Pregliasco: 'Very contagious norovirus needs little to infect'
The virus is transmitted through hands, but also through contaminated food and water
It does not seem to be an easy time for cruise ships: after the outbreak of hantavirus on the MV Hondius, a norovirus outbreak hit a ship arriving in Bordeaux from Brest. More than 1,000 passengers on the Ambition, operated by Ambassador Cruise Line, were detained in Bordeaux after 49 people complained of gastrointestinal complaints. "An outbreak of norovirus on a cruise ship is one of the most typical and frequent scenarios for this gastrointestinal virus, because closed environments, the sharing of common spaces and the high density of people greatly facilitate contagion," virologist Fabrizio Pregliasco, director of the School of Specialisation in Hygiene and Preventive Medicine at the University of Milan, tells LaPresse LaSalute. As reported by the BBC, the French authorities have since allowed asymptomatic passengers to disembark. The isolation guidelines will remain in place for those affected, 'along with preventive measures and reinforced hygiene protocols on board'.
Health authorities in Bordeaux said that analysis of samples taken on the ship confirmed a norovirus outbreak. No serious cases were reported. As stated in a note, the 92-year-old man who died on board last Sunday did not show any symptoms: the cause of death would be unknown. You may not be familiar with the name, but the norovirus 'is one of the main culprits of acute viral gastroenteritis, the so-called stomach flu. Extremely contagious and widespread all over the world, this virus has caused epidemics on cruise ships, but also in RSAs and hospitals, schools, tourist resorts,' recalls Pregliasco. 'Very few viral particles are enough to infect a person. On a ship, the norovirus spreads quickly because many people share buffets, bathrooms and common areas. This virus resists on surfaces for days and contagion can occur even before symptoms appear. In addition, vomiting and diarrhoea can aerosolise infected particles and the constant turnover of passengers can keep the virus circulating,' explains the virologist.
Transmission is mainly fecal-oral. "The virus is transmitted through the hands, but also through contaminated food and water. Then watch out for doorknobs, lifts, tables and toilets. "During episodes of vomiting, the virus can spread through the air a short distance". This is why it is particularly important to take care of hand hygiene. "Better soap and water than alcohol gel alone. Those with symptoms,' the specialist recommends, 'should remain isolated, not prepare food and avoid contact for at least 48 hours after the symptoms have ended. In contrast to hantavirus, in the case of norovirus the incubation period is short: 'It fluctuates between 12 and 48 hours. Symptoms are sudden nausea, violent vomiting, watery diarrhoea, abdominal cramps, mild fever, general malaise and muscle pain. On average it lasts 1-3 days but in elderly and frail individuals it can last longer'. Caution: 'This is a very contagious virus. A person can spread it even before symptoms appear and up to several days after recovery. This is why outbreaks are difficult to control'. There is no specific antiviral therapy: 'Management is mainly supportive. Hydration must be taken care of with water, rehydrating solutions, mineral salts. The diet must be light and based on rice, potatoes, bananas and crackers. Beware of anti-diarrhoeics in children or in the presence of fever or blood,' concludes the virologist.
