Hantavirus myths busted: What people are getting wrong about the virus
Fresh concern over hantavirus has triggered questions about how the rodent-borne disease spreads. Here's busting some myths about hantavirus, the virus behind the recent cruise ship outbreak.
If you have been following the news lately, you may have heard alarming reports about hantavirus, a disease with a fatality rate that can reach over 40%, much higher than Covid-19 in some cases.
But chances are, you have also come across a lot of misleading or misunderstood information about the virus online.
So what exactly is hantavirus? And should people really be worried about another pandemic?
Let’s break down the myths and facts around this disease, which scientists believe has existed in rodent populations for millions of years.
First, “hantavirus” is not a single virus. It is actually a family of around 38 different virus strains carried mainly by rodents.
These viruses can cause two major illnesses in humans:
- Hantavirus Pulmonary Syndrome (HPS) — mostly seen in the Americas
- Hemorrhagic Fever with Renal Syndrome (HFRS) — more common in Asia and Europe
What is Hantavirus Pulmonary Syndrome?
HPS is the form that has recently made headlines because of the suspected outbreak on the expedition cruise ship MV Hondius.
As the name suggests, the disease mainly affects the lungs. Early symptoms can resemble the flu — fever, body ache, fatigue and cough — but severe cases can rapidly progress to breathing failure.
Among the many hantavirus strains, only one known strain, the Andes virus, has shown limited human-to-human transmission. It is mainly found in Argentina and Chile in South America. The virus is carried by a long-tailed rodent called the colilargo mouse (Oligoryzomys longicaudatus).
Most hantavirus infections happen after people inhale tiny viral particles from infected rodent urine, droppings or saliva. However, the Andes strain can occasionally spread between people through prolonged and close contact.
Scientists believe this may explain how infections spread among some passengers onboard the MV Hondius.
Still, experts say hantavirus is nowhere close to being “another Covid.”
The cruise ship itself offers an important clue. Despite around 147 people sharing enclosed spaces onboard for weeks, only a handful of cases were reported. That suggests the virus does not spread easily between humans.
Covid-19 spread rapidly through respiratory droplets and aerosols, infecting large numbers within days. Hantavirus transmission is far more limited and usually linked to rodent exposure rather than casual human contact.
The Asian and European form affects the kidneys
The second major illness caused by hantaviruses is Hemorrhagic Fever with Renal Syndrome (HFRS), which is more common in Asia and Europe.
This disease can cause fever, low blood pressure, bleeding problems and severe kidney injury. Fatality rates usually range from 6% to 15%, depending on the strain involved.
Different strains dominate in different regions:
- Sin Nombre virus — North America
- Andes virus — South America
- Hantaan virus — Asia
- Puumala virus — Europe
This variation is also one reason why creating a universal hantavirus vaccine has been difficult. A vaccine effective against one strain may not work well against another.
China and South Korea already use vaccines against some Asian hantavirus strains linked to HFRS, but there is no globally effective vaccine yet.
Can a mouse bite give you hantavirus?
Another common myth is that any mouse bite can immediately cause hantavirus infection.
In reality, most infections happen through airborne exposure to infected rodent waste in enclosed or poorly ventilated spaces. Direct bites are much less common as a route of infection.
Hantavirus outbreaks are rare, unpredictable and usually limited to specific geographic regions, which makes vaccine development challenging.
Scientists are dealing with a group of viruses that behave differently across strains, causing severe illness in some people while leading to mild or even unnoticed infections in others.
China and South Korea have developed inactivated vaccines against certain Asian hantavirus strains, particularly those linked to Hemorrhagic Fever with Renal Syndrome (HFRS), but there is still no universal vaccine that protects against all hantaviruses worldwide.
What about India?
In India, hantavirus is not currently considered a major public health concern. While studies have found evidence of hantavirus exposure in rodents and some human populations, large outbreaks have not been reported.
Experts say the best precaution remains basic rodent control and avoiding exposure to rodent urine, saliva and droppings.
Research has detected hantavirus antibodies in parts of India, particularly in Kerala and Tamil Nadu, including Vellore.
India’s first known hantavirus isolate, the Thottapalayam virus, was identified in 1964. Later serological studies in 1999 also suggested previous exposure to hantaviruses in some populations.