Researchers from the United States and Africa have discovered that diseases can pass from humans to gorillas, and can even cause death to these wild mountain gorillas.

Gustavo Palacios, study leader and virologist at the Center for Infection and Immunity at Columbia University in New York, along with Mike Cranfield, executive director of the Mountain Gorilla Veterinary Project and a UC Davis wildlife veterinarian, Linda Lowenstein, a veterinary pathologist with the UC Davis Mountain Gorilla One Health Program, and a team of researchers from the Rwanda Development Board have found that wild mountain gorillas are capable of catching infectious diseases from humans. 

The fact that gorillas have had close contact to humans -- such as gorillas living near densely populated areas in Rwanda, the Democratic Republic of Congo and Uganda -- does not help these endangered species. Also, tourists who visit these gorillas in their shelters expose them to even more potential diseases.

Now, this study has found that gorilla's living in the national parks in Africa are being infected by a respiratory disease that is common in humans (gorillas and humans share 98 percent of the same DNA). The outbreaks of these human-caused diseases have become much more frequent in these specific gorilla populations in recent years. This is problematic because the respiratory issues have proved to be fatal to some of the gorillas. In fact, two gorillas died in 2009 due to human viruses. 

"The type of infection we see most frequently is respiratory, which can range from mild colds to severe pneumonia," said Lowenstine.

The two gorillas that died from the human virus were apart of the Hirwa group, which resides in Rwanda. In 2009, this group had 12 gorillas ranging from males to females to juveniles to infants. Eleven were infected by the respiratory disease, which resulted in symptoms such as watery eyes, runny nose, coughing and lethargy. Two of the infected gorillas died. 

When the tissues of the two gorillas were examined, both had the biochemical signature of an RNA virus called human metapneumovirus (HMPV). An adult female and an infant were the ones killed by the virus.

"Because there are fewer than 800 living mountain gorillas, each individual is critically important to the survival of their species," said Cranfield. "But mountain gorillas are surrounded by people, and this discovery makes it clear that living in protected national parks is not a barrier to human diseases."

This study was published in Emerging Infectious Diseases.