Nope, nothing to worry about.
Asian bird flu claims two more victims
Health officials brace for possibility of pandemic
NEW YORK - Officials in Vietnam announced Tuesday that a 35-year-old man and a 14-year-old girl had tested positive for a potentially lethal bird flu virus known as H5N1, which has been spreading among chickens and other birds in Southeast Asia. These are the latest cases in what many public health officials worry is the possible beginning of a worldwide outbreak of a deadly new flu.
The virus has now killed millions of birds and infected more than 50 people, killing three out of every four patients. Now there is evidence that in rare cases it can spread from person to person.
"The virus is clearly going in what we call the wrong direction for us," says Dr. Anthony Fauci, director of the National Institute of Allergies and Infectious Diseases.
The big concern is that the virus will mutate even more until it reaches the point that it spreads easily from person to person. The result would be what scientists call a pandemic — a worldwide outbreak of a virus to which people have no immunity.
That situation is what happened in 1918 when 20 million to 50 million people around the world died from a new strain of flu that also originated in birds. Experts agree there will be another flu pandemic, but no one knows when.
"It absolutely dwarfs all other public health problems that we can imagine," says Dr. Michael Osterholm, director of the Center for Infectious Disease Research and Policy.
There are at least 15 different types of avian influenza that routinely infect birds around the world. The current outbreak is caused by a strain known as H5N1, which is highly contagious among birds and rapidly fatal. Unlike many other strains of avian influenza, it can be transmitted to humans, causing severe illness and death.
Bird flu is not the same as SARS (severe acute respiratory syndrome). Although their symptoms are similar, SARS is caused by completely different viruses. Influenza viruses also are more contagious and cannot be as readily contained as SARS by isolating people who have the infection.
Influenza viruses are highly unstable and have the ability to mutate rapidly, potentially jumping from one animal species to another. Scientists fear the bird flu virus could evolve into a form that is easily spread between people, resulting in an extremely contagious and lethal disease. This could happen if someone already infected with the human flu virus catches the bird flu. The two viruses could recombine inside the victim’s body, producing a hybrid that could readily spread from person to person.
The resulting virus likely would be something humans have never been exposed to before. With no immune defenses, the infection could cause devastating illness, such as occurred in the 1918-19 Spanish flu pandemic, which killed an estimated 40 million to 50 million worldwide.
In rural areas, the H5N1 virus is easily spread from farm to farm among domestic poultry through the feces of wild birds. The virus can survive for up to four days at 71 F (22 C) and more than 30 days at 32 F (0 C). If frozen, it can survive indefinitely.
So far in this outbreak, human cases have been blamed on direct contact with infected chickens and their droppings. People who catch the virus from birds can pass it on to other humans, although the disease is generally milder in those who caught it from an infected person rather than from birds.
If the virus mutates and combines with a human influenza virus, it could be spread through person-to-person transmission in the same way the ordinary human flu virus is spread.
The current outbreak of bird flu is different from earlier ones in that officials have been unable to contain its spread. An outbreak in 1997 in Hong Kong was the first time the virus had spread to people, but it was much more quickly contained. A total of 18 people were hospitalized with six reported deaths. About 1.5 million chickens were killed in an effort to remove the source of the virus.
Unlike the 1997 scare, this outbreak has spread more rapidly to other countries, increasing its exposure to people in varied locations and raising the likelihood that the strain will combine with a human influenza virus.
Bird flu can cause a range of symptoms in humans. Some patients report fever, cough, sore throat and muscle aches. Others suffer from eye infections, pneumonia, acute respiratory distress and other severe and life-threatening complications.
Flu drugs exist that may be used both to prevent people from catching bird flu and to treat those who have it. The virus appears to be resistant to two older generic flu drugs, amantadine and rimantadine. However, the newer flu drugs Tamiflu and Relenza are expected to work – though supplies could run out quickly if an outbreak occurs.
Currently there is no vaccine, although scientists are working to develop one. It probably will take several months to complete and may not be ready in time to stop a widespread human outbreak, if one occurs.
Rapid elimination of the H5N1 virus among infected birds and other animals is essential to preventing a major outbreak. The World Health Organization recommends that infected or exposed flocks of chickens and other birds be killed in order to help prevent further spread of the virus and reduce opportunities for human infection. However, the agency warns that safety measures must be taken to prevent exposure to the virus among workers involved in culling.
To prepare for such an event, the federal government has already purchased two million doses of a vaccine made from a bird flu virus taken from a man who died in Vietnam. Tests haven't yet begun to determine whether it is safe or effective.
"If you wait for that, you are so far behind the eight ball it would be almost impossible to catch up," says Fauci.
Others point out that even 2 million doses is a fraction of what might be needed. And vaccine manufacturers, which have had plenty of problems of their own in the past year, would have trouble meeting the real demand.
"We've got a long ways to go yet to be able to even cover our population in a timely manner, let alone the rest of the world," says Osterholm.
As additional preparation, the United States has stockpiled about 2.3 million doses of antiviral medicine. But other countries have much more: Britain 14 million doses, France 13 million and Canada more than 8 million.
Who would get the scarce drugs and vaccine in the event that a flu epidemic spread to the United States? The Centers for Disease Control and Prevention has asked a group of ethicists to try to decide.