New Bird Flu No Immediate Threat: U.S. Experts

There's been no clear evidence of human-to-human transmission in Chinese outbreak

By Amanda Gardner

HealthDay Reporter

TUESDAY, April 9 (HealthDay News) -- At this point, there's no reason to believe that the emerging H7N9 strain of bird flu that has sickened at least 24 people and killed seven in China is cause for alarm, health officials in the United States say.

For one thing, no cases of human-to-human transmission of the virus have yet been reported -- a necessary precursor to a full-blown pandemic.

"This is very early in the course of identification of human cases," said Dr. John Midturi, assistant professor of internal medicine at the Texas A&M Health Science Center College of Medicine, in Temple.

"We do see something similar every few years with avian [bird] flu," added Richard Webby, a member of the department of infectious diseases at St. Jude's Children's Research Hospital in Memphis.

But this year's strain does seem a little different.

"What's making everyone a little bit more uneasy is that, looking at the sequence of the virus, it appears to have some mutations we think may indicate that the virus might have increased its ability to replicate in humans," Webby said.

But for now, there's no proof of that ability, he cautioned, and the genetic sequence of the virus would still need to change for it to pass easily from person to person.

The first human cases were not identified until March 31, according to published reports.

It's possible that the H7N9 virus is also found in some type of mammal, such as swine, and public-health officials are working to identify possible hosts.

"We don't think that necessarily just this virus growing in [birds] would cause some of these [genetic] changes," said Webby, who's also director of the World Health Organization Collaborating Center for Studies on the Ecology of Influenza Viruses in Lower Animals and Birds. "We can't say with any sort of gusto that the last host of this virus was an avian host. Avian flu is a very generic sort of term.

Chinese authorities are taking precautions against further spread of the virus, suspending sales of live poultry in Shanghai and slaughtering poultry in markets where the virus has been detected.

On Monday, the World Health Organization announced that it was in talks with the Chinese government about sending experts to help investigate the outbreak.

The good news is that most of the human cases "have been associated with poultry exposure, which is typical with most bird flu outbreaks," Midturi said.

However, the flu strain has also been found in live pigeons being sold as poultry at a market in Shanghai. That has unnerved some experts since any infection among wild pigeons would be tougher to control than among penned-in poultry.

The fatality rate from H7N9 also remains unclear. Although the death rate in China seems high, with six deaths out of 16 confirmed cases, authorities don't know at this point how many people have actually been infected. If hundreds or thousands of people contracted the virus with few or no symptoms, the true fatality rate would be much lower, said Midturi, who is also director of infectious disease at Scott & White Memorial Hospital in Temple.

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New Bird Flu No Immediate Threat: U.S. Experts

Title: New Bird Flu No Immediate Threat: U.S. Experts
Category: Health News
Created: 4/9/2013 10:35:00 AM
Last Editorial Review: 4/9/2013 12:00:00 AM

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MERS Virus May Never Become Big Threat in U.S., Experts Say

New strain will most likely weaken over time, infection specialists explain

By Steven Reinberg

HealthDay Reporter

THURSDAY, June 6 (HealthDay News) -- Anyone who has watched the movie "Contagion" has seen how fast a virus can spread and how deadly it can be, but is it reality?

Much like the film, a new emerging virus called the Middle East respiratory syndrome coronavirus (MERS-CoV), which kills half the people it infects, has spread from the Middle East to Europe. Since September, there have been 54 reported cases and 30 deaths, making some consider it a worldwide threat.

"Looking at the overall global situation, my greatest concern right now is the novel coronavirus," Dr. Margaret Chan, director-general of the World Health Organization, told delegates at a recent meeting. "The novel coronavirus is a threat to the entire world."

Experts, however, aren't sure the virus is as big a threat as Chan believes.

"Anytime there is a new virus that has the potential to kill people, we ought to take it seriously," said Dr. Marc Siegel, an associate professor of medicine at NYU Langone Medical Center in New York City.

But while Siegel believes the virus's spread should be tracked and studied, he doubts it will ever become a real threat.

