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PubMed2004

[Effect of environment and occupational hygiene factors of hospital infection on SARS outbreak].

OBJECTIVE: To study the effects of weather conditions and occupational hygiene on SARS outbreak. METHOD: (1) Meteorological parameters around SARS outbreaks in 2003 in 9 cities (Guangzhou, Beijing, Tianjin, Taiyuan, Hong Kong, Taipei, Singapore, Toronto and Hanoi) were analyzed; (2) Causes of hospital infection were also analyzed from an occupational hygiene point of view. RESULTS: (1) The amplitude of air temperature, air pressure and diurnal temperature difference were greater around SARS outbreaks in most of the cities. Higher airborne particles concentration and lower wind speed were measured prior to SARS outbreaks in the cities with the most serious epidemic situation. The ten-day mean value of air temperature before SARS outbreaks in 9 cities was 16.6 degrees C +/- 7.6 degrees C, suggesting that coronary virus infection, which has been considered to cause SARS by now, may be most active at 9 degrees C - 24 degrees C. (2) Occupational hygiene in hospital proved to be an important socio-behavior factor for SARS outbreak. All hospital infection could be attributed to defects in the key links of occupational hygiene. CONCLUSIONS: Greater fluctuations of air temperature and higher airborne particles concentration in winter and spring, as well as poor occupational hygiene conditions are significant promoters of SARS outbreak. Warning of atmospheric conditions favorable to SARS, and improvement in occupational hygiene management is the key to prevention from SARS outbreak.

Attitude to Health↗
PubMed2004

[Foodborne disease outbreaks in China from 1992 to 2001 national foodborne disease surveillance system].

OBJECTIVE: To study the foodborne disease outbreaks in the areas covered by National Foodborne Disease Surveillance System. METHODS: Total 13 provinces were included in the surveillance system, and the foodborne disease outbreaks data during 1992 to 2001 were collected. RESULTS: During 1992-2001, a total of 5770 outbreaks of foodborne disease were reported. These outbreaks caused a reported 162,995 persons to become ill. Among outbreaks for which the etiology was determined, bacterial pathogens caused the largest percentage of outbreaks (38.5%) and the largest percentage of cases (50.9%). Vibrio parahaemolyticus (31.1%) accounted for the largest number of outbreaks and cases. Chemical agents caused 37.5% of outbreaks and 28.6% of cases. CONCLUSION: More work needs to be done to improve the foodborne disease surveillance system.

China↗
PubMed2005

Outbreaks of Salmonella infections associated with eating Roma tomatoes--United States and Canada, 2004.

Three outbreaks of Salmonella infections associated with eating Roma tomatoes were detected in the United States and Canada in the summer of 2004. In one multistate U.S. outbreak during June 25-July 18, multiple Salmonella serotypes were isolated, and cases were associated with exposure to Roma tomatoes from multiple locations of a chain delicatessen. Each of the other two outbreaks was characterized by a single Salmonella serotype: Braenderup in one multistate outbreak and Javiana in an outbreak in Canada. In the three outbreaks, 561 outbreak-related illnesses from 18 states and one province in Canada were identified. This report describes the subsequent investigations by public health and food safety agencies. Although a single tomato-packing house in Florida was common to all three outbreaks, other growers or packers also might have supplied contaminated Roma tomatoes that resulted in some of the illnesses. Environmental investigations are continuing. Because current knowledge of mechanisms of tomato contamination and methods of eradication of Salmonella in fruit is inadequate to ensure produce safety, further research should be a priority for the agricultural industry, food safety agencies, and the public health community.

Canada↗
PubMed1990

[Foci of outbreaks of food poisoning and intestinal infections in Poland 1945-1989].

