Ebola, hantavirus and what these frightening outbreaks really mean

Six years after COVID-19 swept the world, the news cycle is once again abuzz with reports of deadly diseases.

A fatal hantavirus outbreak hit the MV Hondius cruise ship, sending American passengers into a lengthy quarantine in Nebraska. And this past weekend, an Ebola outbreak has rocked central Africa, causing the World Health Organization to declare a public health emergency. Both outbreaks, while serious, do not meet pandemic levels, the organization said.

But that doesn't mean they shouldn't be taken seriously, according to Dr. Peter Hotez, dean of the National School of Tropical Medicine and professor of pediatrics and molecular virology and microbiology at Baylor College of Medicine. After all, these pathogens, he says, signify an important trend about the state of our world when it comes to disease: that "zoonotic spillover epidemics," or outbreaks caused by viruses spread to humans from animals, are becoming more common. In fact, Hotez says we can expect one every year or so.

It's not cause for panic. But it is a wakeup call.

"The most important message around this particular hantavirus outbreak is what it represents," Hotez says. "All of our major epidemics over the last 20 years have been mostly zoonotic spillover events. ... This is a wake up call that, yet, here's another one."

Outbreaks of diseases from animals are becoming more common. Why?

The recent hantavirus and Ebola outbreaks were both born from pathogens spread from animals to humans, notes Horetz. Hantavirus typically spreads to humans via the droppings and saliva of rodents, while Ebola tends to get transmitted from animals like fruit bats and porcupines.

"This is our new normal," Horetz says of zoonotic spillover events. "Every year, every other year, every three years, we should expect to see a major zoonotic spillover event, and a serious epidemic."

Why is that? Well, Horetz says, health professionals can't say for sure. But one possibility could be climate change, which has led to more interactions between humans and wildlife.

"Climate change has an important role," Horetz says. "With the rising temperatures, altered climate patterns, altered weather patterns, altered rainfall patterns, what's happening is animal hosts are migrating to seek new habitats to improve access to their food or their shelter."

Another potential factor, he says, is urban population expansion.

"It's not just the bats and rats coming closer to the people; it's the people coming closer to the bats and rats," Horetz says. "We are now starting to see the formation of these ginormous megacities of 10, 15, 20 million people or more, especially in low and middle income countries, and, with that, deforestation. So, it's people coming closer towards animal habitat."

'We need to get ready'

So, what can we do about the rise of zoonotic spillover events? Horetz encourages health authorities to act preemptively, by working on vaccines and treatments for illnesses that could likely emerge.

"We need to get ready. Now that zoonotic spillover epidemics are going to be the new normal, this is a time to be reinforcing our infrastructure," he says. "We need to be gearing up our ability to develop new countermeasures for these illnesses, improve our ability to make better diagnostics, better antiviral drugs. And, of course, having vaccines available for all of these, as well as therapies using monoclonal antibodies."

This should have been the case for the Andes strain of hantavirus before it hit the MV Hondius cruise ship, he says.

"We should have had an Andes virus vaccine ready to go that we could vaccinate those who were at risk of exposure on the ship for both the passengers and the crew, and we didn't," Horetz says. "That's reflective of our lack of preparedness, both at the local and national scale as well as at the international scale."

Contributing: Dana Taylor, The Excerpt