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Hantavirus: Separating the Facts from the Fear

What it is, who is actually at risk, what symptoms to watch for, and what you should do if you’re worried.

From Dr. Scott Braunstein, Chief Medical Officer of Sollis Health

When a disease makes international headlines, fear tends to move faster than facts. The recent hantavirus cases linked to the MV Hondius cruise ship are generating real concern and lots of questions. I want to give you a clear, honest, clinically grounded picture of the situation, explaining what hantavirus is, who is actually at risk, what symptoms to watch for, and what you should do if you’re worried. 

The short version: for most people in the United States, the risk is very low. But the details are still worth understanding. 

 What Is Hantavirus?

Hantavirus is not a new pathogen. First identified during the Korean War and named after the Hantan River on the border between North and South Korea, it belongs to a family of viruses carried primarily by rodents: deer mice in North America, certain rat species in South America, and others in Europe and Asia. 

Different strains of hantavirus cause different syndromes. In North America and South America, the primary concern is hantavirus pulmonary syndrome (HPS), a severe respiratory illness. In Europe and Asia, hantavirus more commonly causes hemorrhagic fever with renal syndrome (HFRS), which is characterized by low platelets, uncontrolled bleeding, and kidney failure. Mortality rates vary significantly by strain. 

The strain associated with the MV Hondius outbreak is called Andes virus (ANDV), a South American strain responsible for HPS. ANDV is notable for one specific reason: it is the only known hantavirus strain with documented, though rare, human-to-human transmission. That distinction is why this outbreak has attracted significant attention. 

How Does Hantavirus Spread? 

For most hantavirus strains, transmission is straightforward: you must come into direct contact with an infected rodent or its droppings, urine, or saliva, most commonly by inhaling aerosolized particles in enclosed or dusty environments. This might happen when cleaning out a barn, cabin, or garage, or when working or camping in areas with heavy rodent activity. 

Hantavirus is not known to spread through person-to-person contact with one exception, the Andes Virus strain (ANDV). Fortunately, this strain is not transmitted easily through respiratory droplets the way COVID spreads, but usually requires close contact with an infected person. Close contact typically involves prolonged contact in a closed space, such as sleeping in the same bed or sitting directly next to an infected person on a long car or bus ride. It can also be spread by touching something an infected person recently touched and then touching your nose or mouth, or by sharing food, using the same drinking straws, or sharing eating utensils with an infected person. In one study from a prior outbreak in Argentina, among household contacts of infected persons the risk of contracting the disease was 17.6% among intimate partners, and only 1.2% among other household contacts. 

ANDV is most contagious just before and during the febrile prodrome period, when viral loads are highest.  Based on studies from past outbreaks in Argentina, transmission mainly occurred at a time when the infected person was quite ill, with symptoms such as fevers, body aches, and malaise.  

Who Is at Risk and Should I Be Worried?

Based on what we know, the MV Hondius cases appear to be linked to outdoor exposure in Argentina, likely through contact with infected rodents or their droppings in rural settings.

The World Health Organization has assessed global risk from this event as low. This is not COVID. Hantavirus has not demonstrated the kind of transmissibility required to sustain widespread community spread. Past outbreaks of hantavirus—even larger ones—have been quickly contained.

That said, Sollis's physicians are always here if you'd like a professional opinion. It may be worth reaching out to Sollis if:

  • You’ve recently traveled to rural South America (particularly Argentina) and are experiencing unexplained fever, fatigue, or muscle aches
  • You’re a returning traveler with symptoms that feel flu-like but something still seems off
  • You’re anxious after reading the news and want to talk through your risk with a clinician

What Are the Symptoms of Hantavirus?

HPS follows a distinct clinical course:

  • Incubation Period: 7 to 49 days after exposure, most commonly 2 to 3 weeks.
  • Prodromal Phase: 2–7 days. Early symptoms are flu-like and include fever, muscle aches, headache, chills, and gastrointestinal symptoms such as nausea, vomiting, and abdominal pain. Critically, early respiratory symptoms such as nasal congestion, sore throat, and cough are notably absent during this phase. This is one feature that distinguishes HPS from influenza, even though the two can look similar at first glance.
  • Cardiopulmonary Phase: Without early intervention, HPS can progress rapidly to severe respiratory distress, non-cardiogenic pulmonary edema, and cardiogenic shock. Most deaths occur within the first 24 hours of hospital admission. HPS carries an approximately 35% mortality rate, which is why prompt evaluation matters. 

Certain lab findings are also characteristic of HPS: low platelets (thrombocytopenia), elevated hemoglobin concentration, abnormal white blood cell patterns, and impaired kidney function. An experienced clinician who suspects hantavirus will know what to order.

HFRS, caused by other hantavirus strains, presents differently with fever, hemorrhagic features, and acute kidney injury that can require dialysis. Mortality ranges from 1 to 15% depending on the specific strain. 

What Should You Do If You’re Concerned about Hantavirus? 

If you have been in an environment with potential rodent exposure or if you have had close contact with a confirmed case of ANDV and you develop any of the following, seek medical evaluation promptly: 

  • Unexplained fever 

  • Fatigue or muscle aches without obvious cause 

  • Headache 

  • Gastrointestinal symptoms accompanied by any of the above 

Do not wait for symptoms to worsen before seeking care. With HPS, the window between early intervention and rapid deterioration can be narrow. 

This is not a situation for a walk-in urgent care visit or a waiting room. You need a physician who can evaluate you thoroughly, order the right tests, and connect you to specialists if needed without delay. 

How to Protect Yourself from Hantavirus

For anyone spending time in environments where rodents may be present—whether in rural areas domestically or abroad—these precautions apply: 

  • Avoid contact with wild rodents and their nesting areas 

  • Wear gloves and ensure proper ventilation when cleaning areas that may have rodent activity (barns, cabins, garages, storage units) 

  • If traveling to rural Argentina or surrounding South American regions, take extra precautions and familiarize yourself with early symptoms 

  • Seal food in rodent-proof containers when camping or in rural settings 

There is currently no approved vaccine and no approved antiviral treatment for hantavirus. Treatment is supportive, often in an ICU setting, and in severe cases ECMO (extracorporeal membrane oxygenation) can be lifesaving. Investigational therapies are being studied. This reinforces why early detection and access to expert clinical judgment are so important. 

A Note on Hantavirus Treatment and Diagnosis 

Along with the clinical picture, diagnosis of hantavirus requires specific serologic testing: IgM/IgG antibody panels available through specialized labs. The characteristic lab pattern (thrombocytopenia, left shift with immature white cells, hemoconcentration, elevated LDH) can help an astute clinician raise suspicion early, before confirmatory testing returns. 

For suspected cases, the CDC Emergency Operations Center (770-488-7100) is available around the clock for clinical guidance. 

Why Sollis Is Built for Moments like These

When time is of the essence, Sollis members have direct, 24/7 access to physicians who can evaluate them immediately and give them answers fast. No waiting rooms, no guesswork at the urgent care, and no being told to "monitor it at home." Whether you’re a returning traveler with unexplained symptoms or a parent who read the news and wants to understand your family’s risk, our job is to give you clarity fast. 

Hantavirus is exactly the kind of situation where having a physician who knows your medical history and can assess you quickly makes a real difference. If you're curious about what that level of access could mean for you and your family, now is an excellent time to find out.