Post by Pam on Aug 29, 2009 16:59:27 GMT -5
What We Know About Swine Flu
Prevention, transmission, symptoms
By: Katharine Greider | Source: AARP Bulletin Today | April 28, 2009
Pigs routinely get infected with certain types of influenza virus. That’s nothing new. And sometimes people directly exposed to hogs pick up a flu virus circulating in the animal population. (Pigs can catch human flu, too.) It’s also true that new strains of influenza are emerging all the time. For a virus, mutation is the name of the game.
What’s different about the new strain of swine flu first identified last week in Mexico is that it apparently can be transmitted not only from pig to person, but from person to person. The illness is contagious from one day before onset of symptoms to seven days after. And, if the cases emerging from the outbreak’s epicenter in Mexico City are an indication, it can be deadly in relatively healthy young people. These conditions raise the possibility that the virus could spread quickly through communities around the world, taking a heavy toll.
It’s this threat that had federal officials declaring the swine flu a “public health emergency” Sunday, authorizing the distribution to states of 12.5 million doses of the flu medicine Tamiflu from government stockpiles. Meanwhile, the World Health Organization (WHO) and U.S. Centers for Disease Control and Prevention (CDC) have mounted an aggressive investigation into just how this bug behaves. The key questions: How easily does it spread? How dangerous is it to those infected?
With new cases, both confirmed and suspected, being reported by the hour—and with more expected—health officials are scrambling to get a representative picture of the disease. Importantly, most have been relatively mild, perhaps even more so than some cases of seasonal flu.
Though young people have fallen ill from this strain of swine flu, there’s little reason to suspect that a typical pattern of vulnerability won’t hold true, says David A. Pegues, M.D., an epidemiologist in the Division of Infectious Diseases at the University of California, Los Angeles. “People of all ages are susceptible to influenza,” he says. “It’s those that are very young and older, as well as those with underlying heart or lung disease, who are at greatest risk of complications.”
Indeed, in Mexico, among more than 1,900 reported cases, Mexican officials have identified 149 suspected swine flu deaths, giving the outbreak there a far more worrying profile. Some patients have quickly developed pneumonia and respiratory distress. It’s not clear why.
It could be that a pattern of more virulent cases will become apparent outside Mexico once more cases are observed, says Ron Fouchier, who studies animal and human influenza in the department of virology at Rotterdam’s Erasmus University. Or, he says, it could be that there’s a difference in the populations’ underlying health or health care delivery. “It’s just too early to draw any strong conclusions,” he says. Cases have been confirmed in Canada, Scotland, the United Kingdom, Spain and Israel. New Zealand has confirmed cases as winter flu season is set to begin—a potential test of just how transmissible the new strain is, says Fouchier.
“I think we’re going to find more [U.S.] communities where this virus is confirmed,” says Doug Campos-Outcalt, M.D., professor of family and community medicine at the University of Arizona in Phoenix and a scientific analyst for the American Academy of Family Physicians (AAFP). “Physicians should be expecting to get these calls [from patients]. They’re going to have to develop a triage system to determine who should come in and who shouldn’t and to make sure that infection doesn’t get spread in the office.” Fortunately, he says, in the last several years the AAFP and other physician groups have been preparing for such an eventuality.
The CDC already has issued guidelines to doctors about when to suspect swine flu and treat with the prescription antiviral medications Tamiflu and Relenza. Tests have shown the swine flu virus is susceptible to these two drugs, which lessen the severity of illness if taken within 48 hours of onset. The CDC also is recommending they be used to prevent sickness in certain “close contacts” of infected persons who are at risk of complications. Widespread use of the drugs for prevention is not recommended, says Pegues, in part because that can promote drug resistance.
Aside from old-fashioned infection-control practices, the best hope for prevention lies in a vaccine. The CDC has developed “seed stock” of the novel strain for potential use in such a vaccine, but has not yet asked manufacturers to tackle that project, which could take months and divert their efforts from development of next year’s regular flu vaccine.
SWINE FLU SYMPTOMS AND PREVENTION
The symptoms of swine flu are essentially indistinguishable from the familiar misery of seasonal flu: fever, coughing, sore throat, body aches, headache, sometimes vomiting and diarrhea. The CDC suggests people worried about such symptoms call their doctor, especially if they live in a community with swine flu cases or have traveled to such an area. More serious problems like difficulty breathing call for emergency medical attention.
Just like regular seasonal flu virus, the swine flu virus is thought to spread on droplets emitted by coughing and sneezing or deposited on hands and surfaces, then transferred to nose or mouth. Thus, practicing the usual precautions will help prevent its spread:
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Katharine Greider is based in New York and writes about medical issues and health policy.
