‘S. zooepidemicus’ Infects Dogs at Maricopa County Animal Shelter

On January 21, 2018, Mary Martin, Director at Maricopa Animal Care Centers (MCACC), announced that Streptococcus equi subspecies zooepidemicus was found at their east valley shelter located at 2630 W. Rio Salado Parkway in Mesa, AZ. S. epidemicus is a serious bacterial disease that effects horses, dogs, cats and immune compromised people in rare circumstances. As of yet, there are no confirmed cases of human infection after direct contact with infected dogs. Most of the human cases occurred after consuming unpasteurized dairy products from infected cows or working with infected horses. Infected people developed pharyngitis, glomerulonephritis, meningitis and pneumonia.

S. epidemicus is a bacterium often found in the respiratory tract of horses and ruminants including goats and cows. When given the opportunity, it will invade other species. In dogs, it usually causes hemorrhagic pneumonia. Although MCACC has not declared this an outbreak, previous outbreaks at other facilities throughout the U.S. have been associated with crowded, kennel-like situations. At this time 30 dogs are showing clinical signs of illness in the Arizona facility.

Clinical signs of S. epidemicus  in dogs include:

  1. Coughing, sometimes bringing up a bloody material
  2. Nasal Discharge, sometimes bloody
  3. Anorexia
  4. Fever
  5. Bloody Urine
  6. Vomiting
  7. Labored Breathing
  8. Death

S. epidemicus is diagnosed by either culturing the bacteria or with a PCR test performed on samples taken from infected tissues. The advantage with PCR is a much faster turn around time as well as better accuracy. The advantage with culture is that antibiotic sensitivity can be performed to determine the best antibiotic for treatment. Early diagnosis and treatment with antibiotics is the key to saving effected dogs. Unfortunately, doxycycline resistance is starting to occur with S. epidemicus.

To prevent further infections, MCASS has shut down all playgroups and non-mandated services at the east location. They have held press conferences to warn local veterinarians about the disease. They are also adopting out animals for free in order to get them out of the shelter before contracting this disease. This last action step is surprising to many including me for fear of spreading the disease to dogs outside the shelter. According to the New York City Department of Health and Mental Hygiene, ‘Streptococcus equi subspecies zooepidemicus is an extremely rare pathogen in dogs and typically limited to shelter settings. Unpublished observations suggest transmission of Streptococcus equi subspecies zooepidemicus from shelter dogs to other dogs following adoption is unlikely.’

Although I understand their decision is based on the above information, I still worry that this action may end up spreading the disease. I am especially worried about animals and people with compromised immune systems including chemotherapy patients and valley fever patients. Therefore, I recommend isolating newly adopted pets from this shelter from all other animals for a least 2 weeks. Do not bring your existing pets to this shelter. Clean all equipment including bowls, leashes and combs between animals. Last, wash hands well and change clothes after visiting the shelter.  In other words, I would not adopt pets from there right now and strongly feel the facility should be quarantined until the incubation period has passed.

For a more detailed discussion of this horrible disease, watch Dr. Cynda Crawford’s presentation at the UF Maddie’s Shelter Medicine Conference 2011 on Streptococcus zooepidemicus. 


-Slavinski, Sally. “2009 Veterinary Alert#1: Streptococcus equi subspecies zooepidemicus Identified in Shelter Dogs.” NYC Health:  NEW YORK CITY DEPARTMENT OF HEALTH AND MENTAL HYGIENE, 1.12.2008.

-Tanabe, Morgan. “More than 30 dogs showing symptoms of ‘Strep Zoo’ at Maricopa County animal shleter.” ABC15news,com, posted 1.21.18.