Tasmanian pet owners can be assured their dogs are protected from a mystery illness killing canines as it spreads across the United States. The mystery and antibiotic-resistant illness starts with a persistent cough, lasting weeks or months, that sometimes suddenly develops into severe pneumonia. Dogs of all ages and breeds began getting sick in a handful of states in the United States of America (USA) in November, with the illness now seen in more than 14 states. Symptoms include coughing, sneezing, discharge from the eyes or nose, dehydration, wheezing and difficulty breathing. Current biosecurity protection measures are preventing the illness from entering Australian states and territories. A national Department of Agriculture, Fisheries and Forestry spokesperson said the situation in the USA was being monitored. They said any dog arriving from the USA by plane, or by any other means, is quarantined and must adhere to strict biosecurity measures. "The department continues to monitor intelligence about the canine respiratory illness events being reported in the United States, where they are under investigation," they said. "Further advice will depend on events and investigations underway." The DAFF spokesperson said dogs are checked multiple times before entering community. "Within five days of leaving for Australia, all dogs must be examined by a government-approved veterinarian in the country of export and found to be free from clinical signs of infectious or contagious disease," they said. "On arrival, dogs from the USA remain subject to biosecurity control and must complete a minimum 10-day quarantine period at the post-entry quarantine facility in Mickleham, Victoria." They said dogs are then monitored daily by biosecurity officers trained to recognise illness and are checked a minimum of two times before leaving quarantine.