What is an influenza infection?
An influenza infection, or the flu, is a common viral infection of the airways that most commonly occurs in fall and winter. The influenza virus is spread in droplets from the mouth and nose, which can be sent into the air while sneezing or coughing, or passed by sharing crockery or cutlery. People who are older than 65 or who have other medical conditions tend to get the flu more commonly, and are at risk of developing a severe flu. This condition causes fever, cough, a runny nose and muscle aches and pains. In most cases, no specific treatment is needed, and people get better within a week. In rare cases, influenza can cause a severe infection, and this condition can become life-threatening.
The flu is caused by an influenza virus. The virus causes short-lived inflammation in the throat and nose. The influenza virus is spread in droplets from the mouth and nose, which can be sent into the air while sneezing or coughing, or passed by sharing crockery or cutlery. Most infections occur in the fall and winter months. Infants and individuals over the age of 65 tend to have the flu most commonly. People with a weakened immune system or who have other long-term medical conditions are also at higher risk of catching the flu.
The typical symptoms of the flu include fever, coughing, a sore throat, runny nose, muscle and joint pain, and feeling generally unwell. The lymph glands in the throat may be bigger than usual. Symptoms of a severe infection which may need emergency treatment are shortness of breath, wheezing and breathing difficulties.
Diagnosis is made based on the symptoms and the physical examination. If the diagnosis is uncertain, or the symptoms are severe, a sample of mucus from the throat or nose is taken and tested for the virus.
In most cases, no specific treatment is needed. People with the flu should stay home from school or work, rest and take plenty of fluids. Drinking warm drinks or using lozenge may help soothe a sore throat. Paracetamol or ibuprofen can help relieve the headache and muscle aches. If the runny nose is bothersome, decongestant sprays or tablets may be helpful. If the infection is severe, there are some anti-viral medications which target flu, but these make little difference to recovery in people with mild or moderate symptoms.
Keeping up good hygiene when sick, such as washing hands regularly and staying home while unwell, are important to prevent spreading the influenza virus. Vaccination against the flu can help to prevent infection in people who are at high risk of severe infections, such as the elderly and people with other medical conditions.
Other names for the influenza infection