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Norovirus is the leading cause of epidemic gastroenteritis worldwide but the disease is usually self-limiting and generally only causes serious health problems in the young, elderly and immunocompromised. The authors report a case of bowel perforation in an elderly Caucasian lady with confirmed infection with Norovirus genogroup II and no other presumptive cause. To the authors' knowledge this is the first such case of bowel perforation due to Norovirus. Viral gastroenteritis should be considered in the list of differentials when no obvious cause of bowel perforation can be identified to minimise morbidity and mortality.
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BioMed Central
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Cases Journal
Open Access
Case Report
Spontaneous bowel perforation due to norovirus: a case report
Nikhil Pawa, Andrew P Vanezis* and Matthew G Tutton
Address: Department of General Surgery, Colchester University Hospital, Turner Road, Colchester, Essex, CO4 5JL, UK
Email: Nikhil Pawa -; Andrew P Vanezis* -; Matthew G Tutton -
* Corresponding author
Norovirus is the leading cause of epidemic gastroenteritis worldwide but the disease is usually self-
limiting and generally only causes serious health problems in the young, elderly and
immunocompromised. The authors report a case of bowel perforation in an elderly Caucasian lady
with confirmed infection with Norovirus genogroup II and no other presumptive cause. To the
authors' knowledge this is the first such case of bowel perforation due to Norovirus. Viral
gastroenteritis should be considered in the list of differentials when no obvious cause of bowel
perforation can be identified to minimise morbidity and mortality.
Since the developments of molecular diagnostic methods,
Noroviruses have been documented as the leading cause
of epidemic gastroenteritis in all age groups, causing
greater than 90% of non-bacterial and approximately
50% of all epidemic gastroenteritis worldwide [1].
Colloquially known as 'gastric flu' or the 'winter vomiting
bug', Norovirus is a member of the Caliciviridae family of
viruses and is thought to be the leading cause of infectious
gastroenteritis in England and Wales [2]. Initially coined
'Norwalk' virus after the small town of Norwalk in Ohio
where an outbreak of acute gastroenteritis struck a pri-
mary school in the late 1960s, the virus was given its cur-
rent name in 2002 by the International Committee on
Taxonomy of Viruses [3].
The virus is spread by the vomitus and faecal routes and as
such, there is a tendency for outbreaks to occur in
enclosed spaces, namely hospitals, nursing homes,
schools, offices and even cruises ships; in 2006, 679 peo-
ple on the cruise ship 'Carnival Liberty' contracted the
virus [4] and more recently in July 2009, 380 of the 769
passengers aboard the US cruise ship 'MS Marco Polo' on
a UK round-tour contracted the virus.
The norovirus group are singled stranded RNA viruses
with two main strains of the virus affecting humans.
Within these two groups numerous genotypes have been
detected, however it is thought that the genotype II.4 has
been the culprit for a predominant number of viral gastro-
enteritis in the last decade [5]. The numbers of laboratory
reported cases of norovirus infection shows considerable
yearly fluctuation but it is thought that the vast majority
of cases go unreported and as such it is difficult to deter-
mine the true scale of the disease. The majority of cases
occur in the winter period. In a 12 week period in winter
2007 there were 1325 laboratory reported cases in Eng-
land and Wales compared to 1845 cases in a similar time
period in 2002 [6].
Norovirus gastroenteritis is usually mild and self-limiting.
Studies on healthy adults demonstrate a short incubation
period (24-60 hours) and infection duration (12-60
Published: 27 November 2009
Cases Journal 2009, 2:9101 doi:10.1186/1757-1626-2-9101
Received: 1 November 2009
Accepted: 27 November 2009
This article is available from:
© 2009 Pawa et al; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Cases Journal 2009, 2:9101
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hours) with a high frequency of vomiting and diarrhoea
[7]. Other symptoms attributed to the disease include
headaches, low grade pyrexia, abdominal cramps and in
rare cases, seizures.
Case presentation
An 83 year old retired Caucasian lady was admitted to a
UK hospital with a recent history of back pain without any
trauma. She had no significant past medical history of
note and her only regular medication included a statin for
cholesterol. She was a non-smoker and drunk only mini-
mal amounts of alcohol. X-rays on admission demon-
strated severe osteoporosis with multiple collapsed
lumbar vertebrae. Whilst awaiting a brace and social sup-
port she developed diarrhoea and vomiting. An initial
stool sample was negative for clostridium difficile sero-
toxin. Over the next few days her clinical condition dete-
riorated and by day 6 her C-reactive protein was 357. She
developed abdominal distension, pain and a plain x-ray
showed centralised dilated small bowel loops. A subse-
quent CT scan of her abdomen revealed small bowel
obstruction together with mural thickening of the distal
ileum (see Figure 1).
Following CT the patient developed signs of localised
peritonitis and underwent a laparotomy. At surgery necro-
sis and ischaemia was seen in a large portion of mid-ileum
together with large quantities of pus and a localised perfo-
ration. A small bowel resection of 60 cm was performed.
Histology revealed an acute gangrenous ileitis. Blood,
urine and stool cultures were all negative but reverse tran-
scription polymerase chain reaction (RT-PCR) of stool
cultures revealed Norovirus genogroup II. Immunoassay
of the stool was negative for rotavirus and adenovirus. No
specific testing for astrovirus was performed. Immunolog-
ical testing of the histological specimens was not per-
The patient had no prior history of vascular disease to sug-
gest the cause of the ileitis was ischaemic enterocolitis.
Furthermore despite the patient's back pain she had been
mobilising around her bed in the hospital therefore it is
unlikely that the cause of the ileitis was paralytic ileus sec-
ondary to immobility. The patient received only as
required opiate analgesia and this was co-administered
with appropriate laxative cover to avoid constipation. A
diagnosis of acute gangrenous ileitis secondary to Norovi-
rus was therefore made. It was postulated that the virus
had triggered a localised inflammatory response leading
to necrosis which had continued despite clearing of the
virus by host immune responses. The virus was thought to
be a nosocomial infection as there was no recent history
of foreign travel or contact with individuals demonstrat-
ing the symptoms of gastro-enteric disease prior to admis-
sion. However antibody testing for IgG and IgM was not
performed therefore the length of infection with the virus
was unclear.
Following surgery the patient developed a pelvic collec-
tion requiring CT guided drainage which matured into an
enterocutaneous fistula. The fistula was treated conserva-
tively and sealed spontaneously at 10 weeks at which
point she was discharged.
To the best of our knowledge this is the first reported case
of a small bowel perforation secondary to Norovirus
infection. Even so it must be noted that many infected
individuals remain asymptomatic. This is thought to be
due to acquired immunity as well as the body's innate
immunity. However most individuals' acquired immunity
does not last through to the next season of the disease
where they are again at risk of infection, thus explaining
the high rates of infection in all ages [8]. Studies have now
shown asymptomatic individuals to have mean viral
loads similar to those of symptomatic individuals, possi-
bly accounting for the increased number of infections and
the predominance of an asymptomatic transmission route
[9]. This is further supported by excretion studies per-
formed at an aged-care facility, revealing viral shedding
continuing for an average of 28.7 days [10]. Despite this
the mortality rates in healthy adults is low, with most
deaths occurring in the elderly, the young and the immu-
The inclusion of viral gastroenteritis in the differential
diagnosis of patients presenting with an acute abdomen is
paramount. Potential surgical complications, particularly
in high risk groups, must always be considered early to
minimise morbidity and mortality.
Abdominal CT scan revealing small bowel obstruction together with mural thickening of the distal ileumFigure 1
Abdominal CT scan revealing small bowel obstruc-
tion together with mural thickening of the distal
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Cases Journal 2009, 2:9101
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Written informed consent was obtained from the patient
for publication of this case report and accompanying
images. A copy of the written consent is available for
review by the Editor-in-Chief of this journal.
Competing interests
The authors declare that they have no competing interests.
Authors' contributions
MT was the chief clinician looking after the patient. NP
contributed to writing the case presentation and AV con-
tributed to writing the literature review and discussion. All
authors read and approved the final manuscript.
1. Patel MM, Widdowson MA, Glass RI, et al.: Systematic literature
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4. Investigation update on the Carnival Liberty: Centres for disease
control and prevention. [].
