The Butte County Public Health Department has been using public health measures to stop a gastrointestinal illness (GI) outbreak in all monitored shelters.  Since the shelters opened to house Camp Fire evacuees, 145 people have been sick with vomiting and/or diarrhea. As of Wednesday evening, there were 41 people experiencing symptoms at the following shelters:
•Neighborhood Church: 179 total evacuees at the shelter, 21 currently experiencing illness
•Oroville Nazarene Church: 352 total evacuees at the shelter, 10 currently experiencing illness
•Butte County Fairgrounds: 142 total evacuees at the shelter, 9 currently experiencing illness
•East Avenue Church: 200 total evacuees at the shelter, 1 currently experiencing illness
The number of sick people is increasing every day.  Twenty-five people have been to the hospital for medical support. Staff serving the shelters have also been sick. The outbreak has been identified and confirmed by the Butte County public health laboratory to be the Norovirus which is highly contagious.  Norovirus spreads through touching surfaces contaminated with the virus, close contact with someone who is infected, or eating contaminated food or drink.
Norovirus is the leading cause of outbreaks of diarrhea and vomiting in the U.S., and it spreads quickly in schools, shelters, and places where many people are in close quarters. There is no medication to get rid of the virus and there is no vaccine.  Most people are sick for 1-3 days and get better without medical support.  Seniors, young children, and people with chronic diseases can suffer from more severe illness, may get dehydrated, and require medical support. Norovirus particles are extremely small and billions of them are in the stool and vomit of infected people.  Any vomit or diarrhea may contain Norovirus and should be treated as though it does.  People can transfer Norovirus to others for at least 48 hours after symptoms go away.
Butte County Public Health is working with the Red Cross, as well as state and federal partners to prevent and reduce the spread of Norovirus at Camp Fire evacuation shelters with the following actions:
•Coordinated additional medical staff to support affected shelters
•Provided education about the illness and preplanning actions to shelter staff (both medical and Red Cross)
•Established separate shelter areas for sick evacuees, which include separate hand washing and bathroom areas, and limited in-and-out access
•Ensured that shelters are being cleaned with supplies effective against Norovirus and scheduled additional cleaning
•Supplied medical staff with personal protective equipment to minimize exposure
•Provided additional bathrooms and handwashing stations, including bathrooms and handwashing stations dedicated for use by ill persons
•Active monitoring of shelter residents for signs and symptoms of norovirus illness and coordinating laboratory testing to confirm the cause of the outbreak as norovirus
Include fever, nausea, vomiting, diarrhea and stomach pain.  Symptoms last for 1-3 days.  However, after symptoms go away, people are still highly infectious, especially for 48 hours after symptoms go away.  There is no treatment for Norovirus.  The most important steps to prevent the spread of Norovirus is to stay home if you are sick for another 48 hours after symptoms go away and for everyone to regularly wash their hands.
Butte County Public Health Officer Andy Miller, MD stated, “This virus can spread quickly through the community.  Norovirus had begun to spread in our community even prior to the fires.”  Please follow these recommended steps to prevent further spread:
•Stay home if there is any sign of illness such as stomach pain, fever, nausea, vomiting and/or diarrhea.
•Stay home for an additional 48 hours after symptoms are gone.Even though you feel better, you still carry the virus and can infect other people.
•Wash your hands frequently throughout the day with soap and water.
•Clean contaminated surfaces regularly with appropriate disinfectant, such as bleach.
•Do not prepare food and drink for others if you are sick.
•Questions related to symptoms and treatment should be directed to your primary care provider or clinic.
•If your child is sick, notify the school and tell them know your child’s symptoms.
The spread of Norovirus can be prevented by practicing proper hand hygiene.  Important strategies include washing hands with soap and water, especially after using the toilet and changing diapers, and always before eating, preparing or handling food.

Transylvania Public Health has received confirmatory laboratory tests from the N.C. State Laboratory of Public Health. Of those people who were tested by their medical providers, a majority were positive for norovirus. We believe this outbreak was caused by being exposed to a highly-contagious virus in a public place.

