Canine Distemper Cases

April 24, 2025, Veterinary Advisory:

The Division of Animal Health is currently investigating multiple canine distemper cases in puppies that were imported by shelter/rescue groups. All of the affected animals were imported with Official Certificates of Veterinary Inspection indicating that they had been given a clean bill of health prior to shipment. These puppies also arrived with paperwork that indicated that they had been vaccinated against canine distemper prior to import (in some cases more than once), as is required by the Shelter/Rescue regulations (330 CMR 30.00). Please remind your shelter/rescue operator clients of proper sourcing, storage, handling, and administration of vaccines. 

Please remember that canine distemper is a complicated disease and can manifest with varying clinical signs. Many veterinarians currently practicing in New England may never have seen a case because the vaccine has high efficacy when given at the opportune time. Unfortunately, the chance of exposure in the shelter environment is high and protective titers may not be present in even a vaccinated animal at the time of exposure.

If you see respiratory signs, GI signs, tremors, FUOs in shelter animals or recently adopted pups, please recommend appropriate isolation and keep canine distemper high on your list of rule outs. Please report to the Division of Animal Health at your earliest suspicion: www.mass.gov/info-details/reportable-animal-diseases

Information regarding canine distemper is available from the Merck Veterinary Manual:  www.merckvetmanual.com/infectious-diseases/canine-distemper/canine-distemper

Additional information regarding disease risks/preventive protocols/vaccination strategies in the shelter environment is available at UC Davis Koret Shelter web portal: www.sheltermedicine.com/library/resources/vaccination-in-animal-shelters