Causative agent
It is caused by the bacterium Mycoplasma pneumoniae. Mycoplasma pneumoniae infection can occur at any time of the year. Epidemics tend to occur every 3 to 4 years in the general population.

Clinical features
Mycoplasma pneumoniae most commonly causes acute upper and lower respiratory illness and the disease usually has a prolonged, gradual onset. The majority of patients present with mild upper respiratory tract infection. Symptoms include fever, cough, sore throat, malaise and headache. Only 5-10% of infected patients develop atypical pneumonia. It is recognised as one of the most common causes of community-acquired pneumonia in otherwise healthy patients younger than 40 years, with the highest rate in individuals aged 5-20 years. The disease is seldom fatal and complications are uncommon.

Mode of transmission
The disease is mainly transmitted by droplets. It may also be spread from person to person by direct contact with the nose and throat discharges of infected persons; or indirectly through contaminated articles freshly soiled by secretions of the infected person. Outbreaks can occur especially in crowded institutional settings.

Incubation period
The incubation period is about 3 weeks, ranging from 1 to 4 weeks.

Treatment
Antibiotics are very effective in treating Mycoplasma infections.

Prevention
Vaccine is not available at the moment. As a general measure to prevent respiratory diseases, the members of public are advised to:

• Build up good body immunity by having a proper diet, regular exercise and adequate rest, reducing stress and avoiding smoking.

• Observe personal hygiene
• Keep hands clean and wash hands properly.
• Wash hands with liquid soap promptly if they are contaminated by respiratory tract secretions, e.g., after sneezing or coughing.
• Cover nose and mouth when sneezing or coughing.
• No spitting. Always wrap nasal and mouth discharges with tissue paper, and dispose of the tissue paper properly in a lidded rubbish bin.
• Wear mask when symptoms of respiratory tract infection or fever develop. Refrain from work or school and seek medical advice promptly. 

• Observe environmental hygiene
• Maintain good ventilation of indoor areas.
• Avoid attending crowded and poorly ventilated places.