, which threatens at the same time as a still-mysterious coronavirus from the Middle East. The test kits had to be specially made up and distributed under an emergency provision.

“While no cases of H7N9 have been detected at this time in the U.S., 54 people with flu-like symptoms after travel to China have been tested. All have 54 tested negative for H7N9; while six tested positive for seasonal influenza A, and three tested positive for seasonal influenza B,” the Centers for Disease Control and Prevention says in its latest update on the virus.

Emergency operations centers are running 24/7, keeping an eye on both situations. While it's not unusual for the centers to be operating around the clock, it is rare to have two pandemic threats at once to plan for, says Edward Gabriel, who heads preparedness and response issues at the health and Human Services Department. 

"We want the latest and best information that we can get," Gabriel told NBC News. "We also need to look and see where it is moving to. To try to isolate its motion is a pretty significant thing."

If either virus turns into a form that spreads easily from person to person, a pandemic could follow within weeks. Both seem especially deadly in their current form: H7N9 seems to have about a 20 percent fatality rate, while the new coronavirus appears to have killed more than half its victims.

“In the case of the two latest threats — the H7N9 influenza virus and the new coronavirus — the number of infected people is small, and the infections are occurring thousands of miles away from the United States. Yet we should be seriously concerned about both,” Mike Osterholm, an infectious disease expert at the University of Minnesota, wrote in the New York Times on Friday.

“Our public health tools to fight these viruses are limited. We have no vaccines or effective drugs readily available to stop or treat the new coronavirus in the Middle East,” Osterholm adds. 

CDC

Influenza A H7N9 as viewed through an electron microscope. Both filaments and spheres are observed in this photo.

The H7N9 flu can spread silently, as people transmit influenza before they’re sick themselves. If the flu did mutate into a pandemic form, it would probably take at least six months to make enough vaccines to protect large numbers of people.

“It may take longer than it takes the virus to spread,” says Dr. John Treanor, a flu vaccine expert at the University of Rochester Medical Center. “The technology that we have today is such that the bulk of the pandemic disease may have already taken place before a vaccine is in place and can be used,” he added.

“The virus can spread very, very quickly. You are in a race against time.”

That happened in 2009, when the new strain of H1N1 swine flu broke out to cause the first pandemic of a new flu in 40 years. Companies raced to make vaccine but it was months before it was ready.

There are drugs to fight flu – a pill called Tamiflu and an inhaled powder called Relenza. Neither is a cure, however, and both need to be given very quickly to do much good at all.

Right now, H7N9 seems mostly confined to China and the spread has slowed. The World Health Organization reports 32 people have died out of 131 lab-confirmed cases.

“The drop-off in newly reported H7N9 cases in China may be the result of containment measures reportedly taken by Chinese authorities, including closing live bird markets, a venue where the risk of exposure to bird flu viruses can be high," the CDC says. “However it may also be a result of changing seasons, or a combination of both.”

Researchers in Hong Kong did a computer analysis of the outbreak and estimate that at least 200-500 more people have likely been infected with H7N9. The virus seems to cause serious illness mostly in people over 65 – doctors are not sure why yet.

“We estimated that risk of serious illness after infection is 5.1 times higher in persons 65 years and older versus younger ages,” Ben Cowling and colleagues at Hong Kong University wrote in the journal Eurosurveillance.

The evidence suggests that most of the patients got infected directly by birds, probably in poultry markets. So Cowling’s team took all the data and estimated how many younger people were likely to have been infected without knowing they had H7N9. "Our results suggest that many unidentified mild influenza A(H7N9) infections may have occurred, with a lower bound of 210–550 infections to date," they wrote. This would mean the virus isn’t that widespread, but which also confirms its high fatality rate. 

The coronavirus, which some are dubbing Middle East Respiratory Syndrome Coronavirus, or MERS, is a little different story. WHO says 33 infections have been reported, with 18 deaths. Experts are watching cases in France, where one patient who traveled from Dubai was confirmed to have the virus. 

A man who shared a hospital room with the 65-year-old man also has the virus, French officials said Sunday -- something that shows the virus and and does spread in hospitals. 

Officials were relieved that three health care workers who cared for the 65-year-old patient and who got sick have tested negative for the virus.

Also Sunday, WHO Assistant Director-General Keiji Fukuda could probably be passed between people in close contact, but there was no evidence of sustained "generalized transmission in communities."

Some reports suggest an outbreak in Saudi Arabia also affected people in the same hospital.

This worries Dr. Eric Toner of the Center for Health Security at the University of Pittsburgh Medical Center. SARS – severe acute respiratory syndrome – also spread mostly in hospitals. SARS spread to 29 countries in 2003, killing 775 people and making 8,000 sick before it was stopped.