Although more information is continuing to come in, Transylvania Public Health has received more than 70 cases of nausea, vomiting and diarrhea reported by medical providers, as well as phone calls reporting similar symptoms in more than 200 people since Tuesday, July 31.

Norovirus typically causes diarrhea, vomiting, nausea and stomach pain that lasts for 1 to 3 days. Other symptoms can include fever, headache and body aches. These symptoms and length of illness match closely with the symptoms being reported by those who are ill.

People get norovirus from direct contact with an infected person, consuming food or water that has been contaminated with norovirus or touching contaminated surfaces and then putting your unwashed hands in your mouth. It only takes a few virus particles to make someone sick, and those who are ill shed billions of these particles. People are most contagious when they are having symptoms like vomiting and for the first few days after recovering, although they can spread norovirus for two weeks or more after they feel better.
Norovirus symptoms usually appear 24-48 hours after being exposed to the virus. Many (but not all) of the people who reported symptoms to us recalled visiting a local restaurant 1-2 days before becoming ill. Other people reported having close contact with someone who had norovirus symptoms prior to becoming ill.

Public health officials do not believe that this outbreak is connected to the multi-state recall of salads due to cyclosporasis contamination.

According to press reports: “The McDonald’s in Brevard reopened Friday after closing voluntarily to deep clean the restaurant in the middle of the food illness outbreak.”

The California Department of Public Health (CDPH) today warned consumers to avoid eating raw oysters harvested from south and central Baynes Sound, in British Columbia, Canada. The raw oysters are linked to an outbreak of norovirus illnesses.

In California, as of April 27, approximately 100 individuals have reported illness after they consumed raw British Columbian oysters sold by restaurants and retailers throughout the state. Laboratory testing has confirmed norovirus infection in several patients from both California and Canada. Although the number of reported new illnesses has decreased during the last week, the investigation is ongoing.

Canada has reported 172 cases of gastrointestinal illness linked to consumption of raw oysters.

Four oyster farms in the south and central Baynes Sound area of British Columbia that were linked to illnesses were closed between March 23 and April 13, 2018, and remain closed at this time. Restaurants and retailers should not distribute or serve oysters from these farms, which can be recognized by the following landfile numbers located on the shellfish tags: CLF #1402060, CLF #1411206, CLF #1400483, and CLF #278757. Restaurants and retailers are encouraged to check Canada’s above website for closure statuses and notices of re-opening.

Anyone who eats raw oysters should visit their doctors if they become ill, and should report the incident to the local health department.

“Avoid eating raw and undercooked shellfish, including oysters, to reduce your risk of illness,” said CDPH Director and State Public Health Officer Dr. Karen Smith. “If you do eat shellfish, cook it until it reaches an internal temperature of at least 145°F. Quick steaming isn’t sufficient to kill norovirus.”

Norovirus is highly contagious and can spread easily from person-to-person through contaminated surfaces, and by eating contaminated food, including raw or undercooked oysters. Symptoms of norovirus usually begin 12 to 48 hours after a person has come in contact with the virus, and can last for 1 to 3 days. Common symptoms include vomiting, diarrhea, nausea, and stomach cramps. People who develop symptoms of norovirus infection should consult their health care providers.

Norovirus:  Marler Clark, The Food Safety Law Firm, is the nation’s leading law firm representing victims of Norovirus outbreaks. The Norovirus lawyersof Marler Clark have represented thousands of victims of Norovirus and other foodborne illness outbreaks and have recovered over $650 million for clients.  Marler Clark is the only law firm in the nation with a practice focused exclusively on foodborne illness litigation.  Our Norovirus lawyers have litigated Norovirus cases stemming from outbreaks traced to a number of food products and restaurants.

If you or a family member became ill with Norovirus after consuming food and you’re interested in pursuing a legal claim, contact the Marler Clark Norovirus attorneys for a free case evaluation.

The U.S. Food and Drug Administration is working with federal, state, and local officials regarding a norovirus outbreak linked to raw oysters from British Columbia, Canada. The FDA has confirmed that potentially contaminated raw oysters harvested in the south and central parts of Baynes Sound, British Columbia, Canada, were distributed to California, Illinois, Massachusetts, New York, and Washington. It is possible that additional states received these oysters either directly from Canada or through further distribution within the U.S.

