Packy's TB treatment suspended; Zoo weighs next steps

December 2, 2016 - 10:59am

With treatment options limited, zoo consults with outside experts on Packy's care

Oregon Zoo animal-care staff have suspended tuberculosis treatment and are consulting outside experts as they consider next steps in caring for the elderly Asian elephant Packy. At 54, Packy is the oldest male of his species on the continent, and one of the oldest on the planet.

In September, results from the geriatric pachyderm's routine monthly trunk-wash culture indicated the presence of active TB. This was the first positive culture since Packy's initial diagnosis in December 2013, and an indicator that his medications were not successfully treating the infection.

"We had been feeling increasingly optimistic about Packy's treatment regimen, and he had been tolerating it well, so this recent result was disappointing," said Dr. Tim Storms, the zoo's senior veterinarian.

Subsequent lab analysis presented an additional setback and may explain the positive culture result: testing showed Packy's particular strain of TB was resistant to two classes of antibiotics — rifampin, which had been a primary component of his treatment regimen, and quinolones.

"Without those options, we're very limited in our ability to treat this infection," Dr. Storms said. "We've stopped Packy's treatment for the time being, since we now know that it's been ineffective. We're consulting with veterinarians and pharmacologists around the country, considering what to do next."

Managing TB in Asian elephants can be difficult since little is known about treating the disease outside of humans, according to Dr. Storms. In recent years, the zoo has successfully treated two elephants, Rama and Tusko, adding to the collective knowledge about diagnostics and care. Packy's treatment has been more challenging though, due to his advanced age, unpredictable musth cycles, reluctance to accept oral medications, and intolerance for isoniazid, one of the essential first-line TB medications.

Before embarking on the most recent regimen, veterinarians made several attempts to treat Packy with isoniazid, administering this preferred treatment option in combination with other medications. Despite adjustments in dosage levels and delivery methods, treatment had to be stopped due to side effects such as appetite loss and elevated liver enzymes.

After receiving the latest test results, Dr. Storms informed public health authorities, who confirmed that the zoo's current human safety protocols are effective and should remain in place.

"We've continued to work closely with the zoo," said Dr. Jennifer Vines, deputy health officer for Multnomah County. "They've been very careful about making sure visitors, volunteers and staff are safe."

The zoo has also exercised an abundance of caution to ensure the health of its other elephants, Dr. Storms said. A year of continuous treatment would be required before Packy could share the same space with other elephants or come within 100 feet of the public. Unfortunately, the inability to treat him for that duration means it's still not easy for Packy's fans to see him.

"You can catch glimpses of him from time to time in the southernmost yard, which is to the right as you're walking along the pathway into Forest Hall," said elephant curator Bob Lee, who has cared for Packy for 16 years. "And we'll continue to share photos and videos whenever we can."

The Oregon Zoo is recognized worldwide for its Asian elephant program, which has spanned more than 60 years. Considered highly endangered in their range countries, Asian elephants are threatened by habitat loss, conflict with humans and disease. It is estimated that just 40,000 to 50,000 elephants remain in fragmented populations from India to Borneo. The zoo supports a broad range of efforts to help wild elephants, and recently established a $1 million endowment fund supporting Asian elephant conservation.