The etiology of severe acute gastroenteritis among adults visiting emergency departments in the United States

Acute Gastroenteritis Viruses

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Acute diarrhea is the leading cause of morbidity and second commonest cause of mortality in children <5 years old worldwide.

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Most acute diarrheal illnesses are caused by viruses.

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Noroviruses are the commonest cause of diarrhea in all age groups combined, and rotaviruses are still the leading cause of diarrhea for children <5 years old.

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Transmission is mainly by the fecal–oral route through person-to-person contact, contaminated food and water.

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Most cases of viral diarrhea are mild and self-limiting, but severe cases occur, leading to dehydration and death. Repeated episodes lead to malnutrition.

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Most cases can be managed at home with oral rehydration solutions and feeding a regular diet.

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Vaccines will be the best preventive measure. Only rotavirus vaccines are available.

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Breast-feeding, vitamin A supplementation and zinc significantly reduce the frequency and/or severity of diarrhea.

Province-Wide Review of Pediatric Shiga Toxin-Producing Escherichia coli Case Management

OBJECTIVE

To identify the gaps in the care of children infected with Shiga toxin-producing Escherichia coli (STEC), we sought to quantitate care received and management timelines. Such knowledge is crucial to the design of interventions to prevent the development of hemolytic uremic syndrome (HUS).

STUDY DESIGN

We conducted a retrospective case-series study of 78 children infected with STEC in Alberta, Canada, through the linkage of microbiology and laboratory results, telephone health advice records, hospital charts, physician billing submissions, and outpatient antimicrobial dispensing databases. Outcomes were the time intervals between initial presentation and reporting of positive culture result and symptom onset to HUS and to describe the proportions that had baseline blood work performed and received antibiotics.

RESULTS

Seventy-eight children infected with STEC were identified; 13% (10/78) developed HUS. Median time from initial presentation to laboratory stool sample receipt was 33 hours (IQR 18, 42); time to positive culture was 120 hours (IQR 86, 205). Time from symptom onset to HUS diagnosis was 188 ± 37 hours. Baseline blood tests were obtained in 74% (58/78) of infected children. Antibiotics were administered to 50% (5/10) of those who developed HUS and 22% (15/78) of those who did not; P = .11. The provincial telephone advice system received 31 calls regarding 24 children infected with STEC; 23% (7/31) of callers were recommended to seek emergency department care.

CONCLUSIONS

A significant proportion of children developed HUS following multiple interactions with the health care system. Delays in the confirmation of STEC infection occurred. There are numerous opportunities to improve the timing, monitoring, and interventions in children infected with STEC.

Psidium guajava L., from ethnobiology to scientific evaluation: Elucidating bioactivity against pathogenic microorganisms

ETHNOPHARMACOLOGICAL RELEVANCE

The use of popular plants has guided pharmaceutical research aimed at combating pathogenic microorganisms. Psidium guajava L. is a plant of great versatility and it has been used both as food and as a therapeutic agent. Root, bark, leaves, fruits, flowers and seeds are used for medicinal purposes, especially in infusions and decoctions for oral and topical use. P. guajava is utilized in symptomatology treatment related to organ malfunction and of diseases caused by the action of pathogenic and/or opportunistic microorganisms. Many pharmacological studies have been conducted to scientifically assess its therapeutic potential.

AIMS OF STUDY

The aim of the current study is to relate the popular use of this plant and its bioscientific assessment as a therapeutic agent in the treatment of diseases and symptoms caused by the action of protozoa, fungi, bacteria and viruses, and also evaluate the safety for the usage and the interaction with drugs.

MATERIALS AND METHODS

A bibliographic database the ethnobiology of Psidium guajava (2005-2015) and the pharmacological infections and parasitic diseases (2010-2015). Searches were done in scientific disclosure databases such as PubMed, Web of Science, and Scopus.

RESULTS

P. guajava leaf extracts were scientifically investigated for the treatment of diseases caused by protozoa (leishmaniasis, malaria, giardiasis, amoebiasis and trichomoniasis), fungi (dermatosis, systemic and mucocutaneous diseases), bacteria (respiratory, mucocutaneous and gastrointestinal infections, cholera, gastritis and stomach ulcers, oral and periodontal infections, venereal diseases and urinary infections) and viruses (herpes, influenza, rotavirus disease and AIDS). The toxicity assays indicates the safet for usage.

CONCLUSIONS

Highlight and elucidate the therapeutic potential and versatility of P. guajava. They also justify using ethnobiology efficiency to guide pharmacological studies. Some limitations can be observed in this kind of study, as the lack for ethnobiological informations and the absence of some controls in the assays.

