Jan and EddyGorilla Health Threat: Infectious Disease

Due to the genetic similarity between humans and gorillas, gorillas are susceptible to many of the same infectious diseases that affect people. In the last 100 or so years, the gorillas have been exposed to an ever-growing number of humans with whom they share their forest homes. The parks where the mountain and Grauer’s gorillas live are surrounded by the densest human populations in continental Africa. While gorilla ecotourism ultimately helps conserve gorillas by providing the critical funding needed to protect and manage the national parks, it brings thousands of people from the local communities and from around the world into contact with mountain gorillas.

Research* has shown that mountain gorillas can die as a result of catching infections that originated in people. Second only to trauma (e.g. fatal injuries caused by fights, accidents or snares), infectious disease is the leading cause of death in mountain gorillas, accounting more than 20% of mortality. The most common infection is respiratory disease, which can range from a mild cold to severe pneumonia, in individuals or in whole groups.

Through ranger-based monitoring and the veterinary team’s routine health checks, gorillas showing signs of respiratory disease—runny nose, coughing, lethargy—are flagged for more intensive observation. As in humans, typical respiratory illnesses usually start as a viral infection, which cannot be treated. Most gorillas with viral respiratory disease recover on their own, but others deteriorate and succumb to secondary bacterial infections causing even more several respiratory disease, like bronchopneumonia, which can be fatal. Fortunately, bacterial infections can be treated if caught early enough.

When it becomes apparent that a gorilla has a severe respiratory infection and is not improving, the Gorilla Doctors will stage a medical intervention to dart the individual with antibiotics. Usually, a single darted injection of a powerful antibiotic such as ceftriaxone is enough to help most gorillas recover, but sometimes a second dose is required a few days after the first darting. In dire cases, the gorilla may be darted with an anesthetic drug so that the Gorilla Doctors can administer intravenous fluids and clean its nasal passages. During such interventions, samples are taken so that the exact cause of the disease can be identified. Knowing the precise cause of the infection helps inform the Gorilla Doctors’ medical decisions when dealing with future disease outbreaks. Samples are stored in a biobank for evaluation by researchers studying gorilla health issues.

*Emerging Infectious Diseases 17(4): 711-713

Watch a video of the Gorilla Doctors darting a sick gorilla with antibiotics: