Great Apes in Africa

Gorilla Exam Photo
WCS field veterinarian William Karesh examines a gorilla in the Congo Forest.
©William Karesh

Chimpanzees, gorillas, and humans are close evolutionary relatives and therefore vulnerable to more than 140 of the same diseases. As the numbers of researchers, eco-tourists, local people, and soldiers increase in and around the lowland forests of central Africa, the likelihood of viruses, parasites, and other pathogens passing between them and great apes rises. Research suggests that tens of thousands of great apes have already perished from Ebola hemorrhagic fever virus, which is also deadly to humans.

The Congo Basin is vital habitat for more than 100,000 western lowland gorillas and more than 80 percent of Earth’s wild chimpanzees. Since 1999, WCS has been the only organization systematically collecting comprehensive health data on these populations. In addition, our field vets have been educating park rangers, communities, and field researchers on how to prevent the transmission of Ebola and other zoonotic diseases. They train field staff and biologists to safely obtain biological samples in an effort to shed light on many diseases that threaten wild great apes.


All wild western lowland gorillas live in the Congo Basin, where hunting, farming, ecotourism, political conflict, research, and conservation-related activities bring great apes and humans into closer contact. Emerging infectious diseases, such as Ebola and anthrax, are endemic to these dense forests and have proven deadly to both humans and great apes. The bushmeat trade poses a major direct threat to gorillas and chimpanzees. And through the handling and consumption of wild meat in the trade, humans are exposed to a slew of potential pathogens. The Ebola virus is an especially troublesome example, as there is currently no available treatment for those infected and the mortality rate can be as high as 90 percent.

Making matter worse, this region lacks adequate public health resources. Human cases of measles, influenza, and tuberculosis—infectious diseases extremely dangerous to great apes—are common in communities living near or in great ape habitat.


  • Create preventive healthcare programs to protect great apes, field staff, tourists, and communities against infectious diseases in areas where humans come directly or indirectly into contact with wildlife
  • Guide existing local public health agents on methods to decrease the prevalence of diseases that infect humans and great apes
  • Train local personnel in the safe collection of biological samples and health surveys of animals and humans

What WCS is Doing

In disease “hot zones,” WCS-Global Health develops baseline health profiles for great apes. Field veterinarians and staff conduct intensive ecological surveys to observe and obtain data and diagnostic samples from gorilla and chimpanzee carcasses. WCS’s Animal Health Monitoring Network encourages rapid reporting and response to wildlife mortalities and illnesses. This network provides critical information to researchers and public health agencies and serves as warning system to possible future outbreaks in human communities. Using hidden video camera traps in Congo Basin forests, WCS teams and their partners explore ways in which a newly developed human vaccine against Ebola may be administered to great apes. This visual data also sheds light on ways diseases could spread within the forest community.

From the Newsroom

WCS Says the Key to Saving Mountain Gorillas Is Saving the Guards that Protect ThemJanuary 7, 2009

Protecting gorillas in Virunga National Park, in the Democratic Republic of Congo, relies on supporting the rangers who have sacrificed much to save the mountain gorillas and other wildlife. WCS has pledged $15,000 to help support the park guards and their families.

Haven for Rarest GorillaNovember 26, 2008

Gorilla population surveys, conducted by WCS, have helped the government of Cameroon create a new national park, which will protect more than 600 gorillas and other threatened species, such as chimpanzees, forest elephants, buffalos, and bongo.

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