– By Sofia Costa, Communications Manager at Swissnex in Brazil

The Amazon rainforest, often referred to as the “lungs of the Earth,” harbors one-third of the planet’s species and is home to the greatest concentration of biodiversity on the planet. Yet, this vital ecosystem is under unprecedented threat. Rising deforestation rates are disrupting its delicate balance, placing countless species at risk and increasing the likelihood of zoonotic diseases—those transmitted from animals to humans.

When natural habitats are destroyed, humans and wildlife are forced into closer contact, creating ideal conditions for pathogens to jump between species. Over 75% of emerging infectious diseases originate from pathogens, originally circulating in animals, posing significant risks to global health. Mammals and birds worldwide incubate around 1.6 million viruses, some of which possess lethal potential if or when transmitted to humans. These diseases claim millions of lives annually, with COVID-19 being a stark example of the devastating consequences of zoonotic spillover.

To explore these risks and the pressing need to protect biodiversity, we interviewed Dr. Alessandra Nava, a Brazilian scientist at Fiocruz Amazônia. Dr. Nava specializes in emerging infectious diseases linked to deforestation and environmental change. Her work, which includes collecting small mammal samples for the Fiocruz Amazônia Biobank, plays a pivotal role in understanding and mitigating the spread of zoonotic pathogens.

Through her research, Dr. Nava sheds light on how preserving biodiversity is essential not only for ecological balance but also for preventing future pandemics.

The increasing proximity between humans and wildlife, driven by deforestation and habitat destruction, is amplifying the risk of zoonotic diseases. These pathogens, responsible for over 75% of emerging infectious diseases, pose a growing threat to global health and stability.

How does a pathogen jump between species, from animals to humans?
Dr. Nava: “The frequency of contact between species that would not naturally meet makes it possible for pathogens to adapt to other hosts. The loss of biodiversity and contact rates between humans and wild animals is also a route to these emergencies.”

What are the risks and possible scenarios when a pathogen passes from an animal to a human species?
Dr. Nava: “It depends on the pathogen in question and its infectivity. In other words, it is transmissibility. We have seen with COVID-19 that pathogens with high transmissibility lead to disastrous consequences, from an increased number of patients to a collapse of the health system, jeopardizing all care and reception of the population.”

What should we do to prevent possible viruses from becoming transmissible to humans?
Dr. Nava: “Do not commercialize wild animals for consumption or as pets, do not release hunting, and keep our forests standing and with high biodiversity. Many zoonotic diseases will emerge and re-emerge and increase their area of occurrence due to climate emergencies. We must be prepared for this scenario.”

The loss of biodiversity harms our health and threatens the ecological cycles that sustain life. According to the United Nations Environment Program, biodiversity is declining faster than at any other time in history, with over one million species currently at risk of extinction.

In your opinion, what is the most severe loss we are experiencing in biodiversity?
Dr. Nava: “We lose ecosystem services and the forest’s ability to return moisture to the atmosphere. The loss of biodiversity also leads to the loss of the dilution effect, which is apparent when we compare diseases that occur in southeast Brazil, such as spotted fever, and those that occur in the northern region, which are still uncertain. Capybaras, as competent reservoirs for the bacteria and resilient animals, remain in highly anthropized environments while species more sensitive to anthropic pressure disappear.”

What consequence should we be most afraid of?
Dr. Nava: “The loss of the forest’s ability to regulate the hydrological cycle is one of the most important.”

What is the first step we should take to change the path we are on now?
Dr. Nava: “As Thomas Lovejoy would say, “Regreening!” Standing forests are necessary. Our need and craving for fossil fuels and agribusiness are crucial points that must be reevaluated.”

Safeguarding biodiversity is critical not only for ecological balance but also for preventing pandemics. Understanding the social and environmental factors behind disease emergence, alongside proactive monitoring and community involvement, is essential to mitigating future health crises.

Considering your career collecting samples of small mammals for Fiocruz Amazônia, what is Fiocruz doing proactively to predict or prevent another pandemic?
Dr. Nava: “At Fiocruz Amazônia, we actively monitor emerging pathogens through a partnership with IBAMA and ICMbio, collecting samples from various wild species in the state. The human component is also very present in understanding the type of contact the community has with wildlife, the points of fragility for an emergency, and the changes in the landscape that can lead to an emergency. Understanding these variables is crucial to staying one step ahead.”

How can the One Health approach help mitigate these consequences in the Amazon region and globally?
Dr. Nava: “The one-health approach understands that mitigating and solving problems requires a variety of perspectives, including prior knowledge and baggage that can interact to create global improvement possibilities, targeting not only humans but also animals, the environment, and the ecosystem.”

The One Health approach is gaining traction globally. In Switzerland, the University of Zurich recently established Europe’s first One Health University Institute (OHI).

How does Brazilian universities’ approach compare to that of countries in the global north?

Dr. Nava: “In Brazil, various institutional initiatives are beginning to address the single health approach. Oswaldo Cruz Foundation has a program on One Health ( Fio Saúde Única ), and also Brazilian government has an interministerial One Health group. Undergraduate courses are still far off, but the climate agenda pushes us to be more agile.”

The challenges posed by biodiversity loss, climate change, and zoonotic diseases demand urgent action. As Dr. Alessandra Nava highlights, solutions require a multidisciplinary approach, bridging science, policy, and community engagement. Standing forests, proactive monitoring, and the implementation of the One Health approach are critical steps to safeguard our ecosystems and health.

This conversation underscores the importance of global collaboration to address these interconnected challenges. By fostering knowledge exchange and innovation, we can work toward a healthier planet for all species.

Stay tuned as Swissnex in Brazil continues to explore the intersection of science, sustainability, and innovation, sharing insights and solutions from experts at the forefront of this vital work.