The November issue of Journal of the Infectious Diseases describes an outbreak of community-acquired infection caused by Mycoplasma pneumoniae, in which cases of pneumonia and disease life-threatening neurological conditions have been recorded.

Epidemiologists from the United States have investigated the epidemic of pneumonia and serious neurological illnesses occurring among students at 4 schools in Rhode Island. During the investigation, cases of encephalitis, encephalomyelitis and pneumonia occurring in schoolchildren from September 1, 2006 to February 9, 2007 were identified, and serological examinations, PCR and culture studies were carried out to identify pathogens in oropharynx and nasopharynx samples. Students with positive serological tests (presence of IgM antibodies against M. pneumoniae) and without an alternative diagnosis were considered to be infected M. pneumoniae. At school, epidemiologists used questionnaires to identify students and family members who saw a doctor for pneumonia and cough. Researchers compared the observed and expected incidence of pneumonia.

It turned out that the incidence of pneumonia in primary school pupils (122 cases per 1000 school years) was more than 5 times higher than expected. Encephalitis and encephalomyelitis were recorded in 3 students (group 1) and 76 people (group 2) suffered from pneumonia. Of these 2 groups of students, 2 (66%) and 57 patients (75%), respectively, were diagnosed with M. pneumoniae. Of the 202 family contacts of the students, 20 people (10%) were responsible for 61% of the doctor's visits for pneumonia or cough. Of the 19 home contacts of students with pneumonia, 8 people (42%) developed pneumonia and 6 patients (32%) consulted a doctor to cough.

Thus, M. pneumoniae can cause an epidemic of community-acquired pneumonia and acute respiratory disease with cough, and can also lead to life-threatening neurological diseases. Although M. pneumoniae has been isolated from schoolchildren, transmission of the pathogen through intrafamily contact has increased the size of the epidemic. Epidemiologists suggest that the interruption of M. pneumoniae intra-familial transmission should be considered a priority preventive measure in future outbreaks of this type.