High Protective Efficacy of Probiotics and Rice Bran against Human Norovirus Infection and Diarrhea in Gnotobiotic Pigs

Probiotics have been recognized as vaccine adjuvants and therapeutic agents to treat acute gastroenteritis in children. We previously showed that rice bran (RB) reduced human rotavirus diarrhea in gnotobiotic pigs. Human noroviruses (HuNoVs) are the major pathogens causing non-bacterial acute gastroenteritis worldwide. In this study, Lactobacillus rhamnosus GG (LGG) and Escherichia coli Nissle 1917 (EcN) were first screened for their ability to bind HuNoV P particles and virions derived from clinical samples containing HuNoV genotype GII.3 and GII.4, then the effects of LGG+EcN and RB on HuNoV infection and diarrhea were investigated using the gnotobiotic pig model. While LGG+EcN colonization inhibited HuNoV shedding, probiotic cocktail regimens in which RB feeding started 7 days prior to or 1 day after viral inoculation in the LGG+EcN colonized gnotobiotic pigs exhibited high protection against HuNoV diarrhea and shedding, characterized by significantly reduced incidence (89 versus 20%) and shorter mean duration of diarrhea (2.2 versus 0.2 days), as well as shorter mean duration of virus shedding (3.2 versus 1.0 days). In both probiotic cocktail groups, the diarrhea reduction rates were 78% compared with the control group, and diarrhea severity was reduced as demonstrated by the significantly lower cumulative fecal scores. The high protective efficacy of the probiotic cocktail regimens was attributed to stimulation of IFN-γ⁺ T cell responses, increased production of intestinal IgA and IgG, and maintenance of healthy intestinal morphology (manifested as longer villi compared with the control group). Therefore, probiotic cocktail regimens containing LGG+EcN and RB may represent highly efficacious strategies to prevent and treat HuNoV gastroenteritis, and potentially other human enteric pathogens.

Viral associated diarrhea in immunocompromised and cancer patients at a large comprehensive cancer center: a 10-year retrospective study

BACKGROUND

Viral associated diarrhea (VAD) due to Norovirus (NV), Rotavirus (RV) and Adenovirus (AV) is common in immunocompromised and cancer patients. We sought to determine if the clinical characteristics, morbidity and seasonality of infection differed according to the type of enteric virus identified.

METHODS

Cases of NV, RV and AV were identified in stool specimens submitted to the clinical microbiology laboratory between November 2005 and February 2015. Clinical characteristics of patients, potential risk factors and outcomes were compared.

RESULTS

A total of 97 VAD cases were identified: NV (n = 49), RV (n = 34) and AV (n = 14). The majority of cases were in patients with leukemia and lymphoma. NV (59%), RV (74%) and AV (78%) were identified in hematopoietic stem cell transplant (HSCT) recipients; and in patients with graft versus host disease (GVHD): NV (34%), RV (46%) and AV (57%). Nine cases of NV were genotyped; all were due to genotype II. Nine of 49 (18%) cases of NV, 7 of 34 (20%) cases of RV and 2 of 14 (14%) cases of AV were considered to be health care acquired (HCA). In multivariate analysis, immunosuppression (OR 2.8 95% CI 1.26-6.60, p = .01) and neutropenia (OR 4.8 95% CI 1.27-18.5, p = .01) were identified as risk factors for NV diarrhea compared to RV and AV.

CONCLUSIONS

In our study, agents responsible for VAD occurred year round but predominated in the winter time; caused prolonged illness and were frequently health care associated. Presentations were atypical in many cases without upper gastrointestinal symptoms such as nausea and vomiting.

Norovirus in Transplantation

Noroviruses are among the most common cause of diarrhea in transplant recipients. The clinical spectrum of norovirus infection after transplant is increasingly being recognized. As substantial morbidity is now associated with norovirus infections in this population; the quest for rapid diagnostic modalities and newer therapies has expanded. Transplant recipients with norovirus infection are at risk for several complications, including protracted illness with malnutrition, organ failure, and chronic viral shedding. This review summarizes the current knowledge on the epidemiology, complications, diagnosis, and treatment of norovirus infection in the transplant setting.

Incidence of Norovirus-Associated Medical Encounters among Active Duty United States Military Personnel and Their Dependents

Background

Norovirus is a leading cause of gastroenteritis episodes and outbreaks in US military deployments, but estimates of endemic disease burden among military personnel in garrison are lacking.

Methods

Diagnostic codes from gastroenteritis-associated medical encounters of active duty military personnel and their beneficiaries from July 1998–June 2011 were obtained from the Armed Forces Health Surveillance Center. Using time-series regression models, cause-unspecified encounters were modeled as a function of encounters for specific enteropathogens. Model residuals (representing unexplained encounters) were used to estimate norovirus-attributable medical encounters. Incidence rates were calculated using population data for both active duty and beneficiary populations.

Results

The estimated annual mean rate of norovirus-associated medically-attended visits among active duty personnel and their beneficiaries was 292 (95% CI: 258 to 326) and 93 (95% CI: 80 to 105) encounters per 10,000 persons, respectively. Rates were highest among beneficiaries <5 years of age with a median annual rate of 435 (range: 318 to 646) encounters per 10,000 children. Norovirus was estimated to cause 31% and 27% of all-cause gastroenteritis encounters in the active duty and beneficiary populations, respectively, with over 60% occurring between November and April. There was no evidence of any lag effect where norovirus disease occurred in one population before the other, or in one beneficiary age group before the others.

Conclusions

Norovirus is a major cause of medically-attended gastroenteritis among non-deployed US military active duty members as well as in their beneficiaries.

