Oregon Zoo Calf Undergoes Treatment for EEHV Infection
Veterinarians are using plasma transfusions and antivirals to treat the Asian elephant calf for the 1B viral strain.
Updated on Oct. 30, 2026 in Pet Health
Oregon Zoo elephant calf Tula-Tu is receiving treatment after testing positive for the EEHV-1B virus. Veterinary staff are managing the infection with plasma transfusions and antivirals following behavioral changes noted in late October.
Why it matters
EEHV is a latent virus that remains a primary threat to Asian elephant calves between the ages of 1 and 8. The outcome of Tula-Tu’s treatment will provide further data on how vaccine-primed immune systems respond to different strains of this complex virus.
EEHV is considered a latent threat to nearly all Asian elephants, with calves between 1 and 8 years old facing the highest risk of mortality. Over 200 deaths have been documented in the wild, though the exact transmission dynamics remain under active research.
The players
Oregon Zoo
The local facility currently providing veterinary care for the infected elephant calf.
Tula-Tu
The Asian elephant calf currently undergoing treatment for an EEHV-1B infection.
Oregon Veterinary Diagnostic Laboratory
The facility responsible for confirming the calf’s viral load through specialized testing.
The details
Tula-Tu’s care team at the Oregon Zoo initiated treatment after detecting behavioral changes and low white-cell counts. Following confirmation of the virus at the Oregon Veterinary Diagnostic Laboratory, the calf has undergone plasma transfusions and antiviral therapy. Current clinical indicators, including viral loads and platelet counts, remain stable as the team continues to analyze the calf's immune response.
Timeline
2026: Tula-Tu received an mRNA vaccine targeting the EEHV-1A strain.
October 24, 2026: Zoo staff noted behavioral changes in the calf.
October 25, 2026: Laboratory testing confirmed the presence of the EEHV-1B virus.
Beyond the Bridges
This case follows a series of regional and international efforts to combat EEHV, including the 2018 death of a calf at the Oregon Zoo. The current treatment approach builds on those lessons and later partnerships, such as the 2023 establishment of a hematology lab in Sabah.
While the treatment occurs behind the scenes, visitors to the Oregon Zoo should check the facility's official announcements for any temporary impacts on elephant habitat viewing schedules. The zoo continues to monitor the calf’s recovery and updates are provided as clinical data evolves.
The takeaway
The Oregon Zoo’s immediate response underscores the ongoing challenge of managing latent viral infections in vulnerable elephant populations. Residents can continue to support these research and conservation efforts through the zoo’s established educational and monitoring programs.
Further reading
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