The Denver Zoo’s two Amur tigers have fully recovered from COVID-19, the zoo announced Wednesday.

Yuri and Nikita were diagnosed with the virus in mid-October, but are now considered fully healthy after three consecutive negative tests.

“Keepers say both tigers are doing well and are no longer showing any symptoms, and have good appetites,” officials wrote on Twitter.

The 11-year-old felines were originally tested through fecal and nasal swab samples after animal care staff noticed the two coughing, sneezing, acting lethargic and experiencing nasal discharge.

The two tigers were the first animals to test positive for COVID-19 at the zoo. But in recent weeks, 11 African lions have tested positive and continue to recover, officials said.

Both the lions and tigers were unvaccinated, officials said, but veterinarians are planning to vaccinate the felines as soon as more doses of the animal-specific vaccine become available.