How a baby elephant at the Fort Worth Zoo is helping fight a deadly virus

Brazos, a two-year-old Asian elephant at the Fort Worth Zoo, could help cure a deadly viral infection that is killing young elephants in the wild and in captivity.

Brazos was recently vaccinated with a revolutionary vaccine that targets elephant endotheliotropic herpesvirus (EEHV), the zoo announced Thursday. This virus infects elephants naturally but usually remains inactive. Scientists don't know why or how the virus is activated, but once activated, it can cause a rapid and fatal hemorrhagic disease, which is the leading cause of death in Asian elephant calves and young African elephants.

“Brazos vaccination is a major step toward preventing EEHV deaths in elephants,” said Sarah Cannizzo, associate veterinarian at the Fort Worth Zoo, in a prepared statement. “It’s a great example of the power of collaboration: collaboration between zoos, collaboration between zoos and scientists, and collaboration between elephant and veterinary departments.”

In 1995, Kumari, a 16-month-old Asian elephant at the National Zoo in Washington, D.C., was the first to be diagnosed with the virus. This set in motion decades of research to understand the virus and develop tests that can detect it.

A unique vaccine was developed by Paul Ling, a virologist at Baylor College of Medicine, and administered to a 40-year-old Asian elephant at the Houston Zoo in June. The vaccine targets a strain of the virus found primarily in Asian elephants. Similar to a COVID vaccine, it uses mRNA to teach an elephant's immune cells to recognize and fight the disease.

While three other Asian elephants at the Houston Zoo have now received the vaccine, Brazos is unique in that he had no antibodies to the virus. When a mother elephant gives birth, she passes on her antibodies to her calf, but these disappear over time. This is why young elephants are so susceptible to the disease. The Fort Worth Zoo regularly monitors the antibody status of its elephants; Brazos' most recent blood test found no antibodies.

His vaccination, which included an initial shot and a booster shot, will allow researchers to see how well it works in an elephant that is not infected with the virus or still has antibodies from its mother.

“Should this vaccination effort be successful and result in widespread vaccine distribution, Brazos will be one of the few elephants that helped make this possible,” Ling said in a statement.

Miriam Fauzia is a science reporter at The Dallas Morning News. Your scholarship is supported by the University of Texas at Dallas. The News makes all editorial decisions.