Flu: Overview

Flu, also called influenza, is a viral infection of the upper airways. It is usually more severe than the common cold, although it may appear like the common cold in the early stages. Typical symptoms include some or all of these symptoms: high fever, cough, sneezing, muscle aches, runny/blocked nose, headache, sore throat, general weakness, and other symptoms.

Flu is more common in adults than in children. Flu can be dangerous, especially to young children and older patients. Complications include: middle ear infection, bronchitis, and pneumonia. Fatality is possible. See your doctor immediately if flu is suspected.

   •   •   •

Back to: « Flu

   •   •   •

Influenza (flu) is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness. Serious outcomes of flu infection can result in hospitalization or death. Some people, such as older people, young children, and people with certain health conditions, are at high risk for serious flu complications. The best way to prevent the flu is by getting vaccinated each year.

The upcoming season's flu vaccine will protect against the influenza viruses that research indicates will be most common during the season. This includes an influenza A (H1N1) virus, an influenza A (H3N2) virus, and one or two influenza B viruses, depending on the flu vaccine.

Source: CDC1

   •   •   •

Flu (Influenza)

Each year, seasonal influenza sickens millions and causes thousands of hospitalizations and flu-related deaths. NIAID is conducting and supporting research to find new and improved ways to diagnose, treat and prevent influenza infection. This includes working toward a universal flu vaccine that could provide long-lasting protection against multiple strains of influenza, such as those that cause seasonal flu as well as emerging forms capable of causing a global pandemic.

Source: NIAID (NIH)2

   •   •   •

Influenza, or flu, is a respiratory infection caused by several flu viruses. Like the common cold, it infects the nose, throat, and lungs. Most people who get the flu get better within a week, although they may have a lingering cough and tire easily for a while longer. The best way to prevent the flu is by getting a flu vaccine every year.

The flu differs in several ways from the common cold (PDF). For example, people with colds rarely get fevers or headaches or suffer from the extreme exhaustion that flu viruses cause. The most familiar aspect of the flu is the way it can "knock you off your feet" as it sweeps through entire communities.

The Centers for Disease Control and Prevention (CDC) estimates that 5 to 20 percent of Americans come down with the flu during each flu season, which typically lasts from October to March. Children are two to three times more likely than adults to get sick with the flu, and children frequently spread the virus to others.

For elderly people, newborn babies, pregnant women, and people with certain chronic illnesses, the flu and its complications can be life-threatening. Although most people recover from the illness, CDC estimates that between 3,000 and 49,000 Americans die from the flu and its complications every year.

Seasonal Flu

Seasonal flu refers to the flu outbreaks that occur each year, mainly in the late fall and winter. The disease spreads through communities, creating an epidemic. During the epidemic, the number of cases peaks in about three weeks and subsides after another three to four weeks.

Pandemic Flu

Pandemic flu refers to particularly contagious strains of flu that spread rapidly from person to person to create a worldwide epidemic (pandemic). In the past century, there were influenza pandemics in 1918, 1957, 1968, and 2009.

Source: NIAID (NIH)3

   •   •   •

Flu is a respiratory infection caused by a number of viruses. The viruses pass through the air and enter your body through your nose or mouth. Between 5% and 20% of people in the U.S. get the flu each year. The flu can be serious or even deadly for elderly people, newborn babies, and people with certain chronic illnesses.

Symptoms of the flu come on suddenly and are worse than those of the common cold. They may include

Is it a cold or the flu? Colds rarely cause a fever or headaches. Flu almost never causes an upset stomach. And "stomach flu" isn't really flu at all, but gastroenteritis.

Most people with the flu recover on their own without medical care. People with mild cases of the flu should stay home and avoid contact with others, except to get medical care. If you get the flu, your health care provider may prescribe medicine to help your body fight the infection and lessen symptoms.

The main way to keep from getting the flu is to get a yearly flu vaccine. Good hygiene, including hand washing, can also help.

NIH: National Institute of Allergy and Infectious Diseases

Source: MedLinePlus (NIH)4

   •   •   •

People older than 65 are at high risk of influenza (the flu) and its complications, such as pneumonia. This also is true for people living in nursing homes or other long-term care facilities. A yearly flu vaccine can help protect you from the flu.

Source: OWH (DHHS)5

   •   •   •

Influenza (the flu) is an infection mainly affecting the nose, throat, airways, and lungs. It is caused by a virus and usually is spread through coughing or sneezing. It can cause mild to severe illness, and at times can lead to death. Some people, such as older adults, young children, and people with certain health conditions, are at high risk for serious complications from flu, including pneumonia.

Source: OWH (DHHS)6

   •   •   •

Summary

Flu is a respiratory infection caused by a number of viruses. The viruses pass through the air and enter your body through your nose or mouth. Between 5% and 20% of people in the U.S. get the flu each year. The flu can be serious or even deadly for elderly people, newborn babies, and people with certain chronic illnesses. Symptoms of the flu come on suddenly and are worse than those of the common cold. They may include . -Body or muscle aches. -Chills . -Cough . -Fever . -Headache . -Sore throat . Is it a cold or the flu? Colds rarely cause a fever or headaches. Flu almost never causes an upset stomach. And stomach flu isn't really flu at all, but gastroenteritis. Most people with the flu recover on their own without medical care. People with mild cases of the flu should stay home and avoid contact with others, except to get medical care. If you get the flu, your health care provider may prescribe medicine to help your body fight the infection and lessen symptoms. . The main way to keep from getting the flu is to get a yearly flu vaccine. Good hygiene, including hand washing, can also help. NIH: National Institute of Allergy and Infectious Diseases. [from MedlinePlus]

Source: GTR (NCBI/NIH)7

   •   •   •

Influenza or 'the flu' is a highly contagious disease caused by infection from influenza type A or B (or rarely C) virus. These viruses infect the upper airways and lungs.

