Outbreaks of acute gastroenteritis associated with Norwalk-like viruses in campus settings

High COVID-19 transmission potential associated with re-opening universities can be mitigated with layered interventions

Controlling COVID-19 transmission in universities poses challenges due to the complex social networks and potential for asymptomatic spread. We developed a stochastic transmission model based on realistic mixing patterns and evaluated alternative mitigation strategies. We predict, for plausible model parameters, that if asymptomatic cases are half as infectious as symptomatic cases, then 15% (98% Prediction Interval: 6-35%) of students could be infected during the first term without additional control measures. First year students are the main drivers of transmission with the highest infection rates, largely due to communal residences. In isolation, reducing face-to-face teaching is the most effective intervention considered, however layering multiple interventions could reduce infection rates by 75%. Fortnightly or more frequent mass testing is required to impact transmission and was not the most effective option considered. Our findings suggest that additional outbreak control measures should be considered for university settings.

Norovirus outbreaks on college and university campuses

Objective: To describe norovirus outbreaks at colleges and universities. Participants: None. Conducted September 2016 to March 2018. Methods: College and university norovirus outbreaks reported to the US National Outbreak Reporting System (NORS, 2009-2016) or published and indexed by EMBASE, PubMed, and Web of Science (1985-2017) were analyzed. Results: Seventy-seven norovirus outbreaks were reported to NORS and 23 were identified in the systematic literature review. Outbreaks occurred more frequently during the beginning of the school year (September-February). NORS outbreaks were more often spread by person-to-person transmission (61%) and, in published outbreaks, by food (57%). The reported exposures of published outbreaks were campus dining (n = 8) and ill food service workers (n = 7). Higher attack rates were associated with smaller on-campus population size, social networks or residences, and specific food exposures. Common control measures were communal area disinfection and health/hygiene education. Conclusions: Recommendations summarized to prevent and control norovirus outbreaks at colleges or universities.

Household transmission of acute gastroenteritis during the winter season in Japan

Objectives

Acute gastroenteritis, including illness caused by norovirus, is sometimes transmissible among susceptible persons who experience close contact, including those within a household, and it disturbs social activities of patients and their family. However, epidemiological assessment of the transmissibility and its heterogeneity has not been conducted. The present study aimed to quantify the frequency of household transmission that was likely caused by norovirus, and characterize its determinants.

Methods

A household survey was conducted, analyzing the history of suspected norovirus infection from January to March, 2017. Noro-like illness was clinically defined as a patient with either: (i) diarrhea or vomiting multiple times a day; or (ii) diarrhea or vomiting persisting for 2 or more days.

Results

Among 380 households, 132 households (34.7%) were eligible for epidemiological analysis, with an estimated secondary attack risk of 13.8% (38/276). Age-specific secondary attack risk was highest among index case patients aged 0 to 14 years (25.8%). The prevalence of vomiting in this age group was higher than in other age groups, with an odds ratio of household transmission estimated at 4.3.

Conclusions

Age-dependent heterogeneity was successfully identified, offering critical insights into future considerations for norovirus control at various social settings.

The unwelcome houseguest: secondary household transmission of norovirus

Norovirus is the leading cause of acute gastroenteritis in the USA. Although secondary household transmission of norovirus is frequently reported in outbreaks, little is known about specific risk factors for susceptibility and infectiousness in the household. Three norovirus outbreaks were investigated and data were collected on individuals exposed in the primary outbreak setting and their household members. Potential individual- and household-level risk factors for susceptibility and infectiousness were assessed using univariate and multivariate generalised linear mixed models. In the univariate models, the secondary attack rate (SAR) was significantly higher when living in a household with two or more primary cases (incidence rate ratio (IRR) = 2·1; 95% confidence interval (CI) 1·37-3·29), more than one primary case with vomiting (IRR = 1·9; CI 1·11-3·37), and at least one primary case with diarrhoea (IRR = 3·0; CI 1·46-6·01). After controlling for other risk factors in the multivariate models, the SAR was significantly higher among those living in a household with two or more primary cases (adjusted IRR = 2·0; CI 1·17-3·47) and at least one primary case with diarrhoea (adjusted IRR = 2·8; CI 1·35-5·93). These findings underscore the importance of maintaining proper hygiene and isolating ill household members to prevent norovirus transmission in the household.

