Causes and How It Spreads


Mycoplasma pneumoniae is a type of bacteria that causes illness by damaging the lining of the respiratory system (throat, lungs, windpipe).

How It Spreads

A sick young woman sneezing into a tissue

People spread Mycoplasma pneumoniae bacteria to others by coughing or sneezing.

M. pneumoniae spread from person to person. People without symptoms may carry the bacteria in their nose or throat at one time or another. People spread M. pnuemoniae by coughing or sneezing, which creates small respiratory droplets in the air that contain the bacteria. Other people then breathe in the bacteria.

Most people who spend a short amount of time with someone who is sick with M. pneumoniae do not become ill. However, it is common for the bacteria to spread between people who live together. M. pneumoniae infections usually have long incubation periods (the time between breathing in the bacteria and developing symptoms). The incubation period is usually between 1 to 4 weeks.1

M. pneumoniae outbreaks occur mostly in crowded settings like schools, college residence halls, military barracks, nursing homes, and hospitals. During school-based outbreaks, if people in the community get sick it is usually family members of ill school children.2,3,4


1Winchell JM. Mycoplasma pneumoniae – A national public health perspectiveExternal. Curr Pediatr Rev. 2013;9(4):324–33.

2 Foy HM, Grayston JT, Kenny GE, Alexander ER, McMahan R. Epidemiology of Mycoplasma pneumoniae infection in familiesExternal. JAMA. 1966;197:859–66.

3 Walter ND, Grant GB, Bandy U, et al. Community outbreak of Mycoplasma pneumoniae infection: School-based cluster of neurologic disease associated with household transmission of respiratory illnessExternal. J Infect Dis. 2008;198:1365–74.

4 CDC. Mycoplasma pneumoniae respiratory illness — two rural counties, West Virginia, 2011. MMWR Morb Mortal Wkly Rep. 2012;61:834–8.