What is norovirus detected on cruise ship in France? How is it different from hantavirus?

A new day, a new cruise ship, and a new outbreak, "norovirus", that has now sent fresh alarms after a 92-year-old passenger aboard Ambassador Cruise Line’s cruise ship Ambition died on Sunday (May 10).

On Wednesday (May 13), health authorities said that the results of samples taken confirm an outbreak of norovirus, BBC reported.

Over 1,700 passengers and crew members aboard a cruise ship docked in Bordeaux, France, were confined; however, French authorities later said that passengers with no symptoms may leave the ship.

Several passengers aboard the vessel suffered from upset stomachs. Most of the passengers are from Britain or Ireland. On Tuesday (May 12), they arrived in Bordeaux.

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The health officials noted that around 50 of them have shown symptoms of stomach issues. Initially, tests ruled out a norovirus outbreak, a highly contagious form of gastroenteritis, but it was later confirmed as a norovirus.

This comes just days after the hantavirus outbreak linked to a Dutch-flagged expedition ship, MV Hondius, killed three people, leading to multiple infections.

Now, what is this norovirus? And how is it different from hantavirus? We take a closer look.

What is norovirus?

Norovirus is a group of viruses that causes severe vomiting and diarrhoea. A common but highly contagious virus. It causes severe vomiting and diarrhoea. The virus usually occurs seasonally in colder months.

The first norovirus outbreak was reported in 1968 at a school in Norwalk, Ohio, USA, and, for this reason, the first strain of the virus was called the Norwalk virus, according to the Cleveland Clinic.

The virus causes gastroenteritis. One can contract the virus through close contact with someone who has it. Touching contaminated surfaces and then touching your mouth, nose, or eyes, or eating or drinking contaminated food or beverages, can lead to norovirus infection.

When the virus enters the body, it causes inflammation and swelling in the stomach and intestines. This is a condition called gastroenteritis, which causes norovirus symptoms. The virus is contagious as it spreads easily. Once in the body, norovirus releases billions of tiny viral particles that can make others ill as well.

After exposure to norovirus, symptoms may take anywhere from 12 to 48 hours to appear. Even after the symptoms stop, an infected individual can remain contagious for up to 48 hours. Norovirus can be dangerous for those with weak immune systems.

Globally, around 685 million cases are reported per year. Of that, over 200 million cases affect children, according to reports.

What are its symptoms and prevention?

Symptoms of norovirus include nausea and vomiting, diarrhoea, stomach cramps, fever, headache, and body aches.

There are several ways of preventing this virus if in contact, according to health experts: washing hands thoroughly with soap and water for at least 20 seconds, disinfecting frequently touched surfaces with bleach-based cleaners, avoiding close contact with others, and staying home when sick.

While symptomatic, avoid preparing food for others. Maintaining food safety practices — such as thoroughly cooking shellfish and washing fruits and vegetables. Staying hydrated is essential to prevent dehydration.

How is norovirus different from hantavirus?

Norovirus is highly contagious, but not deadly, while hantavirus is deadlier than norovirus. Norovirus affects millions and is rarely fatal, whereas hantavirus has a high fatality rate. In its most severe forms, hantavirus has a fatality rate of 35-50 per cent.

Symptoms: Both hantavirus and norovirus have different symptoms. Norovirus' symptoms are gastrointestinal and mainly cause vomiting and diarrhoea. Meanwhile, hantavirus' symptoms are related to respiratory issues and can lead to severe lung complications.

Transmission: The modes of transmission also differ. One gets infected with norovirus after eating contaminated food, drinking contaminated water, or direct person-to-person contact with an infected individual. Hantavirus primarily spreads to humans through exposure to the urine, droppings, or saliva of infected rodents.

Incubation period: For hantavirus, the incubation period is usually long, with symptoms typically appearing 1-8 weeks after exposure. In cases of norovirus, symptoms start within 12 to 48 hours after exposure.

Severity: As mentioned, the severity levels also differ. Hantavirus is deadly and severe, whereas norovirus is not fatal, and people can recover within days, but with a weakened immune system, things might get dangerous.

Treatment: Patients with hantavirus often require intensive hospital care, including oxygen support or mechanical ventilation in severe cases. In norovirus infections, fluids and electrolytes can help manage symptoms.

Following the death, "Ambition has now been released by the relevant French health authorities to continue normal operations," the Essex-based cruise line said, BBC reported.

It added that heightened sanitation protocols, medical surveillance, and isolation measures continue to remain in effect across the ship.

With inputs from agencies