Jan. 28, 2004
Lisa Schlein
Geneva
Graphic: Graphic showing the spread of bird flu across Asia (AFP/Martin Megino)
In the first warning to U.S. citizens about bird flu, the government urged doctors Tuesday to ask patients with flu-like symptoms if they have traveled to places in Asia where bird flu has broken out.
The goal is to prevent the possible human spread of the virus, although there have been no documented cases of this occurring during the Asian outbreak.
“We are taking this very seriously right now,” said Dr. Julie Gerberding, head of the Centers for Disease Control and Prevention in Atlanta.
No cases of bird flu in either people or birds have been seen so far in the United States.
Gerberding said if doctors find that patients with flu symptoms have been in Vietnam or other places with bird flu, they should test for the virus. If it turns out they have influenza A, then state and local health departments working with CDC can check further to see if it is the H5N1 bird flu strain.
Tell doctors about overseas travel
Gerberding said people who might have the flu should voluntarily tell doctors about their Asian travels if no one asks them about it.
Bird flu basics
• Introduction
The rapid spread of bird flu, which is not uncommon among chickens and other fowl, has caught the attention of global health authorities. Click on the topics to learn more about the illness and why scientists are so concerned.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.
• What is it?
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.
Photo: Chickens look out from their cage in a poultry farm in Crevedia (25km north of Bucharest), January 27, 2004. Romania has joined other states in banning the import of poultry, eggs and other related products from Thailand, Taiwan, Vietnam and Japan on fears of the deadly bird flu virus, and imposed tougher hygiene measures at poultry farms. (REUTERS/Bogdan Cristel)
• Why the concern?
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.
• Transmission
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.
• History
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.
• Symptoms
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.
• Treatment
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. Sources: AP, CDC & WHO
• Prevention
“I want to emphasize that right now it appears to be very unlikely, but we want to be very vigilant and to make sure we are doing everything we can to detect any possible introduction here,” Gerberding said.
She urged people who travel to areas with outbreaks to stay away from poultry farms, live animal markets or any surfaces contaminated with bird droppings.
So far, H5N1 bird flu has been found in eight Asian countries, and eight people are known to have died from the infection. While all appear to have caught the virus from chickens, experts suspect the disease can be passed person to person, since that occurred during a similar outbreak in Hong Kong in 1997.
Photo: A Chinese man holds feathers near chickens at a market in Guangzhou, southern China, Saturday, Jan. 17, 2004. China on Thursday banned all chicken imports from Vietnam, Japan and South Korea over fears of a bird flu spreading rapidly as its health ministry issued an urgent notice for vigilance against the disease. (AP Photo/Ng Han Guan)
The ultimate fear, though, is that someone will catch the bird flu while already infected with the ordinary human flu virus. The two viruses might swap genes, creating a mutant that could spread easily with disastrous results.
No travel alert or advisory yet
Considering the millions of chickens infected with the virus, spread to humans appears to be rare. Gerberding said there is no indication so far for a travel alert or advisory for Americans going to areas affected by the outbreak.
Last year’s SARS outbreak was the last time U.S. doctors were told to be on special alert for the introduction of a contagious respiratory virus from abroad. Typically flu is much more contagious than SARS, so containing a human outbreak might be much more difficult than stopping SARS, which health officials did by isolating infected people.
Gerberding said the CDC is reviewing its infection control guidelines to be used “in the worst case scenario if we should have a patient with this disease and there is any suggestion of person-to-person transmission.” She said these would be similar to measures for containing regular flu and SARS.
According to the CDC, outbreaks of H5N1 flu have been reported among poultry in Cambodia, China, Indonesia, Japan, Myanmar, South Korea, Thailand and Vietnam. Another strain of the disease has been seen in wild flocks or poultry in Laos, Pakistan and Taiwan.
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