Brazil Deforestation Plans Seeds for Pandemics

As Brazil’s current leader continues to champion the deforestation of the Amazon, experts are warning that such destruction is planting the seeds for the next uncontrolled disease outbreak, as wild animals and their attendant viral and bacterial hitchhikers increasingly cede territory to humans whose immune systems can be defenceless against such “novel” assailants.

“Scientists warn that the next emergent pandemic could originate in the Brazilian Amazon if [President Jair] Bolsonaro’s policies continue to drive Amazon deforestation rates ever higher,” writes Mongabay News. Researchers already know that areas of human encroachment—the “nexus between forest and agribusiness, mining, and other human development”—is where new diseases typically arise.

“Wild vertebrates, particularly rodents, bats, and primates, harbour pathogens that are novel to the human immune system and, if we clear their habitat and put ourselves in closer contact with them, we can increase the risk that a spillover event occurs, introducing a novel pathogen,” said Andy MacDonald, an ecologist with the Institute of Geosciences at the University of California.

Such spillover events are growing ever more commonplace. Mongabay cites a 2008 international and interdisciplinary research project, which determined that “at least 60% of the 335 new diseases that emerged between 1960 and 2004 originated with non-human animals.” Habitat destruction has been the key driver behind this explosion in disease, with researchers around the world confirming direct causal links between broken ecosystems and spikes of disease in humans, including a major surge of yellow fever in the Brazilian state of Minas Gerais following the collapse of an iron mining tailings dam in 2016.

That catastrophe had a particularly devastating effect on monkey populations in the area, biologist Márcia Chame told Mongabay. Distressed and malnourished after their homes and food sources were significantly damaged by the dam collapse, the weakened monkeys were more susceptible to yellow fever, and many fell ill. Mosquitoes, also displaced by deforestation, fed on the monkeys, eventually transferring the disease to humans.

It was this complex combination of factors—the dam collapse, its effect on the monkeys, and other landscape modifications that left “forest fragments running in peri-urban areas”—that created sufficient interaction between monkey, mosquito, and human populations to produce an epidemic, Chame explained.

There is growing concern, as well, that deforestation produced by wildfire may be fast becoming a particular incubation point for zoonotic diseases. After an August 2019 meeting in Colombia to discuss the impacts of the devastating wildfires then ongoing in the Amazon, experts in such diseases issued a formal statement warning that, after a wildfire, the region—which they described as “endemic for many communicable or zoonotic diseases”—can “trigger a selection for survival, and with it change the habitat and behaviours of some animal species.” Those animals can then become “reservoirs of zoonotic bacteria, viruses, and parasites.”

More research is desperately needed to better understand the full effects of human incursion and zoonotic diseases. A 2019 study on development and its relationship with both environmental degradation and disease spread in the Amazon concluded that “too little attention has focused on the emergence and reemergence of vector-borne diseases that directly impact the local population, with spillover effects on other neighbouring areas,” Mongabay says.

Also desperately needed, and not likely to be in any way forthcoming under Brazil’s current regime: rainforest protection.

“In 2019, deforestation in the Brazilian Amazon reached its highest level in 10 years (9,762 km2),” writes Mongabay. Deforestation in protected Indigenous reserves increased even more quickly, “expanding by 74% in 2019 under Bolsonaro as compared to 2018.” In 2020, Amazon deforestation escalated further, “doubling from August 2019 to March 2020, compared with the same period in 2018-19.”

Mongabay adds that the Brazilian congress is poised to permanently legalize the still technically illegal felling of trees on public land, while Bolsonaro himself continues to push through legislation that would “allow large-scale mining, oil and gas drilling, and industrial agribusiness within Brazil’s Indigenous reserves, largely without input from the people living there.”

Brazil’s Indigenous peoples are responding with passionate resistance rooted in a profound understanding of their traditional lands and ecosystems.

At a media conference on climate change communication, held in New York City a few short days before the current pandemic erupted, a group of Indigenous representatives stressed the need to protect the biodiversity of rainforests—both to prevent future pandemics, and to secure some hope of future cures (possibly even near-term future), Mongabay recalls.

Meanwhile, scientists continue “warning urgently that more pandemics lie ahead,” the publication adds. The coronavirus outbreak represents “the very tip of the iceberg” for the zoonotic pathogens awaiting our (unhappy) discovery, Emory University disease ecologist Thomas Gillespie recently told Scientific American.