What did you uncover about simian arteriviruses’ ability to jump into humans?
Simian arteriviruses are endemic to some species of African primates. In captive-primate facilities, these viruses have led to outbreaks that cause haemorrhagic fever and death. We used simian haemorrhagic fever virus (SHFV) as a representative of this virus family, and first identified CD163 as the receptor it uses to enter cells. We weren’t happy to see that the human version was completely functional for the virus.
Then we asked whether SHFV can use all the other machinery of the human cell to replicate. Not only did we find human cell lines in which it could do that, but also in one case, SHFV produced an astronomical number of copies of itself. Next, we showed that, in at least one cell type, SHFV seems to resist the interferon response, a crucial component of innate immunity. The last item on our checklist is our adaptive immune system, such as antibodies, which is what would hopefully save the day if the worst happened. Unfortunately, like HIV, SHFV is part of a group of viruses against which humans have no existing immunity.
What should we be doing about this?
We need to be watching for arterivirus infections in humans, which have currently never been observed. For instance, we could run blood tests on people in the regions of Africa where primates are endemically infected with arteriviruses to see whether anybody has antibodies to these viruses—if they do, that would suggest a previous infection. Unfortunately, there are no antibody tests for these viruses yet.