How does the flu virus work?

Newswise — Viruses are nasty, yet surprisingly simple organisms. Most human flu viruses have 11 genes at most, compared to the more than 20,000 genes found in humans.

What makes flu so potentially dangerous is that it’s not very good at making copies of itself, which leads to mutations, or slight changes in its genetic code. Though most mutations don’t amount to anything, some can lead to new versions – or strains – of the flu that could spread more easily or make people sicker once infected.

Dr. Richard Scheuermann, professor of pathology at UT Southwestern Medical Center, said a virus’ ability to mutate partly explains why the seasonal flu vaccine is ineffective against the H1N1 or “swine flu” strain.

“H1N1 is very different from the normal seasonal flu, especially in parts of the virus normally recognized by our protective immune system,” said Dr. Scheuermann, who is also principal investigator of the National Institutes of Health-funded Influenza Research Database. “H1N1 has not mutated in such a way as to make people sicker, but it is important to follow the public health guidelines for who should get vaccinated as the H1N1 vaccine becomes more widely available.”

Does the H1N1 outbreak mean you have to skip the ham this holiday season?With H1N1 – or swine flu - continuing to make headlines in the media, many people who traditionally feast on ham are wondering whether it’s necessary to skip pork and go all-turkey or even vegetarian this holiday season.

Lona Sandon, assistant professor of clinical nutrition at UT Southwestern Medical Center, said diners should go ahead and enjoy ham at their holiday celebrations.

“You can’t catch swine flu from eating pork or pork products,” said Ms. Sandon, a spokeswoman for the American Dietetic Association. “Cooking pork to an internal temperature of at least 160 degrees Fahrenheit kills most bacteria and viruses, including H1N1.”

Raw pork is also safe from swine flu, but individuals handling raw meat of any kind should make sure they wash their hands with soap and warm running water afterwards to avoid spreading bacteria found on raw meat that can cause food poisoning, she said.

What are the ‘underlying medical conditions’ that can raise dire consequences?

Almost without fail, news reports concerning a H1N1 virus-related death include the notation that the infected individual had “underlying medical conditions” which figured into the disease’s dire outcome.

But what exactly does that all-too-common phrasing mean in regard to the H1N1 virus, commonly known as “swine flu?” What are the most common underlying medical conditions?

Dr. Jeffrey Kahn, chief of pediatric infectious diseases at UT Southwestern Medical Center, said the terminology refers to those conditions which are known to be risk factors for severe influenza infection. In other words, individuals with these conditions are more likely to get severe disease when infected with influenza than those who do not have conditions.

Asthma, chronic pulmonary lung disease, pregnancy, diabetes and other immune-suppressing illnesses are considered “underlying medical conditions” that may contribute to H1N1 becoming fatal. Dr. Kahn said anyone with a medical condition such as those should get both the seasonal flu and H1N1 vaccines.

“People with other health problems such as asthma or cancer are simply more vulnerable,” he said. “Why otherwise healthy people get very ill remains unclear, but it could be that some people have a genetic susceptibility to this virus.”

Do you need vaccinations if you’re well past puberty?

When you’re rolling a sleeve up to get the flu shot this year, you might take a minute and ask whether any other immunizations are due, or overdue.

Dr. R. Doug Hardy, an infectious disease specialist at UT Southwestern Medical Center, says that while immunizations are one of the 10 greatest American achievements of the past century, only children’s vaccines are well utilized.

“People need to be more aware of the value of adult vaccines,” Dr. Hardy says.

He said the numbers are low partly because many adults incorrectly assume that the vaccines they received as children will last a lifetime. Still others weren’t immunized as children.

Dr. Hardy says adults should discuss the recommended vaccination schedule with their doctor and determine whether they should be immunized against any of the following conditions:

• Influenza• Pneumococcal (polysaccharide)• Hepatitis A/B• Measles, mumps, rubella (MMR)• Tetanus, diphtheria, pertussis (Td/Tdap)• Human papillomavirus (HPV)• Varicella• Meningococcal

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