An outbreak of acute gastroenteritis in a geriatric long-term-care facility: combined application of epidemiological and molecular diagnostic methods

Associations of infection control measures and norovirus outbreak outcomes in healthcare settings: a systematic review and meta-analysis

BACKGROUND

Although most norovirus outbreaks in high-income countries occur in healthcare facilities, information on associations between control measures and outbreak outcomes in these settings is lacking.

METHODS

We conducted a systematic review/meta-analysis to assess associations between norovirus outbreak control measures and outcomes in hospitals and long-term care facilities (LTCFs), globally. Using regression analyses stratified by setting (hospital/LTCF), we compared durations, attack rates, and case counts for outbreaks in which control measures were reportedly implemented to those in which they were not.

RESULTS

We identified 102 papers describing 162 norovirus outbreaks. Control measures were reportedly implemented in 118 (73%) outbreaks and were associated with 0.6 (95% CI: 0.3-1.1) times smaller patient case counts and 0.7 (95% CI: 0.4, 1.0) times shorter durations in hospitals but 1.5 (95% CI: 1.1-2.2), 1.5 (95% CI: 1.0-2.1) and 1.6 (95% CI: 1.0-2.6) times larger overall, resident and staff case counts, respectively, and 1.4 (95% CI: 1.0-2.0) times longer durations in LTCFs.

CONCLUSIONS

Reported implementation of control measures was associated with smaller/shorter outbreaks in hospitals but larger/longer outbreaks in LTCFs. Control measures were likely implemented in response to larger/longer outbreaks in LTCFs, rather than causing them. Prospective observational or intervention studies are needed to determine effectiveness.

Prospective cohort study to investigate the burden and transmission of acute gastroenteritis in care homes: epidemiological results

OBJECTIVES

To estimate the incidence of gastroenteritis in individuals in care homes.

DESIGN

Prospective cohort study.

SETTING

Five participating care homes in North West England, UK.

PARTICIPANTS

Residents and staff present at the five study care homes between 15 August 2017 and 30 May 2019 (n=268).

OUTCOME MEASURES

We calculated incidence rates for all gastroenteritis cases per 1000 person-years at risk and per 1000 bed-days at risk. We also calculated the incidence rate of gastroenteritis outbreaks per 100 care homes per year.

RESULTS

In total 45 cases were reported during the surveillance period, equating to 133.7 cases per 1000 person-years at risk. In residents the incidence rate was 0.62 cases per 1000 bed-days. We observed seven outbreaks in all care homes included in surveillance, a rate of 76.4 outbreaks per 100 care homes per year. 15 stool samples were tested; three were positive for norovirus, no other pathogens were detected.

CONCLUSIONS

We found that surveillance of infectious gastroenteritis disease in care homes based on outbreaks, the current general approach, detected a majority of cases of gastroenteritis. However, if policymakers are to estimate the burden of infectious gastroenteritis in this setting using only routine outbreak surveillance data and not accounting for non-outbreak cases, this study implies that the total burden will be underestimated.

Sickness presenteeism among health care providers in an academic tertiary care center in Riyadh

The term sickness presenteeism (SP) has been described as the act of going to work despite having a state of health that may be regarded as poor enough to justify sick leave. SP has been observed to be prevalent among three-quarters of health care providers (HCPs). Working while sick not only puts patients at risk but also decreases productivity and increases the probability of medical errors. Moreover, SP has been identified as a risk factor for many negative health outcomes among the HCPs themselves, such as depression, burnout, and serious cardiac events. The aim of this study was to identify the reasons for and prevalence of SP and perceptions of the impact of this practice on patient safety among HCPs. A cross-sectional study was conducted, including 279 purposively selected healthcare professionals (doctors, nurses, dentists, pharmacists and other health care professionals) working at the Ministry of National Guard Health Affairs-King Abdulaziz Medical City (MNGHA-KAMC). While nearly all of the participants (91%) believed that working while sick exposed patients to risk, the rate of SP during the past year was reported as 74%, and one fourth of respondents reported working while sick 3-4 times during the past year. More than half of the participants were not aware of the existence of a departmental policy regarding sick leave. The most common reasons reported for working while sick were not wanting to burden co-workers (71%), feelings of duty toward patients (67%), and avoiding an increased future workload caused by absence (59%). A lack of awareness regarding the existing rules and polices related to sick leave was reported by more than half of the participants. Several predisposing and enabling factors were reported as determinants influencing SP, e.g., observation of the practice of SP by peers and feelings of sympathy towards coworkers, including not wanting to overburden them, were reported to be determinants informing the decision of whether to work while sick.

