98-458: Norovirus , also known as Norwalk virus and sometimes referred to as the winter vomiting disease , is the most common cause of gastroenteritis . Infection is characterized by non-bloody diarrhea , vomiting , and stomach pain . Fever or headaches may also occur. Symptoms usually develop 12 to 48 hours after being exposed, and recovery typically occurs within one to three days. Complications are uncommon, but may include dehydration , especially in
196-500: A common ancestor in AD 867. The group 2 and group 4 viruses last shared a common ancestor in approximately AD 1443 (95% highest posterior density AD 1336–1542). Several estimates of the evolution rate have been made varying from 8.98 × 10 to 2.03 × 10 substitutions per site per year. The estimated mutation rate (1.21 × 10 to 1.41 × 10 substitutions per site per year) in this virus is high even compared with other RNA viruses. In addition,
294-508: A fucose sugar to the end of the ABO(H) precursor in gastrointestinal cells and saliva glands . The ABH-antigen produced is thought to act as a receptor for human norovirus: A non-functional fucosyltransferase FUT2 provides high protection from the most common norovirus strain, GII.4. Homozygous carriers of any nonsense mutation in the FUT2 gene are called non-secretors , as no ABH-antigen
392-571: A lipid viral envelope . Surfaces where norovirus particles may be present can be sanitised with a solution of 1.5% to 7.5% of household bleach in water, or other disinfectants effective against norovirus. In healthcare environments, the prevention of nosocomial infections involves routine and terminal cleaning . Nonflammable alcohol vapor in CO 2 systems is used in health care environments where medical electronics would be adversely affected by aerosolized chlorine or other caustic compounds. In 2011,
490-527: A recombination hotspot exists at the ORF1-ORF2 (VP1) junction. Viral replication is cytoplasmic. Entry into the host cell is achieved by attachment to host receptors, which mediates endocytosis . Positive-stranded RNA virus transcription is the method of replication. Translation takes place by leaky scanning and RNA termination-reinitiation. Humans and other mammals serve as the natural host . Transmission routes are fecal-oral and contamination. When
588-503: A US and foreign itinerary; there were 12 in 2015, and 10 from 1 January to 9 May 2016. An outbreak may affect over 25% of passengers, and a smaller proportion of crew members. Epidemiological studies have shown that individuals with different ABO(H) (histo- blood group ) phenotypes are infected with NoV strains in a genotype -specific manner. GII.4 includes global epidemic strains and binds to more histo-blood group antigens than other genogroups. FUT2 fucosyltransferase transfers
686-419: A full recovery within three to eight days. However, in poor countries treatment for severe infections is often out of reach and persistent diarrhea is common. Dehydration is a common complication of diarrhea . Severe dehydration in children may be recognized if the skin color and position returns slowly when pressed. This is called "prolonged capillary refill " and "poor skin turgor ". Abnormal breathing
784-514: A genomic organization consistent with viruses belonging to the family Caliciviridae . The name "norovirus" ( Norovirus for the genus) was approved by the International Committee on Taxonomy of Viruses (ICTV) in 2002. In 2011, however, a press release and a newsletter was published by ICTV, which strongly encouraged the media, national health authorities, and the scientific community to use the virus name Norwalk virus, rather than
882-523: A hazard are higher on the hierarchy of control than personal protective equipment (PPE). At the level of physically based engineering interventions, effective ventilation and high frequency air changes, or air filtration through high efficiency particulate filters , reduce detectable levels of virus and other bioaerosols , improving conditions for everyone in an area. Portable air filters, such as those tested in Conway Morris A et al. present
980-462: A high risk for norovirus infection. Foods other than shellfish may be contaminated by infected food handlers. Many norovirus outbreaks have been traced to food that was handled by only one infected person. Between March and August 2017, in Quebec, Canada, there was an outbreak of norovirus that sickened more than 700 people. According to an investigation by Canada's CFIA Food Control Agency, the culprit
1078-559: A linear, non-segmented, positive-sense RNA genome of approximately 7.5 kilobases , encoding a large polyprotein which is cleaved into six smaller non-structural proteins (NS1/2 to NS7) by the viral 3C-like protease (NS6), a major structural protein ( VP1 ) of about 58~60 kDa and a minor capsid protein ( VP2 ). The most variable region of the viral capsid is the P2 domain , which contains antigen-presenting sites and carbohydrate-receptor binding regions. Groups 1, 2, 3, and 4 last shared
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#17327758415341176-427: A particularly high risk of airborne transmission, as they were spreading a much higher number of aerosol particles than e.g., the act of shouting. Exposure does not guarantee infection. The generation of aerosols, adequate transport of aerosols through the air, inhalation by a susceptible host, and deposition in the respiratory tract are all important factors contributing to the over-all risk for infection. Furthermore,
1274-443: A person becomes infected with norovirus, the virus replicates within the small intestine . The principal symptom is acute gastroenteritis , characterized by nausea, forceful vomiting, watery diarrhea , and abdominal pain, that develops between 12 and 48 hours after exposure, and lasts for 24–72 hours. Sometimes there is loss of taste, general lethargy , weakness, muscle aches, headache , cough , and/or low-grade fever . The disease
1372-440: A person who vomited spread the infection across a restaurant, suggesting that many unexplained cases of food poisoning may have their source in vomit. In December 1998, 126 people were dining at six tables; one person vomited onto the floor. Staff quickly cleaned up, and people continued eating. Three days later others started falling ill; 52 people reported a range of symptoms, from fever and nausea to vomiting and diarrhea. The cause
