As the coronavirus continues to spread among humans around the world,conservationists are warning of its possible risk to another group: Africa's endangered mountain gorillas.Congo's Virunga National Park is home to about 30 percent of the world's mountain gorillas.The park is barring visitors until June 1 because scientists believethe gorillas may be able to catch the new coronavirus.Neighboring Rwanda also is shutting downvisitorand research activitiesin three national parks that are home to gorillas and chimpanzees.Mountain gorillas can contract some respiratory diseases that humans contract.A simple cold can kill a gorilla, says the Worldwide Fund for Nature.That is why park visitors are not supposed to get too close to gorillas.Rules call for a 7-meter distance between gorillas and humans.About 1,000 mountain gorillas live in protected areas in Congo, Uganda and Rwanda.Permitting the public to visit these areas is important and profitable.However, COVID-19, the disease caused by the coronavirus,led Virunga park officials to order the temporary ban.Conservationists have welcomed the decision.Paula Kahumbu leads the Kenya-based conservation group WildlifeDirect.She says that "every possible effort must be made"to protect mountain gorillas because so few are left in the wild."We know that gorillas are very sensitive to human diseases," Kahumbu said."If anyone has a cold or a flu they are not allowed to go and see the gorillas."She Added that people can spread the virus before they show any signs of infection.So, visitors could "put those gorillas at risk."Even under normal conditions, park measures to protect the gorillas from tourists may not be enough.Gladys Kalema-Zikusoka is the founder and leader of the Uganda-based Conservation Through Public Health.She noted a study done this year by her organization and Ohio University.It looked at Bwindi Impenetrable National Park.She said the research showed that the rule separating gorillas and tourists was ineffective.Kalema-Zikusoka said the study showed that the seven-meter rulewas violated almost every time a group of visitors entered the park.She said visitors were to blame about sixty percent of the time.In the other cases, it was the gorillas that moved too close to the humans.Uganda has not announced a shutdown of gorilla park tourism.However, the number of visitors from Europe and other places has sharply decreased.The mountain gorilla population shrank severely in the past 100 yearsbecause of disease and hunting, which is illegal.Mountain gorillas have been listed as endangered since 1996.But, their population is now growing.Tourism brings much foreign money into Rwanda and Uganda.Tourism earnings are important in efforts to protect mountain gorillas.Officials can use it to help local communities or invest in anti-hunting operations.A gorilla tracking permit costs up to $600 in Uganda.A similar permit costs more than $1,000 in Rwanda.Some observers worry a decrease in tourism during the coronavirus crisis could endanger gorillas.Hunters might become more active if they think the crisis has weakened security.