Source: Queensland Health8

   •   •   •

influenza (flu): An acute contagious viral respiratory infection marked by fevers, muscle aches, headache, cough and sore throat.

Source: Australian Institute of Health and Welfare9

   •   •   •

influenza: An acute contagious viral respiratory infection marked by fevers, muscle aches, headache, cough and sore throat.

Source: Australian Institute of Health and Welfare10

   •   •   •

Influenza, or the flu as it is often called, is a contagious disease caused by the influenza virus. Influenza attacks the respiratory tract in humans (nose, throat and lungs), has the potential to cause mild to severe illness and at times can lead to death.

Source: MedLinePlus Magazine (NIH)11

   •   •   •

Influenza (the flu) spreads quickly and can be serious. Find out the symptoms, when to see a doctor, and how to protect yourself from catching flu.

Source: New Zealand Health12

   •   •   •

Influenza - or the flu - is a virus that spreads quickly from person to person. Symptoms include fever, chills, aches, runny nose, a cough and stomach upset. Immunisation is your best defence against the flu.

Source: New Zealand Health13

   •   •   •

Influenza, commonly known as flu, is caused by a virus, usually influenza A or B. The illness is very infectious and easily spreads in crowded populations and in enclosed spaces. Flu viruses are always changing so this winterís flu strains will be slightly different from last winterís.

Source: GOV.UK14

   •   •   •

Flu: An acute viral infection of the respiratory tract, occurring in isolated cases, in epidemics, or in pandemics; it is caused by serologically different strains of viruses (influenzaviruses) designated A, B, and C, has a 3-day incubation period, and usually lasts for 3 to 10 days. It is marked by inflammation of the nasal mucosa, pharynx, and conjunctiva; headache; myalgia; often fever, chills, and prostration; and occasionally involvement of the myocardium or central nervous system.15

   •   •   •

Influenza, Human: An acute viral infection in humans involving the respiratory tract. It is marked by inflammation of the Nasal Mucosa; the Pharynx; and conjunctiva, and by headache and severe, often generalized, myalgia.16

   •   •   •

Flu: A viral infectious disease that results in infection, located in respiratory tract, has material basis in Influenzavirus A, has material basis in Influenzavirus B, or has material basis in Influenzavirus C, which are transmitted by droplet spread of oronasal secretions during coughing, sneezing, or talking from an infected person. It is a highly contagious disease that affects birds and mammals and has symptom chills, has symptom fever, has symptom sore throat, has symptom runny nose, has symptom muscle pains, has symptom severe headache, has symptom cough, and has symptom weakness.17

   •   •   •

Flu: A viral infection adverse event that demonstrates an influenza viral infection. Influenza is an infectious disease caused by RNA viruses of the family Orthomyxoviridae (the influenza viruses), that affects birds and mammals18

   •   •   •

Flu: A viral infectious disease that results in infection, located in respiratory tract, has material basis in Influenzavirus A, has material basis in Influenzavirus B, or has material basis in Influenzavirus C, which are transmitted by droplet spread of oronasal secretions during coughing, sneezing, or talking from an infected person. It is a highly contagious disease that affects birds and mammals and has symptom chills, has symptom fever, has symptom sore throat, has symptom runny nose, has symptom muscle pains, has symptom severe headache, has symptom cough, and has symptom weakness.19

   •   •   •

References

  1. Source: CDC: cdc.gov/ flu/ about/ disease/ index.htm
  2. Source: NIAID (NIH): niaid.nih.gov/ topics/ flu/ Pages/ default.aspx
  3. Source: NIAID (NIH): niaid.nih.gov/ topics/ Flu/ understandingFlu/ Pages/ overview.aspx
  4. Source: MedLinePlus (NIH): medlineplus.gov/ flu.html
  5. Source: OWH (DHHS): womenshealth.gov/ aging/ diseases-conditions/ influenza.html
  6. Source: OWH (DHHS): womenshealth.gov/ mens-health/ top-health-concerns-for-men/ influenza-pneumonia.html
  7. Source: GTR (NCBI/NIH): ncbi.nlm.nih.gov/ gtr/ conditions/ C0021400/ 
  8. Source: Queensland Health: conditions.health.qld.gov.au/ HealthCondition/ condition/ 8/ 118/ 82/ influenza-the-flu
  9. Source: Australian Institute of Health and Welfare: aihw.gov.au/ reports-statistics/ health-welfare-overview/ australias-health/ glossary
  10. Source: Australian Institute of Health and Welfare: aihw.gov.au/ reports-statistics/ population-groups/ older-people/ glossary
  11. Source: MedLinePlus Magazine (NIH): medlineplus.gov/ magazine/ issues/ fall06/ articles/ fall06pg18-21.html
  12. Source: New Zealand Health: health.govt.nz/ your-health/ conditions-and-treatments/ diseases-and-illnesses
  13. Source: New Zealand Health: health.govt.nz/ your-health/ conditions-and-treatments/ diseases-and-illnesses/ influenza
  14. Source: GOV.UK: gov.uk/ government/ publications/ health-protection-in-schools-and-other-childcare-facilities/ chapter-9-managing-specific-infectious-diseases
  15. Source: NCI Thesaurus
  16. Source: MeSH (U.S. National Library of Medicine)
  17. Source: Disease Ontology
  18. Source: OAE Ontology
  19. Source: Monarch Initiative

   •   •   •

Note: This site is for informational purposes only and is not medical advice. See your doctor or other qualified medical professional for all your medical needs.