FDA and the states are conducting a traceforward investigation to determine where the raw oysters were distributed and ensure they’re removed from the food supply. Retailers should not serve raw oysters harvested from the following harvest locations (or landfiles) within Baynes Sound: #1402060, #1411206, #1400483, and #278757.

Oysters can cause food-related illness if eaten raw, particularly in people with compromised immune systems. Food contaminated with noroviruses may look, smell, and taste normal.

Currently in Canada, a total of 172 cases of gastrointestinal illness linked to oyster consumption have been reported in three provinces: British Columbia (132), Alberta (15), and Ontario (25). No deaths have been reported. Individuals became sick between mid-March and mid-April 2018.

The Vermont Department of Health is investigating an outbreak of norovirus at The Windjammer Restaurant and its affiliated Upper Deck Pub in South Burlington, following more than 50 reports of illness and nine lab-confirmed cases of norovirus infection.

Health officials said the restaurant’s management has been cooperating in the investigation and has voluntarily closed for 48 hours to conduct a thorough cleaning of the establishment, including discarding prepared food items. According to The Windjammer’s management, several employees were out sick with similar symptoms. The restaurant is working closely with the Health Department to ensure the employees have the opportunity to be tested for norovirus and receive information about hand washing and glove use policies.

Noroviruses are a group of viruses that cause acute gastroenteritis illness, sometime called the “stomach flu,” but they are not related to influenza. Norovirus is very contagious and can spread easily from person to person via fecal-oral route, contact with contaminated surfaces, and through ingestion of contaminated food or water.

Illness from norovirus often begins suddenly. Symptoms usually include nausea, vomiting, diarrhea and some stomach cramping. While everyone can be affected, older people, children and those with chronic health conditions are at greater risk of complications. Symptoms usually resolve within 24-48 hours. Because of the risk of severe dehydration, drinking plenty of fluids such as juice or water or an oral rehydration solution is recommended. Sports drinks are not the best source for replacing lost nutrients and minerals. Anyone who is experiencing symptoms should contact their health care provider.

The Health Department has been reaching out by text messaging and calls to people who may have dined at the restaurant or pub since March 11, 2018. Patrons are asked to each complete a questionnaire designed to aid in the investigation. A link to the questionnaire and more information can be found at the department’s norovirus web page: www.healthvermont.gov/norovirus

Tacoma-Pierce County Health Department has identified new cases of norovirus, bringing the total number from the outbreak at two El Toro Restaurants to 434. The Tacoma location, 5716 N. 26th St., has 423 cases. The restaurant in University Place, 3820 Bridgeport Way W., has 11.

Both restaurants closed for a thorough cleaning and sanitizing, a Health Department requirement for outbreaks like this. They have since reopened. Reports from people who say they got sick after dining at the restaurants have slowed down.

“Norovirus is highly contagious and is more common in cold weather months,” said Katie Lott, food and community safety program manager. “The best thing people can do to protect themselves and keep the virus from spreading is wash their hands frequently and stay home when they’re sick,” she said.

The outbreak started at the restaurant in Tacoma’s Westgate neighborhood. The Health Department closed the restaurant Jan. 8 after receiving the first reports of illness. The Department worked with the restaurant to ensure it was thoroughly cleaned and sanitized before it reopened Jan. 9. On Jan. 11, the Department received confirmation from the state’s Public Health Laboratories that a customer who ate at the Tacoma restaurant during the onset period tested positive for norovirus.

On Jan. 10, the Health Department received illness reports from diners who ate at the El Toro Restaurant in University Place. The restaurant followed the same protocol and closed for cleaning and sanitizing. It reopened on Jan. 11.

Two staff members at the Tacoma location worked while ill during the time customers dined and later got sick. It’s still unclear if the outbreaks at the two locations are connected.

“Because of the nature of norovirus outbreaks, we may never know the exact affected items that caused illness,” Lott said. “All the cases have dining at the El Toro Restaurants in common,” she said.