“These cases, whether confirmed or not, should be a wake-up call,” Toner writes in his blog.

The good news is that SARS was stopped using good hospital hygiene. Face masks, gloves and careful disinfection prevented its spread. And SARS only spread once people were noticeably ill, unlike flu, which people can spread before they feel sick and after they feel better.

The bad news is that hospitals may have forgotten this lesson. “SARS was stopped by healthcare workers being aware of the disease, having a high index of suspicion of anyone with fever and respiratory symptoms who had recently been in an affected region, and quickly implementing infection control measures with any suspect case,” Toner says.

“Until now, all cases of MERS originated in the Middle East, but as the confirmed French case demonstrates, the virus is only a plane ride away from other parts of the world. In the 10 years since the SARS outbreak, many hospitals have become lax in their attention to respiratory precautions.”

Gabriel says he’s working to make sure this isn’t the case with U.S. hospitals. “Hygiene practices are now better than they ever have been,” Gabriel said. “We send out reminders daily.”

Related:

• WHO: New SARS-like virus can probably spread person to person
• US races to make new vaccines against bird flu
• New virus has officials worried about skimpy resources

This story was originally published on Sun May 12, 2013 9:33 AM EDT

Alzheimer’s disease is the fastest growing threat to health in the United States, but Americans are still most likely to die from diseases caused by their own habits such as overeating and tobacco, according to a new report on global death and disease.

In contrast, AIDS and alcohol are the biggest health threats among Russians, malnutrition threatens children in Africa and Afghanistan and violence is taking the lives of many young men across much of Latin America.

The team at the University of Washington in Seattle looked at thousands of sources of data, from individual death certificates to global surveys on illness, for their report. It compares various causes of death and diseases across 187 countries.

Groups like the Alzheimer’s Association have been warning that the U.S. will have to cope with a tsunami of Alzheimer’s disease as the population ages. A report last month projected that the number of patients with this untreatable form of dementia will triple in the next 40 years, to 13.8 million in 2050.

The University of Washington team looked at Alzheimer's trends and found it’s already up 392 percent as a cause of premature death, as measured by years of life lost. As an overall cause of death – how many people die of Alzheimer's instead of something else – it’s up more than 500 percent.

As for causes of disease, they are mostly self-imposed.

 “Overall, the three risk factors that account for the most disease burden in the United States are dietary risks, tobacco smoking, and high body-mass index,” reads the report, called the Global Burden of Diseases, Injuries, and Risk Factors 2010.

Heart disease, lung and throat cancer and stroke cost Americans the most years of life in 2010, the study, led by the university’s Christopher Murray, found. The single biggest risk factor in the U.S. is diet.

But there’s good news. “Of the 25 most important causes of burden, as measured by disability-adjusted life years, interpersonal violence showed the largest decrease, falling by 26 percent from 1990 to 2010,” the report finds

There’s other good news in the report: AIDS infections appear to have peaked globally and people are living longer and healthier lives.

“While HIV/AIDS has exacted a devastating toll on many countries in sub-Saharan Africa, increasing by 328 percent in terms of healthy years lost from 1990 to 2010, the epidemic appears to have peaked in 2004,” the report says.

Death rates from HIV are now falling, according to the World Health Organization. Programs to get people treated with cocktails of lifesaving drugs, which can also prevent new infections, are the reason. “This success is largely attributable to the massive scale-up in antiretroviral therapy over the past decade,” the report reads.

Other rich countries have similar health profiles to the United States. Residents of Britain and Canada both also suffer most from overeating and smoking. In Britain, the single biggest helath risk to children is second-hand smoke.

In contrast, the three biggest causes of poor health in Ecuador are alcohol abuse, poor diet and high blood pressure. Children are the most hurt by poor breastfeeding.

In Afghanistan, most disease is caused by air pollution from  household fireplaces and cookstoves, underweight children and poor diet.

“A troubling mortality trend is among young adults, especially young men, who are now dying at very high rates in eastern Europe, central Asia, and eastern and southern Africa. This is largely due to the epidemics of alcohol‐related mortality and HIV/AIDS, respectively,” the report says.

“The average mortality rates among males aged 25 to 39 fell by little more than 19.7 percent over the four decades as compared to much higher declines in other age‐groups.”

Related stories:

Alzheimer's to triple by 2050, report finds

New focus on AIDS treatment saves lives

A scan of all the mutations in the human gene map shows something surprising – people of European descent are evolving fast, and not for the better.

The study finds that in the past 5,000 years, European-Americans have developed a huge batch of potentially harmful genetic mutations – many more than African-Americans.

The study, published in the journal Nature, may help explain why so many people develop diseases even though they don’t have common genetic mutations. It can also help explain why different people have so many different reactions to the same drug, said Joshua Akey of the University of Washington in Seattle who led the study.

