Scientists Exclude Human Herpes Virus in Endangered Gorillas Using Chewed Plants – ScienceDaily

A mountain gorilla walks in the forest of the Virunga Volcanoes Conservation Area in East Africa. He stops at a piece of wild celery, sits down and starts chewing. He bares the fibrous strands of the vegetable with his teeth, extracting the fleshy, juicy bits, then drops the chewed stem to the ground and walks away.

Minutes later, veterinarians observing the scene write down the gorilla’s name and retrieve the saliva-soaked plant, which carries important information about that gorilla’s health.

This simple, non-invasive tool made from a chewed plant helps Gorilla Doctors, who know each gorilla by name, provide personalized health care to wild, endangered mountain gorillas living in Rwanda, the Democratic Republic of the Congo (DRC) and Uganda.

Scientists at the University of California, Davis, used the technique to rule out the presence of human herpesviruses among mountain gorillas in the region. Their findings are described in a study published in American Journal of Primatology.

Gorilla Doctors is a partnership between the Karen C. Drayer Wildlife Health Center, or WHC, within the UC Davis School of Veterinary Medicine and the Mountain Gorilla Veterinary Project. The program monitors the health of mountain gorillas and provides veterinary care to injured and sick gorillas.

Individual care

Although the human herpesvirus may be no more than herpes in a person, it can be more serious if introduced to gorillas or other species. After extracting DNA from the discarded plants and screening them for orally transmitted pathogens, the study found no evidence of human herpesvirus infection among the free-ranging gorillas.

“We were able to do this study entirely using chewed plants,” said lead author Tierra Smiley Evans, research faculty at WHC and One Health Institute at UC Davis. “This allowed us to collect specimens from every known habituated mountain gorilla in Uganda and Rwanda. This shows that we can monitor gorillas – and potentially other primate species – over time, non-invasively, at the individual level and help answer questions about their conservation.”

Stay alert

Gorilla trekking in this region is a big draw and the wild gorillas here are used to humans. Although gorilla tourism promotes the conservation of their habitats, it also requires a high level of care to prevent the exchange of disease between humans and gorillas.

The study’s finding that human herpesviruses did not spread indicates that the guidelines Gorilla Doctors and gorilla management authorities use to limit the distance between humans and gorillas in the park are helping to prevent the spread of the disease. It also serves as a reminder to remain vigilant to prevent new viruses from entering the population.

“Gorilla Doctors research has proven that human viruses cause respiratory disease in endangered mountain gorillas,” said co-author Kirsten Gilardi, DVM, executive director of Gorilla Doctors and director of the WHC at UC Davis. “Dr. Evans’ research findings that human herpesviruses were not found in gorilla saliva are reassuring. This is further evidence that park gorilla visitation policies, such as wearing face masks and maintaining a minimum distance of 23-33 feet, are effective in reducing the risk of human disease transmission to mountain gorillas.”

Gorilla ID

Chewed plant analysis is a relatively new tool for Gorilla Doctors to provide personalized care for this endangered species. Meeting time is of course also important and gorilla doctors and rangers know individual gorillas by sight. Such recognition is greatly aided by the wrinkles above each gorilla’s nose. Mountain gorillas have distinct nose prints used by veterinarians and rangers to identify them, similar to fingerprints used to identify humans.

Evans said the characters and dramas of gorilla life become quickly apparent when observing mountain gorillas. Evans recalls observing a young male gorilla a decade ago when she was collecting samples for her Ph.D. studies.

“He was in his teenage years and always causing trouble. He was also my favorite because he was an interesting, very inquisitive person,” she said. “I recently went back and there, 10 years later, is this cool, big silver back, with babies crawling all over it. Someone said, “This is Kabukojo.” I said, “You’ve got to be kidding me!” We were all old; we had all changed.”

Additional study co-authors include Linda Lowenstein, Benard Sebide, Peter Barry, Fred Nizeimana, Jean Bosco Nohelli, Ricky Okello, Michael Cranfield, Jonah Mazette and Christine Kreuder Johnson of UC Davis; Jean Felix Kinani of One Health Approach for Conservation in Rwanda; and Antoine Mudakikwa of the Rwanda Development Board.

The research was funded by the William J. Fulbright, the US Agency for International Development and the National Institutes of Health.

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