Person-to-person transmission of norovirus resulting in an outbreak of acute gastroenteritis at a summer camp

BACKGROUND

A significant proportion of norovirus (NV) gastroenteritis outbreaks described in the Spanish literature have been because of contaminated food or water.

AIM

This study describes an outbreak of acute gastroenteritis because of NV in which there was person-to-person transmission.

MATERIALS AND METHODS

A retrospective cohort study was carried out; we established the case definition for primary and secondary cases. An epidemiological survey was designed, including possible food exposures, and clinical and laboratory data. Water and stool samples were taken from affected individuals and food handlers. The presence of NV was detected using a reverse transcription-PCR assay. We analyzed the risk of gastroenteritis using relative risk and its 95% confidence interval as the measure of association, and estimated the basic reproductive number (R0).

RESULTS

The primary attack rate was 45.0%, with no significant differences between sexes. The secondary attack rate during the camp stay was 22.7%. The basic reproductive number for 5 days was R0=2.62. The most frequent symptoms were abdominal pain (85.7%) and vomiting (81.9%). Epidemiological analysis showed no association with food or drinking water. A total of 66.6% (8/12) of stool samples tested positive for NV (genogroup II).

CONCLUSION

Control measures in general, and hand hygiene in particular, should be extended to the families once the children return home, to prevent secondary cases in NV outbreaks.

Predicting young adults' intentions to get the H1N1 vaccine: an integrated model

Young adults 19 through 24 years of age were among the populations that had the highest frequency of infection from the 2009 H1N1 pandemic. However, over the 2009-2010 flu season, H1N1 vaccine uptake among college students nationwide was around 8%. To explore the social cognitive factors that influenced their intentions to get the H1N1 vaccine, this study compares the predictive power of the theory of planned behavior (TPB), the health belief model (HBM), and an integrated model. The final model shows that several HBM variables influenced behavioral intentions through the TPB variables. The results suggest that even though the TPB seemed a superior model for behavior prediction, the addition of the HBM variables could inform future theory development by offering health-specific constructs that potentially enhance the predictive validity of TPB variables.

Exploring optimistic bias and the integrative model of behavioral prediction in the context of a campus influenza outbreak

This study aims to determine the utility of constructs from the Integrative Model of Behavioral Prediction in predicting behaviors associated with flu prevention in a college campus. Building on previous studies that document substantial optimistic bias among college students, this study explores possible roles for optimistic bias in the Integrative Model of Behavioral Prediction. The authors conducted an online survey among a stratified random sample (N = 429) of undergraduate students in a university that experienced a large H1N1 influenza outbreak in the fall of 2009. The authors offer 3 major findings: (a) the 3 primary components in the Integrative Model of Behavioral Prediction predicted the intention to perform hand washing and sanitizing, with self-efficacy being the strongest predictor; (b) unrealistic optimists had significantly lower intentions to perform hand hygiene practices compared with realists or unrealistic pessimists; and (c) comparative optimism was a significant moderator of the relation between self-efficacy and behavioral intention, controlling for perceived risk. Theoretical and practical implications of these findings are discussed.

Determinants of personal and household hygiene among college students in New York City, 2011

BACKGROUND

Although several studies have characterized the hygiene habits of college students, few have assessed the determinants underlying such behaviors.

OBJECTIVES

Our study sought to describe students' knowledge, practices, and beliefs about hygiene and determine whether there is an association between reported behaviors and frequency of illness.

METHODS

A sample of 299 undergraduate students completed a questionnaire assessing demographics, personal and household hygiene behaviors, beliefs and knowledge about hygiene, and general health status.

RESULTS

Variation in reported hygiene habits was noted across several demographic factors. Women reported "always" washing their hands after using the toilet (87.1%) more than men (65.3%, P = .001). Similarly, freshmen reported such behavior (80.4%) more than sophomores (71.9%), juniors (67.7%), or seniors (50%, P = .011). Whereas 96.6% of participants thought that handwashing was either "very important" or "somewhat important" for preventing disease, smaller proportions thought it could prevent upper respiratory infections (85.1%) or gastroenteritis (48.3%), specifically. There was no significant relationship between reported behaviors and self-reported health status.

CONCLUSION

The hygiene habits of college students may be motivated by perceptions of socially acceptable behavior rather than scientific knowledge. Interventions targeting the social norms of incoming and continuing students may be effective in improving hygiene determinants and ultimately hygiene practices.

Too scared or too capable? Why do college students stay away from the H1N1 vaccine?

