OVC Alum Hopes Discovery May Solve Deadly Chimp Disease

When scientists one day crack the mystery of a disease killing chimps in a West African animal sanctuary, Dr. Ismail “Izzy” Hirji, DVM ’14, can claim part of the credit.

Most of the time, Hirji serves as a veterinarian in Toronto, including running a mobile service for wildlife rescue and exotic pets. In 2016 and 2017, he was the resident veterinarian and assistant manager of the Tacugama Chimpanzee Sanctuary in Sierra Leone.

Since then, he has served there as a volunteer veterinarian each spring; he was unable to visit in 2020 or this year.

Located in a national park not far from the capital, Freetown, the 140-acre reserve is the only sanctuary for orphaned chimps in the country. About 90 animals are normally housed there at a time.

Over the past 15 years, a mysterious illness has been killing chimps at Tacugama, more than 50 in all. Affected animals show gastrointestinal and neurological symptoms – loss of coordination, gas bloating, vomiting, diarrhea, disorientation – and most die.

The affliction normally strikes during the spring dry season and appears to affect only animals at the sanctuary, as far as researchers can tell.

It was during his first year there that Hirji found himself serving as the front-line link in an international chain of researchers aiming to unravel the disease. Recently, the group uncovered a promising clue.

This year, they published a paper in Nature Communications describing a previously unknown bacterial species linked to the disease. Hirji co-authored the paper along with members of a team led by Dr. Tony Goldberg, an epidemiologist and veterinarian at the University of Wisconsin, Madison.

Referring to the paper and his role as a practising veterinary consultant on the project, Hirji says, “We discovered a new bacterial species only identified in chimps of Sierra Leone and specifically this sanctuary.”

After screening for various bacteria, viruses and other pathogens, Goldberg’s lab members found a suspect microbe – a species of Sarcina bacteria – in blood and tissue samples from about two-thirds of the sick chimps. None turned up in samples from healthy animals.

Scientists have yet to show that this new bacterium causes the mystery illness at the Tacugama sanctuary, but they’re zeroing in on it as a likely candidate.

The COVID-19 pandemic kept Hirji from returning to the sanctuary in 2020, but he hopes to help in learning more about the illness and the bacteria. 

“I won’t rest until we figure out how to help those chimps,” he says. “Those chimps are like family to me. To see your family die from something you can’t do anything about and then have to perform a post-mortem is a heart-wrenching endeavour.”

His own part in the story in 2016 turned out to be an endeavour of its own, as described in a New York Times article this year.

“My goal was to restart this investigation from the bottom up,” says Hirji, who reviewed the collected information about the disease that year and wrote a report.

By then, Goldberg had offered to conduct genomic sequencing of the collected blood and tissue from sick and healthy chimps that had been stored in freezers in a Sierra Leone hospital. But someone needed to organize and ship the 30 kilograms’ worth of samples overseas.

That job fell to Hirji.

Nothing about the assignment proved straightforward.

After a police escort failed to arrive for the planned trek with the frozen samples to the airport, Hirji had to improvise. He and a helper resorted to a private car and then – after the ferry turned out to be closed – a private boat to get the material to the airport.

After last-minute paperwork complications, the samples were finally loaded aboard the plane. Across the ocean, the shipment was transferred from New York to Wisconsin, where Goldberg was waiting to unpack it.

“He got them to the lab, and they were still frozen. The samples made it,” says Hirji.

Goldberg’s lab found the bacteria in the liver, spleen and brain of diseased chimps.

Now, Hirji aims to return to Sierra Leone to look more closely at the chimps and their environment, including surveying the sanctuary for the bacteria. “We need to connect the bacteria to clinical disease.”

Meanwhile, the sanctuary already takes preventive measures. Chimps are kept out of forested areas in the dry season and are fed antacid medication and probiotics.

Tacugama belongs to the Pan African Sanctuary Alliance, a group of wildlife centres in Africa that protect primates. The sanctuary was the subject of a documentary airing on National Geographic Wild.

Veterinarians from overseas have spent stints working at the Sierra Leone sanctuary since 1995. A colleague there helped Hirji land his first posting in 2016.

Only two other species of Sarcina are known, says Hirji, including one that causes GI symptoms in humans and animals. “What we discovered in chimps can now be applied to help humans with a similar illness.”

The World Organization for Animal Health contacted the team this year to learn more.

Hirji says it’s important to track emerging diseases, including zoonotic diseases that jump from animals to people, as with the virus that causes COVID-19. “Most pandemics come from wildlife,” he says, adding that it’s also important to conserve wild spaces.

“We use animals and their environments in so many ways. It’s important for us to reflect on the impact that our actions have on the homes of wild animals.”

He completed his DVM at the Ontario Veterinary College in 2014, following his B.Sc. here in 2010.

Besides working with veterinary practices in downtown Toronto, he’s the primary veterinarian for the Story Book Farm Primate Sanctuary in Durham, Ont., which rescues primates from biomedical research and the exotic animal trade.

Growing up in Toronto, he knew he wanted to work with animals, especially primates. “The University of Guelph was the go-to school in Ontario for that.”

Among his early inspirations was primate biologist Jane Goodall. In 2019, he met Goodall when she visited Tacugama for the first time. (She received an honorary degree from U of G in 1998.) 

“She had followed the work of the sanctuary but had never visited since it was built,” says Hirji. “She said, ‘This is one of the best places for chimps anywhere.’ That was a moment of full-on-emotion. For me, it was full circle.”

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