Marler Clark, The Food Safety Law Firm, is the nation’s leading law firm representing victims of Norovirus outbreaks. The Norovirus lawyers of Marler Clark have represented thousands of victims of Norovirus and other foodborne illness outbreaks and have recovered over $600 million for clients.  Marler Clark is the only law firm in the nation with a practice focused exclusively on foodborne illness litigation.  Our Norovirus lawyers have litigated Norovirus cases stemming from outbreaks traced to a number of food products and restaurants.

If you or a family member became ill with Norovirus after consuming food and you’re interested in pursuing a legal claim, contact the Marler Clark Norovirus attorneys for a free case evaluation.

The Tacoma/Pierce County Department of Health updated the El Toro Norovirus outbreak this afternoon.

As of today, the Health Department has a total of 542 cases—520 from the Tacoma location and 22 suspect cases from the University Place location. We have a lab confirmation of norovirus from the Tacoma location.

According to the departments, outbreaks can last a few days, a few weeks, or a few months. This a large number of cases for us, but we know cases of norovirus typically go unreported. And likely, the high number reflects secondary cases—people who became ill from eating at the restaurant, then went home and infected family members. It’s highly contagious. People will get norovirus an average of five times in their lives and not necessarily realize what it is—and they will probably not report it to the health department.

Norovirus outbreaks typically have greater numbers of cases than other types of outbreaks because of the low number of virus particles needed to cause infection and the rapid person-to-person transmission. This outbreak had much higher numbers than usual because:

  • The exposure period lasted eight days before we received notification people were sick.
  • We shared more about this outbreak than others in the past. Media coverage and our own public outreach through our blog and social media expanded awareness of the outbreak and how to report foodborne illness. More people became aware their symptoms might be norovirus, and they contacted us. 

In the case of the El Toro Restaurants, both received 65 critical points—not a passing score—during their last routine inspections, but they passed their follow up inspections. (See the two-year inspection history for the Tacoma El Toro and University Place El Toro.)

We rely on people who have become sick to report their illness to us. For an outbreak at a food establishment, we look for two or more reports:

  • From different households.
  • With meals at the same food establishment during the same time period.
  • Common incubation times and symptoms.

We match these criteria to what we know about different foodborne pathogens. In this case, they matched norovirus and the restaurants were the only thing all the sick people had in common. Then we investigate if any employees were sick, what tasks they performed, and what foods the sick people ate.

On Jan. 1, the state’s new Paid Sick Leave Law took effect. The law requires employers provide their employees with paid time off to take care of their health. Learn more about paid sick leave on the Labor and Industries website.

Because norovirus and the flu are in circulation, we want everyone to take preventative steps to stay healthy and keep those around you from getting sick. Wash your hands often, cover your coughs and sneezes, and stay home if you’re sick. Learn more about norovirusthe flu, and handwashing.

Marler Clark, The Food Safety Law Firm, is the nation’s leading law firm representing victims of Norovirus outbreaks. The Norovirus lawyers of Marler Clark have represented thousands of victims of Norovirus and other foodborne illness outbreaks and have recovered over $600 million for clients.  Marler Clark is the only law firm in the nation with a practice focused exclusively on foodborne illness litigation.  Our Norovirus lawyers have litigated Norovirus cases stemming from outbreaks traced to a number of food products and restaurants.

If you or a family member became ill with Norovirus after consuming food and you’re interested in pursuing a legal claim, contact the Marler Clark Norovirus attorneys for a free case evaluation.

Tacoma-Pierce County Health Department has identified new cases of norovirus, bringing the total number from the outbreak at two El Toro Restaurants to 434. The Tacoma location, 5716 N. 26th St., has 423 cases. The restaurant in University Place, 3820 Bridgeport Way W., has 11. Both restaurants closed for a thorough cleaning and sanitizing, a Health Department requirement for outbreaks like this. Reports from people who say they got sick after dining at the restaurants have slowed down.

“Norovirus is highly contagious and is more common in cold weather months,” said Katie Lott, food and community safety program manager. “The best thing people can do to protect themselves and keep the virus from spreading is wash their hands frequently and stay home when they’re sick,” she said.

The outbreak started at the restaurant in Tacoma’s Westgate neighborhood. The Health Department closed the restaurant Jan. 8 after receiving the first reports of illness. The Department worked with the restaurant to ensure it was thoroughly cleaned and sanitized before it reopened Jan. 9. On Jan. 11, the Department received confirmation from the state’s Public Health Laboratories that a customer who ate at the Tacoma restaurant during the onset period tested positive for norovirus.