Feasibility of viral dust infection via air movement and dispersion of dried viral particles from the floor

The contributions of splash from vomiting and the dispersion of dried-up virus from a contaminated floor surface to community gastroenteritis outbreaks caused by Norovirus (NoV) were evaluated, using Feline calicivirus (FCV) as an NoV surrogate. There was no difference in the size distribution of FCV-containing particles around 0.75 µm) collected from a virus-sprayed chamber 1 and 12 hr after nebulization. FCV clearly dispersed after hitting a floor surface contaminated with dried virus. These results suggest that NoV can likely form airborne droplet nuclei, and dust may be the main route of infection transmission. J. Med. Virol. 89:931-935, 2017. © 2016 Wiley Periodicals, Inc.

Evaluation of the Impact of the Source (Patient Versus Staff) on Nosocomial Norovirus Outbreak Severity

Objective:

To study the dependence of infection risk and outbreak size on the type of index case (ie, patient or staff).

Methods:

Nosocomial outbreaks were reviewed and categorized into those started by patients and those started by staff. Infection risks and outbreak sizes were evaluated taking into account the index case category.

Results:

Of the 30 nosocomial outbreaks of norovirus with person-to-person transmission, 20 (67%) involved patients as the index cases. Patient-indexed outbreaks affected significantly more patients than did staff-indexed outbreaks (difference in means, 16.25; 95% confidence interval [CI95], 5.1 to 27.0). For the numbers of affected staff, no dependence on the index case category was detectable (difference in means, -1.05; CI95, -9.0 to 6.9). For patients exposed during patient-indexed outbreaks, the risk of acquiring a norovirus infection was approximately 4.8 times as high as the corresponding risk for patients exposed during staff-indexed outbreaks (odds ratio [OR], 4.79; CI95,1.82 to 8.28). The infection risk for exposed staff during patient-indexed outbreaks was approximately 1.5 times as high as the corresponding risk during staff-indexed outbreaks (OR, 1.51; CI95, 0.92 to 2.49).

Conclusions:

Patient-indexed norovirus outbreaks generally affect more patients than do staff-indexed outbreaks. Staff appear to be similarly affected by both outbreak index category groups. This study demonstrates the importance of obtaining complete outbreak data, including the index case classification as staff or patient, during norovirus outbreak investigations. Such information may be useful for further targeting prevention measures.

Prevention and control practices for human noroviruses in long-term care facilities in South Carolina

BACKGROUND

Long-term care facilities (LTCFs) are the most common setting for human norovirus (HuNoV) outbreak. Our study aimed to determine gaps in prevention and control practices for HuNoV in LTCFs in South Carolina (SC).

METHODS

Two researchers visited a convenience sample of 26 LTCFs in SC during July-November 2013. Directors were interviewed to determine facility prevention and control practices. Relative frequencies and means were calculated using SAS 9.3 (SAS Institute, Cary, NC).

RESULTS

Most directors had little knowledge of proper sanitizing and disinfecting products and reported missing written procedures for cleaning staff-visitor bathrooms. Only 18 had recommendations for when residents should wash hands. Many used the wrong products for pathogen removal after vomit-fecal events, had no written procedures for cleaning contaminated soft surfaces, did not remove other individuals during clean-up of vomit-fecal episodes, and did not clean a large area surrounding vomit-fecal episodes. Eighteen did not assign specific staff to care for sick; 16 did not designate specific toilets for sick; and 15 did not restrict visitors during an outbreak.

CONCLUSION

Directors' responses indicated gaps in prevention and control practices for HuNoV in LTCFs in SC.

A decade of norovirus disease risk among older adults in upper-middle and high income countries: a systematic review

BACKGROUND

Noroviruses (NoVs) are the most common cause of acute gastroenteritis (AGE) causing both sporadic and outbreak-associated illness. Norovirus (NoV) infections occur across all ages but certain sub-groups are considered at increased risk due to heightened transmission and/or symptom severity. Older adults are potentially at high risk of NoV-associated illness due to frequent outbreaks in long-term care facilities (LTCFs) and severe health outcomes following infection. Elucidation of NoV risk among older adults will support prevention, treatment and control efforts.