This paper is a comparative study on epidemiological data compiled from papers of intestinal infections and intoxications in Poland during the years 45-89. The following criteria were applied: kind of food as vehicle of infection/intoxication in outbreaks; place of appearance of outbreaks; bacterial aetiological agents of cases and serotypes of Salmonella as causative agent in outbreaks. The number and percentage of outbreaks and cases in outbreaks were analyzed. Most cases and outbreaks were connected with dishes from meat in 1945-1979 and with dishes from uncooked eggs in 1985-1989. Most outbreaks during all analyzed years were connected with private homes, but most cases--with public cafeterias until 1979; with coffee, ice cream and confectionery places in 1985-1987 and with private homes in 1988-1989. Most cases and outbreaks were caused by Staphylococcus aureus in 1961-1970, Salmonella typhimurium was dominating aetiological agent in 70 ths and S.enteritidis in 83-89 years.

Disease Outbreaks↗
PubMedDate not supplied

[Outbreaks of food poisonings of microbial and parasitic origins].

In order to know the agents and foods related more frequently with food-borne disease outbreaks, we reviewed all the outbreaks studied between 1980 and 1989 by the National Laboratory of Public Health. A total of 79 outbreaks of food-borne diseases of microbial origin were reviewed. The causative agent was identified in 50 (73%) outbreaks. Twenty-four per cent of the outbreaks occurred in parties, 10.3 per cent in school or nurseries, 8.6 per cent in restaurants and 8.6 per cent in hospitals. Staphylococcus aureus was the most common agent, causing 48.2 per cent of the outbreaks. Salmonella enterica was involved in 34 per cent of them. The most frequent serovar was typhimurium. Foods involved were: cheese in 29.3 per cent of the cases; cakes in 15.5 per cent; cooked meat in 15.1 per cent; milk in 13.8 per cent; and fish and seafood in 7.0 per cent of the cases. Since the number of studied incidents represents only a small proportion of all the outbreaks occurring in the country, the constant exchange of information among the laboratories which work on the problem and the promotion of the health care team are necessary in order to improve the epidemiologic surveillance systems and the study and prevention of food-borne disease and food poisoning outbreaks.

Bacterial Infections↗
PubMed1997

General outbreaks of infectious intestinal disease associated with milk and dairy products in England and Wales: 1992 to 1996.

Twenty general outbreaks of food poisoning in England and Wales associated with the consumption of milk and dairy products were reported to the PHLS Communicable Disease Surveillance Centre between 1992 and 1996. A total of 600 people were ill and at least 45 people were admitted to hospital but no deaths were reported. Salmonella species were responsible for 11 outbreaks, Campylobacter species for five, Vero cytotoxin producing Escherichia coli O157 (VTEC) for three, and Cryptosporidium parvum for one. Outbreaks were associated with hotels (2 outbreaks), a psychogeriatric hospital, schools (3), a Royal Air Force base, a farm visit, an outdoor festival (2), and community outbreaks associated with milk supplied direct from farms (8). Milk was implicated in 16 outbreaks; 10 of which were associated with unpasteurised milk. Two outbreaks were associated with eating contaminated ice cream, and two with eating contaminated cheese. All these outbreaks could have been prevented by pasteurisation and simple hygienic measures.

Adult↗
PubMed1997

[Epidemiological characteristics of outbreaks of diarrhea and food poisoning in the Israel Defense Forces in the years 1978-1995].

