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Cases of monkeypox are on the rise in the United States, with approximately 67,600 cases worldwide, including approximately 25,500 in the United States. Simultaneously, the world is still facing a COVID-19 pandemic, despite the decrease in the number of cases.
Researchers say these types of viruses, known as zoonotic diseases, or those that spread between humans and animals, will become more common as factors such as the destruction of animal habitats and the human expansion into previously uninhabited areas is intensifying.
Humans and animals interact more
Monkeypox was first discovered in monkeys in 1958 and in humans in 1970, according to the Centers for Disease Control and Prevention.
Things like deforestation, population growth and ranching have broken down the boundaries between where humans and wild animals live, bring them into closer contact.
Since 1990, approximately 1 billion acres of forest have been cleared to make way for other uses. Deforestation rates have declined, with an average of 25 million acres cleared each year from 2015 to 2020, compared to about 40 million per year in the 1990s, according to a United Nations report.
Besides the impact on the climate, deforestation means loss of habitat that often ends up bringing wildlife closer to people.
“You just see the effects of changing the environment, changing animal behavior, changing human behavior, bringing wildlife and humans into more contact where they can have more contamination,” Lanre Williams said. -Ayedun, the senior vice president of international programs at World Relief, a nonprofit sustainable development organization.
These changing patterns in animals migration and reproduction can influence how pathogens behave in their natural host, perhaps becoming more contagious in the process, said Dr. Carl Fichtenbaum, vice president of clinical research in internal medicine at the University of Cincinnati.
“Depending on the particular germ, when it has the opportunity to do this multiple times, the germ adapts to the new species,” he said.
A United Nations study found that approximately 60% of known infectious diseases in humans and 75% of all emerging infectious diseases are zoonotic or transmitted between species, from animals to humans.
Some of them include Ebola, Zika, and COVID-19, which scientists say started in bats.
Could the current monkeypox epidemic have been predicted?
Monkeypox is endemic, or regularly found, in some African countries. But because monkeypox can be “self-limiting” and not as transmissible as other viruses. “This wasn’t something you would have thought would become such a big epidemic,” Williams-Ayedun said.
The virus was nearly eradicated at one point when people in these areas received vaccinations against smallpox, a relative of monkeypox, in greater numbers. But now vaccination rates are much lower among people 40 and under, Williams-Ayedun said.
People are also traveling further and more frequently these days.
“It’s easy to spread disease globally, and we’ve seen that something happening in what we think is a remote part of the world somewhere can very easily become a concern where we live,” said she declared.
Luis Escobar, assistant professor in the Department of Fish and Wildlife at Virginia Tech, said that if researchers were able to predict where small outbreaks of monkeypox are more likely to occur — poorer regions, areas of war or social conflict, or remote locations — it’s in places where data is less accessible.
“My perception is that the data may not be enough,” he said. “The data may not have been sufficient to anticipate a global epidemic of this magnitude.”
He added that scientists need to investigate zoonotic diseases “in every corner of the world because we don’t know what [region] will trigger the next pandemic.”
Fichtenbaum agrees and said that with the thousands of germs in the ecosphere, it’s hard to know which ones will spread to pandemic-level proportions.
“I think it would be really dishonest if someone said, ‘Well, I can predict this germ is going to be the next big germ,'” he said. “I think we’re not very good at it, the same way we’re not very good at predicting earthquakes.”
The spread of zoonotic diseases will likely become more frequent
Escobar said that in looking to the future, researchers have overlooked past data in their work to fight the spread of disease.
“The research I do is kind of to anticipate the future,” he said. “But we’re putting a lot of effort into trying to reconstruct the past. We’re analyzing data from the last century – in terms of wildlife diseases, climate, forestry laws over the last 100 years – and with that, we understand What’s going on now.”
He and his colleagues used this data in simulations to predict trends in the next 50 to 100 years. But zoonotic diseases may not take that long.
Escobar’s research suggests that over the next 12 to 20 years, there could be a significant increase in diseases transmitted to humans by bats. Diseases endemic to the Latin American bat population could begin to spread across the southern United States as Latin America warms, he said, affecting the distribution and amount of bats.
Moreover, diseases that only affect animals could tell us a lot about what society might look like in the future.
For example, as global warming continues to intensify, a virus common to fish could decimate aquaculture, causing hits to food production and the economy, Escobar said.
What can we do there?
Fichtenbaum argues that public policy will need to address the spread of zoonotic diseases.
“I think right now a lot of the attention on climate change has been focused on, ‘Well, it’s bad for the environment, and we’re going to see flooding, and we’re going to see heat waves, and that can affect economic survival. But people don’t always think about it in terms of human health and disease, which is very expensive.”
In recent years, some researchers in the field of studying zoonoses have pushed for a “one health” approach, the merging of public health, veterinary health and environmental health, Ayedun-Wliliams said.
It is also important to help people find jobs, safe shelter and food, as scarcity can lead to hunting of wild animals or cutting down of trees for homes, and in turn lead to zoonotic diseases, she said.