On Jan. 10, the Health Department received illness reports from diners who ate at the El Toro Restaurant in University Place. The restaurant followed the same protocol and closed for cleaning and sanitizing. It reopened on Jan. 11.

Two staff members at the Tacoma location worked while ill during the time customers dined and later got sick. It’s still unclear if the outbreaks at the two locations are connected.

“Because of the nature of norovirus outbreaks, we may never know the exact affected items that caused illness,” Lott said. “All the cases have dining at the El Toro Restaurants in common,” she said.

Learn more about norovirus at www.tpchd.org/norovirus. We have been providing updates on our blog. If we have new information on this investigation, we will post it to our blog Tuesday, Jan. 16. Find our blog at www.tpchd.org/blog.

About Tacoma-Pierce County Health Department: Tacoma-Pierce County Health Department’s mission is to protect and improve the health of all people and places in Pierce County. As part of our mission, the Health Department tackles known and emerging health risks through policy, programs and treatment in order to protect public health. We are one of only 163 accredited health departments in the country and among six in the state to have met or exceeded the Public Health Accreditation Board’s quality standards. Learn more at www.tpchd.org.

Norovirus

Norovirus is the leading cause of gastroenteritis, or what we commonly think of as stomach flu symptoms. It causes 23 million cases of gastroenteritis per year, or over half of all gastroenteritis cases in the U.S., and is the second most common virus after the common cold.

Norovirus is usually transmitted from the feces to the mouth, either by drinking contaminated food or water or by passing from person to person. Because noroviruses are easily transmitted, are resistant to common disinfectants, and are hard to contain using normal sanitary measures, they can cause extended outbreaks.

SYMPTOMS OF NOROVIRUS

The norovirus incubation period tends to be 24 to 48 hours, after which symptoms begin to appear. An infection normally lasts only 24 to 60 hours. However, in some cases, dehydration, malnutrition, and even death can occur. These complications are more likely among children, older people, and patients in hospitals and nursing homes with weakened immune systems. Common symptoms include:

  • Nausea
  • Diarrhea
  • Vomiting
  • Abdominal pain
  • Headache
  • Low-grade fever
NOROVIRUS DIAGNOSIS

Norovirus usually takes its course and goes away on its own after one to three days. It is hard to diagnose using samples in a lab, and so is usually diagnosed based on the combination of common symptoms, including mild fever, vomiting, and short duration of illness.

NOROVIRUS TREATMENT

There is no specific treatment for norovirus. However, it is essential to replenish fluids and minerals, as these are depleted with diarrhea.

HOW TO PREVENT NOROVIRUS INFECTION

The good news is that norovirus does not multiply on food, since it is a virus and not a bacterium. There is no way to tell whether foods – like shellfish, which are often eaten raw – are contaminated with norovirus. The only way to assure you don’t get norovirus from foods like shellfish is to cook them thoroughly. Here are other norovirus prevention methods:

  • Wash hands properly, especially after being at events with catered meals, nursing homes, schools, or on cruise ships
  • Wash raw vegetables thoroughly before serving them
  • While traveling, only drink boiled drinks or carbonated bottled beverages
  • Avoid letting anyone known to have norovirus in kitchen spaces
ADDITIONAL RESOURCES FOR NOROVIRUS

About-Norovirus.com is a comprehensive site with in-depth information about norovirus infection.

Marler Clark, The Food Safety Law Firm, is the nation’s leading law firm representing victims of Norovirus outbreaks. The Norovirus lawyers of Marler Clark have represented thousands of victims of Norovirus and other foodborne illness outbreaks and have recovered over $600 million for clients.  Marler Clark is the only law firm in the nation with a practice focused exclusively on foodborne illness litigation.  Our Norovirus lawyers have litigated Norovirus cases stemming from outbreaks traced to a number of food products and restaurants.

If you or a family member became ill with Norovirus after consuming food and you’re interested in pursuing a legal claim, contact the Marler Clark Norovirus attorneys for a free case evaluation.

