Shelter Outbreak of a Rapid Mortality Canine Respiratory Disease
from Dr. Castelein of MADACC
The recent Southeastern Wisconsin shelter outbreak of canine respirator disease causing a rapid mortality in dogs infected mirrors the outbreaks of the Miami-Dade Animal Shelter in February 2008 and the Lied Animal Shelter in Las Vegas of February 2007. Test results from the Wisconsin Veterinary Diagnostic Lab have confirmed the causative agent as Streptococcus.equi.zooep idemicus; a group C Streptococcus. This is an opportunistic bacterial pathogen that in certain conditions can gain access to the lungs and after reproducing in lung tissue releases a hemolytic toxin. The toxin causes a diffuse hemorrhagic condition in the lungs and a fever spike from 106 to 107 degrees. Within hours of the onset of fever the infected dog is showing central nervous signs of depression and loss of coordination with advanced pulmonary signs of labored breathing. Once the fever spike occurs the mortality rate is high but treatment early in the infection with a modern Penicillin class drug is effective. It is important to note the morbidity rate is very low because the infection requires predisposing environmental factors of stress, respiratory system compromise, and an aerosol source of bacteria; all rarely presenting themselves together in the natural environment. To date, outbreaks have been limited to facilities where large populations of dogs exist with all the animals in close proximity of each other. These conditions are not seen by the pet living at home with its owner and so the spread of this disease to publicly owned animals is of little threat.
