Are #Bats and #Rodents special reservoirs? New study found that "Animal orders of established importance as zoonotic reservoirs including bats and rodents were UNEXCEPTIONAL, maintaining numbers of zoonoses that closely matched expectations for mammalian groups of their size. 1/n

More host species = more viral species all together. As simple as that!
"[...] reservoir species richness was correlated with both the number of zoonotic viruses (65.5% of deviance) and the viral richness (56.4% of deviance) of different reservoir orders" 2/n

"variation in the number of zoonoses maintained by each reservoir group was consistent with a largely host-neutral model, whereby more species-rich reservoir groups host more virus species and therefore a larger number of zoonotic species". 3/n

"The only potentially “special” reservoirs identified by this analysis were the cetartiodactyls (even-toed ungulates and whales) and primates, which hosted more zoonoses than would be predicted for mammalian groups with their species richness." 4/n

"Virus species within those families [inc. Coronaviridae] with a bat reservoir were no more likely to be zoonotic than those transmitted by other hosts" 5/n

"While our results do not dispute the existence of distinct features of bat immunity or life history [...], they provide NO compelling evidence that these traits translate into an increased probability of bat-associated viruses infecting humans" 6/n

"In summary, our analysis suggests that variation in the frequency of zoonoses among major bird and mammal reservoir groups is an emergent property of variation in host and virus species richness". Elementary my dear Watson!

"aiming to identify high-risk viruses on the assumption that some taxonomic orders of hosts are disproportionate sources of zoonoses risks missing important zoonotic viruses while simultaneously reenforcing patterns that may reflect detection biases rather than zoonotic risk" 8/n

All the quotes from the thread are from a great paper, freshly out, by #Mollentze and @DanielStreicker
Thank you to both for this important work. Title: "Viral zoonotic risk is homogenous among taxonomic
orders of mammalian and avian reservoir hosts"
https://doi.org/10.1073/pnas.1919176117