Acute infectious diseases of the gastrointestinal tract and food poisoning are problems of great importance in the Israel Defense Forces (IDF). They involve individual and epidemic morbidity, with impairment of health of individual soldiers and in the activities of units. Outbreaks of gastrointestinal infectious diseases must be reported to the IDF army health branch, which conducts epidemiological investigation. This study is based on data from yearly epidemiological reports for 1978-1989, and from a computerized database for the years 1990-1995. The incidence of outbreaks is characterized by an unstable trend. It was highest at the end of the 80's (68.3 per 100,000 soldiers on active duty) and lowest for the last 2 years (1994-1995, 36.3 per 100,000). The incidence of soldiers involved in food-borne outbreaks has been more stable, constantly declining during the course of the years. There was marked seasonality with a peak in the summer months. Sporadic morbidity was constant in 1990-1995, with a yearly attack rate of 60% in soldiers on active duty. Shigella strains were the leading cause of outbreaks until 1993, while in 1994-1995 their proportion decreased, with an increase in the proportion of Salmonella strains. As to Staphylococcus aureus, its role in causing food poisoning has been characterized by marked changes. Shigella sonnei replaced Shigella flexneri as the leading strain. 73.3% of outbreaks were small, with fewer than 40 soldiers involved, while 5.4% of outbreaks affected more than 100 soldiers. Outbreaks in which a bacterial agent was identified or which occurred in new-recruit bases were larger than those in which a bacterial agent was not identified, or which occurred in active field unit bases. In conclusion, the rates of infectious disease of the gastrointestinal tract are still high, although there has been a marked decrease since 1994. The incidence of outbreaks has also decreased, as well as the role of Shigella as a leading causative agent.

Bacterial Infections↗
PubMed1998

Model Analysis of Spatial Patterns in Mountain Pine Beetle Outbreaks.

The mountain pine beetle [MPB, Dendroctonus ponderosae Hopkins (Coleoptera: Scolytidae)] is an aggressive bark beetle, one that typically needs to kill host trees in order to successfully reproduce. This ecological adaptation has resulted in an organism that is both economically important and ecologically significant. Even though significant resources have been expended on MPB research, and a great deal of knowledge exists regarding individual aspects of MPB ecology, some of the most basic questions regarding outbreaks remain unanswered. In our opinion, one reason for the lack of synthesis and predictive power is the inadequate treatment of spatial dynamics in outbreak theories. This paper explicitly addresses the role of spatial dynamics in the precipitation and propagation of MPB outbreaks. We first describe a spatially dynamic model of the MPB/forest interaction that includes chemical ecology, spatial redistribution of beetles, attack, and resulting host mortality. The model is a system of 6 coupled, partial differential equations with 7 state variables and 20 parameters. It represents an attempt to capture the relatively complex predator/prey interaction between MPB and host trees by including the minimum phenomenological descriptions necessary for ecological credibility. This system of equations describes the temporal dynamics of: beetle attraction as a function of pheromone concentration; the change in numbers of flying and nesting beetles; tree resistance/susceptibility; and tree recovery from attack. Spatial dynamics are modeled by fluxes due to gradients in pheromones and kairomones, and the random redistribution of beetles in absence of semiochemicals. We then use the parameterized model to explore three issues central to the ecology of MPB/forest interaction. The first of these is in response to the need for objective ways to compare patterns of successful beetle attacks as they evolve in space. Simulation results indicate that at endemic levels, the pattern of successful attacks are determined almost exclusively by the underlying distribution of susceptible host trees (environmental determinism). As an outbreak develops, the pattern of successfully attacked trees switches to one that is dynamically driven by the self-generated semiochemical landscape (dynamic determinism). This switch from an environmentally determined spatial pattern to a dynamically driven pattern is the hallmark of an outbreak. We discuss the application of a spatial correlation coefficient that can be used to differentiate between the spatial distribution of killed trees in endemic and outbreak phases. The second issue we address through simulation is synchrony in adult emergence. Synchronous adult emergence is critical for the mass attack strategy necessary for overcoming tree defenses. Results from these simulations indicate that the degree of synchrony in adult emergence can have important consequences for assessing the risk of an outbreak. The final issue we investigate through simulation is the effect of spatial pattern of nurse trees (those successfully attacked the previous year) on outbreak potential. Simulations indicated that the spatial proximity of nurse trees was an important determinant of subsequent successful attacks. We conclude with a discussion of the general implications of our simulation experiments. Copyright 1998 Academic Press.

Journal Article↗
PubMed1996

Outbreaks of nosocomial rotavirus gastro-enteritis in a paediatric ward.

