The patient has a cold, cough without much sputum, a temperature of 101 F, muscle aches and feels weak and miserable. Sinusitis occurs in half. Untreated it lasts 3 weeks followed by weakness. The interval between contact cases is 3 weeks. The disease forms unusual antibodies.
Antibodies can also cause a false positive test for syphilis.
The X ray pneumonia is patchy and more than expected. These changes can last as long as 4 months. The white blood cell count, usually a reliable indicator of bacterial disease, is not raised. Not all hospital labs can do diagnostic tests, but a positive cold agglutinin test and high sedimentation rate will establish the likelihood during an epidemic and lead to appropriate treatment because several conditions confused with mycoplasmal pneumonia are susceptible to the same antibiotics. The disease responds to erythromycin or tetracycline and similar drugs.