Mysterious and deadly chimpanzee illness is associated with human illness

Chimpanzees were mysteriously dead for about a decade in the Takugama Reserve in Sierra Leone by 2016, when Tony Goldberg set out to figure out why.

Sanctuary staff, veterinarians, and biologists have conducted several investigations into the disease over the years. It was not contagious, did not infect humans, and did not appear in other sanctuaries, but killed chimpanzees with tacugama in an unmistakable and alarming pattern.

“It was always the same season and always the same symptoms,” said Andrea Pizarro, the conservation manager of the reserve. Chimpanzees exhibit what appears to be neurological symptoms: lack of coordination, difficulty walking, seizures. There are also signs of gastrointestinal disorders such as bloating and vomiting. None of the suffering chimpanzees survived when the syndrome appeared.

Occasionally, a chimpanzee that looked fine one day was found dead the next day. This is happening in all sanctuaries, probably in the wild. However, over the years, postmortem examinations showed the same pattern of bowel damage as the symptomatic chimpanzees.

An average of over 90 chimpanzees live in the sanctuary, a major tourist attraction and the only place for orphan chimpanzees in Sierra Leone. These are western chimpanzees, an endangered subspecies. Fifty-six chimpanzees from Takugama have recently died of this mysterious disease in a country that has made chimpanzees a national animal.

What made the mystery even more puzzling was that the pattern of illness occurred only in Takugama. Of course, chimpanzees could get sick and die suddenly in other sanctuaries, but the unique pattern of the disease occurred in only one place. Some studies focusing on viruses and toxic plants did not give a definite answer.

In 2016, Goldberg, a public health research and veterinarian at the University of Wisconsin-Madison and head of the Kibaale Eco-Health Project, was contacted by the Pan-African Sanctuary Alliance to solve the mystery. He and his colleagues in Wisconsin worked with other veterinarians and biologists in Africa and elsewhere to perform a comprehensive analysis of the blood and tissue of dead chimpanzees frozen in a nearby hospital. ..

“I took five years,” he said. On Wednesday, he and other researchers reached a landmark in their veterinary detective work in a Nature Communications report that identified a new species of bacteria that was clearly associated with the syndrome.

So far, research has not found that bacteria are the only cause of the disease, but it may contain more unidentified species that threaten human and animal health. A new window in the genus Salsina. Opened.

Goldberg emphasized that this is not a pandemic. Bacteria are not contagious and do not cause widespread harm.

From the beginning, there was nothing simple about research, including bringing the raw materials for research into the lab. Goldberg acknowledged Ismail Hirji, a privately-owned Canadian veterinarian who was a clinical veterinarian in the sanctuary in 2016, for overcoming these early obstacles. “He just moved the mountains to get these samples out of Sierra Leone,” Goldberg said.

The first hurdle involved the process of applying for a permit to transport a sample of diseased tissue taken from an endangered species. Hilji recalled that the paperwork took about a year.

The required police escorts did not appear on the day the samples were shipped. Hilji et al. Dashed at the last minute by car and small boat, as the ferry that normally carries travelers to the airport was closed. In the boat, he said, “We were basically carrying a 30 kg sample in our head.”

Despite facing more difficulties at the airport, such as lack of refrigeration, the group eventually obtained samples by plane to the Goldberg lab in Wisconsin.

Researchers then use genomic studies, visual examination of tissues, and other techniques to screen extensively of blood and tissue from healthy and diseased chimpanzees for viruses, bacteria, and parasites. have started.

Lear Owens, a PhD and veterinary degree candidate working in Goldberg’s lab, found that only bacteria were likely to be the cause in the first DNA survey, including 68% of sick chimpanzee samples. However, there were no healthy chimpanzee bacteria, so they began to concentrate on them.

Owens grew the bacteria in culture and sent them to other laboratories for sequencing and tissue samples. It was almost impossible to grow in the laboratory, but the bacteria finally grew on smears of brain tissue. Under the microscope, the tissue revealed the general shape of the bacterium: spheres and cylinders. And she said. “I got to this.

“When you look straight, it looks like a four-leaf clover,” she said, but it’s actually a four-leaf cube.

It showed that it belonged to the genus Sarcina, which contained only two known species. One inhabits the soil and the other, first identified in 1844 as Sarsina bentricuri, was known to cause gastrointestinal symptoms in humans and animals such as those received by the Takugama Chimp. ..

In humans, Sarcina ventriculi can multiply after surgery and produce gas that fills the intestinal wall. When the infection reaches that stage, most people die.

According to Goldberg, the jargon is emphysematous gastroenteritis, “that’s what chimpanzees had.”

Further investigation by Owens revealed that the bacteria in chimpanzee samples, including brain tissue to which gut flora certainly does not belong, are not the same species reported in humans and animals over the years. It was bigger and there was a big difference in its genome.

Researchers have proposed in a treatise to name the new species salcinatroglodyte because it was found in the chimpanzee, pantroglodyte.

Researchers need to grow bacteria better before the proposed name is accepted as an official new species. At this stage, they only show that the bacteria are associated with the disease, not the cause.

And the illness still appears mysteriously. The syndrome always peaks in March, for example, in the dry season. Keeping the chimpanzee inside in the afternoon seems to help prevent it. And their diet and something around it may also play a role.

However, researchers have offered potential treatments. One of the effective drugs is omeprazole, a component of Prilosec. This reduces stomach acid, the environment in which bacteria grow.

Some antibiotics are more effective than others. Sanctuary manager Pissarro said last week that a chimpanzee had begun to develop the syndrome, but staff are on antibiotics and other treatments and are now on track. However, the syndrome can die even after it looks like recovery.

New bacteria, or such other bacteria, may be more prevalent than scientists are aware of, Goldberg said. Sarsina was not the subject of much research. Human and animal disease and death caused by Sarcina ventriculi can actually be caused by new bacteria or similar species. If so, this is a more notable group of bacteria.

“It falls into the category of what we have to see,” he said, “but don’t worry.” The Sarsina pandemic is unlikely to be offshore, he said.

But Goldberg said, “Looking back, we realize that many human and animal diseases from other causes are actually caused by this version of the bacterium.”