Prevention, transmission, symptoms
By: Katharine Greider | Source: AARP Bulletin Today | April 28, 2009
Pigs routinely get infected with certain types of influenza virus. That’s nothing new. And sometimes people directly exposed to hogs pick up a flu virus circulating in the animal population. (Pigs can catch human flu, too.) It’s also true that new strains of influenza are emerging all the time. For a virus, mutation is the name of the game.
What’s different about the new strain of swine flu first identified last week in Mexico is that it apparently can be transmitted not only from pig to person, but from person to person. The illness is contagious from one day before onset of symptoms to seven days after. And, if the cases emerging from the outbreak’s epicenter in Mexico City are an indication, it can be deadly in relatively healthy young people. These conditions raise the possibility that the virus could spread quickly through communities around the world, taking a heavy toll.
It’s this threat that had federal officials declaring the swine flu a “public health emergency” Sunday, authorizing the distribution to states of 12.5 million doses of the flu medicine Tamiflu from government stockpiles. Meanwhile, the World Health Organization (WHO) and U.S. Centers for Disease Control and Prevention (CDC) have mounted an aggressive investigation into just how this bug behaves. The key questions: How easily does it spread? How dangerous is it to those infected?
With new cases, both confirmed and suspected, being reported by the hour—and with more expected—health officials are scrambling to get a representative picture of the disease. Importantly, most have been relatively mild, perhaps even more so than some cases of seasonal flu.
Though young people have fallen ill from this strain of swine flu, there’s little reason to suspect that a typical pattern of vulnerability won’t hold true, says David A. Pegues, M.D., an epidemiologist in the Division of Infectious Diseases at the University of California, Los Angeles. “People of all ages are susceptible to influenza,” he says. “It’s those that are very young and older, as well as those with underlying heart or lung disease, who are at greatest risk of complications.”
Indeed, in Mexico, among more than 1,900 reported cases, Mexican officials have identified 149 suspected swine flu deaths, giving the outbreak there a far more worrying profile. Some patients have quickly developed pneumonia and respiratory distress. It’s not clear why.
It could be that a pattern of more virulent cases will become apparent outside Mexico once more cases are observed, says Ron Fouchier, who studies animal and human influenza in the department of virology at Rotterdam’s Erasmus University. Or, he says, it could be that there’s a difference in the populations’ underlying health or health care delivery. “It’s just too early to draw any strong conclusions,” he says. Cases have been confirmed in Canada, Scotland, the United Kingdom, Spain and Israel. New Zealand has confirmed cases as winter flu season is set to begin—a potential test of just how transmissible the new strain is, says Fouchier.
“I think we’re going to find more [U.S.] communities where this virus is confirmed,” says Doug Campos-Outcalt, M.D., professor of family and community medicine at the University of Arizona in Phoenix and a scientific analyst for the American Academy of Family Physicians (AAFP). “Physicians should be expecting to get these calls [from patients]. They’re going to have to develop a triage system to determine who should come in and who shouldn’t and to make sure that infection doesn’t get spread in the office.” Fortunately, he says, in the last several years the AAFP and other physician groups have been preparing for such an eventuality.
The CDC already has issued guidelines to doctors about when to suspect swine flu and treat with the prescription antiviral medications Tamiflu and Relenza. Tests have shown the swine flu virus is susceptible to these two drugs, which lessen the severity of illness if taken within 48 hours of onset. The CDC also is recommending they be used to prevent sickness in certain “close contacts” of infected persons who are at risk of complications. Widespread use of the drugs for prevention is not recommended, says Pegues, in part because that can promote drug resistance.
Aside from old-fashioned infection-control practices, the best hope for prevention lies in a vaccine. The CDC has developed “seed stock” of the novel strain for potential use in such a vaccine, but has not yet asked manufacturers to tackle that project, which could take months and divert their efforts from development of next year’s regular flu vaccine.
SWINE FLU SYMPTOMS AND PREVENTION
The symptoms of swine flu are essentially indistinguishable from the familiar misery of seasonal flu: fever, coughing, sore throat, body aches, headache, sometimes vomiting and diarrhea. The CDC suggests people worried about such symptoms call their doctor, especially if they live in a community with swine flu cases or have traveled to such an area. More serious problems like difficulty breathing call for emergency medical attention.
Just like regular seasonal flu virus, the swine flu virus is thought to spread on droplets emitted by coughing and sneezing or deposited on hands and surfaces, then transferred to nose or mouth. Thus, practicing the usual precautions will help prevent its spread:
- Use a tissue when you cough or sneeze, and throw it away promptly. If you don’t have a tissue, cough into your sleeve.
- Wash your hands thoroughly and often, especially after sneezing or coughing, using soap and water or an alcohol rub.
- Wipe surfaces like doorknobs using a regular cleaner.
- If you’re sick with flu-like symptoms, even if you don’t feel sick enough to go to the doctor, stay home from work or school to avoid giving the virus to someone else.
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Katharine Greider is based in New York and writes about medical issues and health policy.