Although college students were among the populations that had the highest frequency of infection for H1N1 influenza, only 8% of them received H1N1 vaccine this past flu season nationwide. During the peak of this pandemic, information about H1N1 vaccine was widely available. However, knowledge test and behavioral data indicated that most college students were not equipped with basic facts about H1N1 and the H1N1 vaccine. To investigate socio-psychological factors that might have deterred this high-risk population from learning about and getting the H1N1 vaccine, this study tested the utility of a risk information seeking model in addressing this health communication problem. Data collected from an online survey of 371 college students showed that respondents seemed to overestimate how much they knew about the vaccine. Risk information seeking, however, positively influenced their intentions to get the vaccine. Results suggested that to communicate effectively to this population, it is important to emphasize the difference between perceived knowledge and actual knowledge, monitor emotional responses to potential risks, and promote getting flu vaccination as a socially desirable behavior.

Examining the effects of thought records and behavioral experiments in instigating belief change

OBJECTIVE

While the efficacy and effectiveness of CBT protocols are well established, much less is known about the comparative contribution of the various techniques within CBT. The present study examined the relative efficacy, in comparison to a control condition, of two central techniques in CBT: thought records (TRs) and behavioral experiments (BEs).

METHOD

A mixed within and between participants design was used to compare the efficacy of a single session TR and a single session BE intervention with a control intervention, in a non-clinical sample. Ninety one participants were randomly allocated to one of the three conditions.

RESULTS

The overall pattern of results suggests that both TR and BE had a beneficial therapeutic impact in comparison to the control condition on beliefs, anxiety, behavior and a standardized measure of symptoms. There was evidence of a small advantage of the BE over the TR intervention in that the target belief changed earlier and change generalized to beliefs about others as well as the self.

CONCLUSIONS

The findings confirm the utility of both TR and BE interventions and point to BEs as more useful in effecting belief change in that the change in the BE condition occurred sooner and generalized further.

Comparison of the Activity of Alcohol-Based Handrubs Against Human Noroviruses Using the Fingerpad Method and Quantitative Real-Time PCR

Noroviruses (NoV) are the most common cause of acute nonbacterial gastroenteritis in the United States, and human hands play an important role in their transmission. Little is known about the efficacy of hand hygiene agents against these highly infectious pathogens. We investigated the activity of seven commercially available hand hygiene products against human noroviruses by in vivo fingerpad tests. The in vivo activity of alcohol-based handrubs ranged from 0.10 to 3.74 log reduction and was not solely dependent on alcohol concentration. A handrub (VF481) based on 70% ethanol and a blend of other skin care ingredients reduced Norwalk virus (NV) by 3.74 log in 15 s and provided significantly greater NV reduction than all the other products tested (P < 0.001). Furthermore, VF481 was the most effective product tested against the NoV genogroup II strains Snow Mountain virus (GII.2) and a GII.4 strain. These results demonstrate that alcohol by itself is not effective against NoV, but effective formulation of alcohol-based handrubs can achieve significant reduction of norovirus RNA on fingers.

Norovirus as a foodborne disease hazard

Norovirus (NoV) is the most common cause of infectious gastroenteritis in the world. Gastroenteritis caused by bacterial and parasitic pathogens is commonly linked to food sources, but the link between NoV and contaminated foods has been more difficult to establish. Even when epidemiological information indicates that an outbreak originated with food, the presence of NoV in the suspect product may not be confirmed. If food is found to contain a common strain of NoV that circulates widely in the community, it is not possible to use strain typing to link the contamination to patient cases. Although food is certainly implicated in NoV spread, there are additional person-to-person and fomite transmission routes that have been shown to be important. NoV has an extremely low infectious dose, is stable in the environment, and resists disinfection. Cell culture methods are not available, so viability cannot be determined. Finally, many NoV outbreaks originate with when an infected food handler contaminates ready-to-eat food, which can be interpreted as foodborne or person-to-person transmission. This review will discuss both the physical characteristics of NoVs and the available epidemiological information with particular reference to the role of foods in NoV transmission.

Model systems for the study of human norovirus Biology

The relative contribution of norovirus to disease burden on society has only recently been established and they are now established as a major cause of gastroenteritis in the developed world. However, despite the medical relevance of these viruses, an efficient in vitro cell culture system for human noroviruses has yet to be developed. As a result, much of our knowledge on the basic mechanisms of norovirus biology has come from studies using other members of the Caliciviridae family of small positive stranded RNA viruses. Here we aim to summarise the recent advances in the field, highlighting how model systems have played a key role in increasing our knowledge of this prevalent pathogen.