An Introduction to Norovirus

The Centers for Disease Control and Prevention (CDC) estimates that noroviruses cause nearly 21 million cases of acute gastroenteritis annually, making noroviruses the leading cause of gastroenteritis in adults in the United States. [1] According to a relatively recent article in the New England Journal of Medicine:

The Norwalk agent was the first virus that was identified as causing gastroenteritis in humans, but recognition of its importance as a pathogen has been limited because of the lack of available, sensitive, and routine diagnostic methods. Recent advances in understanding the molecular biology of the noroviruses, coupled with applications of novel diagnostic techniques, have radically altered our appreciation of their impact. Noroviruses are now recognized as being the leading cause of epidemics of gastroenteritis and an important cause of sporadic gastroenteritis in both children and adults.

Of the viruses, only the common cold is reported more often than a norovirus infection—also referred to as viral gastroenteritis. [2]

Nature has created an ingenious bug in norovirus. [3] The round blue ball structure of norovirus is actually a protein surrounding the virus’s genetic material. [4]  The virus attaches to the outside of cells lining the intestine, and then transfers its genetic material into those cells.  Once the genetic material has been transferred, norovirus reproduces, finally killing the human cells and releasing new copies of itself that attach to more cells of the intestine’s lining. [5]

Norovirus (previously called “Norwalk-like virus” or NLV) is a member of the family Caliciviridae. The name derives from the Latin for chalice—calyx—meaning cup-like, and refers to the indentations of the virus surface. [6] The family of Caliciviridae consists of several distinct groups of viruses that were first named after the places where outbreaks occurred.  The first of these outbreaks occurred in 1968 among schoolchildren in Norwalk, Ohio.  The prototype strain was identified four years later, in 1972, and was the first virus identified that specifically caused gastroenteritis in humans.  Other discoveries followed, with each strain name based on the location of its discovery—e.g., Montgomery County, Snow Mountain, Mexico, Hawaii, Parmatta, Taunton, and Toronto viruses.  A study published in 1977 found that the Toronto virus was the second most common cause of gastroenteritis in children.  Eventually this confusing nomenclature was resolved, first in favor of calling each of the strains a Norwalk-like virus, and then simply, a norovirus – the term used today.

Humans are the only host of norovirus, and norovirus has several mechanisms that allow it to spread quickly and easily.  Norovirus infects humans in a pathway similar to the influenza virus’ mode of infection. In addition to their similar infective pathways, norovirus and influenza also evolve to avoid the immune system in a similar way.  Both viruses are driven by heavy immune selection pressure and antigenic drift, allowing evasion of the immune system, which results in outbreaks.  Norovirus is able to survive a wide range of temperatures and in many different environments.  Moreover, the viruses can spread quickly, especially in places where people are in close proximity, such as cruise ships and airline flights, even those of short duration. [7] As noted by the CDC in its Final Trip Report:

Noroviruses can cause extended outbreaks because of their high infectivity, persistence in the environment, resistance to common disinfectants, and difficulty in controlling their transmission through routine sanitary measures.

Norovirus outbreaks can result from the evolution of one strain due to the pressure of population immunity. [8] Typically, norovirus outbreaks are dominated by one strain, but can also involve more than one strain. [9] For example, some outbreaks associated with shellfish have been found to contain up to seven different norovirus strains. [10] Swedish outbreak studies also reveal a high degree of genetic variability, indicating a need for wide detection methods when studying these outbreaks. [11]

By way of further example, in 2006, there was a large increase in the number of norovirus cases on cruise ships. Norovirus cases were increasing throughout Europe and the Pacific at the same time. [12] One issue with cruise ships is the close contact between people as living quarters are so close, and despite education efforts, there still seems to be a lack of public understanding regarding how the illness is spread. [13] On the other hand, reporting occurs much more quickly in these situations because of the close proximity and concentration of illness, allowing for the quicker detection of outbreaks. [14] Cruise ship outbreaks often occur when new strains of norovirus are appearing, providing a good indicator system for new norovirus strains.   In this case, two new variants appeared within the global epidemic genotype, suggesting a strong pressure for evolution against the human immune system. [15] This points to the need for an international system of guidelines in tracing norovirus outbreaks.