Metagenomic analysis of viruses associated with field-grown and retail lettuce identifies human and animal viruses

The emergence of culture- and sequence-independent metagenomic methods has not only provided great insight into the microbial community structure in a wide range of clinical and environmental samples but has also proven to be powerful tools for pathogen detection. Recent studies of the food microbiome have revealed the vast genetic diversity of bacteria associated with fresh produce. However, no work has been done to apply metagenomic methods to tackle viruses associated with fresh produce for addressing food safety. Thus, there is a little knowledge about the presence and diversity of viruses associated with fresh produce from farm-to-fork. To address this knowledge gap, we assessed viruses on commercial romaine and iceberg lettuces in fields and a produce distribution center using a shotgun metagenomic sequencing targeting both RNA and DNA viruses. Commercial lettuce harbors an immense assemblage of viruses that infect a wide range of hosts. As expected, plant pathogenic viruses dominated these communities. Sequences of rotaviruses and picobirnaviruses were also identified in both field-harvest and retail lettuce samples, suggesting an emerging foodborne transmission threat that has yet to be fully recognized. The identification of human and animal viruses in lettuce samples in the field emphasizes the importance of preventing viral contamination on leafy greens starting at the field. Although there are still some inherent experimental and bioinformatics challenges in applying viral metagenomic approaches for food safety testing, this work will facilitate further application of this unprecedented deep sequencing method to food samples.

Molecular epidemiology of norovirus in children and the elderly in Atlanta, Georgia, United States

Noroviruses are an important cause of gastroenteritis, which can be severe at the extremes of ages. Data documenting the endemic burden of norovirus among children and elderly adults are lacking. Stool specimens submitted for clinical testing were collected from elderly (≥ 65 years) adults and children (<18 years) with acute vomiting and/or diarrhea seeking care at several metropolitan Atlanta adult and pediatric hospitals from January 2013-June 2013. Specimens were tested for norovirus with real-time RT-PCR and sequenced if norovirus was detected. Corresponding clinical and demographic data were abstracted from retrospective chart review. Norovirus was detected in 11% (11/104) of elderly specimens and 11% (67/628) of pediatric, with GII.4 Sydney_2012 detected in 64% (7/11) of elderly norovirus-positive and 11% (8/67) of pediatric specimens, P < 0.001. In comparison to hospitalized children, hospitalized elderly with norovirus were more commonly admitted to the intensive care unit (ICU) (36% vs. 7%, P = 0.02). Norovirus in the elderly can be associated with severe illness requiring ICU admissions. The pediatric group demonstrated greater variability in genotype distribution. Ongoing surveillance of norovirus genotypes is crucial for norovirus vaccine development in understanding circulating and emerging genotypes.

Prevalence and Seasonal Distribution of Norovirus Detection in Stools Submitted From Pediatric Patients for Enteric Pathogen Testing

The prevalence and seasonal distribution of norovirus infection in children is not well defined. In this study, stool specimens from children suspected of having gastroenteritis were evaluated for the presence of norovirus. When tested retrospectively, 17.4% of samples were positive, primarily with Genogroup GII, peaking in fall and winter.

Progress toward norovirus vaccines: considerations for further development and implementation in potential target populations

Human norovirus infection causes significant medical and financial costs in the USA and abroad. Some populations, including young children, the elderly, and the immunocompromised, are at heightened risk of infection with this virus and subsequent complications, while others, such as healthcare workers and food handlers are at increased risk of transmitting it, and some are at risk of both. Human noroviruses are heterogeneous with new strains emerging periodically. In addition to viral diversity, incompletely understood characteristics, such as virus-host cell binding and duration of immunity after infection add to the challenges of creating a norovirus vaccine. Although much progress has been made in recent years, many questions remain to be answered. In this review, we discuss the important areas and relevant literature in considering human norovirus vaccine development and potential targets for implementation.

A case-control study of risk factors for rotavirus infections in adults, Denmark, 2005–2009

Rotavirus (RV) infections affect young children, but can also occur in adults. We sought to identify risk factors for RV infections in adults aged ⩾18 years in Denmark, and to describe illness and genotyping characteristics. From March 2005 to February 2009, we recruited consecutive cases of laboratory-confirmed RV infection and compared them with healthy controls matched by age, gender and municipality of residence. We collected information on illness characteristics and exposures using postal questionnaires. We calculated univariable and multivariable matched odds ratios (mOR) with conditional logistic regression. The study comprised 65 cases and 246 controls. Illness exceeded 10 days in 31% of cases; 22% were hospitalized. Cases were more likely than controls to suffer serious underlying health conditions [mOR 5·6, 95% confidence interval (CI) 1·7–18], and to report having had close contact with persons with gastrointestinal symptoms (mOR 9·4, 95% CI 3·6–24), in particular young children aged <3 years and adults aged >18 years. Close contact with young children or adults with gastrointestinal symptoms is the main risk factor for RV infection in adults in Denmark. RV vaccination assessments should consider that RV vaccination in children may indirectly reduce the burden of disease in adults.

Clinical characteristics and molecular epidemiology of noroviruses in outpatient children with acute gastroenteritis in Huzhou of China

BACKGROUND

Noroviruses (NoVs) are considered major causative pathogens associated with the morbidity and mortality of young children with acute gastroenteritis. However, few studies have examined NoVs causing acute diarrhea among outpatient children worldwide. This study was conducted to investigate the clinical features and molecular epidemiology of NoVs in outpatient children with acute gastroenteritis in Huzhou, China, between April 2013 and April 2014.

