Remaining apes 'doing well' but tested regularly for signs of the bacteria

Bulera , the Jacksonville Zoo and Gardens ' beloved 35-year-old female western lowland gorilla, was the first to die.

Then bonobo brothers Jumanji, 38, and Jenga, 13, and two more western lowland gorillas, Kevin , 3, and Oliver, 8, also succumbed to the highly contagious bacterial illness that spread through the zoo's ape population in 2024.

The five deaths, according to spokeswoman Emily Long, devastated zoo staff, particularly the health and care teams who closely worked with the animals.

"The outbreak was an incredibly challenging and deeply heartbreaking time for everyone at the zoo," she said. "The animals are family to us."

Six months later, the zoo 's remaining primates are in fine form.

"We are happy to report that the apes have been doing well," Long said. "We remain cautiously optimistic and hopeful for a healthier and brighter 2025."

Everything zoo staff learned during the outbreak has been shared with other zoos, as well as conservation programs that work with apes in the wild. That data could help save primate lives worldwide, said Tracy Fenn , the zoo's curator of mammals.

“We have the unique opportunity to be involved in vital conservation efforts, such as species survival plans, habitat restoration and reintroduction programs," she said. "I feel truly fortunate to work toward a mission that aligns with my own values: conserving wildlife and wild places for future generations. Every day, I know that my work, and the efforts of all of my colleagues here at the zoo, plays a part in protecting global biodiversity."

Signs of shigella first appeared Aug. 18

The deadly infection to blame for the Jacksonville Zoo's crisis was shigella , a highly contagious bacterial illness that typically spreads through feces, food or water. Effects can be severe in apes, which are susceptible to gastrointestinal infections that can spread to other organs.

Apes with underlying conditions are even more at risk: Several of the ones that died in Jacksonville had cardiac disease.

Zoo staff saw the first signs of shigella on Aug. 18. They provided ill apes with fluids and antibiotics, quarantined them and closely monitored their condition.

Still, Bulera died four days later on Aug. 22; the bonobos on Aug. 26; Kevin on Sept. 10; and Oliver on Nov. 29.

Staff worked "around the clock, ensuring the highest level of care as we navigated this difficult period," Long said.

Ape health experts from other facilities in the Association of Zoos and Aquariums arrived to help out with medical procedures and daily routines. A representative of the Great Ape Heart Project and a local cardiologist were also recruited.

The animal care teams in contact with the ill gorillas wore personal protective equipment including suits, shoe covers, masks and gloves. Intensive cleaning protocols are in place, with bedding materials changed multiple times a day, according to the zoo.

And they recorded every detail.

"It was extremely important that we carefully documented the disease’s progression and how our animals responded," Long said.

Most of the zoo's 21 apes ultimately showed symptoms , ranging from mild, moderate to severe. But the infection was contained to the primates and, because they were quarantined, was not a threat to the public.

"Animal health and care teams … practiced extreme caution while implementing strict biosecurity protocols," Long said. "A dedicated team provided care to apes that have presented symptoms and a different team provided care to animals that remain healthy to minimize cross-contamination."

Staff has continued to be vigilant, conducting routine surveillance testing for signs of shigella, separating gorillas and bonobos and closing off inactive water sources in the animals' enclosures.

"We continue to enforce stringent biosecurity protocols," she said. "Additionally, we have completed both external and internal soil and water testing, all of which have shown no evidence of the bacteria."

The cause of the outbreak remains a mystery.

"We will likely never know," Long said. "It is possible that an ape was an asymptomatic chronic carrier of the bacteria and began to shed it for unknown reasons. It’s also possible that the bacteria came from an asymptomatic staff member, but this is highly unlikely."

Though rare, shigella has impacted primates in other zoos as well. In 2021 the infection was deadly for three apes at the ABQ BioPark in Albuquerque and in 2004 for four monkeys at the Vienna Zoo in Austria , according to online reports.

Death part of zoo staff's 'cycle of attachment and loss'

Such loss can be an "emotional burden" for zoo staff, particularly when they have formed close bonds with animals that can live for decades and those that are endangered, according to a study in the National Library of Medicine database .

Such as the case with Bulera , the beloved 35-year-old female western lowland gorilla who had been at the Jacksonville Zoo since 2009 and whose species is considered critically endangered.

"Zoo professionals and volunteers play essential roles in the well-being and conservation of a diverse array of animal species," according to the study. "A natural part of these zoo positions involves animal loss … [which] can have profound psychological impacts. These losses can further be complicated by the need to continue their occupational responsibilities as well as the public visibility of their work."

Meanwhile, zoo staff also have to cope with the more frequent deaths of more short-lived species.

"This variability can make it challenging for zoo professionals to navigate their grief and can create a constant cycle of attachment and loss," according to the study.

Long said the Jacksonville Zoo "makes the well-being of our staff a top priority." An Employee Assistance Program is always available and, in the case of the ape deaths, a counselor was brought in as well.

Public support also helped, she said.

During the outbreak, the zoo posted updates on the apes on its website and on social media . The public followed the crisis, commenting about their favorite gorillas and buoying the staff. When the crisis subsided, they rejoiced.

"I'm so thankful," one Facebook commenter wrote. "I know it's been a sad, scary road they and those who care for them have been traveling. Sending comfort, good vibes and the hopes of continued good health."

The zoo set up a memorial to the lost apes, a decorated table with a notebook, pen and jar for guests to write messages. The memorial "really helped visitors and staff through the mourning process," Long said.

Another Facebook commenter wrote that the memorial "was touching. … Tears were flowing. What a beautiful thing to do."

"We are deeply grateful for the overwhelming support and love we've received from our community," Long said. "Their encouragement has been a source of strength for our team and it has meant the world to us as we worked to care for our animals."