Maricopa County Animal Care and Control is extending a quarantine at its east shelter as it continues to fight an outbreak of two deadly canine viruses.

Spokesman Jose Santiago said the shelter is continuing to monitor the dogs for symptoms of parvo and distemper, as well as re-vaccinate them.

“We have had to euthanize 37 dogs since June 3. Out of that 37, 16 of them have tested positive for the distemper virus," Santiago said. "And the rest have shown severe enough symptoms that while we were waiting on test results, we felt that we had to euthanize those dogs.”

Santiago urges dog owners to make sure their pets are properly vaccinated.