METHODS

Stool specimens from 1346 outpatient children enrolled (under 5 years of age) with acute gastroenteritis were examined for NoVs by multiplex RT-PCR, and sequences of the partial capsids of NoVs were analyzed phylogenetically, while the relevant clinical data were analyzed statistically.

RESULTS

Of 1346 specimens, 383 (28.5%, 383/1346) were positive for NoVs. The proportion of GII genotypes (26.9%) was significantly higher than that of GI genotypes (1.6%). The GII.4 genotype was the most prevalent of GII genotypes and was clustered into GII.4/Sydney (37.8%) and GII.4/2006b (62.2%), whereas GI strains were clustered into GI.1. Additionally, the younger children (12 to <24 months of age) were more susceptible to NoVs than children in other age groups, and the highest percentage of NoV infections occurred in April 2013. The diarrheal frequency (times/d) and WBC counts of the infected outpatient group with NoVs were significantly higher than were those of the uninfected outpatient group.

CONCLUSION

NoVs were confirmed to be the major viral agents responsible for acute gastroenteritis in outpatient children in Huzhou, China, and GII.4/Sydney and GII.4/2006b variants were identified as the predominant strains in this study.

Multiplex polymerase chain reaction tests for detection of pathogens associated with gastroenteritis

A wide range of enteric pathogens can cause infectious gastroenteritis. Conventional diagnostic algorithms are time-consuming and often lack sensitivity and specificity. Advances in molecular technology have provided new clinical diagnostic tools. Multiplex polymerase chain reaction (PCR)-based testing has been used in gastroenterology diagnostics in recent years. This article presents a review of recent laboratory-developed multiplex PCR tests and current commercial multiplex gastrointestinal pathogen tests. It focuses on two commercial syndromic multiplex tests: Luminex xTAG Gastrointestinal Pathogen Panel and BioFire FilmArray gastrointestinal test. Multiplex PCR tests have shown superior sensitivity to conventional methods for detection of most pathogens.

A study on the epidemiology and aetiology of acute gastroenteritis in adult patients presenting at the infectious diseases hospital in tirana, Albania

BACKGROUND

Acute gastroenteritis remains a common cause of hospital emergency room visits in Albania. However, the aetiology of severe gastroenteritis leading to hospitalization in adults frequently remains unclear.

AIMS

Our objective was to study the epidemiology and causes of community-acquired, acute gastroenteritis in adult patients presenting to hospital.

STUDY DESIGN

Cross sectional study.

METHODS

A prospective study was conducted from January 2010 to January 2012, among patients ≥15 years old with community-acquired gastroenteritis presenting to the emergency room of the University Hospital "Mother Theresa" in Tirana, Albania. Stool samples and rectal swabs were collected from the patients for microbiological testing.

RESULTS

The median age of the study patients was 33 (15-88) years and 577 (58%) were females. The median age of males was 35 (15-87) years. The vast majority of cases occurred in urban area (849, 85%), p<0.01. Patients were admitted throughout the year with peak admissions for patients infected by bacterial pathogens in summer and those affected by viral pathogens in autumn. A total of 917 (91.7%) patients underwent a laboratory examination. The overall isolation rate was 51%. Bacterial pathogens were found in 29%, viral pathogens in 19% and protozoal pathogens in 2.5% of patients. No aetiological agent or other cause of acute diarrhoea was found in 449 (49%) patients. Twenty-nine (3.2%) patients were hospitalized.

CONCLUSION

Despite extensive laboratory investigations, enteropathogens were detected in only 51% of adult patients who presented to the hospital ER with acute gastroenteritis. Viral infections ranked as the second most common cause of gastroenteritis in adults.

Norovirus infection in immunocompromised hosts

Acute gastroenteritis caused by noroviruses often has a duration of 2-3 days and is characteristically self-limiting. In contrast, chronic infection caused by noroviruses in immunocompromised individuals can last from weeks to years, making clinical management difficult. The mechanisms by which noroviruses establish persistent infection, and the role of immunocompromised hosts as a reservoir for noroviruses in the general human population, are not known. However, study of this patient cohort may lead to new insights into norovirus biology and approaches to treatment.

Detection of diarrheal viruses circulating in adult patients in Thailand

A total of 332 fecal specimens collected during January-December 2008 from adult patients with diarrhea were screened for group A and C rotaviruses, noroviruses GI and GII, sapovirus, Aichi virus, human parechovirus, enterovirus, adenovirus and astrovirus by RT-multiplex PCR. The detection rate for diarrheal viruses was 4.2 %. Adenovirus and enterovirus were equally detected as the most predominant viruses, with prevalence of 1.2 %, followed by Aichi virus (0.9 %) and norovirus GII (0.6 %). Mixed infection with norovirus GII and human parechovirus was also detected (0.3 %). This study provides epidemiological data for a wide variety of diarrheal viruses circulating in adult patients with diarrhea in Chiang Mai, Thailand.

Site-specific clinical evaluation of the Luminex xTAG gastrointestinal pathogen panel for detection of infectious gastroenteritis in fecal specimens

We evaluate the clinical performance of the Luminex xTAG gastrointestinal (GI) pathogen in vitro diagnostic (IVD) assay in a comparison between clinical and public health laboratories. The site reproducibility study showed 98.7% sensitivity with high positive and negative agreement values (96.2% and 99.8%, respectively), while assay performance against confirmatory methods resulted in 96.4% sensitivity with similar positive and negative agreement values (90.1% and 99.5%, respectively). High-throughput detection of multiple GI pathogens improved turnaround time, consolidated laboratory workflow, and simplified stool culture practices, thus reducing the overall cost and number of specimens processed.