5. Lopman B, Zambon M, Brown DW: The evolution of Norovirus,
the 'Gastric flu'. PLoS Med 2008, 5:e42. doi:10.1371/jour-
6. Health Protection Report- Norovirus Update 2007 [http://]
7. Kaplan JE, Feldman R, Campbell DS, et al.: The frequency of a Nor-
walk-like pattern of illness in outbreaks of acute gastroen-
teritis. Am J Public Health 1982, 72:1329-32.
8. Lindesmith L, Moe C, Marionneau S, et al.: Human susceptibility
and resistance to Norwalk virus infection. Nat Med 2003,
9. Ozawa K, Oka T, Takeda N, et al.: Norovirus Infections in Symp-
tomatic and Asymptomatic Food Handlers in Japan. J Clin
Microbiol 2007, 45:3996-4005.
10. Tu ET, Bull RA, Kim MJ, et al.: Norovirus Excretion in an Aged-
Care Setting. J Clin Microbiol 2008, 46:2119-21.
... Norovirus (NoV) gastroenteritis has been documented as the worldwide leading cause of the majority of acute cases of viral gastroenteritis [1,2]. Originally named Norwalk virus after its identification in the town of Norwalk in Ohio, USA, [1,2] NoV belongs to the Caliciviridae family of viruses. ...
... Norovirus (NoV) gastroenteritis has been documented as the worldwide leading cause of the majority of acute cases of viral gastroenteritis [1,2]. Originally named Norwalk virus after its identification in the town of Norwalk in Ohio, USA, [1,2] NoV belongs to the Caliciviridae family of viruses. Although it does not show the characteristic Caliciviridae morphology, it is assigned to this family due to its genomic structure [1]. ...
... The spread of the virus can be via contaminated food and water, fecal-oral, or airborne via contaminated aerosols. It is usually mild and self-limiting [1][2][3][4]. It has a short incubation period (24-60 hrs.) and an infection duration of about 12-60 hrs. ...
Full-text available
Introduction Norovirus (NoV) gastroenteritis has been documented as the worldwide leading cause of the majority of acute cases of viral gastroenteritis. Here, we present a Case of NoV that progressed into colon perforation. Presentation of case A 47-year-old woman was admitted via the emergency unit with diarrhoea, lower abdominal pain, vomiting and fever. The virological testing of her stool revealed a NoV infection. The abdominal CT scan showed massive pneumatosis intestinalis. Following the scan findings, the patient was admitted for a diagnostic laparotomy the same day. A side-to- side ileosigmoidostomy was performed. We performed two clinical re-evaluations of the patient, the first one took place 2 weeks after we discharged the patient and another one-year later. The patient is in perfect health. Discussion To the best of our knowledge and following a thorough bibliographical search, this is the first case report in Germany and the first case report of colon perforation due to NoV infection in adults in the European Union Conclusion A NoV infection could, along with the typical symptoms, indicate a life-threatening bowel ischemia and/or necrosis.
... However, also severe courses of norovirus infections in adults with gastrointestinal necrosis have been reported. [8][9][10] Obviously in the presented patient PI and pneumoperitoneum was caused by transmigration of gas through the bowel walls, as no perforation could be detected in diagnostic laparoscopy. In accordance, another patient with PI and concomitant free abdominal air due to AIDS was reported, who showed no perforation in exploratory laparotomy. ...
... Bowel perforation due to NoV gastroenteritis is rare. In adults, only one case of spontaneous bowel perforation due to NoV infection was reported in an 83 year old Caucasian patient [10]. In the previous case, necrosis with a perforation was observed in mid-ileum. ...
Full-text available
Noroviruses have been recognized as the leading cause of epidemic and sporadic gastroenteritis since the advent of molecular diagnostic technique. They have been documented in 5-31% of pediatric patients hospitalized with gastroenteritis. Although norovirus gastroenteritis is typically mild and self-limited, it causes severe, but sometimes fatal, conditions in the vulnerable population such as immunocompromised patients, young children, and the elderly. Bowel perforation due to norovirus infection is rare. We report a case of small bowel perforation with norovirus gastroenteritis in the infant with Down syndrome during the hospitalization with pneumonia. Severe dehydration may cause bowel ischemia and could have triggered bowel perforation in this case. Physicians should be alert to the potential surgical complications followed by severe acute diarrhea, especially in high risk groups.