1470-401: A prolonged capillary refill , poor skin turgor , and abnormal breathing. Other useful findings (when used in combination) include sunken eyes, decreased activity, a lack of tears, and a dry mouth. A normal urinary output and oral fluid intake is reassuring. Laboratory testing is of little clinical benefit in determining the degree of dehydration. Thus the use of urine testing or ultrasounds
1568-563: A readily deployable solution when existing ventilation is inadequate, for instance in repurposed COVID-19 hospital facilities. The United States Centers for Disease Control and Prevention (CDC) advises the public about vaccination and following careful hygiene and sanitation protocols for airborne disease prevention. Many public health specialists recommend physical distancing (also known as social distancing ) to reduce transmission. A 2011 study concluded that vuvuzelas (a type of air horn popular e.g. with fans at football games) presented
1666-544: A role in many military campaigns and is believed to be the origin of the term "no guts no glory". Gastroenteritis is the main reason for 3.7 million visits to physicians a year in the United States and 3 million visits in France. In the United States gastroenteritis as a whole is believed to result in costs of US$ 23 billion per year, with rotavirus alone resulting in estimated costs of US$ 1 billion
1764-452: A significant clinical benefit. Antibiotics are not usually used for gastroenteritis, although they are sometimes recommended if symptoms are particularly severe or if a susceptible bacterial cause is isolated or suspected. If antibiotics are to be employed, a macrolide (such as azithromycin ) is preferred over a fluoroquinolone due to higher rates of resistance to the latter. Pseudomembranous colitis , usually caused by antibiotic use,
1862-587: A space, the greater chance of transmission. Airborne transmission is complex, and hard to demonstrate unequivocally but the Wells-Riley model can be used to make simple estimates of infection probability. Some airborne diseases can affect non-humans. For example, Newcastle disease is an avian disease that affects many types of domestic poultry worldwide that is airborne. It has been suggested that airborne transmission should be classified as being either obligate, preferential, or opportunistic, although there
1960-609: A wide variety of animals. There are a number of non-infectious causes of inflammation of the gastrointestinal tract. Some of the more common include medications (like NSAIDs ), certain foods such as lactose (in those who are intolerant), and gluten (in those with celiac disease ). Crohn's disease is also a non-infectious cause of (often severe) gastroenteritis. Disease secondary to toxins may also occur. Some food-related conditions associated with nausea, vomiting, and diarrhea include: ciguatera poisoning due to consumption of contaminated predatory fish, scombroid associated with
2058-437: A year. The first usage of "gastroenteritis" was in 1825. Before this time it was commonly known as typhoid fever or "cholera morbus", among others, or less specifically as "griping of the guts", "surfeit", "flux", "colic", "bowel complaint", or any one of several other archaic names for acute diarrhea. Cholera morbus is a historical term that was used to refer to gastroenteritis rather than specifically cholera . Many of
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#17327758415342156-535: Is an inflammation of the gastrointestinal tract including the stomach and intestine . Symptoms may include diarrhea , vomiting , and abdominal pain . Fever , lack of energy, and dehydration may also occur. This typically lasts less than two weeks. Although it is not related to influenza , in the U.S. and U.K., it is sometimes called the " stomach flu ". Gastroenteritis is usually caused by viruses ; however, gut bacteria , parasites , and fungi can also cause gastroenteritis. In children, rotavirus
2254-787: Is another sign of severe dehydration. Repeat infections are typically seen in areas with poor sanitation, and malnutrition . Stunted growth and long-term cognitive delays can result. Reactive arthritis occurs in 1% of people following infections with Campylobacter species. Guillain–Barré syndrome occurs in 0.1%. Hemolytic uremic syndrome (HUS) may occur due to infection with Shiga toxin -producing Escherichia coli or Shigella species. HUS causes low platelet counts , poor kidney function , and low red blood cell count (due to their breakdown) . Children are more predisposed to getting HUS than adults. Some viral infections may produce benign infantile seizures . Viruses (particularly rotavirus (in children) and norovirus (in adults)) and
2352-835: Is believed to be introduced to pigs by wild birds and there is no specific treatment available. It is not transmissible to humans. Airborne transmission Airborne transmission or aerosol transmission is transmission of an infectious disease through small particles suspended in the air. Infectious diseases capable of airborne transmission include many of considerable importance both in human and veterinary medicine . The relevant infectious agent may be viruses , bacteria , or fungi , and they may be spread through breathing, talking, coughing, sneezing, raising of dust, spraying of liquids, flushing toilets , or any activities which generate aerosol particles or droplets . Aerosol transmission has traditionally been considered distinct from transmission by droplets , but this distinction
2450-458: Is generally not needed. Other potential causes of signs and symptoms that mimic those seen in gastroenteritis that need to be ruled out include appendicitis , volvulus , inflammatory bowel disease , urinary tract infections , and diabetes mellitus . Pancreatic insufficiency , short bowel syndrome , Whipple's disease , coeliac disease , and laxative abuse should also be considered. The differential diagnosis can be complicated somewhat if