UNLABELLED: Faecal samples were collected from patients with gastro-enteritis during two winter seasons on a paediatric ward. Three outbreaks of nosocomial rotavirus gastro-enteritis were identified by latex agglutination and the virus strains were characterized by polyacrylamide gel electrophoresis of the genome nucleic acid and by subgrouping and serotyping enzyme-linked immunosorbent assays (ELISA). One outbreak was caused by serotype 1 rotavirus, one by serotype 2 and the remaining outbreak was caused by a mixture of serotypes 1 and 4. Identical electrophoretic patterns of the rotavirus genome in each outbreak combined with the ELISA results indicate that these three outbreaks were hospital-acquired cases. The index cases in the three outbreaks were community-acquired and one of two index cases in the second outbreak was hospital-acquired. On each occasion, susceptible roommates were easily infected from the index cases and then cross-infection occurred in the paediatric ward. Possible vehicles were the medical staff, especially doctors, parents of infected patients and infected patients who were moved to other rooms. One patient who had been treated with a series of antitumour therapies excreted rotaviruses in faeces for a long time period and probably played a role as a source of the outbreak. Moreover, some patients still excreted rotaviruses in their normal stool 1 week after recovery from gastro-enteritis. These findings indicate that continual examination of stool samples for rotaviruses until they are negative may be important to prevent the spread of rotavirus infection. CONCLUSION: Nucleic acid analysis and serotyping ELISA are useful tools for analyzing nosocomial rotavirus gastro-enteritis and important to prevent the spread of rotavirus infection in institutions.

Child↗
PubMedDate not supplied

Where's the beef? The role of cross-contamination in 4 chain restaurant-associated outbreaks of Escherichia coli O157:H7 in the Pacific Northwest.

BACKGROUND: From March through August 1993, outbreaks of Escherichia coli O157:H7 occurred at 4 separate Oregon and Washington steak and salad bar restaurants affiliated with a single national chain. OBJECTIVE: To determine the cause of outbreaks of E coli O157:H7 at 4 chain restaurants. METHODS: Independent case-control studies were performed for each outbreak. Available E coli O157:H7 isolates were subtyped by pulse-field gel electrophoresis and by phage typing. RESULTS: Infection was not associated with beef consumption at any of the restaurants. Implicated foods varied by restaurant but all were items served at the salad bar. Among the salad bar items, no single item was implicated in all outbreaks, and no single item seemed to explain most of the cases at any individual restaurant. Molecular subtyping of bacterial isolates indicated that the first 2 outbreaks, which occurred concurrently, were caused by the same strain, the third outbreak was caused by a unique strain, and the fourth was multiclonal. CONCLUSIONS: Independent events of cross-contamination from beef within the restaurant kitchens, where meats and multiple salad bar items were prepared, were the likely cause of these outbreaks. Meat can be a source of E coli O157:H7 infection even if it is later cooked properly, underscoring the need for meticulous food handling at all stages of preparation.

Adolescent↗
PubMed2004

Barriers to public health management of a pertussis outbreak in Arkansas.

BACKGROUND: During the 2001-2002 respiratory season, Arkansas experienced one of its worst pertussis outbreaks. This crisis occurred shortly after the September 11, 2001, terrorist attacks. OBJECTIVE: To determine whether vulnerabilities in the public health infrastructure existed in the context of emerging infectious diseases or possible bioterrorist attacks. DESIGN: Key personnel involved in the Arkansas pertussis outbreak were interviewed, and health department epidemiologic data were reviewed. SETTING: Observations were made for the statewide private-public management of the epidemic. PARTICIPANTS: Physicians, infectious disease specialists, epidemiologists, field nurses, health department staff, laboratory staff, and administrators. MAIN OUTCOME MEASURES: Diagnosis capability; vaccine, prophylaxis, and treatment programs; and effectiveness of global outbreak management. RESULTS: Diagnosis of pertussis was a major barrier to management of the outbreak. The nonspecific clinical diagnosis, unreliability of testing methods, excessive number of samples, unavailability of reagents, and inadequate transport system, laboratory personnel, and equipment all impeded effective diagnosis. Vaccine shortage was not believed to contribute to the extent of the outbreak. Prophylaxis was problematic because of feared adverse effects of drugs and uncertainty about the efficacy of new drugs, but compliance was found to be good. From a public health perspective, isolation procedures, school absence policies, and health department referrals to private physicians all contributed to confusion. Problems with communications, staffing, and public cooperation were identified. Despite these barriers, the epidemic was well tolerated, with no known mortality and limited morbidity. CONCLUSIONS: Despite many identified barriers to effective public health management, Arkansas tolerated its worst epidemic of pertussis in many years. However, were the state to experience an outbreak of a more pathogenic agent, introduced either naturally or of bioterrorist origin, these vulnerabilities could become critical. Natural outbreaks serve as excellent experiences on which to recognize and correct barriers to public health management.

