The current outbreak of a new coronavirus disease, named COVID-19, raises the question of where diseases like this come from and where the risks lie. By the middle of February almost 2000 people had died in this outbreak, which has also had a global economic impact.
It is clear that the virus may have an animal reservoir. In other words, it may be permanently found in a host species of animal, where it does not normally cause disease. Viruses can spill over from the host to other animals and humans. Evidence points to a possible initial spillover of the virus into humans and other animals in an animal market in Wuhan in China.
Bats are prone to act as reservoir for viruses. Chinese populations of the horseshoe bat genus (Rhinolophus) have already been found to host viruses similar to the new coronavirus. This suggests that it’s important to watch out for related viruses in this genus of bats elsewhere, including African countries.
Scientists on the continent do keep a watch by doing bio-surveillance and specifically looking for pieces of coronavirus genomes in bat species. If these are found, the researchers can determine the genome sequence and analyse how it is related to other animal and human coronaviruses.
If it’s closely related, it may be an indication of where the spillover of new viruses came from and whether it poses a risk of a disease outbreak.
The horseshoe bat genus is found around the world and there are 40 species in Africa. But so far no viruses related to the cause of COVID-19 disease have been reported from African bat species.
Novel coronaviruses
No outbreaks of coronaviruses with a link to bats have been reported in Africa. But we still need to be vigilant.
Coronaviruses are known to have a high mutation rate and can recombine with other coronaviruses, creating new virus variants with the potential to emerge as outbreak viruses in humans. The emergence of novel coronaviruses is also strongly linked to a high diversity present in host populations and to contact between bats, humans and other animals, creating opportunities for spillover.
Understanding viral presence and diversity is the first step. And further understanding of the many factors that may play a role in the spillover of pathogens from bats to humans requires systematic surveillance of bat populations through a variety of disciplines.
This is particularly needed on the African continent in view of high species diversity and other pressures.
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