Most norovirus outbreaks from contaminated food occur in food service settings, according to a Vital Signs report by the Centers for Disease Control and Prevention. Infected food workers are frequently the source of these outbreaks, often by touching ready-to-eat foods served in restaurants with their bare hands. The food service industry can help prevent norovirus outbreaks by enforcing food safety practices, such as making sure workers always practice good hand hygiene on the job and stay home when they are sick.

Norovirus often gets a lot of attention for outbreaks on cruise ships, but those account for only about 1 percent of all reported norovirus outbreaks. Norovirus is highly contagious and can spread anywhere people gather or food is served, making people sick with vomiting and diarrhea. [16]“Norovirus outbreaks from contaminated food in restaurants are far too common.” said CDC Director Tom Frieden, M.D., M.P.H. “All who prepare food, especially the food service industry, can do more to create a work environment that promotes food safety and ensures that workers adhere to food safety laws and regulations that are already in place.” [17]

How is Norovirus Transmitted?

Norovirus causes nearly 60% of all foodborne illness outbreaks.  Norovirus is transmitted primarily through the fecal-oral route, with fewer than 100 norovirus particles needed to cause infection. [18] Transmission occurs either person-to-person or through contamination of food or water.[19]  CDC statistics show that food is the most common vehicle of transmission for noroviruses; of 232 outbreaks of norovirus between July 1997 and June 2000, 57% were foodborne, 16% were spread from person-to-person, and 3% were waterborne. [20] When food is the vehicle of transmission, contamination occurs most often through a food handler improperly handling a food directly before it is eaten. [21]

Infected individuals shed the virus in large numbers in their vomit and stool, shedding the highest amount of viral particles while they are ill.   Aerosolized vomit has also been implicated as a mode of norovirus transmission. [22] Previously, it was thought that viral shedding ceased approximately 100 hours after infection; however, some individuals continue to shed norovirus long after they have recovered from it, in some cases up to 28 days after experiencing symptoms. [23] Viral shedding can also precede symptoms, which occurs in approximately 30% of cases.  Often, an infected food handler may not even show symptoms.  In these cases, people can carry the same viral load as those who do experience symptoms. [24]

A Japanese study examined the ability of asymptomatic food handlers to transfer norovirus. Approximately 12% of asymptomatic food handlers were carriers for one of the norovirus genotypes.  This was the first report of norovirus molecular epidemiology relating asymptomatic individuals to outbreaks, suggesting that asymptomatic individuals are an important link in the infectivity pathway.  Asymptomatic infection may occur because some people may have acquired immunity, which explains why some show symptoms upon infection and some do not.  Such immunity does not last long, though.  These discoveries reveal just how complicated the pathway of norovirus infection is, as well as how difficult it is to define the true period of infectivity.  Furthermore, it remains unclear why some people do not become sick with norovirus even when they are exposed.  Very little is known about the differences in hygiene practices, behaviors, and personal susceptibility between those who become infected and those who do not, which brings up the potential for more research. [25] Discrepancies exist in the published research about infective doses for norovirus, with earlier studies having used a much higher dose to trigger immune responses.

Symptoms & Risks of a Norovirus Infection

Norovirus illness usually develops 24 to 48 hours after ingestion of contaminated food or water. Symptoms typically last a relatively short amount of time, approximately 24 to 48 hours. [26] These symptoms include nausea, vomiting, diarrhea, and abdominal pain.  Headache and low-grade fever may also accompany this illness.   People infected with norovirus usually recover in two to three days without serious or long-term health effects.