Arkansas↗
PubMed2003

Evaluation of control measures implemented in the severe acute respiratory syndrome outbreak in Beijing, 2003.

CONTEXT: Beijing, China, experienced the world's largest outbreak of severe acute respiratory syndrome (SARS) beginning in March 2003, with the outbreak resolving rapidly, within 6 weeks of its peak in late April. Little is known about the control measures implemented during this outbreak. OBJECTIVE: To describe and evaluate the measures undertaken to control the SARS outbreak. DESIGN, SETTING, AND PARTICIPANTS: Data were reviewed from standardized surveillance forms from SARS cases (2521 probable cases) and their close contacts observed in Beijing between March 5, 2003, and May 29, 2003. Procedures implemented by health authorities were investigated through review of official documents and discussions with public health officials. MAIN OUTCOME MEASURES: Timeline of major control measures; number of cases and quarantined close contacts and attack rates, with changes in infection control measures, management, and triage of suspected cases; and time lag between illness onset and hospitalization with information dissemination. RESULTS: Health care worker training in use of personal protective equipment and management of patients with SARS and establishing fever clinics and designated SARS wards in hospitals predated the steepest decline in cases. During the outbreak, 30 178 persons were quarantined. Among 2195 quarantined close contacts in 5 districts, the attack rate was 6.3% (95% confidence interval [CI], 5.3%-7.3%), with a range of 15.4% (95% CI, 11.5%-19.2%) among spouses to 0.36% (95% CI, 0%-0.77%) among work and school contacts. The attack rate among quarantined household members increased with age from 5.0% (95% CI, 0%-10.5%) in children younger than 10 years to 27.6% (95% CI, 18.2%-37.0%) in adults aged 60 to 69 years. Among almost 14 million people screened for fever at the airport, train stations, and roadside checkpoints, only 12 were found to have probable SARS. The national and municipal governments held 13 press conferences about SARS. The time lag between illness onset and hospitalization decreased from a median of 5 to 6 days on or before April 20, 2003, the day the outbreak was announced to the public, to 2 days after April 20 (P<.001). CONCLUSIONS: The rapid resolution of the SARS outbreak was multifactorial, involving improvements in management and triage in hospitals and communities of patients with suspected SARS and the dissemination of information to health care workers and the public.

China↗
PubMed2000

A diagnostic EIA for detection of the prevalent SRSV strain in United Kingdom outbreaks of gastroenteritis.