Screening for faecal contamination in primary schools in Crete, Greece

BACKGROUND

Hygienic conditions in primary schools are a major concern for both governmental organizations and families. Particularly, the occurrence of faecal indicators on children's hands and various school surfaces has been associated with increased risk of diarrhoeal diseases. The presence of faecal streptococci on environmental surfaces and children's hands and the possible correlation with socio-economic factors were examined.

METHODS

Overall, 1956 samples from hands and 1470 samples from surfaces were collected from 20 primary schools in Heraklion, Crete, Greece.

RESULTS

Faecal streptococci were found at 52.9% of children's hands and at 16.7% of other surfaces. Children, who had parents with the highest education level (>12 years), had the lowest percentage (48.8%) of faecal contamination on their hands. Furthermore, boys exhibited higher levels of hands contamination compared with girls. Among the environmental surfaces examined, the school canteen reception was the most contaminated area.

CONCLUSION

High faecal contamination was detected in primary schools in the examined region. Children's hands were highly infected (52.9%), while boys exhibited higher levels of contamination. The educational level of parents correlated well with the contamination of children's hands.

Gender and ethnic differences in hand hygiene practices among college students

BACKGROUND

Poor hand hygiene on college campuses can be improved by promoting handwashing behavior. This observational study was conducted to evaluate gender and race/ethnic differences in hand hygiene practices among college students.

METHODS

Hand hygiene practices in college students were evaluated in 4 settings (soap and water; soap and water and visual prompts; soap and water and hand sanitizers; and soap and water, hand sanitizers, and visual prompts). The degree of hand hygiene (ie, adequate handwashing time, use of hand sanitizer, and hand-drying method) also was evaluated at various locations on campus.

RESULTS

Overall, 72.9% of students washed their hands, 58.3% practiced hand hygiene (using either soap or hand sanitizer), and 26.1% washed their hands adequately. Hand sanitizer use was low when students were given the option, and paper towel was the most common hand-drying method. In general, hand hygiene practices were better in academic buildings than in the student recreation center. Visual prompts improved handwashing behavior only among students in the "other" ethnic category, but not by gender.

CONCLUSIONS

Handwashing is the most effective way of preventing the spread of infectious diseases, and our findings have implications for the design of effective hand hygiene education programs in college students.

Gastrointestinal infections in the athlete

Gastrointestinal (GI) infections can be troublesome and debilitating to athletes and difficult to manage for sports medicine physicians. A clinician should obtain a comprehensive medical history of the athlete whenever symptoms of the GI tract appear. The predominant chief complaint in GI infections is diarrhea. Athletes may need a comprehensive physical examination to appropriately diagnose the ailment and to determine the need for more aggressive treatment. Multiple laboratory tests exist to aid in diagnosing the infectious pathogen causing gastroenteritis. This article discusses GI infections caused by viral, parasitic, bacterial, and food-borne infectious pathogens. The epidemiology, pathogenesis, history, symptoms, mode of transmission, laboratory detection, treatment, and prevention of these infections are reviewed.

Molecular epidemiology of norovirus gastroenteritis outbreaks in North Carolina, United States: 1995–2000

Noroviruses (NoVs) are the most common cause of acute non-bacterial gastroenteritis outbreaks in the US. We investigated 16 gastroenteritis outbreaks in North Carolina (NC), from 1995 to 2000, to further characterize the epidemiology of NoV using RT-PCR on stool and ELISA on sera. NoV were identified in 14 outbreaks by RT-PCR. Sequence analyses of the amplicons indicated the outbreak strains belonged to the following clusters: five GII/4, three GI/3, one GI/4, one GII/2, one GII/5, one GII/7, and one GII/13 (prototype strain). We detected NoV in stool samples from one outbreak but could not determine its specific cluster within the GII genogroup based on polymerase sequence analysis. The five GII/4 strains were classified as the "95/96 US common strain" and occurred throughout the 5-year period. In contrast to national trends, the majority (86%) of NoV outbreaks identified in North Carolina were foodborne. Of the 12 food-related NoV outbreaks, we were able to document transmission by food handlers in two outbreaks. Person-to-person transmission from primary cases was suggested in three outbreaks. Our results indicate that NoVs are important agents of viral gastroenteritis outbreaks in NC.