2548-457: Is ignored or left untreated. Specific diagnosis of norovirus is routinely made by polymerase chain reaction (PCR) assays or quantitative PCR assays, which give results within a few hours. These assays are very sensitive and can detect as few as 10 virus particles. Tests such as ELISA that use antibodies against a mixture of norovirus strains are available commercially, but lack specificity and sensitivity. After infection , immunity to
2646-510: Is limited research that show the importance of each of these categories. Obligate airborne infections spread only through aerosols; the most common example of this category is tuberculosis. Preferential airborne infections, such as chicken pox, can be obtained through different routes, but mainly by aerosols. Opportunistic airborne infections such as influenza typically transmit through other routes; however, under favourable conditions, aerosol transmission can occur. Environmental factors influence
2744-415: Is managed by discontinuing the causative agent and treating it with either metronidazole or vancomycin . Bacteria and protozoans that are amenable to treatment include Shigella Salmonella typhi , and Giardia species. In those with Giardia species or Entamoeba histolytica , tinidazole treatment is recommended and superior to metronidazole. The World Health Organization (WHO) recommends
2842-608: Is most common, but Entamoeba histolytica , Cryptosporidium spp., and other species have also been implicated. As a group, these agents comprise about 10% of cases in children. Giardia occurs more commonly in the developing world, but this type of illness can occur nearly everywhere. It occurs more commonly in persons who have traveled to areas with high prevalence, children who attend day care , men who have sex with men , and following disasters . Transmission may occur from drinking contaminated water or when people share personal objects. Water quality typically worsens during
2940-533: Is no longer used. Respiratory droplets were thought to rapidly fall to the ground after emission: but smaller droplets and aerosols also contain live infectious agents, and can remain in the air longer and travel farther. Individuals generate aerosols and droplets across a wide range of sizes and concentrations, and the amount produced varies widely by person and activity. Larger droplets greater than 100 μm usually settle within 2 m. Smaller particles can carry airborne pathogens for extended periods of time. While
3038-442: Is not recommended in children, however, as it may cross the immature blood–brain barrier and cause toxicity. Bismuth subsalicylate , an insoluble complex of trivalent bismuth and salicylate, can be used in mild to moderate cases, but salicylate toxicity is theoretically possible. It is estimated that there were two billion cases of gastroenteritis that resulted in 1.3 million deaths globally in 2015. Children and those in
Norovirus - Misplaced Pages Continue
3136-521: Is not usually available but may be performed by public health agencies during outbreaks. Prevention involves proper hand washing and disinfection of contaminated surfaces. There is no vaccine or specific treatment for norovirus. Management involves supportive care such as drinking sufficient fluids or intravenous fluids . Oral rehydration solutions are the preferred fluids to drink, although other drinks without caffeine or alcohol can help. Alcohol-based hand sanitizers are not effective against
3234-406: Is produced. Approximately 20% of Caucasians are non-secretors due to G428A and C571T nonsense mutations in FUT2 and therefore have strong – although not absolute – protection from the norovirus GII.4. Non-secretors can still produce ABH antigens in erythrocytes, as the precursor is formed by FUT1. Some norovirus genotypes (GI.3) can infect non-secretors. The norovirus was originally named
3332-435: Is recommended as a prevention for children. Treatment involves getting enough fluids. For mild or moderate cases, this can typically be achieved by drinking oral rehydration solution (a combination of water, salts and sugar). In those who are breastfed, continued breastfeeding is recommended. For more severe cases, intravenous fluids may be needed. Fluids may also be given by a nasogastric tube . Zinc supplementation
3430-440: Is recommended in children. Antibiotics are generally not needed. However, antibiotics are recommended for young children with a fever and bloody diarrhea. In 2015, there were two billion cases of gastroenteritis, resulting in 1.3 million deaths globally. Children and those in the developing world are affected the most. In 2011, there were about 1.7 billion cases, resulting in about 700,000 deaths of children under
3528-403: Is recommended. Electrolytes and kidney function should also be checked when there is a concern about severe dehydration. A determination of whether or not the person has dehydration is an important part of the assessment, with dehydration typically divided into mild (3–5%), moderate (6–9%), and severe (≥10%) cases. In children, the most accurate signs of moderate or severe dehydration are
3626-437: Is relatively common in developed countries and in low-mortality developing countries (20% and 19% respectively) compared to high-mortality developing countries (14%). Proportionately it causes more illness in people in the community or in hospital outpatients (24% and 20% respectively) as compared with hospital inpatients (17%) in whom other causes are more common. Age and emergence of new norovirus strains do not appear to affect
3724-478: Is the cause of about 10% of cases in children. In some countries, Campylobacter jejuni is the primary cause of bacterial gastroenteritis, with half of these cases associated with exposure to poultry . In children, bacteria are the cause in about 15% of cases, with the most common types being Escherichia coli , Salmonella , Shigella , and Campylobacter species. If food becomes contaminated with bacteria and remains at room temperature for several hours,
3822-407: Is the most common cause of gastroenteritis in children, and produces similar rates in both the developed and developing world . Viruses cause about 70% of episodes of infectious diarrhea in the pediatric age group. Rotavirus is a less common cause in adults due to acquired immunity. Norovirus is the cause in about 18% of all cases. Generally speaking, viral gastroenteritis accounts for 21–40% of