METHODS

We conducted a systematic literature review to summarize the published risk estimates of NoV-associated illness, hospitalization and death among individuals aged 65 years and older. A structured search using defined NoV and gastroenteritis (GE) terms was performed in the PubMed and EMBASE databases of human studies published between January 1, 2003 and May 16, 2013.

RESULTS

We identified 39 studies from high income (HI) and upper-middle income (UMI) countries. Thirty-six percent of publications provided risk estimates based on laboratory-confirmed or epidemiologically-linked population-based surveillance data using molecular diagnostic methods. Over the study period, estimated annual NoV rates and extrapolated number of cases among older adults in HI and UMI countries were: 29-120/10,000 or 1.2-4.8 million NoV-associated illnesses; 18-54/10,000 or 723,000-2.2 million NoV-associated outpatient visits; 1-19/10,000 or 40,00-763,000 NoV-associated inpatient visits; 0.04-0.32/10,000 or 2000-13,000 NoV-associated deaths. NoV was responsible for approximately 10-20 % of GE hospitalizations and 10-15 % of all-cause GE deaths among older adults. Older adults experienced a heightened risk of nosocomial infections. Those in LTCFs experience frequent NoV outbreaks and the range in attack rates was 3-45 %, case hospitalization rates 0.5-6 % and case fatality rates 0.3-1.6 %.

CONCLUSIONS

Older adults are at increased risk of severe NoV-associated health outcomes. NoV-associated hospitalization rates were higher, more severe, resulted in longer stays and incurred greater costs than for younger patients. NoV-associated mortality rates were approximately 200 % higher among individuals 65 years and older compared to <5 years. The burden of NoV among older adults is expected to rise along with societal aging and increased need for institutionalized care. NoV prevention in older adults, including potential vaccination, may significantly impact risk of severe illness.

Impact of hand hygiene on the infectious risk in nursing home residents: A systematic review

BACKGROUND

In nursing homes, the infectious risk is high, making infection control using approaches such as hand hygiene (HH) a major issue. However, the effectiveness of HH in these settings is not well documented, and HH compliance is low.

METHODS

We systematically searched PubMed, Scopus, Web of Science, and Cochrane Clinical Trials for studies in nursing homes that either described a HH-related intervention or assessed HH compliance and included a measured infectious outcome. Two reviewers independently performed the study selection.

RESULTS

Fifty-six studies met the inclusion criteria and were reviewed. Most were outbreak reports (39%), followed by observational studies (23%), controlled trials (23%), and before-after intervention studies (14%). Thirty-five studies (63%) reported results in favor of HH on at least one of their outcome measures; in addition, the infection control success rate was higher when at least one HH-related intervention (eg, staff education on HH, increased availability of handrub solution) was included (70% vs 30% for no intervention). However, only 25% of randomized trials concluded that HH-related interventions led to a reduction in the infectious risk.

CONCLUSION

The results of this systematic review suggest that more evidence on HH effectiveness in nursing homes is needed. Future interventional studies should enhance methodologic rigor using clearly defined outcome measures, standardized reporting of findings, and a relevant HH observation tool.

Prevention of Nosocomial Transmission of Norovirus by Strategic Infection Control Measures

Background.

Nosocomial outbreaks of norovirus infection pose a great challenge to the infection control team.

Methods.

Between November 1, 2009, and February 28, 2010, strategic infection control measures were implemented in a hospital network. In addition to timely staff education and promotion of directly observed hand hygiene, reverse-transcription polymerase chain reaction for norovirus was performed as an added test by the microbiology laboratory for all fecal specimens irrespective of the request for testing. Laboratory-confirmed cases were followed up by the infection control team for timely intervention. The incidence of hospital-acquired norovirus infection per 1,000 potentially infectious patient-days was compared with the corresponding period in the preceding 12 months, and the incidence in the other 6 hospital networks in Hong Kong was chosen as the concurrent control. Phylogenetic analysis of norovirus isolates was performed.

Results.

Of the 988 patients who were tested, 242 (25%) were positive for norovirus; 114 (47%) of those 242 patients had norovirus detected by our added test. Compared with the corresponding period in the preceding 12 months, the incidence of hospital-acquired norovirus infection decreased from 131 to 16 cases per 1,000 potentially infectious patient-days (P < .001 ), although the number of hospital-acquired infections was low in both the study period (n = 8) and the historical control periods (n = 11). The incidence of hospital-acquired norovirus infection in our hospital network (0.03 cases per 1,000 patient-days) was significantly lower than that of the concurrent control (0.06 cases per 1,000 patient-days) (P = .015). Forty-three (93%) of 46 norovirus isolates sequenced belonged to the genogroup II.4 variant.

