You’re probably safe from the Hantavirus outbreak, but here’s what you absolutely must not do, experts say

Death of three passengers on board The expedition ship MV Hondius has triggered an international scramble to track down passengers and crew who were exposed to a rare strain of hantavirus in the Andes. The outbreak has reignited public fear about a virus that most Americans associate with exposure to rural rodents and raised the troubling question of whether human-to-human spread could become more common.

Two scientists working on opposite ends of the hantavirus problem: Dr. virologist Scott Pegan of UC Riverside School of Medicine and veterinary public health expert Dr. Marieke Rosenbaum says the same thing: Don’t panic, but take this seriously.

An independent environment on a cruise ship

For most of its known history, hantavirus has been a disease brought on by close contact with rodents: a dusty barn, a rat-infested cabin, a granary. The Andean strain circulating on the MV Hondius is unusual because it appears to be able to spread between humans. But Pegan said conditions on the ship were extraordinary.

“This is a hypothesis that the virus creates a higher titer in saliva,” Pegan said of the blood test, which measures the concentration of specific antibodies. He compared it to aspects of the early strain of COVID-19, which was also christened with a name. own famous cruise shipDiamond Princess. As society learned six years ago, cruise ships are the perfect breeding ground for viruses. “And that will of course be a respiratory area, and that will probably infect more people.”

But that doesn’t mean the Andean virus behaves like COVID. The transmission Pegan describes is what virologists call nosocomial, meaning spread by hospital-acquired or close contact.

“When a patient comes into the hospital and they don’t really know what they have, and then no one does any protection, and all of a sudden the health care workers are in this situation because they’ve taken such intimate care of the individual,” he explained.

A cruise ship cabin has functionally the same problem, he said. “If it wasn’t on a cruise ship in a small container, it wouldn’t be able to support the spread.”

Rosenbaum, who has studied urban rats in Boston for more than a decade as part of the Boston Urban Rat Study, agrees.

“The risk of human-to-human transmission of hantavirus is really low, and this trip was the perfect condition for the virus to spread to more people than I think it would have otherwise,” he said. “If these people were at home and started feeling sick, they would probably stay home and there wouldn’t be as much contact with other people.”

The real risk is not contact but cleaning

Both researchers emphasized that the average person’s risk of contracting hantavirus has not changed due to the cruise ship outbreak. The virus still spreads almost entirely as it always has, through aerosolized particles in rodent urine, feces, or saliva.

“You know, you’re not going to come face to face with a heavy-breathing mouse coming at you,” Pegan said.

Instead, the problem lies in how many of us typically interact with rodents while cleaning. “In most cases, like in the United States, it’s usually because someone was cleaning up an area that was infested with mice and maybe they didn’t use enough PPE, masks, etc. to do that,” Pegan said. “They basically dust off old mouse urine and things like that, which then releases it into the air and they breathe it in.”

“You should be careful if you are cleaning an area with rodent urine or feces,” Rosenbaum said. “You should wear gloves, a mask, and spray the area with water, because if you just vacuum it will aerosolize all the dry particles, feces, and urine particles, potentially increasing your inhalation rate.” And there is absolutely no vacuuming.

He added that the most dangerous exposures often occur indoors: attics, sheds, basements or any enclosed space “where ventilation is limited, so you’re aerosolizing that material and it has nowhere to go.”

What to do (and not do)

Both scientists offered the same short, no-frills list of advice: Don’t sweep or vacuum rodent droppings; wet contaminated areas before cleaning; wear gloves and mask; ventilate the area; If you have recently traveled to South America and develop a fever along with muscle aches, tell your doctor.

“If someone walks in and says, I have muscle aches and I recently went to South America, they are probably getting a blood test for hantavirus,” Pegan said. Diagnosis is not perfect: it is most reliable 72 hours after the onset of symptoms.

Seeing a mouse on the street is no reason to panic, Pegan said.

“That’s actually the main way that hanta is still very widely spread: Mostly through feces, urine and saliva mixed together. The mouse can bite you and things like that,” he said, but added that unless you’re in the same airspace as a mouse, you probably won’t have a problem.

The ‘wicked problem’ of surveillance

While Pegan focuses on the molecular mechanism of the virus and developing vaccines and antibody treatments, Rosenbaum is working on a harder-to-finance and harder-to-solve question: What’s really floating around in the rodents that live among us?

For more than a decade, he has run the Boston Urban Rat Study, partnering with the city’s inspection services to test for pathogens such as leptospirosis, Staphylococcus aureus, influenza A and hantavirus in wild Norway rats. His team is currently finishing a paper on hantavirus in Boston rats.

