I figured I might as well hit double digits before circling back to update the earlier reviews of COVID-19 in animals. This group doesn’t get talked about much, but there are some important issues to consider with regard to non-human primates.

Not surprisingly, many non-human primates are known to be, or are likely, susceptible to SARS-CoV-2. In particular, it has been shown that the ACE2 receptor (ACE2) from apes, as well as African and Asian monkeys, is a good match for SARS-CoV-2. New World monkeys are likely not as susceptible because of some differences in their ACE2 receptors. Some lemurs are probably also susceptible.  See the Figure below from the ACE2 receptor study for more details.

My standard disclaimer is that ACE2 receptor assessment can be useful, but it doesn’t tell us the whole story. However, it’s probably fairly accurate here. Experimentally, rhesus macaques, and a few other species, have been shown to be susceptible to infection, as predicted by the shape of their ACE2 receptors.

The relevance of susceptibility is an important question. Specifically, what could it mean for the animals, and for people?

If SARS-CoV-2 got into a group of susceptible non-human primates, I’d expect a similar outcome as with introduction into a population of people. Some would be fine, some would get sick, and some would die from the infection. If the population is small and isolated, the virus would presumably burn out because it would run out of susceptible hosts in the short term and be eliminated. The more animals and the more contact they have with other groups, the greater the risk of longer-term persistence (and possibly mutation from being passed over and over again from animal to animal). My guess is this risk would mainly be sporadic and short term in specific groups.

The big concern is the potential impact on of an outbreak of SARS-CoV-2 in threatened animal populations, since an outbreak in a single group like this could be devastating for the overall population. Ebola had a huge impact on some gorilla populations – in fact Ebola virus was estimated to have killed up to one-third of critically endangered Western lowland gorillas overall, and 95% of individuals in some groups.  Transmission of human respiratory viruses such as respiratory syncytial virus, metapneumovirus and rhinovirus has also resulted in outbreaks (and deaths) in some other threatened populations of non-human primates. Clearly, if we can spread those respiratory viruses to our closest animal relatives, we can presumably do the same with SARS-CoV-2.

The risk TO people from COVID-19 in non-human primates is pretty low. The risk FROM people is pretty high. That’s why there are currently efforts to restrict contact of people with high-risk wild primate populations, including restricting field research, restricting access by tourists, increasing enforcement of boundaries (since human habitats often abut, or merge into, protected habitats), and requiring the use of masks and other preventive measures when people have to be in the vicinity of these animals. Strict infection control measures for SARS-CoV 2 are in place in some sanctuaries, such as those described by the Jane Goodall Institute.

Unfortunately there are also downsides to these precautions, including economic impacts for local communities, loss of research, difficulties with rehabilitation, and potentially increased poaching risks as there are fewer people around. However, the cost-benefit needs to be considered, and these measures are necessary to prevent potentially devastating disease outbreaks in these threatened populations.

What are the best ways to prevent disease from SARS-COV-2 in non-human primates?

  • Control COVID-19 in people
  • Reduce contacts between people and non-human primates
  • Control COVID-19 in people

Figure from https://www.nature.com/articles/s42003-020-01370-w