It likely has to do with population explosion, Akey said. European populations expanded after the Ice Age ended and prosperous agricultural societies emerged. “The number of mutations that exist is directly attributable to the population growth that happened in the last 5,000 years,” Akey told NBC News.

“The things that allowed us to go from millions to billions of has also been the same process that has been pumping in all these new mutations.”

Akey and colleagues at genetics institutions across the country examined the gene sequences of more than 6,500 people – more than 4,200 European-Americans and 2,200 African-Americans. They were looking for small changes in the genetic code called single nucleotide variants – one-letter differences in the genetic code of A,C, T and G.

They found “an enormous excess of rare variants” in the European-Americans. And 73 percent of these mutations only appeared in the human genome in the past 5,000 to 10,000 years. Most were mutations that are known to weaken proteins, Akey said, and most of these harmful mutations were also in the people of European descent.

Now researchers are working to see which of these mutations might be associated with diseases. But many are in known disease-causing genes, such as the LAMC1 gene associated with premature ovarian failure, LRP1, which is linked with both Alzheimer’s disease and obesity and the CPE gene linked to hardening of the arteries.

Most are rare mutations – meaning they only affect a few people. “Some genes might be more disease-causing than other genes,” Akey said.

It may explain why it’s been so hard to find clear genetic links to many diseases. “We have been looking for disease risk where it isn’t,’ he said. “The last five to 10 years have been dominated by looking for common genetic variations that dominate common diseases. There is a lot of disease risk that is unexplained. Maybe there are classes of mutations that haven’t been looked at.”

The findings could explain why some people can smoke for a lifetime and never get lung cancer or heart disease, while someone else might suffer a heart attack despite having healthy blood pressure and cholesterol levels.

It definitely shows evolution in action, Akey said. “It’s just the process of evolution playing out in real time,” he said. “The dramatic population expansions that occurred over the past couple thousand years had a profound consequence on our genetic variability.”

Genetic mutations usually occur by accident – they are just mistakes that get made when DNA gets copied. They become important to evolution when they affect a person’s ability to survive and have children. The expansion of civilization, and the ability of societies to care for people who are less fit, was probably a factor in allowing these mutations to spring up, Akey said. “I think that is undoubtedly true,” he said.

Some of the genes identified in the scan also affect peoples’ response to drugs. That could explain why some people are helped, for example, by a cholesterol-lowering drug while others may not be. There wouldn’t have been much “selective pressure” on these genes before the modern drug era, but that doesn’t mean the genes were not influenced by something else. “It turns out that genes involved in adverse drug responses also have different biological roles,” Akey said – for instance, detoxifying certain foods.

There may even be more evolution in the future, Akey predicted. One example – phenylketonuria or PKU. It’s caused by a mutation in a gene that breaks down an amino acid called phenylalanine. People with PKU mutations must eat a strict, low-protein diet or they can develop seizures and mental retardation.

Now newborns are routinely tested for PKU so they can start the diet immediately and avoid any brain damage. Akey said because these kids can now grow up and lead normal lives, they will likely start having children and the gene may become more common in the population.

Related stories:

• New project shows us living beyond our genes
• Fixing genes using cloning?
• Genetic test catches disease in newborns

LONDON -- They were the final resting place for victims of the Black Death, but London’s underground medieval plague pits are now unlocking the secrets of modern-day infectious diseases.

The bodies of tens of thousands of Londoners were thrown into communal graves after one of the most devastating epidemics in human history swept through Europe in the 14th century.

Between 1348 and 1351, the Black Death -- or bubonic plague -- killed up to three in five people as it spread rapidly through pre-industrial cities, unchecked by sanitation or modern medicine. That, and subsequent waves of the Yersinia pestis bacterium, claimed the lives of tens of millions of Europeans.

WHO map: Spread of bubonic plague in Europe

Direct descendants of the same plague still exist, killing about 2,000 people each year – although they are often now treatable with antibiotics.

Earlier this month, a 7-year-old girl contracted a genetic variant of Black Death at a campground in Colorado.

The girl, who was treated for the illness in a Denver hospital, is thought to have caught the disease in the same way as her medieval ancestors - from fleas living on rodent carcasses.

Next month, a conference of forensic scientists will hear how an international team of experts - led by researchers based at McMaster University in Hamilton, Canada, and the University of Tubingen in Germany - sequenced the entire genome of the Black Death using DNA extracted from plague victims.

The team used DNA from bodies buried at pits including one at East Smithfield, now underneath the heart of central London.

It is the first time an ancient disease has been reconstructed, providing clues as to how it has evolved and whether it could strike again in future.

The scientists hope their work heralds a new era of research into infectious disease.

Additional reporting by Alastair Jamieson, NBC News

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