... As shown in diarrhea-associated deaths [29,30], the age at the onset of the disease of <5 years in the majority of the GDPU patients may suggest this age group as a risk factor of GDPU-associated mortality. A prevalence of RVs [29] and NoVs infections [30] among children <5 years of age may not simply account for this finding as the immunocompromised elderly developed DP associated with NoVs gastroenteritis [31]. Impaired immunity in the young [1,2] may play a crucial role in the pathogenesis of GDPU associated with these viruses' infections. ...
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Background. There is no literature review on gastroduodenal perforation or ulcer (GDPU) with rotavirus (RV) and norovirus (NoV) gastroenteritis. Methods. Pediatric cases of GDPU or upper gastrointestinal bleeding with RV and NoV gastroenteritis were searched from September 1974 until October 2015 using PubMed, Google for English, other-language-publications, and Ichushi ( for Japanese-language publications. All reports confirming GDPU or upper gastrointestinal bleeding with RV and NoV gastroenteritis were eligible for inclusion in the study. In addition, clinical characteristics were reviewed. Results. A boy with duodenal ulcer (DU) and NoV gastroenteritis was described. There were 32 GDPU cases (23 RVs and 9 NoVs cases), including our case; with the exception of 1 case, all were Japanese. Mean age, male/female ratio, and symptoms' duration before admission were 21.6 months, 2.2, and 4.0 days, respectively. Vomiting was the most common symptom, followed by diarrhea, lethargy, fever, abdominal distension, and convulsion. Dehydration, hematemesis, melena, drowsiness or unconsciousness, shock, metabolic acidosis, leukocytosis, anemia, positive C-reactive protein, high blood urea nitrogen, and hyponatremia commonly occurred. Helicobacter pylori was a minor cause of GDPU. Duodenal (DP) or gastric perforation (GP) developed in 14 cases (10 DP/RVs, 1 GP/RV, and 3 DP/NoVs). Duodenal ulcer or gastric ulcer (GU) developed in 18 cases (10 DU/RVs, 4 DU/NoVs, 1 GU/RV, 1 GU + DU/NoV, and 2 upper gastrointestinal bleeding/RVs). The predominant perforation or ulcer site was in the duodenum. With the exception of 2 deaths from DU, all cases recovered. Conclusions. Race, young age, male, severe dehydration, metabolic acidosis, drowsiness and unconsciousness, and shock may be potential risk factors of GDPU associated with RV and NoV gastroenteritis. Limitation of this descriptive study warrants further investigations to determine the risk factors in these infections that could be associated with GDPU.
... Norovirus infections have been associated with complications such as bowel perforation and oesophageal rupture (Pawa et al., 2009), and findings of excess mortality in the elderly (w60 years) in community based norovirus gastroenteritis has been reported (Gustavsson et al., 2011). It was estimated that norovirus causes 8-20 deaths/1 000 000 persons, or one death every seventh reported outbreak van Asten et al., 2011). ...
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Diarrhea is considered to be the second leading cause of death due to infections among children <5 years of age worldwide that may be caused by bacteria, parasites, viruses and non-infectious agents. The major causative agents of diarrhea in developing countries may vary from those in developed countries. Noroviruses are considered to be the most common cause of acute diarrhea in both children and adults in industrialized countries. On the other hand, there is lack of comprehensive epidemiological evidence from developing countries that norovirus is a major cause of diarrhea. In these regions, asymptomatic norovirus infections are very common, and similar detection rates have been observed in patients with diarrhea and asymptomatic persons. This review summarizes current knowledge of norovirus infection in developing countries and seeks to position infections with noroviruses among other enteropathogens as disease burden in these regions.
