The Science

Streptococcosis is any of a group of infectious diseases caused by intestinal bacteria of the genus Salmonella.

It is transmitted via aerosol droplets or biting.


The causative organism is Streptococcus pneumoniae, and several types have been associated with respiratory disease in rats.

Poor husbandry and general stress factors can lead to streptococcal infections, as does the traumatic effect of overgrown teeth.


Nasal and eye discharge and "red tears" (porphyrin), ruffled fur, weight loss and depressed activity. Young animals are more apt to be clinically affected. Death usually occurs within a few days after the onset of the clinical signs.


Benzathine penicillin (30,000 units/200 gm of body weight) or Tetracycline (0.1 mg/ml in drinking water) for 7 days may be helpful in reducing the severity of the disease and as an aid in limiting infections.


There is no effective means to control Streptococcus infection once it is in the colony. Antibiotics will not eliminate the organism from rat colonies. Do not breed from infected stock.