Although symptoms usually only last one to two days in healthy individuals, norovirus infection can become quite serious in children, the elderly, and immune-compromised individuals. [27] In some cases, severe dehydration, malnutrition, and even death can result from norovirus infection, especially among children and among older and immune-compromised adults in hospitals and nursing homes. [28] In England and Wales, 20% of those over the age of 65 die due to infectious intestinal illness other than Clostridium difficile.  Recently, there have been reports of some long-term effects associated with norovirus, including necrotizing entercolitis, chronic diarrhea, and post-infectious irritable bowel syndrome, but more data is needed to support these claims. [29]

Diagnosing a Norovirus Infection

Diagnosis of norovirus illness is based on the combination of symptoms, particularly the prominence of vomiting, little fever, and the short duration of illness. [30] If a known norovirus outbreak is in progress, public health officials may obtain specimens from ill individuals for testing in a lab.  These lab tests consist of identifying norovirus under an electron microscope. A reverse transcriptase polymerase chain reaction test (RT-PCR assay) also can detect norovirus in food, water, stool samples, and on surfaces. These tests isolate and replicate the suspected virus’ genetic material for analysis. [31] An ELISA can also be performed, which detects antigens. They are easier to perform than RT-PCR, but less sensitive and can also result in many false negatives. [32]

Treating a Norovirus Infection

There is no specific treatment available for norovirus.  In most healthy people, the illness is self-limiting and resolves in a few days; however, outbreaks among infants, children, elderly, and immune-compromised populations may result in severe complications among those affected.  [33] Death may result without prompt measures.  The replacement of fluids and minerals such as sodium, potassium and calcium – otherwise known as electrolytes – lost due to persistent diarrhea is vital. This can be done either by drinking large amounts of liquids, or intravenously.

Recent research has looked into the potential for developing a norovirus vaccine. Researchers indicate that coming up with a norovirus vaccine would be similar to vaccinating for influenza, by using screening in order to select for the most prevalent strains. This is a quite challenging process.  Other challenges include the fact that cell culture and small-animal models are limited, host pre-exposure histories are complicated, and there is always the potential for the evolution of novel immune escape variants, rendering the vaccine useless. [34] Furthermore, scientists would likely face a lack of funding to develop a vaccine because vaccine development is expensive. [35]

Preventing Norovirus Infection

Common settings for norovirus outbreaks include restaurants and events with catered meals (36%), nursing homes (23%), schools (13%), and vacation settings or cruise ships (10%).  Proper hand washing is the best way to prevent the spread of norovirus.

The good news about norovirus is that it does not multiply in foods as many bacteria do. [36] In addition, thorough cooking destroys this virus.   To avoid norovirus, make sure the food you eat is cooked completely.  While traveling in in areas that have polluted water sources, raw vegetables should be washed thoroughly before being served, and travelers should drink only boiled drinks or carbonated bottled beverages without ice.

Shellfish (oysters, clams, mussels) pose the greatest risk and any particular serving may be contaminated with norovirus; there is no way to detect a contaminated oyster, clam, or mussel from a safe one.  Shellfish become contaminated when their waters become contaminated—e.g., when raw sewage is dumped overboard by recreational or commercial boaters).   Shellfish are filter feeders and will concentrate virus particles present in their environment. With shellfish, only complete cooking offers reliable protection; steaming does not kill the virus or prevent its transmission. [37] Some researchers suggest that norovirus monitoring in shellfish areas could be a good preventive strategy as well.  Waterborne norovirus outbreaks are ubiquitous, but difficult to recognize. Improved analysis of environmental samples would have the potential to significantly improve the detection for norovirus in shellfish waters. [38]

Finally, and as briefly mentioned earlier, outbreaks of norovirus infections have become synonymous with cruise ships. [39] Healthcare facilities also experience a high incidence of norovirus outbreaks.  [40] The CDC has published information regarding the prevention of norovirus outbreaks on cruise ships and in healthcare facilities on its website.  Once a case has occurred, even more stringent hygienic measures than normal are required in order to prevent an outbreak, particularly on an enclosed space such as a cruise ship.

Norovirus:  Marler Clark, The Food Safety Law Firm, is the nation’s leading law firm representing victims of Norovirus outbreaks. The Norovirus lawyers of Marler Clark have represented thousands of victims of Norovirus and other foodborne illness outbreaks and have recovered over $600 million for clients.  Marler Clark is the only law firm in the nation with a practice focused exclusively on foodborne illness litigation.  Our Norovirus lawyers have litigated Norovirus cases stemming from outbreaks traced to a number of food products and restaurants.

If you or a family member became ill with Norovirus after consuming food and you’re interested in pursuing a legal claim, contact the Marler Clark Norovirus attorneys for a free case evaluation.