3920-594: Is the most common cause of severe disease. In adults, norovirus and Campylobacter are common causes. Eating improperly prepared food, drinking contaminated water or close contact with a person who is infected can spread the disease . Treatment is generally the same with or without a definitive diagnosis, so testing to confirm is usually not needed. For young children in impoverished countries, prevention includes hand washing with soap, drinking clean water , breastfeeding babies instead of using formula , and proper disposal of human waste . The rotavirus vaccine
4018-662: Is typically diagnosed clinically, based on a person's signs and symptoms. Determining the exact cause is usually not needed as it does not alter the management of the condition. However, stool cultures should be performed in those with blood in the stool, those who might have been exposed to food poisoning , and those who have recently traveled to the developing world. It may also be appropriate in children younger than 5, old people, and those with poor immune function. Diagnostic testing may also be done for surveillance. As hypoglycemia occurs in approximately 10% of infants and young children, measuring serum glucose in this population
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4116-724: Is useful in treating abdominal pain . The primary treatment of gastroenteritis in both children and adults is rehydration . This is preferably achieved by drinking rehydration solution, although intravenous delivery may be required if there is a decreased level of consciousness or if dehydration is severe. Drinking replacement therapy products made with complex carbohydrates (i.e. those made from wheat or rice) may be superior to those based on simple sugars. Drinks especially high in simple sugars, such as soft drinks and fruit juices, are not recommended in children under five years of age as they may increase diarrhea. Plain water may be used if more specific ORT preparations are unavailable or
4214-800: Is usually self-limiting , and severe illness is rare. Although having norovirus can be unpleasant, it is not usually dangerous, and most who contract it make a full recovery within two to three days. Norovirus can establish a long-term infection in people who are immunocompromised , such as those with common variable immunodeficiency or with a suppressed immune system after organ transplantation . These infections can be with or without symptoms. In severe cases, persistent infections can lead to norovirus‐associated enteropathy , intestinal villous atrophy, and malabsorption . Noroviruses are transmitted directly from person to person (62–84% of all reported outbreaks) and indirectly via contaminated water and food. Transmission can be aerosolized when those stricken with
4312-463: Is usually a type of bacterial gastroenteritis, while the persistent form is usually parasitic. Acid-suppressing medication appears to increase the risk of significant infection after exposure to several organisms, including Clostridioides difficile , Salmonella , and Campylobacter species. The risk is greater in those taking proton pump inhibitors than with H 2 antagonists . A number of parasites can cause gastroenteritis. Giardia lamblia
4410-456: Is usually self-limiting. Severe illness is rare; although people are frequently treated at the emergency ward, they are rarely admitted to the hospital. The number of deaths from norovirus in the United States is estimated to be around 570–800 each year, with most of these occurring in the very young, the elderly, and persons with weakened immune systems. Symptoms may become life-threatening in these groups if dehydration or electrolyte imbalance
4508-474: Is usually transmitted by contaminated water or food. Toxigenic Clostridioides difficile is an important cause of diarrhea that occurs more often in the elderly. Infants can carry these bacteria without developing symptoms. It is a common cause of diarrhea in those who are hospitalized and is frequently associated with antibiotic use. Staphylococcus aureus infectious diarrhea may also occur in those who have used antibiotics. Acute " traveler's diarrhea "
4606-584: The Food and Drug Administration (FDA) in the US. There is no specific medicine to treat people with norovirus illness. Norovirus infection cannot be treated with antibiotics because it is a virus. Treatments aim to avoid complications by measures such as the management of dehydration caused by fluid loss in vomiting and diarrhea, and to mitigate symptoms using antiemetics and antidiarrheals . Norovirus causes about 18% of all cases of acute gastroenteritis worldwide. It
4704-443: The developing world are most commonly affected. As of 2011, in those younger than five, there were about 1.7 billion cases resulting in 0.7 million deaths, with most of these occurring in the world's poorest nations. More than 450,000 of these fatalities are due to rotavirus in children under five years of age. Cholera causes about three to five million cases of disease and kills approximately 100,000 people yearly. In
4802-613: The same strain of the virus – the genotype – protects against reinfection for between six months to two years. This immunity does not fully protect against infection with the other diverse genotypes of the virus. In Canada , norovirus is a notifiable disease . In both the US and the UK it is not notifiable. Hand washing with soap and water is an effective method for reducing the transmission of norovirus pathogens. Alcohol rubs (≥62% isopropyl alcohol ) may be used as an adjunct, but are less effective than hand-washing, as norovirus lacks
4900-565: The "Norwalk agent" after Norwalk, Ohio , in the United States, where an outbreak of acute gastroenteritis occurred among children at Bronson Elementary School in November 1968. In 1972, electron microscopy on stored human stool samples identified a virus, which was given the name "Norwalk virus". Numerous outbreaks with similar symptoms have been reported since. The cloning and sequencing of the Norwalk virus genome showed that these viruses have
