Basic Information on Influenza


Influenza is a common infectious disease.

Infectious Agent:
Myxovirus group (Influenza virus) type A, B and C.

Mode of transmission:
Inhaling infected droplets from the air; spreads from person to person.

Incubation period:
24-28 hours.


3D graphical representation of a generic influenza virion’s ultrastructure, image courtesy of CDC/ Doug Jordan, M.A.

Case Definition:

Suspected Case:
Any person with sudden onset of fever greater than 39º centigrade, and sore throat or cough in the absence of another known cause. Headache, myalgias, and prostration are often present.

Confirmed Case:
Any suspected case with laboratory confirmation by isolation of virus in culture, by IFAT or by serologic test demonstrating a rise in specific antibody titter.


The goal of treatment is to alleviate the symptoms. Antibiotics are not effective against viruses. Bed rest is advisable until the fever subsides.
A mild analgesic, such as paracetamol 0.5 – 1 g every 4-6 hours usually relieves the headache and generalized pains and warm fluids help to relieve the discomfort of the symptoms.
Pholcodine 5-10 mg 3-4 times daily may be used to suppress unproductive cough.
Specific treatment of complications such as bronchitis and pneumonia may be necessary.


  • Good ventilation of public buildings;
  • Avoidance of crowded places during an epidemic;
  • Encourage sufferer to cover their faces with a mask or handkerchief when coughing and sneezing;
  • Annual winter vaccination (Anti influenza vaccine) is recommended for patients suffering from chronic pulmonary, cardiac or renal disease.
  • For older individuals who have been exposed to the virus, the drug amantadine may be given to prevent them from actually getting the flu. This may also be used for treatment.