Cases of Colorado dogs with mysterious illness and cough decline

Why it matters: Many canines that caught the illness had to be hospitalized. The number of cases that evolved into "severe" pneumonia more than doubled at Colorado State University's Veterinary Teaching Hospital.

The intrigue: Researchers still aren't sure what spurred the origin of last fall's spike.

• The wave of disease differed from previous versions, CSU scientists say, with more dogs experiencing prolonged coughs and developing secondary pneumonia.

What they're saying: "It is good news to see that the number of cases of canine respiratory disease continues to decline," Colorado State Veterinarian Dr. Maggie Baldwin said Wednesday in a statement.

• "However, it's important to continue to manage animal vaccines and lifestyles appropriately," including continuing vaccinations for respiratory disease annually, she said.

Be smart: Veterinarians advise pet owners to consult with their care providers on the best practices for dogs that are frequently in high-social situations, immunocompromised and older.