Influenza

• Definition
· Influenza is a seasonal viral illness affecting the respiratory track.

• Overview
· Influenza outbreaks occur every winter season.
· Influenza symptoms have a very abrupt onset and are more severe then a simple “cold.”
· Influenza infections are one of the most common diseases and are highly contagious.
· Influenza infects up to 250,000 people in the United States every year and about 36,000 people die every year from influenza.
· Influenza infections typically resolve within seven days.

• Types
There are three types of Influenza: Influenza A, Influenza B, Influenza C
· Influenza A causes more disease and also infects pigs, birds, horses, dogs, and seals.
· Influenza A and Influenza B are the two types of the Influenza virus responsible for most flu outbreaks.
· Influenza A virus type is identified by two types of proteins (H protein and N protein) found in the surface of the Influenza virus and there are 16 distinct H protein types and nine distinct N protein types.
· Influenza A type changes almost every year and the extent of the infection is based on the changes in the surface proteins (H protein and N protein).
· Influenza A outbreaks associated with large changes in the surface proteins include: Avian flu and Swine flu.

• Symptoms
· Influenza A infection appears similar to a simple “cold” but the onset is very fast and symptoms are more severe.
· Influenza A symptoms include the abrupt onset of
- fever
- chills
- dry cough
- muscle pain
- joint pain
- fatigue
- sore throat

• Complications
· Influenza A infection complications more often occur in elderly patients or people with impaired immune systems.
· Influenza A infection can be complicated by the development of pneumonia and respiratory difficulties.

· Reye’s syndrome, which is a severe form of liver failure, can occurs in young children who are given aspirin when infected with influenza or chicken pox

• Treatment
· Influenza A infections can typically be treated with prescription medications:
- Tamiflu
- Relenza
- Amantadine
References
Advisory Committee on Immunization Practices. Prevention and Control of Influenza: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep. 2006 Jul 28;55(RR-10):1-42. [PMID: 16874296]
Prevention of antigenically drifted influenza by inactivated and live attenuated vaccines. N Engl J Med. 2006 Dec 14;355(24):2513-22. [PMID: 17167134]

Posted on April 28, 2009

2 Responses to “Influenza”

  1. Health and Wellness: Medicues Swine Flu and You says:
    April 28, 2009 at 2:29 am

    [...] Cristopher Geiler, M.D. -Swine flu is a variant of Influenza A which is the seasonal flu virus. Swine flu will typically infect pigs and not humans. · In late [...]

    Reply
  2. Health and Wellness: Medicues The first American death due to Swine Flu says:
    April 30, 2009 at 12:43 am

    [...] is about 36,000 people who die from influenza every year in the [...]

    Reply

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