Late in 1990, when Paul Kagame was hiding on the Congolese side of the Virunga mountains preparing to invade Rwanda, his army were not the only inhabitants of that thickly forested volcanic range. The Virungas are also home to mountain gorillas (大猩猩). Soldiers are notoriously excited when it comes to wildlife, but Mr. Kagame ordered his men not to shoot the apes. “They will be valuable one day,” he said. He was right.
By 2017, with Mr. Kagame now installed as Rwanda's president, that country's wildlife-tourism industry, of which gorilla-watching on the Rwandan side of the Virungas accounts for 90%, was worth around $438 million a year. But now the world's gorillas, and also their great-ape cousins, the chimpanzees, bonobos and orangutans, face another threat from their human neighbours: covid-19.
Great apes share about 98% of their DNA with human beings, and are vulnerable to many of the same diseases. So far, there have been no reported cases of wild apes sickening with the new coronavirus (冠状病毒). But research done by Amanda Melin of the University of Calgary, in Canada, and her colleagues, suggests that many primates are at risk.
The virus infects people by locking onto ACE2, a protein found on the surface membranes (细胞膜) of certain cells - particularly those of the airways into the lungs. The ape version of ACE2 is, Dr Melin has discovered, identical to the human variety, so apes are likely to be particularly susceptible to SARS-COV-2.
Covid-19 is novel, but primatologists (灵长类动物学家) like Dr Wrangham, who is familiar with the harm caused by diseases of human origin, are already worried. They estimate that Ebola virus alone is responsible for the deaths of a third of the world's wild gorillas over the past three decades. Jane Goodall, a primatologist doing research on chimpanzees in Tanzania is also worried. The country has not enforced a full anti-covid lockdown, so villagers who live around the park could spread the disease to the chimps. Worse still, mountain-gorilla groups are normally harems that have several females but only a single adult male. If this silver-back were to die of covid-19, the females - likely to have been infected as well - would probably disperse to join other groups, spreading the virus further.
Mr. de Merode says that if a gorilla tested positive for covid-19, his park “would consider a veterinary (兽医的) intervention to isolate (隔离) and treat the individual, but we would then be in unknown territory”. Most primatologists think isolating a sick ape would be impractical. Rather, laments Dr Wrangham, “we would just have to sit back and watch.”