4998-522: The 20 μm size range initially travel with the air flow from cough jets and air conditioning like aerosols, but fall out gravitationally at a greater distance as "jet riders". As this size range is most efficiently filtered out in the nasal mucosa , the primordial infection site in COVID-19 , aerosols/droplets in this size range may contribute to driving the COVID-19 pandemic . Airborne diseases can be transmitted from one individual to another through
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#17327758415345096-874: The CDC published a clinical practice guideline addressing strategies for the prevention and control of norovirus gastroenteritis outbreaks in healthcare settings. Based on a systematic review of published scientific studies, the guideline presents 51 specific evidence-based recommendations, which were organized into 12 categories: 1) patient cohorting and isolation precautions, 2) hand hygiene, 3) patient transfer and ward closure, 4) food handlers in healthcare, 5) diagnostics, 6) personal protective equipment, 7) environmental cleaning, 8) staff leave and policy, 9) visitors, 10) education, 11) active case-finding, and 12) communication and notification. The guideline also identifies eight high-priority recommendations and suggests several areas in need of future research. LigoCyte announced in 2007 that it
5194-515: The United States, it is the cause of about half of all foodborne disease outbreaks. The virus is named after the city of Norwalk, Ohio , US, where an outbreak occurred in 1968. Norovirus infection is characterized by nausea , vomiting , watery diarrhea , abdominal pain, and in some cases, loss of taste. A person usually develops symptoms of gastroenteritis 12 to 48 hours after being exposed to norovirus. General lethargy, weakness, muscle aches, headaches, and low-grade fevers may occur. The disease
5292-543: The World Health Organization recommended that the rotavirus vaccine be offered to all children globally. Two commercial rotavirus vaccines exist and several more are in development. In Africa and Asia these vaccines reduced severe disease among infants and countries that have put in place national immunization programs have seen a decline in the rates and severity of disease. This vaccine may also prevent illness in non-vaccinated children by reducing
5390-428: The age of five. In the developing world, children less than two years of age frequently get six or more infections a year. It is less common in adults, partly due to the development of immunity . Gastroenteritis usually involves both diarrhea and vomiting . Sometimes, only one or the other is present. This may be accompanied by abdominal cramps. Signs and symptoms usually begin 12–72 hours after contracting
5488-519: The air. The pathogens transmitted may be any kind of microbe , and they may be spread in aerosols, dust or droplets. The aerosols might be generated from sources of infection such as the bodily secretions of an infected individual, or biological wastes. Infectious aerosols may stay suspended in air currents long enough to travel for considerable distances; sneezes , for example, can easily project infectious droplets for dozens of feet (ten or more meters). Airborne pathogens or allergens typically enter
5586-712: The bacteria Escherichia coli and Campylobacter species are the primary causes of gastroenteritis. There are, however, many other infectious agents that can cause this syndrome including parasites and fungus . Non-infectious causes are seen on occasion, but they are less likely than a viral or bacterial cause. Risk of infection is higher in children due to their lack of immunity . Children are also at higher risk because they are less likely to practice good hygiene habits. Children living in areas without easy access to water and soap are especially vulnerable. Rotaviruses , noroviruses , adenoviruses , and astroviruses are known to cause viral gastroenteritis. Rotavirus
5684-404: The bacteria multiply and increase the risk of infection in those who consume the food. Some foods commonly associated with illness include raw or undercooked meat, poultry, seafood, and eggs; raw sprouts; unpasteurized milk and soft cheeses; and fruit and vegetable juices. In the developing world, especially sub-Saharan Africa and Asia, cholera is a common cause of gastroenteritis. This infection
5782-423: The bacterias Yersinia pestis (which causes plague ) and Francisella tularensis (which causes tularaemia ), which both can cause severe pneumonia, if transmitted via the airborne route through inhalation. Poor ventilation enhances transmission by allowing aerosols to spread undisturbed in an indoor space. Crowded rooms are more likely to contain an infected person. The longer a susceptible person stays in such
5880-949: The body via the nose , throat , sinuses and lungs . Inhalation of these pathogens affects the respiratory system and can then spread to the rest of the body. Sinus congestion, coughing and sore throats are examples of inflammation of the upper respiratory airway. Air pollution plays a significant role in airborne diseases. Pollutants can influence lung function by increasing air way inflammation. Common infections that spread by airborne transmission include SARS-CoV-2 ; measles morbillivirus , chickenpox virus ; Mycobacterium tuberculosis , influenza virus , enterovirus , norovirus and less commonly other species of coronavirus , adenovirus , and possibly respiratory syncytial virus . Some pathogens which have more than one mode of transmission are also anisotropic , meaning that their different modes of transmission can cause different kinds of diseases, with different levels of severity. Two examples are
5978-503: The case. In addition to "Norwalk agent" and "Norwalk virus", the virus has also been called "Norwalk-like virus", "small, round-structured viruses" (SRSVs), Spencer flu, and "Snow Mountain virus". Common names of the illness caused by noroviruses still in use include "Roskilde illness", "winter vomiting disease", "winter vomiting bug", "viral gastroenteritis", and "acute nonbacterial gastroenteritis". Gastroenteritis Gastroenteritis , also known as infectious diarrhea ,
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#17327758415346076-491: The cases of infectious diarrhea in developed countries. Norovirus is the leading cause of gastroenteritis among adults in America accounting for about 90% of viral gastroenteritis outbreaks. These localized epidemics typically occur when groups of people spend time proximate to each other, such as on cruise ships , in hospitals, or in restaurants. People may remain infectious even after their diarrhea has ended. Norovirus