Treatment of norovirus infections: moving antivirals from the bench to the bedside

Noroviruses (NV) are the most common cause of acute gastrointestinal illness in the United States and worldwide. The development of specific antiviral countermeasures has lagged behind that of other viral pathogens, primarily because norovirus disease has been perceived as brief and self-limiting and robust assays suitable for drug discovery have been lacking. The increasing recognition that NV illness can be life-threatening, especially in immunocompromised patients who often require prolonged hospitalization and intensive supportive care, has stimulated new research to develop an effective antiviral therapy. Here, we propose a path forward for evaluating drug therapy in norovirus-infected immunocompromised individuals, a population at high risk for serious and prolonged illness. The clinical and laboratory features of norovirus illness in immunocompromised patients are reviewed, and potential markers of drug efficacy are defined. We discuss the potential design of clinical trials in these patients and how an antiviral therapy that proves effective in immunocompromised patients might also be used in the setting of acute outbreaks, especially in confined settings such as nursing homes, to block the spread of infection and reduce the severity of illness. We conclude by reviewing the current status of approved and experimental compounds that might be evaluated in a hospital setting.

Evaluation and treatment of colonic symptoms

Important considerations for constipation include: 1. Initial evaluation should evaluate for fecal incontinence, fecal impaction, medication side effects, concerning symptoms, underlying medical or metabolic issues and irritable bowel syndrome. 2. History and examination should be used to determine if a defecatory disorder is most likely. a. If defecatory disorder is likely, testing with balloon expulsion or anal manometry can be considered and, if confirmed, treatment with biofeedback (if testing not available, it is reasonable to trial fiber and laxatives because many patients have a mixed disorder). b. If it is unlikely, proceed with trial of fiber and/or osmotic laxatives. 3. If continued symptoms, consider trial of newer agent (lubiprostone or linaclotide). 4. If ineffective, consider testing for colon transit time and referral to gastroenterology.

Advanced techniques for detection and identification of microbial agents of gastroenteritis

Gastroenteritis persists as a worldwide problem, responsible for approximately 2 million deaths annually. Traditional diagnostic methods used in the clinical microbiology laboratory include a myriad of tests, such as culture, microscopy, and immunodiagnostics, which can be labor intensive and suffer from long turnaround times and, in some cases, poor sensitivity. [corrected]. This article reviews recent advances in genomic and proteomic technologies that have been applied to the detection and identification of gastrointestinal pathogens. These methods simplify and speed up the detection of pathogenic microorganisms, and their implementation in the clinical microbiology laboratory has potential to revolutionize the diagnosis of gastroenteritis.

Integration of technology into clinical practice

It is an exciting time in clinical microbiology. New advances in technology are revolutionizing every aspect of the microbiology laboratory, from processing of specimens to bacterial identification; as a result, the microbiology laboratory is rapidly changing. With this change comes the challenge of selecting and implementing the technology that is most appropriate for each laboratory and clinical setting. This review focuses on issues surrounding implementation of new technology such that the improvements to clinical care are maximized.

Clinical characteristics and genetic diversity of noroviruses in adults with acute gastroenteritis in Beijing, China in 2008-2009

Norovirus (NoV) infections that cause acute gastroenteritis are commonly observed during colder months. This study was conducted to investigate the clinical features and molecular epidemiology of NoVs in adult outpatients with acute gastroenteritis in Beijing, China from August 2008 to July 2009. Five hundred nineteen patients were enrolled, their stool specimens were collected, and 136 (26.2%) were positive for NoV. The elderly were found to be more susceptible to NoVs than other age groups. The greatest number of gastroenteritis cases associated with occurred in October. Six GI and eleven GII NoV genotypes were isolated; among these, the GII.4 genotype was most prevalent (70/140 and 50% were the 2006b variant). The elderly were more susceptible to the GII.4 genotype than to other genotypes. Greater numbers of neutrophils in the peripheral blood were observed in the NoV infected group than in uninfected control group. However, the levels of neutrophils and leukocytes in the non-GII.4 patients infected with NoV were higher than those of the GII.4-infected patients. The data highlight the role of NoV as a primary agent responsible for gastroenteritis in adults in Beijing, China.

Emergency department visit data for rapid detection and monitoring of norovirus activity, United States

Noroviruses are the leading cause of gastroenteritis in the United States, but timely measures of disease are lacking. BioSense, a national-level electronic surveillance system, assigns data on chief complaints (patient symptoms) collected during emergency department (ED) visits to 78 subsyndromes in near real-time. In a series of linear regression models, BioSense visits mapped by chief complaints of diarrhea and nausea/vomiting subsyndromes as a monthly proportion of all visits correlated strongly with reported norovirus outbreaks from 6 states during 2007–2010. Higher correlations were seen for diarrhea (R = 0.828–0.926) than for nausea/vomiting (R = 0.729–0.866) across multiple age groups. Diarrhea ED visit proportions exhibited winter seasonality attributable to norovirus; rotavirus contributed substantially for children <5 years of age. Diarrhea ED visit data estimated the onset, peak, and end of norovirus season within 4 weeks of observed dates and could be reliable, timely indicators of norovirus activity.