... This radiologic pattern is identical to previous observations in a small number of nonimmunocompromised patients with NV-GE. 26,27 However, BEAM chemotherapy, gastrointestinal CMV infection, or GVHD might also cause small bowel edema, but exclusive involvement of the small intestine has been observed infrequently in intestinal CMV infection or GVHD, and radiologic studies in patients with gastrointestinal complications after BEAM chemotherapy (eg, colitis and stomatitis) are missing. 28,29 The coexistence of NV infection and intestinal GVHD could represent a diagnostic and therapeutic challenge. ...
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Norovirus (NV) infections are a frequent cause of gastroenteritis (GE), but data on this disease in immunocompromised patients are limited. We analyzed an NV outbreak, which affected immunosuppressed patients in the context of chemotherapy or HSCT. On recognition, 7 days after admission of the index patient, preventive measures were implemented. Attack rates were only 3% (11/334) and 10% (11/105) among patients and staff members, respectively. The median duration of symptoms was 7 days in patients compared with only 3 days in staff members (P = .02). Three patients died of the NV infection. Commonly used clinical diagnostic criteria (Kaplan-criteria) were unsuitable because they applied to 11 patients with proven NV-GE but also to 15 patients without NV-GE. With respect to the therapeutic management, it is important to differentiate intestinal GVHD from NV-GE. Therefore, we analyzed the histopathologic patterns in duodenal biopsies, which were distinctive in both conditions. Stool specimens in patients remained positive for NV-RNA for a median of 30 days, but no transmission was observed beyond an asymptomatic interval of 48 hours. NV-GE is a major threat to patients with chemotherapy or HSCT, and meticulous measures are warranted to prevent transmission of NV to these patients.
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Noroviruses cause epidemic and sporadic acute gastroenteritis in both children and adults. We report a rare case of intestinal necrosis due to norovirus gastroenteritis in a healthy adult. A 47-year-old man presented with worsening abdominal pain, diarrhea, vomiting, and abdominal fullness. Physical examination revealed abdominal distension and diffuse tenderness. Contrast-enhanced computed tomography revealed intestinal distention, pneumatosis, and portal venous gas, findings suggestive of intestinal necrosis. Norovirus genome was detected in his stools using the RT-PCR method. Upon laparotomy, a segment of necrotic bowel 170 cm from the ileocecal valve was identified, and the lesion was resected with an end ileostomy. The patient's recovery was uneventful, and he was transferred to another hospital on the 7th post-operative day. Ileostomy closure was performed one month after the first surgery at the transfer hospital. He had no recurrent episodes.
Norovirus has been associated with excess deaths. A retrospective study of mortality following norovirus enteritis (NVE) was undertaken. All hospitalized adult patients with a stool sample positive for norovirus genogroup II on polymerase chain reaction, treated at Sahlgrenska University Hospital, Gothenburg, Sweden between August 2008 and June 2009, were included as cases (N = 598, aged 18-101 years). Matched controls without enteritis (N = 1196) were selected for comparison. Medical records were reviewed and deaths up to 90 days following positive sampling were noted, as well as comorbidities and length of hospital stay. Thirty- and 90-day survival rates were calculated. Total 30-day mortality was 7.6% and no deaths were recorded in cases aged 18-59 years. Thirty-day mortality was higher in cases with underlying medical conditions compared with those without these comorbidities (age 60-101 years: 89.5% vs 94.7% alive at Day 30, respectively; P < 0.05). In cases aged > 80 years, mortality was higher in those with community-onset NVE (N = 64) compared with hospital-onset NVE (N = 305) (81.2% vs 90.2% alive at Day 30, respectively; P < 0.05), and compared with controls (N = 128) (81.2% vs 91.4% alive at Day 30, respectively; P < 0.05). Median length of hospital stay was 20 [interquartile range (IQR) 12-29] days for cases with hospital-onset NVE, and seven (IQR 2-13) days for controls (P < 0.001). In conclusion, community-onset NVE requiring hospitalization was associated with higher mortality compared with hospital-onset NVE and matched controls in hospitalized elderly patients.