Conclusions.

Strategic infection control measures with an added test maybe useful in controlling nosocomial transmission of norovirus.

Spatial and temporal analyses to investigate infectious disease transmission within healthcare settings

Background

Healthcare-associated infections (HCAIs) cause significant morbidity and mortality worldwide, and outbreaks are often only identified after they reach high levels. A wide range of data is collected within healthcare settings; however, the extent to which this information is used to understand HCAI dynamics has not been quantified.

Aim

To examine the use of spatiotemporal analyses to identify and prevent HCAI transmission in healthcare settings, and to provide recommendations for expanding the use of these techniques.

Methods

A systematic review of the literature was undertaken, focusing on spatiotemporal examination of infectious diseases in healthcare settings. Abstracts and full-text articles were reviewed independently by two authors to determine inclusion.

Findings

In total, 146 studies met the inclusion criteria. There was considerable variation in the use of data, with surprisingly few studies (N = 22) using spatiotemporal-specific analyses to extend knowledge of HCAI transmission dynamics. The remaining 124 studies were descriptive. A modest increase in the application of statistical analyses has occurred in recent years.

Conclusion

The incorporation of spatiotemporal analysis has been limited in healthcare settings, with only 15% of studies including any such analysis. Analytical studies provided greater data on transmission dynamics and effective control interventions than studies without spatiotemporal analyses. This indicates the need for greater integration of spatiotemporal techniques into HCAI investigations, as even simple analyses provide significant improvements in the understanding of prevention over simple descriptive summaries.

Presenteeism: a public health hazard

"Presenteeism" occurs when an employee goes to work despite a medical illness that will prevent him or her from fully functioning at work. This problem has been well studied in the business and social science literature, and carries increased importance in the health care setting due to the risk of infectious disease transmission in vulnerable patient populations. In this manuscript, we discuss an outbreak of viral gastroenteritis in a long-term care facility and the role presenteeism played in disease transmission and extension of the outbreak. We use existing literature to point out the hazards of presenteeism in the health care sector. We will also discuss factors that may be involved in the decision to work while ill and propose policy changes that may reduce the incidence of presenteeism in health care organizations.

Norovirus outbreaks in nursing homes: the evaluation of infection control measures

Effective infection control measures during norovirus outbreaks are urgently needed in places where vulnerable individuals gather. In the present study, the effect of a number of measures was investigated in daily practice. Forty-nine Dutch nursing homes were monitored prospectively for norovirus outbreaks during two winter seasons. A total of 37 norovirus outbreaks were registered. Control measures were most effective when implemented within 3 days after onset of disease of the first patient. Measures targeted at reduced transmission between persons, via aerosols, and via contaminated surfaces reduced illness in staff and in residents. Reducing illness in staff results in fewer costs for sick leave and substitution of staff and less disruption in the care of residents. The effect of control measures on outbreak duration was limited. This is the first intervention study examining the effect of control measures. Further research is needed to extend and refine the conclusions.

Application of the updated CDC isolation guidelines for health care facilities

The Centers for Disease Control and Prevention has published updated guidelines for isolation precautions that outline how health care workers can prevent the transmission of infectious agents to their patients and to themselves. The guidelines re-emphasize standard precautions, which guide clinicians in the use of appropriate personal protective equipment (PPE), depending on the expected type of exposure. Respiratory hygiene/cough etiquette is incorporated into infection control practices as a new component of standard precautions. The article provides information on the new guidelines as well as information on newly emerging pathogens and methods to prevent disease transmission in health care settings.

Transmission events within outbreaks of gastroenteritis determined through analysis of nucleotide sequences of the P2 domain of genogroup II noroviruses

Tracking the spread of noroviruses during outbreaks of gastroenteritis is hampered by the lack of sequence diversity in those regions of the genome chosen for virus detection and characterization. Sequence analysis of regions of the genes encoding the RNA-dependent RNA polymerase and the S domain of the capsid does not provide sufficient discrimination between genotypically related strains of different outbreaks. However, analysis of sequences derived from the region encoding the P2 domain showed 100% similarity among strains from the same outbreak and <100% similarity among strains of different outbreaks. The prolonged nature of some hospital outbreaks, links between hospitals, and the introduction of multiple strains of a single genotype associated with an outbreak aboard a cruise ship were determined using this method. This provides a powerful tool for tracking outbreak strains and the subsequent analysis and validation of interventions in a background of multiple introductions of virus strains of the same genotype or genetic cluster.