"Fear is the biggest virus going," he said. "The amount of concern is already outweighing the risk. People have seen 'Contagion' too many times."

MERS-CoV is one of many viruses that can cause everything from the common cold to severe acute respiratory syndrome (SARS). This virus, however, is new and it's not SARS.

Comparing this virus to the 2003 SARS outbreak is a mistake, Siegel said. "The SARS outbreak, although it was also a coronavirus, was overly hyped. You ended with 8,000 cases around the world and only about 700 deaths."

Every year, the flu kills more than 30,000 people in the United States alone and 500,000 around the world, he said, to put things in perspective.

When a new virus like MERS-CoV comes along, it is often very deadly, but as it spreads it becomes less so, Siegel explained.

"The fact that it has a 50 percent mortality rate means it's a very serious virus, but as viruses get out in the world more, the mortality rate usually goes down," he explained. "With SARS, it started at 50 percent and ended up at 10 percent."

The reason viruses get less deadly is simply that a virus that kills its host can't survive to infect others. "If the virus kills its host, it's much harder to spread," Siegel said.

The key question is how easily does the virus travel from one person to another. "Right now, it does not look that transmissible. Otherwise, it would have spread already more than it has," he said.

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Threat to U.S. from new “bird flu” virus: possible but unknown

Posted May 17, 2013, 2:23 pm

Beginning in March, 2013, reports started to come out of Eastern China that a new “bird flu” virus was loose and causing infections in humans. The new virus is called H7N9. Should we in the U.S. be worried?

Neither I nor anyone I know can give a confident answer to that question. What makes flu viruses so unpredictable is that they are constantly changing or mutating their genes. They also are constantly swapping their genes with the genes of other flu viruses. When they change or swap their genes, they change their character.

When I hear about a new flu virus, I want to know two things about it: how easily is it spread from one person to another, and how sick does it make the people it infects?

A report from the U.S. Centers for Disease Control and Prevention (CDC), and another from a team from China in this week’s New England Journal of Medicine, indicate that so far the new H7N9 virus has not clearly spread from one person to another, and has not spread outside of Eastern China. But things can change quickly with flu viruses.

H7N9 has made people very sick, however. Indeed, all three of the people infected with virus described in the New England Journal of Medicine died.

As of the end of April, the CDC said that China had reported 126 human cases of the new flu. The people tend to be older (average age in their 60s) and many have had chronic illnesses. Fewer children and young adults have been infected, so far.

The world is full of different flu viruses. Most of them infect just animals, often just one type of animal. Sometimes a flu virus “jumps” from one animal to another. Sometimes, it is even able to jump from animals to humans. That’s what has happened with H7N9. It has jumped from chickens and ducks to humans.

So far, none of the health care workers caring for people stricken with the new virus have contracted the virus. No travelers from China to the U.S. have been found carrying the virus.

In other words, as I write this article, there does not appear to be a clear threat to people outside of Eastern China. But every public health agency around the world is keeping a close eye on China. That’s because a virus that cannot spread easily from one person to another can change or swap genes—and suddenly be capable of spreading easily. We know of no reason why this could not happen with H7N9. And we know that it can produce severe, even fatal, illness.

How bad can a flu virus be? The worst flu outbreak for which we have good records occurred in 1918. A new virus emerged that spread easily between people and made people very sick.

How easily, and how sick? In the course of a few months, 30% of the people in the world caught the virus, and at least 20 million people died. That’s more than were killed in World War I.

Here in Boston, at the height of the pandemic, 200 dead people every day were carried through the streets in horse-drawn wagons, and often buried in mass graves. As in many other cities around the world, overnight there were hundreds and thousands of orphans. The grandmother of one of my colleagues on the faculty here was one of those orphans. I am not being melodramatic: the worse influenza pandemics can be truly awful.

The CDC and scientists at the National Institutes of Health (NIH) are working overtime to protect our health. But these two critically important federal agencies have just had their budgets slashed by the “sequester.”

Regardless of what you think about federal spending in general, if you share my view that we should not be cutting funding for health research and public health, you could do what I have done. Write your representatives in Congress to restore cuts in the CDC and NIH budgets.

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