Influenza

Seasonal Influenza | Bird Flu | Swine Flu | Novel H1N1 Influenza A

According to the Centers for Disease Control and Prevention (CDC), flu season in the United States usually ranges from November through March, and sometimes into early spring. Flu or influenza is caused by viruses, which infect the nose, throat and lungs. (Read about "Respiratory System") Flu is also very contagious. CDC says a person can spread the flu starting one day before he or she even feels sick, and continue to pass the flu virus to others for several days after symptoms start. Those symptoms can include:

• fever
• chills
• dry cough
• muscle aches
• extreme fatigue

In addition, there may be a sore throat, headache and nasal congestion. Nausea, vomiting and diarrhea can sometimes accompany the flu as well, although CDC says these are not the primary symptoms of the flu. (Read about "Diarrhea") What people may call the "stomach flu" is actually gastroenteritis. (Read about "Gastroenteritis")

Most people can recover from the flu in a week or two. But that doesn't mean flu should be taken lightly. Potential complications from the flu are serious and can include bronchitis or pneumonia. (Read about "Acute Bronchitis" "Pneumonia") Left untreated these complications can be life threatening. These kinds of complications become especially serious for infants, young children and as we get older. (Read about "Baby & Young Child Care" "Seniors and Flu")

Although you can't always avoid people who have the flu, you can talk to your doctor about flu shots. (Read about "Immunizations") Flu shots are available for just about everyone, even children as young as 6 months old. CDC recommends a flu shot yearly for most people. The American Academy of Family Physicians (AAFP) says it is even more important for people in certain high risk groups to consider flu shots, including those who live in nursing homes or other long-term care facilities, people with chronic heart disease, lung disease, diabetes, kidney disease, anemia or immune system problems including AIDS, and people over the age of 50. (Read about "Coronary Heart Disease" "Respiratory System" "Diabetes" "Kidney Disease" "Anemia" "The Immune System" "HIV / AIDS") The American Lung Association (ALA) says that people with asthma (Read about "Asthma") should also consider getting a flu shot. AAFP says if you do want a flu shot, the time to think about getting it is October and November.

A flu vaccine may contain egg protein, so if you are allergic to eggs, you should discuss this with your doctor. (Read about "Food Allergies" "Allergies") In addition, people currently suffering from an acute illness and/or fever should wait until fully recovered before receiving the vaccine.

Flu vaccine is normally given by a shot in the arm. The Food and Drug Administration (FDA) has also approved flu vaccines delivered as a nasal spray. The nasal spray should not be used by people with compromised immune systems, according to FDA, and may not be safe for people over the age of 50 or for people with asthma or other reactive airway diseases.

There are also prescription anti-viral medications that can be taken after flu symptoms appear. These medications can reduce the duration of your illness, but they must be taken soon after symptoms begin, within the first 48 to 72 hours. In some cases, medication can be used as a preventative; however, these medications are not a substitute for getting a flu vaccine. These medications also may not be effective against all strains of the flu. These drugs - called neuraminidase inhibitors - are available in different forms, including a liquid that is swallowed and a mist that is inhaled orally. The oral mist is not recommended for people with asthma, COPD or other airway diseases. (Read about "Asthma" "Chronic Obstructive Pulmonary Disease") These drugs are also not appropriate for people with compromised immune systems, infants and others. There are additional concerns about side effects, which you should discuss with your doctor.

Avian influenza (bird flu)

Avian influenza virus usually refers to influenza A viruses found chiefly in birds, but infections can occur in humans. The risk is generally low to most people, because the viruses do not usually infect humans. However, confirmed cases of human infection have been reported.

(Read about "Bird Flu")

Swine influenza (swine flu)

Swine influenza (swine flu) is a respiratory disease of pigs caused by type A influenza virus that regularly cause outbreaks of influenza among pigs. Swine influenza viruses may circulate among swine throughout the year, but most outbreaks occur during the late fall and winter months similar to outbreaks in humans.

Swine flu viruses do not normally infect humans; however, human infections with swine flu do occur. CDC says that most commonly, these cases occur in persons with direct exposure to pigs (for example, children near pigs at a fair or workers in the swine industry). In addition, there have been documented cases of people spreading swine flu to others. In 2009, an outbreak of flu was at first referred to as swine flu. This strain, however, turned out to be a combination of several different types of flu (See Novel H1N1 Influenza A below)

The symptoms of swine flu in people are similar to the symptoms of regular human seasonal influenza and include fever, lethargy, lack of appetite and coughing. Some people with swine flu also have reported runny nose, sore throat, nausea, vomiting and diarrhea. To diagnose swine influenza A infection, a respiratory specimen would generally need to be collected within the first 4 to 5 days of illness (when an infected person is most likely to be shedding virus). However, some people, especially children, may shed virus for 10 days or longer.

Novel H1N1 Influenza A

In early 2009, what came to be known as novel H1N1 influenza A surfaced in Mexico and the United States. It quickly spread around the globe and was declared the first pandemic of the 21st century by the World Health Organization.

