HEALTH: INFLUENZA (THE FLU) FLU SYMPTOMS & PREVENTION Swine Flu>>
What is Influenza (Flu, Flue)?
Influenza (flu) is a viral infection that attacks the respiratory system,
including your nose, throat, bronchial tubes and lungs. Influenza, which is
commonly called the flu, is not the same as the stomach viruses that
cause diarrhea and vomiting. People often use the term flu or flue to describe any kind of mild illness, such as a cold or a stomach virus that has symptoms like the flu.
But the real flu is different. Flu symptoms are usually worse than a cold and last longer. The flu usually does not cause vomiting or diarrhea. The flu is a contagious infection of the nose, throat, and lungs caused by the influenza virus.
Anyone can get the flu, but young children, older adults, people with weakened immune systems and those with chronic illnesses are especially vulnerable. If you're at high health risk of the flu, your first line of defense is an annual flu shot as a preventive health measure. Most flu outbreaks happen in late fall and winter.
Compared with most other viral respiratory infections, such as the common cold, influenza (flue) infection often causes a more severe illness with a mortality rate (death rate) of about 0.1% of people who are infected with the virus.
Approximately 50 million people died worldwide in the 1918 influenza pandemic. Today, according to the Centers for Disease Control and Prevention, as many as 36,000 people in the United States die each year of complications of influenza and more than 200,000 are hospitalized.
The flu is a serious illness that can be fatal in people
whose immune systems are weakened, the elderly, and those with chronic health
conditions. Even healthy people who develop the flu cannot work, attend school,
or participate in normal activities for several days. Complications of the flu
can develop in anyone and include pneumonia, ear infections, sinus infections,
or bronchitis.
While a vaccine is available to prevent the flu, its effectiveness varies according to the degree of match between the viral strains used to prepare the vaccine and those strains actually in circulation in a given year. Not everyone receives the flu vaccine, and even some of those who do can develop flu symptoms.
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Also see: Emphysema Lung Cancer Bronchitis Asthma Allergies Pneumonia Sinuses Common Cold Swine Flu
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Health: Causes of Influenza (Flu, Flue)
The flu is caused by influenza viruses A, B, and C. There are different strains of the flu virus every year. In temperate climates, influenza A usually arrives between early winter and early spring. Influenza B can appear at any time of the year.
Influenza types A and B are responsible for epidemics of respiratory illness that occur almost every winter and are often associated with increased rates of hospitalization and death. Influenza type C differs from types A and B in some important ways. Type C infection usually causes either a very mild respiratory illness or no symptoms at all; it does not cause epidemics and does not have the severe public health impact of influenza types A and B. Efforts to control the impact of influenza (flue) are aimed at types A and B.
Influenza viruses continually change over time, usually by mutation. This constant changing often enables the virus to evade the immune system of humans, birds, and other animals, so that the health of humans and animals is susceptible to changing influenza (flue) virus infections throughout life. Once you've had the flu, you develop antibodies to the strain that caused it, but those antibodies won't protect you from new strains. That's why doctors recommend getting a flu shot every year.
Flu viruses travel through the air in droplets when someone with the
infection coughs, sneezes or talks. You can inhale the droplets
directly, or you can pick up the germs from an object, such as a
telephone or computer keyboard, and then transfer them to your eyes,
nose or mouth.
Flu symptoms appear 1 - 7 days later (usually within 2 - 3 days). Because the flu spreads through the air and is very contagious, it often strikes a community all at once, causing an epidemic health illness. This creates a cluster of school and work absences. Many students become sick within 2 or 3 weeks of the flu's arrival in a school.
Tens of millions of people in the United States get the flu each year. Most get better within a week or two, but thousands become sick enough to be hospitalized. About 36,000 people die each year from complications of the flu.
Sometimes people confuse colds and flu, which share some of the same symptoms and typically occur at the same time of the year. However, the two diseases are very different. Most people get a cold several times each year, and the flu only once every few years.
People often use the term "stomach flu" to describe a viral illness where vomiting or diarrhea is the main symptom. This is incorrect, as the stomach symptoms are not caused by the flu virus. Flu infections are primarily respiratory infections.
Health: Risk Factors of Influenza (Flu, Flue)
You're at increased health risk of influenza or its complications if you:
- Are an infant or young child.
