Science at work 15 November 2022
Covid-19 | Improving knowledge on coronaviruses carried by bats to protect human populations
"We are looking to understand the interactions between humans, livestock and wildlife in Zimbabwe", says Mathieu Bourgarel, a CIRAD researcher specializing in bats. "To this end, we are using the One Health approach, and working with our Zimbabwean partners to study how coronaviruses and other viruses emerge and circulate in Africa so as to quantify the health risks and prevent future epidemics."
The research team is collecting biological samples from mammals, particularly bats and rodents, and conducting virological and serological analyses. Ecological studies of wildlife species, which act as reservoirs for some viruses, are also on the agenda.
Coronaviruses are a family of viruses whose types "alpha" and "beta" affect mammals. SARS-Cov-2, which is causing the Covid-19 pandemic, is a beta coronavirus. A few months ago, Zimbabwean and French researchers identified different types of coronaviruses in two colonies of insectivorous and cavernous micro-bats in the Kwekwe and Hurungwe districts.
“The local population frequently visits these bats’ habitat, in order to collect guano to use as fertilizer for their crops. It is therefore essential to know the pathogens carried by the bats, because they could be transmitted to humans. The current pandemic is, among other things, linked to the reduction of wildlife habitat”, says Dr Elizabeth Gori, a specialist in veterinary biochemistry and molecular biology at the University of Zimbabwe.
Being better prepared for the next epidemic
The researchers collected samples of droppings from bats belonging to these colonies. Back in the laboratory, these samples are now being analysed and the coronaviruses extracted. Scientists sequence the genetic signature of the virus, its RNA, in order to reveal its genetic characteristics.
“If we know the genetic characteristics of these viruses better, we will be able to react better, thanks to rapid and customized diagnoses according to already-known strains. We are in a way preparing a toolbox to be used in the event of transmission of a new coronavirus to humans”, Dr Florian Liégeois, IRD virologist, explains.
In addition to these analyses, the researchers plan to collect new samples of droppings, saliva and blood from the same bats, in order to increase knowledge of the genetic diversity of coronaviruses as well as their prevalence among these populations.
"All these research and training activities, initiated as part of the FSPI-CAZCOM project funded by the French Ministry of Europe and Foreign Affairs, are intended to make Zimbabwe more self-sufficient in terms of controlling major animal diseases and zoonotic diseases such as Covid-19", Mathieu Bourgarel concludes, stressing the importance of involving local people by means of participatory approaches "to improve disease surveillance and detection systems".
*This new project, funded by Montpellier University of Excellence and carried out in Harare, complements an existing international project on the prevalence, genetic diversity and geographical distribution of coronaviruses in wild bats, aimed at assessing the risks in terms of future zoonotic transmission. The latter project, led by IRD, is funded by the ANRS and is looking at the genetics of coronaviruses carried by bats in Zimbabwe, Guinea, Cameroon and the Democratic Republic of Congo.
Bourgarel Mathieu, Pfukenyi Davies Mubika, Boué Vanina, Talignani Loïc, Chiweshe Ngoni, Diop Fodé, Caron Alexandre, Matope Gift, Missé Dorothée, Liégeois Florian. 2018.
Circulation of Alphacoronavirus, Betacoronavirus and Paramyxovirus in Hipposideros bat species in Zimbabwe . Infection, Genetics and Evolution , 58: 253-257