Through 2024 the U.S. Centers for Disease Control and Prevention (CDC) has confirmed 16 gastrointestinal disease outbreaks on cruise ships, 5 of which were logged in the past month. That’s the largest number of cruise ship outbreaks in 12 years.
The CDC tracks outbreaks on ships under the Vessel Sanitation Program’s (VSP) jurisdiction, which includes inspections of a cruise ship’s HVAC and potable water systems, and assessments on how well a crew and the ship’s medical center personnel understand and act on VSP procedures. To qualify as an outbreak, the voyage must have 3% or more of passengers or crew reporting symptoms of GI illness to the ship’s medical staff.
2024 Outbreaks
“Norovirus is often a cause of GI outbreaks on cruise ships, but we don’t always know the cause of the outbreak when we begin an investigation. Finding the agent that caused an outbreak (causative agent) can take time,” noted the CDC.
The VSP not only inspects vessels and tracks outbreaks, but promotes information for travelers on how to stay healthy during cruising and what to do if experiencing symptoms.
Winter Surge of Norovirus on Land
Outbreaks amongst the non-cruising general public are also surging this year in the U.S. The most recent numbers reported by state public health departments participating in the NoroSTAT network show there were 91 outbreaks of norovirus reported during the week of Dec. 5, up from 69 outbreaks the last week of November.
The NoroSTAT network includes Alabama, Colorado, Massachusetts, Michigan, Minnesota, Nebraska, New Mexico, North Carolina, Ohio, Oregon, South Carolina, Tennessee, Virginia, and Wisconsin.
Currently, state, local, and territorial health departments are not required to report individual cases of norovirus illness to CDC. “Healthcare providers should report all outbreaks of acute gastroenteritis—including suspected outbreaks of norovirus—to the appropriate state, local, or territorial health department.”
Norovirus is the leading cause of foodborne illness in the United States, responsible for 58% of such infections acquired in the country each year, according to the CDC.
A norovirus infection is characterized by sudden vomiting and diarrhea. Outbreaks are often seen where people are in close quarters, such as cruise ships, prisons, long-term care or other congregate living situations, and in school systems.
READ MORE:
Norovirus outbreak caused by raw oysters
The New York Times
This month, at least 80 people fell ill from norovirus linked to raw oysters served at a restaurant event in Los Angeles. The Food and Drug Administration has advised people not to eat the oysters implicated in that outbreak, which came from British Columbia. Norovirus is fairly resistant to heat. The C.D.C. recommends cooking oysters and other shellfish until their internal temperature reaches 145 degrees, and thoroughly washing fresh fruits and vegetables.
Norovirus cases are surging. A doctor explains what to look for
CNN
Norovirus is the leading cause of foodborne illness in the US. According to the CDC, it is responsible for 19 million to 21 million illnesses every year. It results in over 2.2 million outpatient medical visits, 465,000 emergency department visits and 109,000 hospitalizations. There is no specific treatment for norovirus. As this is a virus, antibiotics that target bacteria won’t work. There is no directed antiviral against the norovirus, nor is there an approved vaccine to prevent it. Most people will recover without medical intervention. The key is to try to keep down fluids to prevent dehydration, which can be a common side effect.
Special populations more at risk from norovirus
ABC News
Although symptoms will resolve in a few days for most people, certain groups are at high risk for severe dehydration including those under age 1, the elderly and the immunocompromised. Health experts say the best way to prevent getting norovirus is to wash hands with warm soap and water for 20 seconds. Hand sanitizer does not work well against norovirus. The CDC says people should wash their hands after using the toilet or changing diapers as well as when eating, preparing or handling food.
Global, regional, and national age-sex-specific burden of diarrhoeal diseases, their risk factors, and aetiologies, 1990–2021, for 204 countries and territories
The Lancet Infectious Diseases
While there has been a global decline in deaths from diarrhoeal diseases in the past 15 years, they still claim more than 1 million lives annually and are a leading cause of death in children younger than 5 years. Globally in 2021, rotavirus was the predominant cause of diarrhoeal deaths across all ages, followed by norovirus and Cryptosporidium spp. In children younger than 5 years, the fatalities were led by rotavirus, followed by Shigella spp and adenovirus. Other pathogens with a fatal PAF greater than 10% in children younger than 5 years included Cryptosporidium spp, typical enteropathogenic Escherichia coli, and enterotoxigenic E coli producing heat-stable toxin.
Norovirus-associated diarrhea and asymptomatic infection in children aged under four years: a community-cohort study in the Philippines
IJID Regions
This is the first cohort study in Southeast Asia to estimate the incidence rate of NoV-associated diarrhea and asymptomatic infection in children under four. Children aged 0–2 years were followed for two years. Prevalence and incidence rates of NoV-associated diarrhea and asymptomatic infections were calculated. NoV was detected in 17.4% of diarrheal episodes and 10.8% of asymptomatic stool samples. Repeated NoV infections were observed in approximately one-third of the children in this study. Repeated infections suggest that children may acquire genotype- and immunotype-specific immunity, with age being a key factor for NoV-associated diarrhea.