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Tuesday, Nov. 30, 2010

FYI

INFLUENZA

Flu prevention advice nothing to sneeze at


Staff writer

As winter sets in, hospitals are calling for people to get flu shots.

News photo
Little protection: People wear surgical masks in Tokyo's Marunouchi district. SATOKO KAWASAKI PHOTO

Last year, the spread of the H1N1 swine influenza caused an international health scare. How about this year?

Following are some basic questions and answers on influenza:

What is influenza?

In humans, the flu is an infectious disease caused by influenza virus pathogens that enter the body and multiply, causing inflammation of the respiratory tract, muscular pain and other maladies.

According to the book "Shiro! Fusego! Influenza" ("Let's Know About and Prevent Influenza!") by Drs. Masato Tashiro and Harue Okada, the virus can largely be divided into three types: A, B and C.

Type A consists of 144 kinds of viruses that exhibit severe symptoms, Type B is widespread and commonplace every year and Type C is milder and less contagious, the book said.

Influenza viruses enter their host's cells, multiply, exit and repeat this cycle infinitely, the book said. The viruses have H and N thorns. H thorns cling to and enter cells and N thorns break the outer membrane of cells to get out.

Ancient astrologers blamed the disease on the influence of stars. The word influenza is the Italian word for influence.

What is the route of infection?

The viruses are borne in vapor and water droplets exiting the mouth, nose and other orifices of a carrier. If these are subsequently inhaled or otherwise find a new host, they repeat the process in the new victim.

An infection can also occur by having physical contact with something contaminated with the virus, according to the book. If a flu carrier uses a hand, for example, to cover a cough or sneeze and subsequently handles a telephone or grips a train passenger strap, traces of the virus would be left on those items for someone else to come into contact with.

The unsuspecting victim needs only to then touch a nose or mouth to ingest the disease via mucous membranes.

Which influenza is likely to be prevalent this winter?

Any type of A-H3N2, A-H1N1 or B can potentially be prevalent, said Shuichiro Hayashi, an official at the Health, Labor and Welfare Ministry.

Although A-H3N2 could be fatal to senior citizens or people with weak immune systems, Hayashi said A-H1N1 can affect a wide range of people from babies to adults.

Vaccinations against all flu types are amply available at medical institutions, Hayashi said. "As we do not know which (type of influenza) will be prevalent this year, we would urge all generations of people to be cautious," he said. How can infection be prevented?

Wearing a surgical mask in crowded places can be helpful in lessening the chances of inhaling the virus, Tashiro and Okada's book said.

The book urges people to keep their hands washed. When using a mask, make sure it covers the nose, mouth and chin, use metal nose clips, and securely fix the mask with the rubber ear strings.

When taking off the mask, pull it off by the strings, don't make contact with the mask, place it in a plastic bag, and tie the bag before discarding, and then wash your hands again.

The authors also recommend spending at least 15 seconds washing your hands after returning home, using the bathroom, or coughing and sneezing, as well as before cooking or eating. Gargling is also considered helpful, as is a nutritionally balanced and regular diet.

Food supplements and intravenous drips of highly concentrated vitamin C can be effective preventive medicine, according to the book "Issho Influenza ni Kakaranai Taishitsu no Tsukurikata" ("How to Create a Body that will Never Catch Influenza") by Dr. Kazuhiro Murakami.

Keep room humidity levels set at 50 to 60 percent, and drink 1 to 1.5 liters of water per day, Murakami suggests.

The book by Tashiro and Okada suggests getting vaccinated, although vaccines may not work in some cases because influenza viruses can easily mutate.

If infection occurs, what should one do?

Wearing a surgical mask and keeping one's hands washed are common-sense protective measures.

Infected people should cover their mouths and noses when coughing or sneezing, and keep at least 1 meter away from others.

People who suspect they have come down with a new type of flu should go to a hospital, but avoid using public transportation if possible and keep aware of the health of others in their immediate midst.

Is it possible for victims to contract influenza more than one time?

Yes.

Dr. Kiyosu Taniguchi, a researcher at the Infectious Disease Surveillance Center of the National Institute of Infectious Diseases, said that some people are habitual victims of influenza.

This is because the virus mutates and spreads from people to people easily, making it impossible to avoid getting infected with new and different strains, he said.

Taniguchi also noted that theoretically, people can get infected again within a week's time with the same virus, as it takes around two weeks to develop an immunity.

What about past flu epidemics?

The Spanish flu spread around the world between 1918 and 1920. Out of the world's population of 1.8 billion back then, the death toll amounted to between 40 million and 80 million.

The book by Tashiro and Okada even reckoned one of the reasons World War I (1914-1918) ended was because soldiers were falling ill.

Since then, new influenza epidemics have occurred every dozen years.

The Asian flu pandemic in 1957 claimed more than 2 million lives and the Hong Kong flu outbreak in 1968 killed over 1 million.

Can influenza ever be completely eradicated?

"It's impossible," said Taniguchi of the National Institute of Infectious Diseases.

The type A virus originated in waterfowl. Unless all aquatic birds are destroyed, Taniguchi said the disease would be impossible to destroy.

Then there's the problem of people carrying the virus and not displaying any symptoms, he noted, thus ridding the world of the disease can't be done.

The Weekly FYI appears Tuesdays (Wednesday in some areas). Readers are encouraged to send ideas, questions and opinions to National News Desk


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