Small round structured viruses (SRSVs) are the major cause of outbreaks of gastroenteritis in the UK. Diagnosis is problematic due to insensitive electron microscopy (EM) or technically demanding reverse transcription polymerase chain reaction (RT-PCR) techniques. We have studied outbreaks of non-bacterial gastroenteritis using an EIA based upon recombinant capsid protein from the currently prevalent circulating strain of SRSV (Lordsdale Genotype II) and compared its performance against EM and RT-PCR assays. Faecal specimens sent to the Bristol Public Health Laboratory for outbreak investigation from December 1996 to December 1997 were applied retrospectively to the SRSV EIA and results compared with the routine EM and RT-PCR that had been carried out prospectively. Overall, the three tests identified SRSVs in specimens from 70% of the outbreaks (213/305) investigated. Of the 213 total positive outbreaks, the EIA identified 71%, that compared favourably with EM (63%) and RT-PCR (84%). The Lordsdale Genotype II SRSV EIA provides a simple cost-effective assay that will for the first time make detection of currently circulating SRSV strains associated with UK outbreaks available to all routine laboratories. The EIA format makes the assay widely applicable to non-specialist laboratories, unlike the RT-PCR assay, and the improved sensitivity over EM will allow successful screening of UK outbreaks alongside commercial EIAs currently available for adenovirus, astrovirus and rotavirus. Furthermore, the assay will allow rapid identification of emerging SRSV strains.

Capsid↗
PubMed2003

Genotyping of measles and mumps virus strains using amplification refractory mutation system analysis combined with enzyme immunoassay: a simple method for outbreak investigations.

A simple method, based on a modification of the amplification refractory mutation system (ARMS), for genotyping outbreak strains of measles and mumps viruses and detecting these in a simple enzyme immunoassay (EIA) is described. Fifty-three measles strains circulating at the time of an outbreak in London in 2000 and 26 strains circulating at the time of a mumps outbreak in Accrington, UK, in 1999 were investigated. All strains were genotyped by direct sequencing. ARMS primers were then designed to amplify the outbreak strain. The ARMS-EIA for measles and mumps detected all 36 measles outbreak strains as genotype D6, and all 15 mumps outbreak strains as genotype F, respectively. The sensitivity and specificity of both the measles D6 and Mumps F genotype ARMS EIA was 100% compared with direct sequencing. The results show that ARMS-EIA can be used as a rapid alternative to genotyping by direct sequence analysis in outbreak situations.

Alleles↗
PubMed1993

Two successive outbreaks of SRSV-associated gastroenteritis in South Africa.

Two successive outbreaks of gastroenteritis in South Africa were investigated to identify the aetiological agents. Some patients were involved in both outbreaks. Enteropathogenic bacteria or parasites were not evident in either outbreak. Small round structured viruses (SRSVs) were demonstrated in both outbreaks by direct electron microscopy. SRSV UK3/Hawaii virus was identified by immune electron microscopy as the causative agent in the first outbreak. Using new recombinant Norwalk virus (rNV) immunoassays for antibodies and antigen, Norwalk virus was implicated in the second outbreak. Preexisting antibodies to Norwalk virus were not protective and there was no cross protection between Hawaii and Norwalk viruses. There was no anamnestic response to Norwalk virus following the SRSV UK3/Hawaii outbreak although those affected had preexisting antibodies to Norwalk virus. To our knowledge, this is the first definitive diagnosis of SRSV-associated gastroenteritis in South Africa.

Adult↗
PubMed2005

Molecular and epidemiological features of norovirus-associated gastroenteritis outbreaks in Victoria, Australia in 2001.

Norovirus was identified in 30 of 59 gastroenteritis outbreaks occurring in the state of Victoria, Australia in 2001 by RT-PCR and/or electron microscopy (EM). Norovirus outbreaks occurred in hostels/nursing homes (27%), hospitals (13%), youth refuges (3%), social gatherings associated with food consumption (27%), school outings/camps (13%), and pre-school/child-minding centers (17%). Norovirus outbreaks tended to occur in the warmer months. Phylogenetic analysis identified six clusters, one within genogroup 1 (G1) and five within genogroup 2 (G2). Cluster 1, which incorporates the G2 Camberwell/Lordsdale strains, was the most common (39% of outbreaks). In 2 of 27 outbreaks, strains from two G2 clusters, 1 and 5, occurred. Norovirus G2 was more common in the young and very old than in those in intermediate years. Norovirus G2 detection rate was higher in females than in males for adults (>15 years) and the susceptibility of adult females to norovirus G2 infection relative to males increased with age. In one outbreak analyzed, some sequences had a single base substitution, but this did not result in an amino acid (aa) change. The two most common norovirus clusters (G2 clusters 1 and 4) occurred in the capital of Victoria, Melbourne, and regional Victoria, but the least common clusters (G2 clusters 2 and 3 and G1 cluster 8) only occurred in inner Melbourne. Norovirus was occasionally detected by EM but not by RT-PCR. The occurrence of norovirus outbreaks is modulated by a large group of factors, which will have to be considered in any epidemiological model.