Multiplex molecular testing for management of infectious gastroenteritis in a hospital setting: a comparative diagnostic and clinical utility study

Laboratory diagnosis and clinical management of inpatients with diarrhoea is complex and time consuming. Tests are often requested sequentially and undertaken in different laboratories. This causes prolonged unnecessary presumptive isolation of patients, because most cases are non-infectious. A molecular multiplex test (Luminex(®) Gastrointestinal Pathogen Panel (GPP)) was compared with conventional testing over 8 months to determine diagnostic accuracy, turnaround times, laboratory costs, use of isolation facilities and user acceptability. A total of 262 (12%) patients had a pathogen detected by conventional methods compared with 483 (22.1%) by GPP. Most additional cases were detected in patients developing symptoms in the first 4 days of admission. Additional cases were detected because of presumed improved diagnostic sensitivity but also because clinicians had not requested the correct pathogen. Turnaround time (41.8 h) was faster than bacterial culture (66.5 h) and parasite investigation (66.5 h) but slower than conventional testing for Clostridium difficile (17.3 h) and viruses (27 h). The test could allow simplified requesting by clinicians and a consolidated laboratory workflow, reducing the overall number of specimens received by the laboratory. A total of 154 isolation days were saved at an estimated cost of £30 800. Consumables and labour were estimated at £150 641 compared with £63 431 for conventional testing. Multiplex molecular testing using a panel of targets allowed enhanced detection and a consolidated laboratory workflow. This is likely to be of greater benefit to cases that present within the first 4 days of hospital admission.

Rotavirus in adults, Brazil, 2004–2011: G2P[4] dominance and potential impact on vaccination

Objectives

The aim of this study was to monitor rotavirus (RV) infections in adults >18 years with acute gastroenteritis during 2004–2011 national Brazilian RV surveillance. In addition, to characterize the RV group A (RVA) strains in order to gain insight into the supposed vaccine selective pressure imposed to Brazilian children population.

Methods

A total of 2102 convenient fecal specimens were investigated by ELISA, PAGE, and RT-PCR.

Results

RV was detected in 203 (9.6%) of 2102 specimens, and showed a marked peak of detection in September. RVA infection was detected in 9.4% (197/2102) and RV group C (RVC) in 0.3% (6/2102). The most frequent genotypes detected in 2004 and 2005 were G9P[8] (38.5%; 5/13) and G1P[8] (54.5%; 6/11), respectively. The dominant genotype identified from 2006 to 2011 was G2P[4] (64.4%; 116/180). Detection rate varied during the 8-year period of the study from 0.7% to 12.9%.

Conclusion

The high detection rate of G2P[4] in adults provides further evidence that its dominance reflects the seasonality of RVA strains instead of the supposed selective advantage created by vaccination program. It also can be suggested that adult infections may serve as a reservoir to maintain RVA strains in childhood gastroenteritis. Considering the detection rate, the evident reduction of RVA frequency observed in children after vaccine introduction was not present in adults.

A case-control study of incident rheumatological conditions following acute gastroenteritis during military deployment

OBJECTIVES

The aim of this study was to assess the risk of incident rheumatological diagnoses (RD) associated with self-reported diarrhoea and vomiting during a first-time deployment to Iraq or Afghanistan. Such an association would provide evidence that RD in this population may include individuals with reactive arthritis (ReA) from deployment-related infectious gastroenteritis.

DESIGN

This case-control epidemiological study used univariate and multivariate logistic regression to compare the odds of self-reported diarrhoea/vomiting among deployed US military personnel with incident RD to the odds of diarrhoea/vomiting among a control population.

SETTING

We analysed health records of personnel deployed to Iraq or Afghanistan, including responses on a postdeployment health assessment and medical follow-up postdeployment.

PARTICIPANTS

Anonymous data were obtained from 891 US military personnel with at least 6 months of medical follow-up following a first-time deployment to Iraq or Afghanistan in 2008-2009. Cases were defined using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis codes; controls had an unrelated medical encounter and were representative of the study population.

MAIN OUTCOME MEASURES

The primary measure was an association between incident RD and self-reported diarrhoea/vomiting during deployment. A secondary measure was the overall incidence of RD in this population.

RESULTS

We identified 98 cases of new onset RD, with a total incidence of 161/100 000 persons. Of those, two participants had been diagnosed with Reiter's disease (i) (3.3/100 000 persons) and the remainder with non-specific arthritis/arthralgia (157.5/100 000 persons). The OR for acute diarrhoea was 2.67 (p=0.03) after adjusting for important covariates.

CONCLUSIONS

Incident rheumatological conditions, even those classified as 'non-specific,' are significantly associated with prior severe diarrhoea in previously deployed military personnel, potentially indicating ReA and need for preventive measures to reduce diarrhoeagenic bacterial exposures in military personnel and other travellers to the developing regions.

Rotavirus infection among Sudanese children younger than 5 years of age: a cross sectional hospital-based study

Introduction

In Sudan, rotavirus has been one of the important causative agents of diarrhea among children. Rotavirus A is well known as the leading cause of diarrhea in young children worldwide. It was estimated to account for 41% of hospitalized cases of acute gastroenteritis among children in Sub-Saharan Africa. This study aimed to determine the prevalence and the common clinical presentations of rotavirus A infection among Sudanese children with gastroenteritis seeking management in hospitals.