Characterization of a cross-reactive linear epitope in human genogroup I and bovine genogroup III norovirus capsid proteins

The Southampton norovirus (SV) capsid protein was expressed as VLPs by recombinant baculoviruses in insect cells and was used to immunize mice for the production of monoclonal antibodies (mAbs). One mAb, CM54, showed broad cross-reactivity to genogroup I (GI) noroviruses, but was not reactive to GII capsid proteins. Interestingly mAb CM54 reacted to a bovine norovirus capsid protein. Immunoblot analysis indicated the binding site for CM54 was located in the shell domain between amino acid residues 102-225 of the SV capsid protein. The epitope was mapped to high resolution using a peptide array and was located to the sequence LEDVRN at amino acid residues 162-167. Alignment of norovirus capsid protein sequences confirmed the epitope sequence was common to particular groups of human and bovine noroviruses. Modeling of the epitope onto the recombinant NV capsid protein revealed it was located to the inner surface of the shell domain.

A norovirus outbreak at a long-term-care facility: the role of environmental surface contamination

BACKGROUND

The role of environmental surface contamination in the propagation of norovirus outbreaks is unclear. An outbreak of acute gastroenteritis was reported among residents of a 240-bed veterans long-term-care facility.

OBJECTIVES

To identify the likely mode of transmission, to characterize risk factors for illness, and to evaluate for environmental contamination in this norovirus outbreak.

METHODS

An outbreak investigation was conducted to identify risk factors for illness among residents and employees. Stool and vomitus samples were tested for norovirus by reverse transcription polymerase chain reaction (RT-PCR). Fourteen days after outbreak detection, ongoing cases among the residents prompted environmental surface testing for norovirus by RT-PCR.

RESULTS

One hundred twenty-seven (52%) of 246 residents and 84 (46%) of 181 surveyed employees had gastroenteritis. Case-residents did not differ from non-case-residents by comorbidities, diet, room type, or level of mobility. Index cases were among the nursing staff. Eight of 11 resident stool or vomitus samples tested positive for genogroup II norovirus. The all-cause mortality rate during the month of the outbreak peak was significantly higher than the expected rate. Environmental surface swabs from case-resident rooms, a dining room table, and an elevator button used only by employees were positive for norovirus. Environmental and clinical norovirus sequences were identical.

CONCLUSION

Extensive contamination of environmental surfaces may play a role in prolonged norovirus outbreaks and should be addressed in control interventions.

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.

Human caliciviruses in Europe

Caliciviruses are single-stranded RNA viruses, which are divided into four genera based on their morphology and genomic structure. Viruses from two genera, the Norwalk like viruses and Sapporo like viruses, are a common cause of acute, nonbacterial gastroenteritis in humans. Although the first human calicivirus discovered nearly 30 years ago, much of the epidemiological and biological character of these viruses is only now beginning to unfold. Investigation has been difficult due to a number of factors, the viruses cannot be amplified by in vitro cell culture or animal models and electron microscopy (EM) is often not sensitive enough to detect the viruses in stool samples. Recent advances in molecular diagnostic techniques and the advent of a baculovirus expression system have highlighted the clinical and public health importance of calicivirus in all age groups, their ability to cause infection via a number of transmission routes as well as their considerable genetic diversity. These characteristics, in conjunction with the inability of humans to develop long-term immunity make HuCV an important public health issue in Europe and worldwide.

A predominant role for Norwalk-like viruses as agents of epidemic gastroenteritis in Maryland nursing homes for the elderly

Stool specimens from 156 Maryland nursing home residents, who became ill during 20 outbreaks of gastroenteritis from November 1987 through February 1988, were analyzed. All tested negative for astroviruses, enteroviruses, Group A rotaviruses, Sapporo-like caliciviruses, and enteric bacteria (i.e., Salmonella, Clostridium, and Shigella species). Eighty-two (52%) were positive for Norwalk-like viruses (NLVs), members of the family Caliciviridae. Six distinct genetic clusters within genogroups I and II of the NLVs were detected; a genogroup II (GII) virus closely related to the Camberwell virus in the NLV GII/4 genetic cluster was the predominant strain. Serologic evidence of infection with > or = 1 NLV was detected in 61 (56%) of 109 patients tested against 3 NLV antigens (i.e., Norwalk, Hawaii, and Toronto viruses). Sixteen (80%) outbreaks met the definition for an NLV outbreak. Taken together with a retrospective analysis of bacterial gastroenteritis in this same setting, these data support a major role for NLVs as etiologic agents of gastroenteritis in elderly persons.