6174-506: The concentration of airborne pathogens is greater within 2m, they can travel farther and concentrate in a room. The traditional size cutoff of 5 μm between airborne and respiratory droplets has been discarded, as exhaled particles form a continuum of sizes whose fates depend on environmental conditions in addition to their initial sizes. This error has informed hospital based transmission based precautions for decades. Indoor respiratory secretion transfer data suggest that droplets/aerosols in
6272-426: The consumption of certain types of spoiled fish, tetrodotoxin poisoning from the consumption of puffer fish among others, and botulism typically due to improperly preserved food. In the United States, rates of emergency department use for noninfectious gastroenteritis dropped 30% from 2006 until 2011. Of the twenty most common conditions seen in the emergency department, rates of noninfectious gastroenteritis had
6370-403: The developing and developed world by as much as 30%. Alcohol-based gels may also be effective. Food or drink that is thought to be contaminated should be avoided. Breastfeeding is important, especially in places with poor hygiene, as is improvement of hygiene generally. Breast milk reduces both the frequency of infections and their duration. Due to both its effectiveness and safety, in 2009
6468-487: The developing world, children less than two years of age frequently get six or more infections a year that result in significant gastroenteritis. It is less common in adults, partly due to the development of acquired immunity . In 1980, gastroenteritis from all causes caused 4.6 million deaths in children, with the majority occurring in the developing world. Death rates were reduced significantly (to approximately 1.5 million deaths annually) by 2000, largely due to
6566-575: The developing world. Antiemetic medications may be helpful for treating vomiting in children. Ondansetron has some utility, with a single dose being associated with less need for intravenous fluids, fewer hospitalizations, and decreased vomiting. Metoclopramide might also be helpful. However, the use of ondansetron might possibly be linked to an increased rate of return to hospital in children. The intravenous preparation of ondansetron may be given orally if clinical judgment warrants. Dimenhydrinate , while reducing vomiting, does not appear to have
6664-524: The efficacy of airborne disease transmission; the most evident environmental conditions are temperature and relative humidity . The transmission of airborne diseases is affected by all the factors that influence temperature and humidity, in both meteorological (outdoor) and human (indoor) environments. Circumstances influencing the spread of droplets containing infectious particles can include pH, salinity, wind, air pollution, and solar radiation as well as human behavior. Airborne infections usually land in
6762-688: The exception that foods high in simple sugars should be avoided. The BRAT diet (bananas, rice, applesauce, toast and tea) is no longer recommended, as it contains insufficient nutrients and has no benefit over normal feeding. A Cochrane Review from 2020 concludes that probiotics make little or no difference to people who have diarrhea lasting 2 days or longer and that there is no proof that they reduce its duration. They may be useful in preventing and treating antibiotic associated diarrhea . Fermented milk products (such as yogurt ) are similarly beneficial. Zinc supplementation appears to be effective in both treating and preventing diarrhea among children in
6860-589: The extent that it limits the transfer of airborne particles between individuals. The type of mask that is effective against airborne transmission is dependent on the size of the particles. While fluid-resistant surgical masks prevent large droplet inhalation, smaller particles which form aerosols require a higher level of protection with filtration masks rated at N95 (US) or FFP3 (EU) required. Use of FFP3 masks by staff managing patients with COVID-19 reduced acquisition of COVID-19 by staff members. Engineering solutions which aim to control or eliminate exposure to
6958-820: The family Caliciviridae . According to the International Committee on Taxonomy of Viruses , the genus Norovirus has one species, which is called Norwalk virus . Noroviruses can genetically be classified into at least seven different genogroups (GI, GII, GIII, GIV, GV, GVI, and GVII), which can be further divided into other genetic clusters or genotypes . Noroviruses commonly isolated in cases of acute gastroenteritis belong to two genogroups: genogroup I (GI) includes Norwalk virus, Desert Shield virus, and Southampton virus; and II (GII), which includes Bristol virus, Lordsdale virus, Toronto virus, Mexico virus, Hawaii virus and Snow Mountain virus. Most noroviruses that infect humans belong to genogroups GI and GII. Noroviruses from genogroup II, genotype 4 (abbreviated as GII.4) account for
7056-626: The genus name Norovirus when referring to outbreaks of the disease. This was also a public response by ICTV to the request from an individual in Japan to rename the Norovirus genus because of the possibility of negative associations for people in Japan and elsewhere who have the family name "Noro". Before this position of ICTV was made public, ICTV consulted widely with members of the Caliciviridae Study Group and carefully discussed
7154-464: The globe. Reports have shown a link between the expression of human histo- blood group antigens (HBGAs) and the susceptibility to norovirus infection. Studies have suggested the capsid of noroviruses may have evolved from selective pressure of human HBGAs. HBGAs are not, however, the receptor or facilitator of norovirus infection. In fact, co-factors such as bile salts may facilitate the infection, making it more intense when introduced during or after