- Are over age 50.
- Are a resident of a nursing home or other long term health care facility.
- Have a chronic health disorder, such as diabetes or heart, kidney or lung disease.
- Have a weakened immune system, such as from medications or HIV infection.
- Will be pregnant during flu season.
- Work in a health care facility where you're more likely to be exposed to the flu virus.
- Are in regular, close contact with infants or young children.
Children on long-term aspirin therapy also may be at greater health risk.
The flu vaccine is safe for children 6 months and older. If your child
isn't at health risk of the flu but lives with someone who is, you still may
want to have your child vaccinated. That way, your child is less likely
to infect others. The more people immunized, the less likely it is that
the flu will spread through a community.
If you're young and in good health, influenza usually isn't serious. Although you may feel miserable while you have it, the flu usually goes away with no lasting effects. But high-risk children and adults may develop complications such as:
- Ear infections
- Encephalitis
Of these, pneumococcal pneumonia, a serious bacterial infection of the lungs, is the most common and most serious health disorder. For older adults and people with a chronic health illness, pneumonia can be deadly. The best protection is vaccination against both pneumococcal pneumonia and influenza (flue).
Health: Diagnosis of Influenza (Flu, Flue)
Your doctor will ask you about your symptoms and examine you. This usually gives the doctor enough information to find out if you have the flu, especially if many cases of a similar illness have occurred in the area and the local health department reports a flu outbreak.
The evaluation of an individual with flu symptoms should include a
thorough physical exam and, in cases where pneumonia is suspected, a chest X-ray. In
some cases, the doctor may do a blood test that includes a complete blood count, blood cultures, and sputum cultures
The most common method for diagnosing the flu is an antigen detection test, which is done by swabbing the nose and throat, then sending a sample to the laboratory for testing, to find out what type of flu virus you have.
The results of these tests can be available rapidly, and can help decide if specific treatment is appropriate. However, when flu is widespread in the community the diagnosis can often be made by simply identifying symptoms without further testing.
Health: Symptoms of Influenza (Flu, Flue)
Mild cases of the flu may seem like common colds. But most cases of the flu can be distinguished from colds because flu symptoms (cough, muscle aches and pains, sore throat, fatigue, and headache) are more severe than those of the common cold. Flu symptoms also tend to occur suddenly and include high fevers (temperatures of 101 degrees F or more). In children, fevers are typically even higher than those in adults.
You will probably feel tired and less hungry than usual. The flu symptoms usually are the worst for the first 3 or 4 days. But it can take 1 to 2 weeks to get completely better. It usually takes 1 to 4 days to get flu symptoms after you have been around someone who has the virus.
Most people get better without problems. But sometimes the flu can lead to a bacterial infection, such as an ear infection, a sinus infection, or bronchitis. In rare cases, the flu may cause a more serious problem, such as pneumonia.
Certain people are at higher health risk of problems from the flu. They include young children, pregnant women, older adults, and people with long-term illnesses or with impaired immune systems that make it hard to fight infection.
The most prominent of the respiratory flu symptoms is usually a dry, hacking cough. Most people also develop a sore throat and headache. Runny nose (nasal discharge) and sneezing are common. These flu symptoms (except the cough) usually disappear within 4 - 7
days. Sometimes, the fever returns. The cough and tiredness usually
last for weeks after the rest of the illness is over.
Initially, the flu may seem like a common cold with a runny nose, sneezing and sore throat. But colds usually develop slowly, whereas the flu tends to come on suddenly. And although a cold can be a nuisance, you usually feel much worse with the flu.
Common flu symptoms or influenza (flue) include:
- Fever over 101 F (38 C) in adults, and often as high as 103 to 105 F (39.5 C to 40.5 C) in children
- Chills and sweats
- Dry cough
- Muscular aches and pains, especially in your back, arms and legs
- Fatigue and weakness, lack of energy
- Nasal congestion
- Loss of appetite
- Diarrhea and vomiting in children
- Dizziness
- Flushed face
- Worsening of underlying illness, such as asthma or heart failure
When to see a health care provider
If you have flu symptoms and are at risk of complications, see your
doctor right away. Taking antiviral drugs within the first 48 hours
after you first notice flu symptoms may reduce the length of your illness
by a day or two and may help prevent more serious health problems. Seek
immediate health care if you have symptoms of pneumonia.
