The Oregon Zoo is re-opening its popular lorikeet exhibit after several of the colorful parrots died from a mysterious illness.

Ore. Zoo photo

Two lorikeets nuzzle at the Ore. Zoo exhibit.

Veterinarians still don’t know exactly what caused 15 of the rare birds to become ill and die, but they were confident that the remaining birds’ health had stabilized.

"We identified seven different serotypes of Escherichia coli, none of which seemed particularly virulent," said Mitch Finnegan, lead veterinarian at the Oregon Zoo. "We surmise that there must have been some additional,unknown factor that may have compromised the birds' immune systems."

The birds died between Sept. 9 and Sept. 18. Finnegan said others became ill but quickly recovered. However, the exhibit remained closed until zoo veterinarians received additional lab results to ensure the problem was safely contained.

"Even though the birds have been doing well since mid-September, we had to make sure we knew what type of bacteria we were dealing with before we could move forward," said Oregon Zoo Director Tony Vecchio. "To ensure the safety of our visitors, we also compared the seven strains of bacteria to those known to cause illness in people, and, as expected, all of those tests came back negative.”

  SLIDESHOW: Lorikeet landing re-opens

The zoo also installed hand-washing stations at the entrance of the exhibit – in addition to the stations that already existed at the exit – to help prevent further illness.

“Beginning immediately, visitors will be asked to wash their hands prior to entering the exhibit. The stations will help kill any bacteria that may be transmitted from visitors' hands to the birds,” explained zoo spokesman and marketing director Bill LaMarche.

The Lorikeet Landing opened in 1999 and quickly became a favorite among zoo visitors, especially children.

People can purchase juice to feed the birds, which are very inquisitive and often fly down and land on visitors’ arms or hands as they sip from the nectar cups.

Lorikeets are native to the island chains of the South Pacific and nine species live in Lorikeet Landing.

Lorikeets normally eat fruits, flowers, pollen and nectar. Papillae on their tongues are U-shaped for a brush-like appearance and ease of feeding on nectar and pollen.

The rising of the papillae when the tongue is extended gives the lorikeets their name: brush-tongued parrots. Their upper beak is also much more narrow and pointed than other birds of the parrot family.