A Guide to The Virus Linked to Cruise Ship Deaths What Is Hantavirus?

 

Three people have died after a suspected outbreak of hantavirus on board a cruise ship sailing between Argentina and Cape Verde.

So far, one case of the potentially deadly virus has been confirmed, according to the World Health Organization, which stressed that the risk to the public remains low.

However, the suspected outbreak has raised questions over whether the virus, which is normally spread by contact with rodents, is being transmitted between humans.

Virginie Sauvage, the head of France's National Reference Centre for Hantaviruses, told AFP in an interview that identifying the specific strain will provide crucial insight into what happened on the ship.

How common are hantaviruses?

These viruses are found all over the world, with infections occurring year-round. For example, China, Russia, and South Korea report several thousand cases a year.

In the Americas, Finland, and France, there are several hundred cases annually.

Only certain strains of hantaviruses found exclusively in rodents – rats, mice, and voles – are transmitted to humans.

How dangerous are they?

Hantaviruses are split into two groups: viruses from the Old World (Europe, Asia, Africa) and those from the New World (North, Central, and South America).

In the case of Old World viruses, the mortality rate can reach up to 14%. However, in developed countries like France, deaths are extremely rare and occur primarily among people with underlying conditions.

Some cases are asymptomatic or present only with symptoms such as body aches, abdominal pain, and a mild cough. However, kidney problems can rarely occur, leading to acute renal failure, although this is reversible.

On the other hand, the fatality rate for New World viruses can exceed 40%. These viruses spread rapidly to the lungs and can cause shortness of breath or heart problems.

How is treatment administered?

The sooner treatment is received, the better the prognosis.

Since there is no specific cure for hantavirus, doctors focus on managing symptoms.

If the virus has a severe impact on the lungs, oxygen therapy in the intensive care unit may be required.

People who work in particular industries, such as forestry or farming, are particularly at risk.

Like any infection, the most at risk are the elderly, those with weaker immune systems, and people with pre-existing health problems.

Is it contagious?

It is still unknown whether this was an outbreak of the Andes virus.

This is the only strain for which there are confirmed cases of human-to-human transmission, but this required close and prolonged contact – for example, within a family.

Humans are mainly infected by inhaling aerosols contaminated by the saliva, droppings, or urine of animals or through direct contact with feces, or via bites or scratches.

North American rodents that can carry hantaviruses. (CDC)

For the cruise ship, there are two possible scenarios: human-to-human transmission or isolated infections before people boarded, for example if they took a trip together.

What could sequencing reveal?

Sequencing the virus from an infected passenger on the ship will identify what strain of hantavirus is involved.

Because the ship left from Ushuaia in southern Argentina, the Andes virus is suspected because it circulates there.

Related: Investigations Begin After Suspected Outbreak of Rare Hantavirus Kills 3 People

However, if it is a different New World strain, for example one called Sin Nombre, which only circulates in North America, contamination in South America can be ruled out.

If a New World hantavirus is being transmitted between humans on this ship, that would be unprecedented, to my knowledge.

credit: sciencealert