These include a severe cough that brings up phlegm, a high fever and a
sharp pain when you breathe deeply. If you have bacterial pneumonia,
you'll need treatment with antibiotics.
Health: Conventional Treatment of Influenza (Flu, Flue)
If you do come down with the flu, these measures may help ease your flu symptoms:
- Rest. Get more sleep to help your immune system fight infection.
- Take medications - that relieve symptoms and help you rest. Use an over-the-counter pain reliever such as acetaminophen (Tylenol, others) or ibuprofen (Advil, Motrin, others) cautiously, as needed. Remember, pain relievers may make you more comfortable, but they won't make your symptoms go away any faster and may have side effects. Ibuprofen may cause stomach pain, bleeding and ulcers. If taken for a long period or in higher than recommended doses, acetaminophen can be toxic to your liver. Talk to your doctor before giving acetaminophen to children. And don't give aspirin to children or teens because of the risk of Reye's syndrome, a rare but potentially fatal disease.
- Drink plenty of liquids. Choose water, juice and warm soups to prevent dehydration. Drink enough so that your urine is clear or pale yellow.
- Avoid aspirin (especially teens and children)
- Avoid alcohol and tobacco
- Avoid antibiotics (unless necessary for another illness)
- Try chicken soup. It's not just good for your soul — it really can help relieve flu symptoms by breaking up congestion.
If the flu is diagnosed within 48 hours of when symptoms begin, especially if you are at high risk for complications, antiviral medications may help shorten the length of symptoms by about one day.
Treatment is usually not necessary for children, but if the illness is diagnosed early and the patient is at risk of developing a severe case, it can be started. Treatment will only help if started early and only if the illness is actually influenza (flue). It will not help treat a regular cold.
Much of the illness and death caused by influenza (flue) can be prevented by annual influenza vaccination. Flu vaccine (influenza vaccine made from inactivated and sometimes attenuated [non-infective] virus) is specifically recommended for those who are at high risk for developing serious health complications as a result of influenza infection. These high-risk groups include all people aged 65 years or older and people of any age with chronic diseases of the heart, lung or kidneys, diabetes, immunosuppression, or severe forms of anemia.
Other groups for whom vaccine is specifically recommended are residents of nursing homes and other chronic health care facilities housing patients of any age with chronic health conditions and children and teenagers who are receiving long-term aspirin therapy and who may therefore be at risk for developing Reye syndrome after an influenza virus infection. Influenza vaccine is also recommended for people who are in close or frequent contact with anyone in the high-risk groups defined above. These people include health-care personnel and volunteers who work with high-risk patients and people who live in a household with a high-risk person.
Because the flu is easily spread among children and because many children require hospitalization with the flu, the U.S. Centers for Disease Control and Prevention (CDC) now advises that all children ages 6 to 59 months receive a yearly flu vaccination.
Although annual influenza vaccination has long been recommended for people in the high-risk groups, many still do not receive the vaccine. Some people are not vaccinated because of misconception about influenza (flue) and the vaccine. They mistakenly perceive influenza (flue) as merely a nuisance and believe that the vaccine causes unpleasant side effects or that it may even cause the flu. The truth is that influenza vaccine causes no side effects in most people. The most serious side effect that can occur after influenza vaccination is an allergic reaction in people who have severe allergy to eggs, since the viruses used in the vaccine are grown in hens' eggs. For this reason, people who have an allergy to eggs should not receive the influenza vaccine. Also, the vaccine is not recommended while individuals have active infections or active diseases of the nervous system.
Less than one-third of those who receive the vaccine have some soreness at the vaccination site, and about 5% to 10% experience mild side effects, such as headache or low-grade fever, for about a day after vaccination. These side effects are most likely to occur in children who have not been exposed to influenza virus in the past.
Nevertheless, some older people remember earlier influenza vaccines that did, in fact, produce more unpleasant side effects. Vaccines produced from the 1940s to the mid-1960s were not as highly purified as modern influenza vaccines, and it was these impurities that caused most of the side effects. Since the side effects associated with these early vaccines, such as fever, headache, muscle aches and fatigue, were similar to some of the symptoms of influenza (flue), people believed that the vaccine had caused them to get the flu. However, influenza vaccine produced in the United States has never been capable of causing influenza. One type of influenza vaccine made with live attenuated influenza viruses has been developed, but this vaccine is made with viruses that can confer immunity but do not cause classic influenza (flu) symptoms.
