Influenza is a viral infection.
There are a total of 3 main types of influenza virus: Influenza A, B and C. Current Influenza A (H1N1) (formerly known as swine flu) and the avian flu belong to Type A Influenza virus. Type A and B are common causes for seasonal human influenza epidemics.
Influenza virus is subtyped according to the types of proteins they manifest on the surface of the virus, namely the H (haemaglutinins) and N (neuraminidase) proteins. There are a total of 16 H proteins and 9 of N proteins. The current Influenza A (H1N1) virus is typed as H1N1.
Influenza virus is subtyped according to the types of proteins they manifest on the surface of the virus, namely the H (haemaglutinins) and N (neuraminidase) proteins. There are a total of 16 H proteins and 9 of N proteins. The current Influenza A (H1N1) virus is typed as H1N1.
It is spread via droplet infection through coughing, sneezing and inhalations of the infective droplets by a nearby person. Influenza virus is also known to be able to survive on hard, non porous surfaces for up to 2 days, therefore contact of such respiratory secretions on tables and door knobs etc can also lead to infection when one unknowingly uses his/her contaminated hands to rub the eyes, nose or mouth. It is therefore important that one maintains proper hand hygiene and coughing etiquette (or wearing face mask when one is sick) to limit the risk of passing the infection or acquiring the infection.
An infected patient is infective one day before the onset of his/her symptoms and up to 5 to 7 days from onset of symptoms. That means an infected person can be passing his flu virus to another before he is sick and while he is sick. Therefore when one comes down with flu symptoms, one should see a doctor and rest at home to avoid spreading the disease to other people.
Once infected with the virus, a person may take up to 5 days before manifesting symptoms.
- Abrupt onset of high fever usually greater than 38 degree Celsius with chills
- Accompanied with dry coughing and may have other respiratory tract infection symptoms such as running nose, sore throat, sneezing
- Associated with body aching, headache, malaise and breathlessness
With the current situation of Influenza A (H1N1), a patient is considered to have probable Influenza (H1N1) infection when the patient fulfills the criteria of flu symptoms as well as a positive history of travel to affected countries or had been in contact with patients with pneumonia (lung infection) or other patients with flu.
Currently all patients with symptoms of flu as stated above should receive medical attention regardless of whether a positive history of contact or travel is present or not.
Regular influenza vaccination is recommended to protect against seasonal influenza. It does not protect against the current H1N1 flu virus, but if one comes down with flu symptoms despite having had previous influenza vaccination, it will alert the doctor that the patient may be infected with a different influenza virus such as Influenza A (H1N1) or avian flu virus.