Methods

755 Sudanese children less than 5 years of age suffering from acute gastroenteritis in hospital settings were included. The positive stool specimens for rotavirus A was used for extract Ribonucleic acid (RNA) and the RNA product was loaded on formaldehyde agarose gel and visualized under UV illumination.

Results

Of the 755 children, 430(57%) were males while 325(43%) were female. The age of children ranged from 1 to 60 months. There were 631 (84%) children who were less than 24 months of age. Out of the 755 stool samples, 121(16%) were positive for rotavirus. Of the 121 infected children with rotavirus, 79(65.3%) were male and 42(34.7%) were female and the highest infection rate was seen among 91(75.2%) of children up to 12 months of age. Children of illiterate parents were more infected with rotavirus than children of educated parents. Severe dehydration present among 70% of infected children with rotavirus.

Conclusion

Since this study is hospital-based, the 16% prevalence rate may not reflect the true prevalence among Sudanese children, thus a community-based surveillance is needed.

Rotavirus vaccines: successes and challenges

Since 2006, the availability of two new rotavirus vaccines has raised enthusiasm to consider the eventual control and elimination of severe rotavirus diarrhea through the global use of vaccines. Rotavirus remains the most severe cause of acute diarrhea in children worldwide responsible for several hundred thousands of deaths in low income countries and up to half of hospital admissions for diarrhea around the world. The new vaccines have been recommended by WHO for all infants and in more than 47 countries, their introduction into routine childhood immunization programs has led to a remarkable decline in hospital admissions and even deaths within 3 years of introduction. Challenges remain with issues of vaccine finance globally and the problem that these live oral vaccines perform less well in low income settings where they are needed most. Ongoing research that will accompany vaccine introduction might help address these issues of efficacy and new vaccines and novel financing schemes may both help make these vaccines universally available and affordable in the decade.

Characterising the aetiology of severe acute gastroenteritis among patients visiting a hospital in Qatar using real-time polymerase chain reaction

Background

Acute gastroenteritis (AGE) remains a common cause of clinic visits and hospitalizations, though its aetiology has not been determined in Qatar.

Methods

We performed a prospective, emergency department–based study of 288 children and adults with AGE. Stool specimens were collected at presentation from June to November 2009. Faecal specimens were tested, using real-time PCR, for a panel of four viral (norovirus, adenovirus, astrovirus and rotavirus) and bacterial pathogens.

Results

Viral and bacterial pathogens were detected in 131 (45.5%) and 34 (12.2%) of the 288 patients recruited. The most commonly detected pathogens were norovirus (28.5%), rotavirus (10.4%), followed by adenovirus (6.25%) and astrovirus (0.30%). Norovirus was the most commonly detected viral pathogen amongst all the age groups with an almost even distribution in all age groups. Rotavirus and adenovirus were more common in children under 5 yr of age. Astrovirus was found in only one person.

Conclusions

Viruses, especially noroviruses, are associated with severe diarrhoea in children and adults in Qatar. Further studies to confirm the findings and to explore the causes of illness among patients from whom a pathogen cannot be determined are needed.

Estimates of the burden of foodborne illness in Canada for 30 specified pathogens and unspecified agents, circa 2006

Estimates of foodborne illness are important for setting food safety priorities and making public health policies. The objective of this analysis is to estimate domestically acquired, foodborne illness in Canada, while identifying data gaps and areas for further research. Estimates of illness due to 30 pathogens and unspecified agents were based on data from the 2000-2010 time period from Canadian surveillance systems, relevant international literature, and the Canadian census population for 2006. The modeling approach required accounting for under-reporting and underdiagnosis and to estimate the proportion of illness domestically acquired and through foodborne transmission. To account for uncertainty, Monte Carlo simulations were performed to generate a mean estimate and 90% credible interval. It is estimated that each year there are 1.6 million (1.2-2.0 million) and 2.4 million (1.8-3.0 million) episodes of domestically acquired foodborne illness related to 30 known pathogens and unspecified agents, respectively, for a total estimate of 4.0 million (3.1-5.0 million) episodes of domestically acquired foodborne illness in Canada. Norovirus, Clostridium perfringens, Campylobacter spp., and nontyphoidal Salmonella spp. are the leading pathogens and account for approximately 90% of the pathogen-specific total. Approximately one in eight Canadians experience an episode of domestically acquired foodborne illness each year in Canada. These estimates cannot be compared with prior crude estimates in Canada to assess illness trends as different methodologies were used.

Indirect protection of adults from rotavirus by pediatric rotavirus vaccination

BACKGROUND

Pediatric vaccination has resulted in declines in disease in unvaccinated individuals through decreasing pathogen circulation in the community. About 2 years after implementation of pediatric rotavirus vaccination in the United States, dramatic declines in rotavirus disease were observed in both vaccinated and unvaccinated children. Whether this protection extends to adults is unknown.

METHODS

The prevalence of rotavirus, as determined by Rotaclone enzyme immunoassay, in adults who had stools submitted for bacterial stool culture (BSC) between February to May to Northwestern Memorial Hospital, Chicago, was compared between the prepediatric impact era (2006-2007) and the pediatric impact era (2008-2010). Isolates were genotyped and clinical characteristics of those with rotavirus were compared.