Adolescent↗
PubMed2006

Evaluating spatial surveillance: detection of known outbreaks in real data.

Since the anthrax attacks of October 2001 and the SARS outbreaks of recent years, there has been an increasing interest in developing surveillance systems to aid in the early detection of such illness. Systems have been established which do this is by monitoring primary health-care visits, pharmacy sales, absenteeism records, and other non-traditional sources of data. While many resources have been invested in establishing such systems, relatively little effort has as yet been expended in evaluating their performance. One way to evaluate a given surveillance system is to compare the signals it generates with known outbreaks identified in other systems. In public health practice, for example, public health departments investigate reports of illness and sometimes track hospital admissions. Comparison of new systems with extant systems cannot generate estimates of test characteristics such as sensitivity and specificity, since the actual number of positives and negatives cannot be known. However, the comparison can reveal whether a new or proposed system's signals match outbreaks detected by the existing system. This could help support or reject the new system as an alternative or complement to the extant system. We propose three methods to test the null hypothesis that the new system does not signal true outbreaks more often than would be expected by chance. The methods differ in the restrictiveness of the assumptions required. Each test may detect weaknesses in the new system, depending on the distribution of outbreaks and can be used to construct confidence limits on the agreement between the new system's signals and the outbreaks, given the distribution of the signals. They can be used to assess whether the new system works in that it detects the outbreaks better than chance would suggest and can also determine if the new systems' signals are generated earlier than an extant system.

Data Interpretation, Statistical↗
PubMed2005

Existence of multiple outbreaks of viral gastroenteritis among infants in a day care center in Japan.

A total of 921 fecal specimens collected from 44 infants in a day care center (DCC) in Tokyo, Japan during June 1999 to July 2000 were tested for the presence of rotavirus, norovirus, sapovirus, astrovirus and adenovirus by reverse-transcription-multiplex polymerase chain reaction (RT-multiplex PCR) and sequence analysis. Of 88 fecal specimens from infants with acute gastroenteritis, 51.1% (45) were found to be positive for diarrheal viruses. Astrovirus was the most prevalent (15.9%, 14 of 88), followed by norovirus GII (14.8%, 13 of 88), adenovirus (12.5%, 11 of 88), and sapovirus (2.3%, 2 of 88). Viral mixed infection accounted for 5.7% (5 of 88). Interestingly, 230 of 833 (27.6%) fecal specimens collected from asymptomatic infants were also infected with diarrheal viruses. Of these, astrovirus, norovirus GII, adenovirus and sapovirus were identified in 53, 46, 96 and 22 fecal specimens (23%, 20%, 41.7%, and 9.6%, respectively). Moreover, 13 of 833 (1.6%) normal specimens showed mixed viral infections. Surprisingly, no rotavirus (known as the most common causative agent of acute gastroenteritis in DCCs) was detected in those subjects. Another interesting feature was the demonstration of five separate outbreaks of acute gastroenteritis identified in a single DCC. Outbreak A was associated with both astrovirus serotype 1 and norovirus GII/3 (known as Toronto virus cluster); Outbreak B with adenovirus 12; Outbreak C with norovirus GII/4 (Lordsdale virus cluster); Outbreak D with sapovirus GIV and Outbreak E with astrovirus serotype 1. To our knowledge, this is the first proof of multiple outbreaks of viral gastroenteritis in Japanese infants in a single DCC. Our results confirm the presence as well as the importance of these viruses and warn of the threat they pose.

Adenovirus Infections, Human↗