Some people do not receive influenza vaccine because they believe it is not very effective. There are several different reasons for this belief. People who have received influenza vaccine may subsequently have an illness that is mistaken for influenza (flue), and they believe that the vaccine failed to protect them. In other cases, people who have received the vaccine may indeed have an influenza infection. Overall vaccine effectiveness varies from year to year, depending upon the degree of similarity between the influenza virus strains included in the vaccine and the strain or strains that circulate during the influenza (flue) season. Because the vaccine strains must be chosen nine to 10 months before the influenza (flue) season, and because influenza viruses mutate over time, sometimes mutations occur in the circulating virus strains between the time the vaccine strains are chosen and the next influenza season ends. These mutations sometimes reduce the ability of the vaccine-induced antibody to inhibit the newly mutated virus, thereby reducing vaccine efficacy.
Vaccine efficacy also varies from one person to another. Studies of healthy young adults have shown influenza vaccine to be 70% to 90% effective in preventing illness. In the elderly and those with certain chronic health conditions such as HIV, the vaccine is often less effective in preventing illness. Studies show the vaccine reduces hospitalization by about 70% and death by about 85% among the elderly who are not in nursing homes. Among nursing-home residents, vaccine can reduce the health risk of hospitalization by about 50%, the risk of pneumonia by about 60%, and the risk of death by 75% to 80%. If antigenic drift results in changing the circulating virus from the strains used in the vaccine, vaccine efficacy may be reduced. However, the vaccine is still likely to lessen the severity of the illness and to prevent health complications and death.
Health: Prevention of Influenza (Flu, Flue)
These steps can help you stay healthy, even at the height of flu season:
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Get an annual flu vaccination. The best time to be vaccinated is October or November. This allows your body time to develop antibodies to the flu virus before peak flu season, which in the Northern Hemisphere is usually December through March. However, getting a flu shot later in the flu season may still protect you. It takes up to two weeks to build immunity following a flu shot.
Keep in mind that the flu vaccine doesn't offer complete protection, especially for older adults, but it can reduce the risk and severity of illness. According to the Centers for Disease Control and Prevention (CDC), when the match between flu vaccine and circulating strains of flu virus is close, a flu shot is between 70 and 90 percent effective in warding off illness in healthy people under age 65. It is less effective in older adults. Health experts recommend vaccinations for people over 50 because the flu shot may reduce the risk of flu-related complications, hospitalizations and deaths. The flu vaccine is also recommended for health care workers and anyone who lives or works with a person who is at higher risk of problems from the flu. Your doctor can help you decide if the flu vaccine is a good choice for you. You can get the flu vaccine from your doctor, at public health centers and many pharmacies. In some areas, flu vaccines are also available at senior or community centers and at supermarkets. You can get the vaccine as a shot or in a spray that you breathe in through your nose.
- Wash your hands. Thorough and frequent hand washing is the best way to prevent many common infections. Scrub your hands vigorously for at least 15 seconds, rinse well and turn off the faucet with a paper towel. Or use an alcohol-based hand gel containing at least 60 percent alcohol.
- Eat healthy, sleep well. A poor diet and poor sleep both lower your immunity and make you more vulnerable to infections. A balanced diet that emphasizes fresh fruits and vegetables, whole grains, and small amounts of lean protein works best for most people. On the other hand, the amount of sleep needed for a healthy immune system varies from person to person. In general, adults seem to do best on seven to eight hours of sleep a night. Older children and teens need more rest — between nine and 10 hours every night.
- Exercise regularly. Regular cardiovascular exercise — walking, biking, aerobics — boosts your immune system. Exercise won't prevent infection, but if you do come down with the flu, you may have less severe symptoms and recover more quickly than do people who aren't as fit.
- Avoid crowds during flu season. Flu spreads easily wherever people congregate — in child care centers, schools, office buildings, auditoriums and public transportation. By avoiding crowds whenever possible during peak flu season, you reduce your chances of infection.
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Sources: NIH News In Health/National Institutes of Health/National Library of Medicine/Dept of Health and Human Services_______________________________________________________________________________________________________
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