Noroviruses are highly infectious and easily transmitted by contact with contaminated surfaces and objects, as airborne particles and by contact between individuals. While illness caused by norovirus is usually self-limiting, it can be serious in very young and elderly people, or in those who are debilitated or have a serious illness; they may require hospital treatment. Norovirus outbreaks in hospitals create significant disruption to patient care. They also have huge cost implications for NHS trusts through staff absence and ward closures, which are extremely disruptive and increase pressures on bed demand. The three most important actions during an outbreak of norovirus are effective hand hygiene, isolation of affected patients and enhanced cleaning of the environment. This article outlines how to identify norovirus infection and outbreaks, and describes how an acute trust managed outbreaks of norovirus and the procedures it adopted.
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We conducted a systematic review of studies that used reverse transcription-PCR to diagnose norovirus (NoV) infections in patients with mild or moderate (outpatient) and severe (hospitalized) diarrhea. NoVs accounted for 12%(95% confidence interval [CI] 10%-15%) of severe gastroenteritis cases among children <5 years of age and 12% (95% CI 9%-15%) of mild and moderate diarrhea cases among persons of all ages. Of 19 studies among children <5 years of age, 7 were in developing countries where pooled prevalence of severe NoV disease (12%) was comparable to that for industrialized countries (12%). We estimate that each year NoVs cause 64,000 episodes of diarrhea requiring hospitalization and 900,000 clinic visits among children in industrialized countries, and up to 200,000 deaths of children <5 years of age in developing countries. Future efforts should focus on developing targeted strategies, possibly even vaccines, for preventing NoV disease and better documenting their impact among children living in developing countries, where >95% of the deaths from diarrhea occur.
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Infectious diseases have influenced population genetics and the evolution of the structure of the human genome in part by selecting for host susceptibility alleles that modify pathogenesis. Norovirus infection is associated with approximately 90% of epidemic non-bacterial acute gastroenteritis worldwide. Here, we show that resistance to Norwalk virus infection is multifactorial. Using a human challenge model, we showed that 29% of our study population was homozygous recessive for the alpha(1,2)fucosyltransferase gene (FUT2) in the ABH histo-blood group family and did not express the H type-1 oligosaccharide ligand required for Norwalk virus binding. The FUT2 susceptibility allele was fully penetrant against Norwalk virus infection as none of these individuals developed an infection after challenge, regardless of dose. Of the susceptible population that encoded a functional FUT2 gene, a portion was resistant to infection, suggesting that a memory immune response or some other unidentified factor also affords protection from Norwalk virus infection.
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Noroviruses are the leading cause of outbreaks of gastroenteritis in the world. At present, norovirus genogroup II, genotype 4 (GII/4), strains are the most prevalent in many countries. In this study we investigated 55 outbreaks and 35 sporadic cases of norovirus-associated gastroenteritis in food handlers in food-catering settings between 10 November 2005 and 9 December 2006 in Japan. Stool specimens were collected from both symptomatic and asymptomatic individuals and were examined for norovirus by real-time reverse transcription-PCR; the results were then confirmed by sequence analysis. Norovirus was detected in 449 of 2,376 (19%) specimens. Four genogroup I (GI) genotypes and 12 GII genotypes, including one new GII genotype, were detected. The GII/4 sequences were predominant, accounting for 19 of 55 (35%) outbreaks and 16 of 35 (46%) sporadic cases. Our results also showed that a large number of asymptomatic food handlers were infected with norovirus GII/4 strains. Norovirus GII had a slightly higher mean viral load (1 log unit higher) than norovirus GI, i.e., 3.81 x 10(8) versus 2.79 x 10(7) copies/g of stool. Among norovirus GI strains, GI/4 had the highest mean viral load, whereas among GII strains, GII/4 had the highest mean viral load (2.02 x 10(8) and 7.96 x 10(9) copies/g of stool, respectively). Importantly, we found that asymptomatic individuals had mean viral loads similar to those of symptomatic individuals, which may account for the increased number of infections and the predominance of an asymptomatic transmission route.
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The authors discuss the implications of a new study that presents compelling data to show that norovirus evolution is driven by immune selection pressure.
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Norovirus genogroup II excretion during an outbreak of gastroenteritis was investigated in an aged-care facility. Viral shedding peaked in the acute stage of illness and continued for an average of 28.7 days. The viral decay rate was 0.76 per day, which corresponds to a viral half-life of 2.5 days.
