Remote cities in regions with high levels of forest loss in the area pose the greatest risk of animal pathogens causing epidemics in humans. This is the conclusion reached by a Brazilian working group led by Cecilia S. Andreazzi from the Oswaldo Cruz Institute in Rio de Janeiro using a new model that takes social, economic and historical factors into account in addition to environmental influences. As the team reports in the journal Science Advances, hunting and eating wild animals, so-called bushmeat, is a key factor in the risk of pathogens spreading to humans. Mobility also plays a major role. Although the analysis has so far only referred to the Brazilian Amazon region, the conclusions should also apply to other tropical regions.
According to the working group, Brazil is particularly susceptible to epidemics of originally animal pathogens. “Brazil is currently combining socio-ecological vulnerability with an ongoing economic and political crisis, making the country a possible breeding ground for the next pandemic,” she explains in her publication. Among other things, she cites the political climate in which environmental protection is ignored and laws are passed that promote the exploitation of nature. In addition, the corona pandemic has exacerbated extreme poverty, another factor that favors potential epidemics. It is therefore necessary to develop a prediction model that can be used to identify and monitor critical areas.
The team compared the regional distribution of outbreaks of nine reportable zoonoses in Brazil, including hantavirus, yellow fever and malaria, with social, environmental and geographic factors to uncover associations. This is based on the assumption that a similar collection of factors favors these well-known diseases and novel pathogens. The result also identifies a wide variety of native mammals as risk factors, in addition to the geographically remote and degraded forests. On the other hand, more trees in the city and a lot of forest in the surrounding area have a protective effect.