RESULTS

Of the 5788 BSC sent, 4725 met inclusion criteria and 3530 of these (74.7%) were saved for rotavirus testing. The prevalence of rotavirus among adults who had stool sent for BSC declined from 4.35% in 2006-2007 to 2.24% in 2008-2010 (a relative decline of 48.4%; P = .0007). The decline in the prevalence of rotavirus was of similar significant magnitude in both outpatients and inpatients. Marked year-to-year variability was observed in circulating rotavirus genotypes, with strain G2P[4] accounting for 24%; G1P[8], 22%; G3P[8], 11%; and G12P[6], 10% overall. About 30% of adults from whom rotavirus was isolated were immunocompromised and this remained constant.

CONCLUSIONS

Pediatric rotavirus vaccination correlated with a relative decline of almost 50% in rotavirus identified from adult BSC during the peak rotavirus season, suggesting that pediatric rotavirus vaccination protects adults from rotavirus.

The importance of intergenic recombination in norovirus GII.3 evolution

Norovirus genotype II.3 (GII.3) strains are a major cause of sporadic gastroenteritis. Intergenic recombination between the capsid and RNA-dependent RNA polymerase (RdRp) genes is common and results in the acquisition of an alternative RdRp genotype. This study aimed to explore the evolution of the GII.3 capsid gene, focusing on the influence of intergenic recombination. The capsid genes from six GII.3 norovirus strains, collected from Australian children between 2001 and 2010, were sequenced and aligned with 66 GII.3 capsid sequences from GenBank, spanning 1975 to 2010. The GII.3 capsid gene evolved at a rate of 4.16 × 10(-3) to 6.97 × 10(-3) nucleotide substitutions/site/year from 1975 to 2010 and clustered into five temporally sequential lineages. Clustering of the GII.3 capsid gene sequences was associated with intergenic recombination and switches between RdRp genotypes GII.3, GII.a, GII.b, GII.12, and an undefined ancestral RdRp. Comparison of the substitution rate of the GII.3 and GII.b RdRps suggested that RdRp switching allows a higher evolutionary rate, leading to increased genetic diversity and adaptability. Alignment of GII.3 capsid sequences revealed 36 lineage-specific conserved amino acid substitutions, four of which were under positive selection. Many conserved substitutions were within predicted antibody binding regions and close to host attachment factor binding sites. In conclusion, evolution of GII.3 noroviruses was primarily driven by intergenic recombination. The acquisition of new RdRps may lead to a faster mutation rate and increased genetic diversity, improving overall GII.3 fitness.

Burden of norovirus gastroenteritis in the ambulatory setting--United States, 2001-2009

BACKGROUND

Gastroenteritis remains an important cause of morbidity in the United States. The burden of norovirus gastroenteritis in ambulatory US patients is not well understood.

METHODS

Cause-specified and cause-unspecified gastroenteritis emergency department (ED) and outpatient visits during July 2001-June 2009 were extracted from MarketScan insurance claim databases. By using cause-specified encounters, time-series regression models were fitted to predict the number of unspecified gastroenteritis visits due to specific pathogens other than norovirus. Model residuals were used to estimate norovirus visits. MarketScan rates were extrapolated to the US population to estimate national ambulatory visits.

RESULTS

During 2001-2009, the estimated annual mean rates of norovirus-associated ED and outpatient visits were 14 and 57 cases per 10 000 persons, respectively, across all ages. Rates for ages 0-4, 5-17, 18-64, and ≥65 years were 38, 10, 12, and 15 ED visits per 10 000 persons, respectively, and 233, 85, 35, and 54 outpatient visits per 10 000 persons, respectively. Norovirus was estimated to cause 13% of all gastroenteritis-associated ambulatory visits, with ~50% of such visits occurring during November-February. Nationally, norovirus contributed to approximately 400 000 ED visits and 1.7 million office visits annually, resulting in $284 million in healthcare charges.

CONCLUSIONS

Norovirus is a substantial cause of gastroenteritis in the ambulatory setting.

Burden of disease from cryptosporidiosis

PURPOSE OF REVIEW

The global significance of cryptosporidiosis is widespread and far-reaching. In this review, we present recent data about strain diversity and the burden of disease, along with developments in therapeutic and preventive strategies.

RECENT FINDINGS

Cryptosporidium is an emerging pathogen that disproportionately affects children in developing countries and immunocompromised individuals. Without a diagnostic tool amenable for use in developing countries, the burden of infection and its relationship to growth faltering, malnutrition, and diarrheal mortality remain underappreciated. Disease incidence is also increasing in industrialized countries largely as a result of outbreaks in recreational water facilities. Advances in molecular methods, including subtyping analysis, have yielded new insights into the epidemiology of cryptosporidiosis. However, without practical point-of-care diagnostics, an effective treatment for immunocompromised patients, and a promising vaccine candidate, the ability to reduce the burden of disease in the near future is limited. This is compounded by inadequate coverage with antiretroviral therapy in developing countries, the only current means of managing HIV-infected patients with cryptosporidiosis.

SUMMARY

Cryptosporidiosis is one of the most important diarrheal pathogens affecting people worldwide. Effective methods to control and treat cryptosporidiosis among high-risk groups present an ongoing problem in need of attention.