7252-421: The illness vomit or by a toilet flush when vomit or diarrhea is present; infection can follow eating food or breathing air near an episode of vomiting, even if cleaned up. The viruses continue to be shed after symptoms have subsided, and shedding can still be detected many weeks after infection. Vomiting, in particular, transmits infection effectively and appears to allow airborne transmission . In one incident,
7350-429: The indoor environment), the medical system (e.g. vaccination) and public health at the population level (e.g. testing, quarantine, and contact tracing). Preventive techniques can include disease-specific immunization as well as nonpharmaceutical interventions such as wearing a respirator and limiting time spent in the presence of infected individuals. Wearing a face mask can lower the risk of airborne transmission to
7448-683: The infection rate was still 25%. The outbreak was attributed to a Norwalk-like virus (norovirus). Other cases of transmission by vomit were later identified. In one outbreak at an international scout jamboree in the Netherlands, each person with gastroenteritis infected an average of 14 people before increased hygiene measures were put in place. Even after these new measures were enacted, an ill person still infected an average of 2.1 other people. A US Centers for Disease Control and Prevention (CDC) study of 11 outbreaks in New York State lists
7546-410: The infectious agent. If due to a virus, the condition usually resolves within one week. Some viral infections also involve fever , fatigue, headache and muscle pain . If the stool is bloody , the cause is less likely to be viral and more likely to be bacterial. Some bacterial infections cause severe abdominal pain and may persist for several weeks. Children infected with rotavirus usually make
7644-462: The initial infection of the host tissue. Bile salts are produced by the liver in response to eating fatty foods, and they help with the absorption of consumed lipids . It is not yet clear as to at what specific point in the Norovirus replication cycle bile salts facilitate infection: penetration, uncoating, or maintaining capsid stability. The protein MDA-5 may be the primary immune sensor that detects
7742-555: The introduction and widespread use of oral rehydration therapy . In the US, infections causing gastroenteritis are the second most common infection (after the common cold ), and they result in between 200 and 375 million cases of acute diarrhea and approximately ten thousand deaths annually, with 150 to 300 of these deaths in children less than five years of age. Gastroenteritis is associated with many colloquial names, including " Montezuma's revenge ", "Delhi belly", "la turista", and "back door sprint", among others. It has played
7840-469: The largest decrease in visits in that time period. Gastroenteritis is defined as vomiting or diarrhea due to inflammation of the small or large bowel , often due to infection. The changes in the small bowel are typically noninflammatory, while the ones in the large bowel are inflammatory. The number of pathogens required to cause an infection varies from as few as one (for Cryptosporidium ) to as many as 10 (for Vibrio cholerae ). Gastroenteritis
7938-446: The leading bacterial causes of gastroenteritis worldwide. Gastroenteritis is usually an acute and self-limiting disease that does not require medication. The preferred treatment in those with mild to moderate dehydration is oral rehydration therapy (ORT). For children at risk of dehydration from vomiting, taking a single dose of the anti vomiting medication metoclopramide or ondansetron , may be helpful, and butylscopolamine
8036-549: The majority of adult outbreaks of gastroenteritis and often sweep across the globe. Recent examples include US95/96-US strain, associated with global outbreaks in the mid- to late-1990s; Farmington Hills virus associated with outbreaks in Europe and the United States in 2002 and in 2004; and Hunter virus which was associated with outbreaks in Europe, Japan, and Australasia. In 2006, there was another large increase in NoV infection around
8134-610: The norovirus, according to the NHS information page on the subject; this is due to norovirus being a non-enveloped virus . Norovirus results in about 685 million cases of disease and 200,000 deaths globally a year. It is common both in the developed and developing world . Those under the age of five are most often affected, and in this group it results in about 50,000 deaths in the developing world. Norovirus infections occur more commonly during winter months. It often occurs in outbreaks , especially among those living in close quarters. In
8232-559: The number of circulating infections. Since 2000, the implementation of a rotavirus vaccination program in the United States has substantially decreased the number of cases of diarrhea by as much as 80 percent. The first dose of vaccine should be given to infants between 6 and 15 weeks of age. The oral cholera vaccine has been found to be 50–60% effective over two years. There are a number of vaccines against gastroenteritis in development. For example, vaccines against Shigella and enterotoxigenic Escherichia coli (ETEC), which are two of
8330-877: The person exhibits only vomiting or diarrhea (rather than both). Appendicitis may present with vomiting, abdominal pain, and a small amount of diarrhea in up to 33% of cases. This is in contrast to the large amount of diarrhea that is typical of gastroenteritis. Infections of the lungs or urinary tract in children may also cause vomiting or diarrhea. Classical diabetic ketoacidosis (DKA) presents with abdominal pain, nausea, and vomiting, but without diarrhea. One study found that 17% of children with DKA were initially diagnosed as having gastroenteritis. A supply of easily accessible uncontaminated water and good sanitation practices are important for reducing rates of infection and clinically significant gastroenteritis. Personal hygiene measures (such as hand washing with soap) have been found to decrease rates of gastroenteritis in both
8428-542: The person is not willing to drink them. A nasogastric tube can be used in young children to administer fluids if warranted. In those who require intravenous fluids, one to four hours' worth is often sufficient. It is recommended that breast-fed infants continue to be nursed in the usual fashion, and that formula-fed infants continue their formula immediately after rehydration with ORT. Lactose-free or lactose-reduced formulas usually are not necessary. Children should continue their usual diet during episodes of diarrhea with
