Hantavirus has returned to global headlines after a deadly outbreak linked to a cruise ship raised fresh concern about how the virus spreads and how dangerous it can be.
The recent cluster was reported aboard the MV Hondius, a Dutch-flagged cruise ship carrying 147 passengers and crew. The World Health Organization said it was notified on May 2 about severe respiratory illness among passengers. By May 4, the WHO had identified seven cases, including two laboratory-confirmed Hantavirus infections, five suspected cases, three deaths, one critically ill patient, and three people with mild symptoms.
WHO later said eight cases had been reported, including three deaths, and that five of the eight cases had been confirmed as Hantavirus. The outbreak has triggered contact tracing and international coordination because passengers and crew represented multiple nationalities.
However, the WHO has also tried to reduce public panic. It said Hantavirus is usually acquired through contact with infected rodents or their urine, droppings, or saliva. Limited human-to-human transmission has been documented in previous outbreaks of the Andes virus, but this remains uncommon. WHO currently assesses the risk to the global population from the cruise ship event as low.
What is Hantavirus?
Hantaviruses are a group of viruses carried mainly by rodents. They can infect humans and cause serious disease, including severe lung, heart, kidney, and blood vessel complications.
WHO describes Hantaviruses as zoonotic viruses, meaning they naturally circulate in animals and can occasionally spread to humans. The virus usually does not make rodents visibly sick, but infected rodents can shed it through urine, droppings, and saliva.
In humans, Hantavirus infection can cause two major disease patterns. It can cause Hantavirus Cardiopulmonary Syndrome, also called HCPS or HPS, which mainly affects the lungs and heart in the Americas. In Europe and Asia, Hantaviruses more commonly cause Hemorrhagic Fever with Renal Syndrome, or HFRS, which mainly affects the kidneys and blood vessels.
Recent Cruise Ship Outbreak
The MV Hondius outbreak is important because it involves the Andes virus, a South American Hantavirus strain known for rare but documented person-to-person transmission.
According to WHO, the vessel departed Ushuaia, Argentina, on April 1 and travelled across the South Atlantic, with stops including Antarctica, South Georgia, Nightingale Island, Tristan da Cunha, Saint Helena, and Ascension Island. Investigators were still trying to determine whether passengers had contact with local wildlife during the trip or were exposed before boarding in Ushuaia.
The illness pattern was serious. WHO said symptom onset occurred between April 6 and April 28. Patients developed fever, gastrointestinal symptoms, and then, in severe cases, rapid progression to pneumonia, acute respiratory distress syndrome, and shock.
The public health response has included isolation, care for suspected cases, medical evacuation, lab testing, and contact tracing. WHO also said passengers onboard were advised to practice maximum physical distancing and remain in cabins where possible.
Is Hantavirus the Start of Another Pandemic?
Based on current evidence, health authorities do not treat Hantavirus like COVID 19.
The key difference is transmission. COVID-19 spreads efficiently through respiratory droplets and aerosols between people. Hantavirus usually spreads from rodents to humans. Human-to-human spread is not common and has mainly been documented with the Andes virus among close and prolonged contacts, such as household members or intimate partners.
WHO says the global public risk from the cruise ship cluster remains low, although it continues to monitor the situation. This means the outbreak is serious for exposed passengers and close contacts, but it does not currently suggest a fast-moving global outbreak.
Origin of Hantavirus
The name Hantavirus comes from the Hantaan River in Korea. The first recognized Hantavirus, Hantaan virus, was linked to Korean hemorrhagic fever. This disease affected thousands of soldiers during the Korean War. The prototype virus was isolated in 1978 and named after the Hantaan River.
Over time, scientists discovered that Hantaviruses were not limited to Korea. Related viruses were later found in different parts of Asia, Europe, and the Americas. Each virus is usually linked to a specific rodent host species and a particular geographic region.
For example, the Hantaan virus is associated with hemorrhagic fever with renal syndrome in parts of Asia. Puumala virus causes a generally milder kidney-related illness in Europe. Sin Nombre virus is linked to Hantavirus pulmonary syndrome in North America. The Andes virus, found in South America, is the only currently known Hantavirus for which limited person-to-person transmission has been clearly documented.
How Hantavirus Spreads
The main route of infection is exposure to infected rodents.
People can become infected when they breathe in tiny virus particles from dried rodent urine, droppings, or saliva. This can happen when contaminated dust is disturbed in enclosed or poorly ventilated spaces, such as cabins, sheds, storage rooms, barns, or rodent-infested homes.
The virus can also enter the body through broken skin, the eyes, nose or mouth. Less commonly, infection can occur through a rodent bite.
Higher risk activities include cleaning rodent-infested areas, farming, forestry work, camping, sleeping in rodent-infested places, and handling contaminated materials without protection.
Human-to-human transmission is uncommon. WHO says it has been documented only for the Andes virus in the Americas and is linked to close and prolonged contact. It appears more likely during the early phase of illness, when the virus may be more transmissible.
What Are the Symptoms of Hantavirus?
Symptoms usually appear one to eight weeks after exposure, depending on the virus type. Early symptoms are often vague and can look like flu, dengue, COVID-19, pneumonia, or other febrile illnesses.
