
epidemiology of mycoplasma pneumoniae
infection in families
and ruth mcmahan
the transmission and clinical manifestations of in-
fection with mycoplasma pneumoniae were studied in 114
families in which there was a case of atypical pneumonia.
m pneumoniae was isolated from a throat culture of the
index pneumonia patient in 36 of these families.  trans-
mission to other family members occurred in 23 of the
36 families.  in these 23 families, 84% of the children
and 41% of the adults were infected.  the index cases
are included.  of the total 59 patients with family-contact
infections, 42 had lower-respiratory-tract symptoms, 6
had pharyngitis alone, 9 (all children) were asympto-
matic, and 2 had probably unrelated symptoms.  the
time intervals between cases within a family suggested
a median incubation period of 23 days.  treatment with
tetracycline seemed neither to cure the symptoms com-
pletely nor to abolish the carrier state that often lasted
one to three months.