Genogroup I and II noroviruses detected in stool samples by real-time reverse transcription-PCR using highly degenerate universal primers

Genogroup I noroviruses from five genetic clusters and genogroup II noroviruses from eight genetic clusters were detected in stool extracts using degenerate primers and single-tube, real-time reverse transcription-PCR (RT-PCR) with SYBR Green detection. Two degenerate primer sets, designated MON 431-433 and MON 432-434, were designed from consensus sequences from the major clusters of norovirus based on the RNA-dependent RNA polymerase region of the norovirus genome. Viruses were extracted from stool samples within 20 min using a viral RNA extraction kit. Real-time RT-PCR for noroviruses generated semiquantitative results by means of the cycle threshold data and dilution endpoint standard curves. Presumptive product verification was achieved by evaluation of first-derivative melt graphs. Multiple clusters of noroviruses were identified simultaneously in a multiplex fashion by virtue of slight differences in melting temperature. The detection of 13 different genetic clusters suggests that the MON primers may serve as universal primers for most, if not all, of the noroviruses in a multiplex assay. Our technique provides a framework for broad application of real-time RT-PCR in clinical, environmental, and food testing laboratories for a wide range of noroviruses.

Handwashing among female college students

Handwashing has been recognized as a critical factor in infection control policies. Whereas handwashing compliance among health care workers and school-aged students has been previously documented, practices among college students remain relatively unknown. The objective of this study was to determine handwashing compliance of female college students after using the bathroom. A researcher situated in a toilet stall unobtrusively observed handwashing compliance among 100 female students. Most students (63%) washed their hands, 38% used soap, 32% washed with soap for 5 or more seconds, but only 2% washed their hands with soap for 10 or more seconds. Fewer students left without handwashing when someone else was present in the sink area (9%) than when they were alone (45%) (P =.002). Substantial bacterial colony counts were found on a female bathroom sink faucet and toilet seat confirming the need for programs to increase handwashing compliance. Potential strategies to optimize infection control include harnessing the influence of peer pressure on handwashing and the installation of motion-activated faucets, disposable seat covers, and exit doors that can be pushed open. These results should be confirmed in a larger study that includes both male and female college students.

Evaluation of the NucliSens Basic Kit assay for detection of Norwalk virus RNA in stool specimens

Norwalk-like viruses (NLVs) are a genetically diverse group of human caliciviruses that are the most common cause of epidemic gastroenteritis and are detected typically in stool by reverse transcription (RT)-PCR or electron microscopy (EM). The application of a rapid nucleic acid sequence-based amplification (NASBA) assay for the detection of NLV RNA in stool is described using the NucliSens Basic Kit. Primers and probes for the NLV Basic Kit assay were based on the RNA polymerase region of the prototype NLV, Norwalk virus (NV) genome and could consistently detect 10(4) RT-PCR detectable units of NV RNA in a stool filtrate. When compared directly with RT-PCR on a dilution series of NV stool filtrate, the NucliSens Basic Kit assay was equally sensitive. Cross-reactivity studies with a representative panel of other enteric pathogens were negative. When applied to 15 stool specimens from NV-challenged volunteers, the NASBA Basic Kit application for NV detection yielded 100% sensitivity, 50% specificity, and 67% concordance, using RT-PCR as the 'gold standard'. Despite the specificity of the NASBA primer/probe sequences for NV, other representatives from both NLV genogroups I and II could be detected by the Basic Kit assay in outbreak stool specimens, although the results were inconsistent. Our results suggest that the NucliSens Basic Kit assay provides a rapid and sensitive alternative to RT-PCR for detecting NV RNA in stool specimens. However, improvements in test specificity and primer design will be needed before the assay can be used routinely in the clinical setting.

Rapid response to a conjunctivitis outbreak: the use of technology to leverage information

When an outbreak of conjunctivitis was identified at a rural New England college early in 2002, the college health center medical staff used various information management and communication systems to alert the community to the situation. They called upon the state Department of Human Services and the Centers for Disease Control and Prevention to help them understand and manage the outbreak. Technological systems already in place at the college allowed for rapid collection of data by means of a survey delivered over the Internet and a carriage study facilitated by a Web-based appointment and communication system. Within days, the data were collected and analyzed and an immediate response to contain the outbreak was launched.