This virus was originally referred to as "swine flu" because early lab tests (Read about "Laboratory Testing") showed that many of the genes in this new virus were similar to influenza viruses that normally occur in pigs. But further study showed otherwise. In addition to genes found in swine influenza, other parts of the virus can be traced to humans and still other parts to birds.

The symptoms of H1N1 flu virus in people include

• fever
• cough
• sore throat
• runny or stuffy nose
• body aches
• headache
• chills
• fatigue

CDC says that a significant number of people who have been infected with this virus also have reported diarrhea (Read about "Diarrhea") and vomiting. Severe illnesses and death has occurred as a result of illness associated with this virus.

CDC says that pregnant women (Read about "Healthy Pregnancy") and people with underlying health problems are most in danger from the novel H1N1 influenza A. CDC says that the normal flu vaccine will not protect against H1N1. A special H1N1 vaccine is necessary.

Prevention

Influenza is thought to spread from one person to another when the infected person coughs or sneezes. There are some things you can to do protect yourself and others, according to CDC.

• Cover your nose and mouth with a tissue when you cough or sneeze. Throw the tissue in the trash after you use it. If you don't have a tissue, CDC suggests that you cough or sneeze into your elbow. Be sure to wash the shirt, blouse, jacket, etc. that you are wearing as soon as possible.
• Wash your hands often with soap and water, especially after you cough or sneeze. Alcohol-based hands cleaners are also effective.
• Avoid touching your eyes, nose or mouth. Germs spread that way.
• If you get sick, CDC recommends that you stay home from work or school and limit contact with others to keep from infecting them.

Cold or flu?

At certain times of the year, it seems as if everyone is achy, sneezing or complaining about a sore throat. But with so many symptoms out there, how can you determine if you have a cold (Read about "The Common Cold") or flu? Well, there's no way to know for sure, but there are some differences.

The National Institute of Allergy and Infectious Diseases offers these guidelines:

• Fever - For colds, fever is rare; For flu, fever is characteristic, high (102-104°F), and lasts 3-4 days
• Headache - For colds, headache is rare; For flu, headaches are prominent
• General aches & pains - For colds, general aches are slight; For flu, aches and pains are typical and can be severe
• Fatigue, weakness - For colds, fatigue is quite mild; For flu, fatigue can last up to 2-3 weeks
• Extreme exhaustion - For colds, exhaustion is not a normal symptom; For flu, exhaustion is early and prominent
• Stuffy nose - For colds, stuffy nose is common; In flu, a stuffy nose is sometimes present
• Sneezing - For colds, sneezing is usual; For flu, sneezing is sometimes present
• Sore throat - For colds, sore throat is common; For flu, sore throat is sometimes present (Read about "Sore Throat and Strep Throat")
• Chest discomfort, cough - For colds, chest discomfort is mild to moderate; For flu, chest discomfort is common and can become severe

AAFP says that, while over a hundred different viruses can cause colds, there aren't as many that can cause flu (which is why there's a shot for flu, but not for colds). Although colds and flu seem to be more common in colder weather, you don't actually develop them as a reaction to the colder temperatures. Many experts believe the increase is due to the fact that people tend to spend more time indoors with others during the winter months, which increases the chances of a virus spreading.

Feeling better

There are no foolproof ways to keep yourself free of colds or flu. But the American Pharmaceutical Association (APA) has these suggestions to help you feel better:

• stay in bed and drink plenty of fluids
• breathing in hot vapors from a shower may help you feel better
• elevate your head at night to help nasal passages drain
• blow your nose to clear any congestion, but do it gently and blow both nostrils at the same time
• use medication for specific symptoms when appropriate

Different ingredients in medications do different things. For example, decongestants can relieve congestion and shrink swelling in your nose and sinuses. Antihistamines can stop sneezing and itching. Analgesics can relieve pain; however, APA says never give children or teenagers aspirin since aspirin has been linked to Reye's syndrome in young people who have viral infections. In addition, people who suffer from heart disease, high blood pressure, a thyroid condition, glaucoma, and men who have an enlarged prostate should take decongestants only under a doctor's care. (Read about "Hypertension: High Blood Pressure" "Thyroid" "Glaucoma" "Prostate")

CDC says there are also antiviral drugs that have been approved for preventing or treating the flu. These drugs can reduce the severity of flu symptoms, and shorten the amount of time you are sick by a day or two. CDC says antiviral drugs are effective only against influenza viruses. They will not help the symptoms associated with the common cold or many other flu-like illnesses caused by viruses that circulate in the winter.

Before taking any medications, of course, always tell the doctor and pharmacist about other medications you're already taking. Remember, even over-the-counter medications can produce side effects or potentially dangerous interactions, so always be cautious. (Read about "Medicine Safety")

Related Information:

    Microorganisms

    Respiratory Illnesses

    Chronic Obstructive Pulmonary Disease

    Blood Donation Guidelines