Common early symptoms include fever, headache, muscle aches, chills, dizziness, fatigue and gastrointestinal problems such as nausea, vomiting, diarrhea, and abdominal pain.
In Hantavirus pulmonary syndrome, the disease can suddenly worsen after the early phase. Patients may develop cough, shortness of breath, chest tightness, and fluid buildup in the lungs. Severe cases can progress to shock and respiratory failure.
In hemorrhagic fever with renal syndrome, symptoms may include fever, severe headache, back and abdominal pain, nausea, blurred vision, low blood pressure, bleeding problems, and kidney failure.
Why Hantavirus Can Become Dangerous Quickly
Hantavirus is dangerous because the early stage may look like a common viral illness, while the later stage can progress very fast.
For HPS, CDC says late symptoms usually appear four to 10 days after the initial phase. These include coughing and shortness of breath as the lungs fill with fluid. Once the cardiopulmonary phase begins, patients can deteriorate quickly.
CDC also says that without adequate treatment, most deaths in HPS occur within 24 to 48 hours after the cardiopulmonary phase begins. This is why early recognition and emergency medical care are critical.
Mortality Rate of Hantavirus
The mortality rate depends on the virus strain, region, and disease type.
WHO says Hantavirus infections in Asia and Europe have a case fatality rate of less than 1% to 15%, depending on the virus. In the Americas, Hantavirus cardiopulmonary syndrome can have a case fatality rate of up to 50%, while WHO notes that HCPS commonly has a fatality rate between 20% and 40%.
CDC says 38% of people who develop respiratory symptoms from Hantavirus pulmonary syndrome may die from the disease.
For HFRS, CDC says Hantaan and Dobrava virus infections can be severe, with 5% to 15% of cases fatal. Seoul, Saaremaa and Puumala virus infections are usually more moderate, with fatality below 1%.
Is There a Treatment for Hantavirus?
There is no licensed specific antiviral treatment or vaccine for Hantavirus infection. Treatment is mainly supportive and depends on how the disease affects the body.
For severe pulmonary disease, patients often need emergency care in an intensive care unit. Doctors may monitor heart function, carefully manage fluids, give oxygen, and use mechanical ventilation if needed.
In very severe HPS cases, extracorporeal membrane oxygenation, or ECMO, may be used at specialized centers. CDC says early ECMO at the first sign of decompensation has been associated with an 80% survival rate in patients despite cardiopulmonary collapse.
For kidney-related hantavirus disease, supportive treatment may include dialysis if the kidneys fail.
Ribavirin, an antiviral drug, has been studied in hantavirus pulmonary syndrome, but the CDC says intravenous ribavirin was not shown to be effective for HPS.
How Doctors Diagnose Hantavirus
Diagnosis can be difficult in the first days because early symptoms resemble many other infections. WHO says doctors need a careful history, including possible rodent exposure, travel history, occupational risk, and contact with known cases in regions where Hantaviruses circulate.
Lab confirmation may use serological testing to detect Hantavirus-specific antibodies or molecular methods such as RT PCR during the acute phase of illness.
Because samples can be hazardous, the WHO says non-inactivated biological specimens must be handled and transported under strict biosafety conditions.
How to Prevent Hantavirus
The best protection is to reduce contact with rodents and safely clean contaminated spaces.
People should seal holes and gaps that allow rodents to enter homes, garages, storage areas, and workplaces. Food should be stored securely, and rodent nesting sites should be removed where possible.
When cleaning rodent-contaminated areas, avoid dry sweeping or vacuuming because this can push virus particles into the air. WHO recommends safe cleaning practices, including dampening contaminated areas before cleaning and maintaining good hand hygiene.
During outbreaks, health authorities may isolate cases, monitor close contacts, and apply standard infection prevention measures to limit spread. WHO says the risk of healthcare-associated transmission is very low when appropriate infection prevention and control measures are used.
Who is Most at Risk?
Anyone exposed to infected rodents can become infected. However, the risk is higher for people who work or stay in places where rodents are present.
This includes farmers, forestry workers, cleaners, campers, hikers, people sleeping in cabins or rural buildings, and anyone cleaning closed spaces where rodents may have nested.
Travelers can also be exposed if they visit areas where infected rodents live. The cruise ship outbreak shows why investigators consider both onboard exposure and pre-boarding exposure, especially when passengers have visited remote wildlife-rich or rodent-prone locations.
Hantavirus is rare, but it can be deadly. The recent cruise ship outbreak has gained global attention because it involved severe respiratory illness, deaths, and the Andes virus strain, which can rarely spread between people after close and prolonged contact.
However, Hantavirus is still mainly a rodent-linked disease. It does not spread like COVID-19. The WHO currently assesses the global public risk from the cruise ship cluster as low.
The most important steps are early medical care, careful monitoring of exposed contacts, and strong prevention against rodent exposure. For individuals, the practical message is simple: avoid contact with rodents, clean contaminated areas safely, and seek urgent medical help if flu-like symptoms appear after possible exposure and then worsen into breathing difficulty.
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