Molecular detection and sequencing of "Norwalk-like viruses" in outbreaks and sporadic cases of gastroenteritis in Ireland

Norwalk-like viruses (NLVs) are now established as the most important causative agents of epidemic gastroenteritis worldwide. The overall objective of this study was to determine the molecular epidemiology of Irish NLV isolates for the first time by obtaining sequence data from specimens originating from outbreaks and sporadic cases of gastroenteritis. Eight samples from sporadic cases of gastroenteritis and nine isolates from separate NLV outbreaks were examined. Of the sporadic isolates, six were shown to be genogroup 2 (G2) by RT-PCR, while two were G1. All of the outbreak isolates were G2. All isolates were partially sequenced within a highly conserved region of ORF1 (RNA-dependent RNA polymerase gene). Sequence data were aligned and a dendogram was constructed. The results indicated that the majority of G2 isolates were seen to cluster with Bristol and Lordsdale virus, while the two G1 specimens were related most closely to Southampton virus. Further downstream sequence analysis of a number of the isolates confirmed this result. It is concluded that the majority of NLV isolates circulating in Ireland belong to the Bristol/Lordsdale clade.

Clinical spectrum and transmission characteristics of infection with Norwalk-like virus: findings from a large community outbreak in Sweden

A large foodborne outbreak caused by Norwalk-like virus (NLV) among children and staff at 30 day care centers provided an opportunity to study symptomatology and attack rates among patients in different age groups, as well as secondary transmission rates in centers and households. A retrospective cohort study of 775 subjects from 13 randomly chosen centers was performed. Diarrhea was more common in adults than in children (P=.001), whereas the reverse was noted with regard to vomiting (P=.003). The primary attack rate was 27% (142 of 524 subjects): 54% of adults versus 19% of children (P<.001). The mean incubation time for foodborne cases of infection was 34 hours. The secondary attack rate was 17%. Risk factors for spread into households were the primary case being a child (relative risk [RR], 3.8; 95% confidence interval [CI], 1.9-7.6) and vomiting (RR, 2.4; 95% CI, 1.0-5.5). The incubation time for person-to-person transmission was approximated by a mean serial interval of 52 hours. This is the first reported outbreak of NLV infection in which secondary transmission into households by individuals has been studied.

Viral causes of diarrhea

Viruses are important causes of diarrhea. In healthy adults, the main clinical manifestation is acute, self-limited gastroenteritis. Advances in molecular diagnostics have shown that epidemics of acute gastroenteritis most frequently are due to caliciviruses spread through contaminated food or through person-to-person contact. Application of similar technology is needed to make a definitive statement about the role of such candidate viruses as rotavirus, astrovirus, and adenovirus as the cause of nonepidemic acute gastroenteritis in adults. Rarely a previously healthy adult gets acute CMV colitis. CMV and EBV mainly cause diarrhea in immunocompromised patients, however. Advances in prophylaxis and treatment have reduced the frequency and severity of these diseases. Acute infantile gastroenteritis is caused by rotavirus, calcivirus, astrovirus, and adenovirus. These viral diseases of the gut are seen by the physician as routine and rare clinical problems.

Hospital-acquired infections in Norwegian long-term-care institutions. A three-year survey of hospital-acquired infections and antibiotic treatment in nursing/residential homes, including 4500 residents in Oslo

Point prevalence studies of hospital-acquired infections among the elderly in 65-70 long-term care facilities (LTCF) were carried out once a year over a three-year period in Oslo city, Norway. They showed an overall rate of 6.5% of hospital-acquired infections among 13 762 residents. The infection rate was approximately the same as in hospitals and twice as high as among hospitalized long-term psychiatric patients. Residents who had received surgical treatment within the previous three months had a high rate of postoperative infections, especially wound infections (14.8%). During the study period, the LTCFs were found to be understaffed and overcrowded. They had few private rooms, a lack of bathrooms and toilets, no isolation facilities and deficient ventilation systems. The economic consequences of hospital-acquired infections in these LTCFs were extra costs in medical and nursing care and antibacterial treatment of 157 500 Nkr/day (22500 USD). There would be a substantial cost-benefit in effective preventive measures against hospital-acquired infections in long-term care institutions.