What you need to know about hantavirus

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Three passengers on an Atlantic cruise ship have died, a British man is in intensive care, and two crew members are sick amid an outbreak of hantavirus, spread by rats.

The MV Hondius is currently off the coast of Cape Verde, a West African archipelago that is a popular holiday destination, and is not being allowed to dock because of the risk that infection will spread.

The cruise began in Argentina and was set to travel north up to the Canary Islands. The 69-year-old British passenger was taken to a hospital in Johannesburg.

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Experts have said the illness is likely to be caused by a strain of hantavirus that has a high death rate and can spread more easily, passing between people.

What is hantavirus?

Hantaviruses are a group of 38 viruses carried by rodents such as rats, mice and voles, most of which can cause disease in people. Symptoms vary from too mild to be noticed, to severe sickness and death.

The bugs can trigger two main types of illness, affecting either the lungs, as in this outbreak, or the kidneys. In the lung condition, the chest fills with fluid, which causes the lungs and the heart to stop working properly.

Hantavirus was also in the news last year, when actor Gene Hackman and his wife, concert pianist Betsy Arakawa, were discovered dead in their home in New Mexico. It was found that the disease caused the death of Arakawa, and it is believed Hackman, who had advanced Alzheimer’s, died a week later.

How does hantavirus usually spread?

Hantavirus is usually caught from rodent droppings, often when people breathe in dust contaminated with faeces, urine or saliva from infected animals.

In the UK, it is often caught by people who have been exposed via their job – for example, if they clean outbuildings where rats have been nesting.

“As you as you move the nest, that creates dust, and the virus is found in those bits of dust,” said Professor Adam Taylor, head of the clinical anatomy learning centre at Lancaster University.

“Rats do their business in relatively close proximity to the places that they’re residing.”

Why is person-to-person transmission suspected?

So far, only one person has been confirmed to have hantavirus, with five more suspected cases, according to the World Health Organisation. It is not yet known which type they have. But experts have speculated that the outbreak may involve a type called Andes hantavirus, which can be transmitted from person to person.

That is because the Andes strain is found in Argentina, where the passengers embarked on the cruise. Andes hantavirus also causes lung infections, as has affected the six people affected on this cruise.

“The Andes hantavirus is characterised by respiratory symptoms. It’s most likely this small outbreak in the boat is due to this,” said Professor Antti Vaheri, a virologist at the University of Helsinki.

The Andes strain may be fatal in 40 per cent of cases. “It’s a killer,” added Professor Vaheri.

Professor Rainer Günter Ulrich, former head of the National Reference Laboratory for Hantaviruses at Friedrich-Loeffler-Institut in Germany, said it was a “realistic assumption” that the outbreak involved the Andes hantavirus.

How could the virus have got on the ship?

Passengers or crew could have caught the virus in Argentina, and it then started spreading between passengers. Alternatively, rats in Argentina could have boarded the vessel.

“If a reservoir animal is on board, the virus can be transmitted by aerosolised excreta,” said Professor Ulrich. “To answer these questions, a study is needed to identify the site of the infection and when the first symptoms arose.

How can the cruise passengers stay safe?

Hondius has not been allowed to dock at Cape Verde, to stop the infection from spreading on to the islands.

That means there are about 150 people on the ship, including passengers and crew, under the threat of a deadly illness that can spread through the air.

“To prevent human-to-human transmission – if it really is the case that we have Andes virus on board – isolation of the passengers would be the best, meaning they stay in the cabin,” said Professor Ulrich. “When leaving the cabin, wearing a [high-quality] mask would be recommended.”

A spokesperson for cruise provider Oceanwide Expeditions said as of midnight on Sunday Cape Verde authorities had still not given permission for passengers to disembark. “Local health authorities have visited the vessel to assess the condition of the two symptomatic individuals. They are yet to make a decision regarding the transfer of these individuals into medical care in Cape Verde,” the spokesperson added.

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