Symptoms usually start out as simple sneezes, audible breathing (such as wheezing or labored inhalation or exhalation), coughing, runny nose or eyes, and the appearance of porphyrin on the face. Untreated, respiratory illnesses can results in weight or appetite loss, unkept coats, and eventual death.
Treatment is usually through the administering of oral antibiotics such as Doxycycline, or multiple nebulization sessions where a cocktail of bronchodilators and antibiotics will be breathed in by the rat. Treatments are sometimes lifelong due to the fact that Mycoplasma is often a chronic infection in the airways of rats. The infections are therefore maintained by weekly nebulizations or pulse antibiotic therapy (where long-term antibiotics are given intermittently throughout the animal's life).