Oregon Zoo Calf Tula-Tu Receives EEHV Vaccine

Tula-Tu, a young Asian elephant calf at the Oregon Zoo, has made history as the first elephant on the West Coast to receive a vaccine against elephant endotheliotropic herpesvirus (EEHV). This significant milestone was achieved during the summer of 2026, when Tula-Tu received two doses of an mRNA vaccine targeting the most common strain, EEHV 1A. A third dose is scheduled for administration in the fall. Born on February 1, 2025, Tula-Tu is currently thriving and weighs over 1,300 pounds. The development of this vaccine is viewed as a breakthrough in protecting elephants from a disease that has particularly affected young calves.

The Oregon Zoo's dedication to elephant care spans over 60 years, and the introduction of this vaccine is the result of years of research and collaboration. Following the loss of another calf, Lily, to EEHV in 2018, the zoo intensified its efforts to find a solution. The vaccine was first administered to adult elephants at the Houston Zoo in 2024 and has been gradually rolled out since then. Positive early reports on the vaccine's effectiveness and the absence of adverse side effects among elephants provide hope for the future of the species.

Dr. Carlos Sanchez, the Oregon Zoo’s director of animal health, has emphasized the importance of monitoring and early detection of EEHV. The zoo conducts routine blood tests to swiftly identify potential issues. This proactive approach, in partnership with the Oregon Veterinary Diagnostic Laboratory, enhances their ability to respond promptly to any health concerns. Tula-Tu's participation in ongoing studies will help researchers understand vaccine responses and improve elephant care practices.

In addition to its local efforts, the Oregon Zoo is engaged in international conservation initiatives. The zoo collaborates with wildlife officials in Malaysia to support the establishment of hematology labs and provide training on EEHV diagnostics. This work benefits not only elephants in human care but also aims to improve the health of wild elephant populations, where the disease remains a hidden threat due to the challenges of monitoring in their natural habitats.

The Oregon Zoo's elephant care program is recognized globally, and the introduction of the EEHV vaccine marks a significant step forward in elephant conservation. The zoo's commitment to research, education, and community engagement is vital in advancing the understanding and treatment of this disease. Ongoing efforts will continue to shape the future of elephant health, both in captivity and in the wild, as they strive to protect these majestic creatures for generations to come.