Infectious Disease Doctor Discusses Hantavirus Outbreak and Public Health Preparedness, Misinformation, and Emerging Disease Threats

A rare hantavirus outbreak linked to an expedition cruise ship traveling near South America has drawn international attention and reignited fears about emerging infectious diseases, human-to-human transmission, and global preparedness for the next potential outbreak.

Although infectious disease experts stress that the risk of a widespread pandemic remains extremely low, the appearance of Andes virus-associated hantavirus pulmonary syndrome on a cruise ship has fueled concern across social media and public health circles alike.

Matthew Pullen, MD, an infectious disease physician and member of the Infection Control Today®(ICT®) Editorial Advisory Board, said much of the public anxiety stems from misunderstanding both the virus itself and how it spreads.

“Hantavirus is actually a very large family of viruses,” Pullen explained during an interview with ICT, “The ones we’re hearing about most right now are the Sin Nombre virus and Andes virus.”

According to Pullen, Sin Nombre virus is the hantavirus most commonly associated with the US, particularly in the Southwest and Four Corners region. It is transmitted primarily through exposure to infected deer mice and is not believed to spread person-to-person.

The current concern, however, centers around Andes virus, a hantavirus first identified in Argentina and Chile during the mid-1990s. Unlike the Sin Nombre virus, the Andes virus has shown limited evidence of possible human-to-human transmission in some outbreaks.

“There are a few cases where they’re pretty confident there was human-to-human transmission,” Pullen said. “But there’s still academic debate about whether some of those outbreaks represented true transmission or simply shared exposure.”

Both viruses can cause hantavirus pulmonary syndrome, a severe illness with an estimated case fatality rate approaching 40%.

“It starts like a flu-like illness,” Pullen said. “Body aches, headaches, fever, nausea, vomiting. Then the severe cardiopulmonary phase develops, and that’s what kills people.”

In severe cases, patients develop respiratory failure, pulmonary edema, hemorrhage, and heart failure. Pullen described pathology reports from the original 1993 US hantavirus outbreak in which infected lungs were “twice as heavy as normal lungs” because of fluid accumulation.

Despite the severity of the disease, Pullen emphasized that fears of a COVID-19-style pandemic are scientifically unsupported. “I would say the likelihood is very, very, very low,” he said.

One reason is the virus’s relatively poor transmissibility compared with influenza or SARS-CoV-2. “It doesn’t spread like COVID[-19] does. It doesn’t spread like the flu does,” Pullen said. “The last estimate I saw had an R-naught of about 1.2, meaning not every case even propagates to another case.”

Pullen also noted that highly lethal diseases often struggle to sustain widespread transmission.

“It’s a little grim,” he said, “but diseases with high case fatality rates like Ebola often burn out in a population because they kill so efficiently that they run out of hosts to jump to.”

Still, the outbreak raises broader concerns about global travel, zoonotic disease emergence, and health care preparedness. “What worries me most actually isn’t the virus itself,” Pullen said. “It’s the social conditions around the virus.”

He pointed specifically to the rapid spread of misinformation online. “One morning people on social media were saying this was going to be the next pandemic that would kill us all,” he said. “By that afternoon, those same people were posting that hantavirus was nothing to worry about and that the government was lying.”

Pullen described what he called a “self-eating Ouroboros conspiracy cycle” in which misinformation rapidly mutates and feeds on itself, leaving the public struggling to identify credible information.

He also warned about opportunists using public fear for financial gain. “There was even a physician online promoting ivermectin as a cure for hantavirus,” Pullen said. “Then conveniently mentioning they also sell ivermectin.”

According to Pullen, this type of behavior becomes increasingly common whenever emerging infectious diseases dominate headlines. “People are scared. They want answers,” he said. “And unfortunately there are always people willing to exploit that fear.”

Although the average American is unlikely to encounter hantavirus, Pullen said clinicians should still remain aware of the disease, particularly when evaluating patients with severe unexplained pulmonary illness and relevant travel or environmental exposure histories. “If someone comes in with severe pulmonary syndrome after traveling through Argentina or Chile, that should absolutely bubble up in your mind,” he said.

When asked whether US hospitals are prepared to respond to suspected hantavirus cases, Pullen said most facilities already possess the fundamental infection prevention infrastructure required. “Every hospital should be equipped to do respiratory isolation and airborne precautions,” he said. “The key is recognizing the syndrome early and escalating appropriately.”

He emphasized the importance of involving infection prevention teams, state health departments, and the CDC as soon as unusual pathogens are suspected. “Every state health department should either be able to test for hantavirus or connect you with the CDC,” Pullen said.

Still, he expressed concern about the broader strain on public health infrastructure. “The people working at CDC are phenomenal,” he said. “But they’re being hamstrung by funding limitations and policy decisions.”

Pullen referenced recent federal restrictions on certain CDC testing activities and worried that budget pressures may limit future response capabilities. “I don’t worry about the expertise at CDC,” he said. “I worry about the impact that funding and policy changes are having on what the CDC can actually offer.”

The conversation also turned toward lessons learned—or potentially not learned—from COVID-19. Pullen pointed to “Operation Dark Winter,” a federal pandemic preparedness exercise conducted years before COVID-19 that identified many of the same failures ultimately experienced during the pandemic.

“They identified shortages in PPE, surge capacity problems, misinformation issues, public distrust, all of it,” he said. “Then COVID happened and showed we learned absolutely nothing from that war game.”

He expressed skepticism that the health care system is substantially more prepared today. “I’m not confident we’ve changed much since 2020,” Pullen said.

For frontline health care workers, Pullen said one of the most important lessons remains self-protection. “A sick doctor or nurse can’t take care of a sick patient,” he said. “Health care staff have to advocate for the PPE and protections they need.”

The outbreak also underscores how quickly infectious diseases can spread in highly concentrated environments like cruise ships. “Cruise ships are kind of the perfect environment for transmission,” Pullen explained. “You’re in close quarters, touching common surfaces, dining together, constantly around large groups of people.”

Although norovirus remains the most common cruise ship-associated illness, Pullen said the Andes virus outbreak demonstrates how rapidly global travel can transport emerging pathogens across borders. “The world is a very small place when it comes to viruses,” he said.

For travelers concerned about infectious diseases while cruising, Pullen said the advice remains relatively straightforward. “Wash your hands with soap and water,” he emphasized. “Especially because hand sanitizer doesn’t reliably kill norovirus.”

He also recommended avoiding visibly ill individuals and practicing general situational awareness. “The most common things you’re going to encounter on a cruise ship are still common respiratory viruses and GI illnesses,” Pullen said. “So a lot of the same precautions we already know still apply.”

Ultimately, Pullen believes the current outbreak serves as another reminder that emerging zoonotic diseases will remain a persistent global challenge. “Viruses don’t respect borders,” he said. “And the more interconnected the world becomes, the more important preparedness, communication, and public trust become.”