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We acknowledge the comments by Patel et al. (1) and by Linhares and Velazquez (2) about our article that documented the presence of a single rotavirus genotype (P[4]G2) in Aracaju, northeastern Brazil, after the introduction of a human, monovalent rotavirus vaccine (3). Both letters emphasize that the predominance of P[4]G2 may be caused by a natural genotype variation unrelated to vaccination. We agree that our observation could be explained by natural variation of circulating rotavirus genotypes in the region, but an alternative possibility is that the introduction of the G1P[8] rotavirus vaccine into the childhood immunization schedule created conditions in which P[4]G2 strains had a selective advantage over strains with which the vaccine shares G type, P type, or both. According to a systematic review of rotavirus genotypes reported in the 25 years preceding introduction of the vaccine in Brazil, the prevalence of P[4]G2 strains varied from 19% (1986–1995) to 12% (1996–2000) to 1% thereafter, thus not reaching the detection rate we observed in Aracaju (R.Q. Gurgel et al., unpub data). Furthermore, in the ensuing 8-month period, no genotype other than P[4]G2 had been detected in Aracaju, suggesting that our initial findings were not spurious (R.Q. Gurgel et al., unpub data). In addition, in a separate study we conducted in Recife, a city 500 km north of Aracaju, we observed a significant increase in the proportion of G2 strains detected from 47% (21/45) during the 3-month period immediately after vaccine introduction (March 2006–May 2006) to 100% (11/11) during the same 3-month period 1 year after the vaccine introduction (March 2007–May 2007) (4). We believe that our findings are consistent with results of field trials that indicated that the vaccine provided relatively less protection against P[4]G2 strains than against other rotavirus strain types (5). The beneficial impact of rotavirus vaccination in northeastern Brazil is reflected in the reduction of the detection rate of rotavirus among severe diarrhea cases in our study in Recife, which fell from 27% (45/166 cases) to 5.0% (11/221 cases) in the postvaccine 3-month reporting periods, respectively (4). Our data from Aracaju are indicative of heterotypic protection, although this is not statistically significant (1), against P[4]G2 strains. Further postlicensure studies in Brazil are required to document continuing effectiveness of the national vaccination program as well as to closely monitor the circulating rotavirus strain types (6).
Norovirus, or the winter vomiting virus as it has become more commonly referred to, is responsible for acute epidemics of gastroenteritis and diarrhoea throughout the year and has gained much public notoriety due to its impact on semi-closed communities such as schools, hospitals, offices and cruise liners. In this article Dr Stephanie Dancer provides an expert overview of norovirus and what can be done to stop it spreading.
Records of 642 outbreaks of acute gastroenteritis were reviewed to determine the proportion of outbreaks that were clinically and epidemiologically consistent with Norwalk-like virus infection. Using as our criteria stool cultures negative for bacterial pathogens, mean (or median) duration of illness 12-60 hours, vomiting in greater than or equal to 50 per cent of cases, and, if known, mean (or median) incubation period of 24-48 hours, we found that 23 per cent of waterborne outbreaks, 4 per cent of foodborne outbreaks, and 67 per cent, 60 per cent, and 28 per cent of outbreaks in nursing homes, in summer camps, and on cruise ships, respectively, satisfied the criteria for Norwalk-like pattern. Of 54 outbreaks that satisfied the criteria for Norwalk-like pattern, 14 were investigated for virus etiology. Ten of these (71 per cent) yielded serologic evidence of Norwalk-like virus infection. Norwalk-like viruses are probably an important cause of outbreaks of acute gastroenteritis. Investigation for Norwalk virus antibody in outbreaks that are clinically and epidemiologically consistent with Norwalk-like virus infection is likely to yield diagnostically useful results.
The evolution of Norovirus, the 'Gastric flu'
  • B Lopman
  • M Zambon
  • D W Brown
Lopman B, Zambon M, Brown DW: The evolution of Norovirus, the 'Gastric flu'. PLoS Med 2008, 5:e42. doi:10.1371/journal.pmed.0050042
Systematic literature review of role of Noroviruses in sporadic gastroenteritis
  • MM Patel
  • MA Widdowson
  • RI Glass