“It’s a pretty bad problem,” he said of urban rodent control and disease surveillance, “because it’s going to take a lot of collaboration across sectors to deal with it.”

Norway rats, brown rats that thrive in nearly every major American city, are the reservoir of Seoul virus, a hantavirus that causes hemorrhagic fever with renal syndrome. “Most of the research in America and Europe involved mouse colonies raised for research purposes or for pet or pet food purposes,” Rosenbaum said. “There are very few studies looking at wild mice, so we don’t know much about whether it’s there or not.”

Severe cases of hantavirus are rare in humans, he said, but that’s partly because no one is looking. “You may become infected, develop mild symptoms, overcome the infection, and never go to the doctor and get a diagnosis.”

The problem is that there isn’t enough funding to increase surveillance and research on hantavirus, in part because the large, notable outbreak in America never happened.

“The financing environment in general has changed a lot,” Rosenbaum said. “It can be challenging when it comes to surveillance in mice because people may think we need to spy on humans first.” He compared this to West Nile virus surveillance, which is now a routine public health function in cities, but only because of past outbreaks. “If there is a hantavirus outbreak in New York City that originates from rats, there could probably be more interest in long-term surveillance, but until that happens it probably won’t attract dollar attention.”

Surveillance in wildlife is also quite difficult. “We set traps for mice in the middle of the night,” he said. “It takes a lot of effort, a lot of money, a lot of time.”

Pegan, who recently received a $3.4 million NIH grant for his work on the Crimean-Congo Hemorrhagic Fever (CCHF) virus, a close cousin of hantavirus in the bunyavirus family, made a similar point about therapeutic development. “If you talk about what a vaccine is or what a countermeasure is? There’s really no such thing. And that’s because, once again, we haven’t valued this virus enough to invest the billions of dollars required to get it. That doesn’t mean we can’t get a vaccine. It’s just the prioritization of what we spend the funds and money on.”

His lab has now developed a vaccine platform that targets CCHF and which he says could be adapted to hantaviruses. “We have developed a vaccine platform for bunyaviruses. We were currently using it for CCHF, but this is a platform and can be adapted to hantaviruses like other platforms.” The platform provides protection in as little as three days, he said: “You can get it on Friday, bingewatch netflixand we will return to the public on Monday.

The only hantavirus vaccine available, Hantavax, “is only really effective against Seoul and Hantaan virus, and those are older viruses,” Pegan said. “There is zero evidence that this would work against the Andes or anything else.” (Rosenbaum had a research paper out about finding the Seoul version of hantavirus in Boston rats, but again he calmed fears and said transmission was incredibly rare).

Another epidemic is on the agenda

It may not be hantavirus, but given how social humans are and how viruses evolve, it’s only a matter of time before the world encounters another pandemic.

“I can safely say there will be another pandemic in our future,” Pegan said. “Do we know when and where? We’re a growing population. We’re moving more into areas where some of these viruses are hanging out and where these animals are, and that has consequences.”

This is a collapse of the boundary between humans and wildlife, Pegan said, pointing to the same dynamic that triggered COVID-19, Ebola and now the hantavirus epidemic. “You’re disrupting the human-wildlife interface, and just like with COVID, that’s where you’re going to get these crossover events.”

Decades ago, an Ebola case in a remote village might have gone away on its own. This is no longer the way the world works today. “You’re going to see more situations where people are exposed in these climates and jump on a cruise ship and jump on a plane,” Pegan said. “This is how we live our lives today.”

He stated that a virology researcher was a passenger on the cruise ship: Dr. who observed the birds there. Stephen Kornfeld was again playing with the lines between humans and wildlife. “It will bring more of these,” Pegan said. The combination of population growth, wildlife habitat encroachment, and global travel means more frequent and greater dispersal events. “Evolution It’s not just attached, you know, it’s not like the virus is saying, ‘I’ll never leave the mice.’ But that doesn’t mean that if you keep exposing it over and over again it won’t start sampling other things.”

Rosenbaum said the cruise ship outbreak does not change the immediate risk profile for Americans, but he wants cities to think more about who is most exposed to the outbreak. One of the Boston Urban Rat Survey’s trapping sites was at the heart of Boston’s opioid crisis; here street encampments directly overlapped with rodent activity. “Direct physical contact occurs for this population,” he said. “There are specific individuals that we should consider focusing on when we think about the risk of contracting rodent-borne diseases.”

This story first appeared on: Fortune.com