Hantavirus symptoms, spread and pandemic risk explained by infectious disease expert

More than 100 passengers aboard a luxury cruise ship hit by a hantavirus outbreak have now been evacuated, while health officials across several countries monitor passengers and close contacts for possible infections. Eighteen Americans have been placed in biocontainment units in Nebraska and Georgia.

So far, all 11 reported infections have been linked directly to passengers or crew aboard the MV Hondius, according to Tedros Adhanom Ghebreyesus, director-general of the World Health Organisation.

Hantaviruses usually spread through contaminated rodent droppings or urine. The Andes virus, identified on the cruise ship, is the only strain known to spread between people, though experts say it is unlikely to trigger a Covid-like pandemic.

“At the moment, there is no sign that we are seeing the start of a larger outbreak,” Ghebreyesus said during a press conference in Madrid.

However, he cautioned that the situation could still evolve, as the virus has a long incubation period, potentially leading to additional cases in the coming weeks.

LiveMint spoke with Neha Mishra, HOD and Consultant in Infectious Diseases at Manipal Hospitals, about how the Andes virus spreads, its infectiousness, and whether it poses any pandemic risk.

Q: How similar is the Andes virus to SARS-CoV-2, and could it cause another pandemic?

It is not similar to SARS-CoV-2 at all. This outbreak on the cruise ship is not going to translate into a worldwide pandemic like COVID because it is far less infectious. Covid spread easily because it infected the upper airways, so coughing, sneezing, and even talking could release the virus into the air.

The Andes virus infects much deeper in the lungs, which makes person-to-person transmission much harder.

Q: What are the symptoms of the Andes virus?

Symptoms can appear anywhere from about five days after exposure to as long as six weeks later. It usually starts with very generalised symptoms such as fever, headache, fatigue and muscle aches. Those symptoms can resemble the flu or other infections, but the illness can progress quickly in severe cases.

Q: Is the Andes virus airborne like measles or Covid-19?

Not exactly. It does not spread like measles, where someone can enter a room hours later and still become infected. With hantavirus, people generally need very close, prolonged contact with an infected person for transmission to occur.

Q: How does the virus usually spread?

The most common way it spreads is through exposure to rodent droppings or urine. For example, if someone is cleaning a dusty basement or shed, microscopic particles containing the virus can get stirred up and inhaled. It may also spread through contaminated surfaces if people touch infected material and do not wash their hands properly.

Q: What counts as close and prolonged contact?

To some extent, it depends on what you are doing. The cruise ship doctor who tested positive had repeated close exposure while examining a patient face-to-face. Someone sitting beside an infected person for a long period could also be at risk, especially if the infected person is at their most infectious stage.

Q: Does ventilation matter?

Yes. Poor indoor ventilation can increase the risk of transmission, while outdoor environments are at much lower risk. Cruise ships are unique because they are enclosed spaces with close contact among passengers.”

Q: Should the average person be worried?

No, definitely not. Previous outbreaks were successfully controlled once containment measures were put in place. Since health authorities already understand how the virus spreads and precautions are already in place, this is not believed to have pandemic potential. Measles outbreaks are actually a much bigger concern right now.