8526-661: The presence of noroviruses in the body. Some people have common variations of the MDA-5 gene that could make them more susceptible to norovirus infection. Viruses in Norovirus are non-enveloped, with icosahedral geometries. Capsid diameters vary widely, from 23 to 40 nm in diameter. The larger capsids (38–40 nm) exhibit T=3 symmetry and are composed of 180 VP1 proteins . Small capsids (23 nm) show T=1 symmetry, and are composed of 60 VP1 proteins. The virus particles demonstrate an amorphous surface structure when visualized using electron microscopy . Noroviruses contain
8624-478: The proportion of gastroenteritis attributable to norovirus. In the United States, the estimated annual number of norovirus cases in 2023 was 21 million, representing a rate of 6,270 cases per 100,000 individuals. Norovirus is a common cause of epidemics of gastroenteritis on cruise ships . The CDC, through its Vessel Sanitation Program, records and investigates outbreaks of gastrointestinal illness – mostly caused by norovirus – on cruise ships with both
8722-657: The rainy season and outbreaks are more common at this time. In areas with four seasons , infections are more common in the winter. Worldwide, bottle-feeding of babies with improperly sanitized bottles is a significant cause. Transmission rates are also related to poor hygiene, (especially among children), in crowded households, and in those with poor nutritional status. Adults who have developed immunities might still carry certain organisms without exhibiting symptoms. Thus, adults can become natural reservoirs of certain diseases. While some agents (such as Shigella ) only occur in primates , others (such as Giardia ) may occur in
8820-615: The respiratory system, with the agent present in aerosols (infectious particles < 5 μm in diameter). This includes dry particles, often the remnant of an evaporated wet particle called nuclei, and wet particles. A layered risk-management approach to slowing the spread of a transmissible disease attempts to minimize risk through multiple layers of interventions. Each intervention has the potential to reduce risk. A layered approach can include interventions by individuals (e.g. mask wearing, hand hygiene), institutions (e.g. surface disinfection, ventilation, and air filtration measures to control
8918-420: The same agents cause gastroenteritis in cats and dogs as in humans. The most common organisms are Campylobacter , Clostridioides difficile , Clostridium perfringens , and Salmonella . A large number of toxic plants may also cause symptoms. Some agents are more specific to a certain species. Transmissible gastroenteritis coronavirus (TGEV) occurs in pigs resulting in vomiting, diarrhea, and dehydration. It
9016-497: The suspected mode of transmission as person-to-person in seven outbreaks, foodborne in two, waterborne in one, and one unknown. The source of waterborne outbreaks may include water from municipal supplies, wells, recreational lakes, swimming pools, and ice machines. Shellfish and salad ingredients are the foods most often implicated in norovirus outbreaks. Ingestion of shellfish that has not been sufficiently heated – under 75 °C (167 °F) – poses
9114-432: The use of antibiotics in young children who have both bloody diarrhea and fever. Antimotility medication has a theoretical risk of causing complications, and although clinical experience has shown this to be unlikely, these drugs are discouraged in people with bloody diarrhea or diarrhea that is complicated by fever. Loperamide , an opioid analogue, is commonly used for the symptomatic treatment of diarrhea. Loperamide
9212-639: The virus. Since there is no RNA in this particle, it is incapable of reproducing and cannot cause an infection. The norovirus can survive for long periods outside a human host depending on the surface and temperature conditions: it can survive for weeks on hard and soft surfaces, and it can survive for months, maybe even years in contaminated still water. A 2006 study found the virus remained on surfaces used for food preparation seven days after contamination. Routine protocols to detect norovirus in clams and oysters by reverse transcription polymerase chain reaction are being employed by governmental laboratories such as
9310-434: The young, the old, and those with other health problems. The virus is usually spread by the fecal–oral route . This may be through contaminated food or water or person-to-person contact. It may also spread via contaminated surfaces or through air from the vomit of an infected person. Risk factors include unsanitary food preparation and sharing close quarters . Diagnosis is generally based on symptoms. Confirmatory testing
9408-576: Was frozen raspberries imported from Harbin Gaotai Food Co Ltd, a Chinese supplier, and then Canadian authorities issued a recall on raspberries products from Harbin Gaotai. According to the CDC, there was a surge in norovirus cases on thirteen cruise ships in 2023, which marks the highest number of outbreaks since 2012. Noroviruses (NoV) are a genetically diverse group of single-stranded positive-sense RNA , non- enveloped viruses belonging to
9506-408: Was not immediately identified. Researchers plotted the seating arrangement: more than 90% of the people at the same table as the sick person later reported becoming ill. There was a direct correlation between the risk of infection of people at other tables and how close they were to the sick person. More than 70% of the diners at an adjacent table fell ill; at a table on the other side of the restaurant,
9604-407: Was working on a vaccine and had started phase 1 trials. The company has since been taken over by Takeda Pharmaceutical Company . As of 2019, a bivalent (NoV GI.1/GII.4) intramuscular vaccine had completed phase 1 trials. In 2020 the phase 2b trials were finished. The vaccine relies on using a virus-like particle that is made of the norovirus capsid proteins in order to mimic the external structure of
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