Outbreaks of Acute Gastroenteritis Transmitted by Person-to-Person Contact — United States, 2009–2010


Problem/Condition: Approximately 179 million cases of acute gastroenteritis (AGE) occur in the United States each year, and outbreaks of AGE are a substantial public health problem. Although CDC has conducted national surveillance for waterborne and foodborne AGE outbreaks since 1971 and 1973, respectively, no national surveillance existed for AGE outbreaks resulting primarily from person-to-person transmission before implementation of the National Outbreak Reporting System (NORS) in 2009. Reporting Period: 2009-2010. Description of System: NORS is a national surveillance system launched in 2009 to support the reporting of all waterborne outbreaks and enteric disease outbreaks from foodborne, person-to-person, animal contact, environmental, and unknown modes of transmission. State and local public health agencies in the 50 U.S. states, the District of Columbia, five U.S. territories, and three Freely Associated States report these outbreaks to CDC via NORS using a standardized online data entry system. Data are collected on general outbreak characteristics (e.g., dates, number of illnesses, and locations), demographic characteristics of cases (e.g., age and sex), symptoms, case outcomes, and laboratory testing information and results. Only outbreaks reported in NORS with a primary mode of transmission of person-to-person contact are included in this report. Results: During 2009-2010, a total of 2,259 person-to-person AGE outbreaks were reported in NORS from 42 states and the District of Columbia. These outbreaks resulted in 81,491 reported illnesses, 1,339 hospitalizations, and 136 deaths. No etiology was reported in approximately 40% (n = 840) of outbreaks. Of the remaining 1,419 outbreaks with a reported etiology, 1,270 (89%) were either suspected or confirmed to be caused solely by norovirus. Other reported etiologies included Shigella (n = 86), Salmonella (n = 16), Shiga toxin-producing Escherichia coli (STEC) (n = 11), and rotavirus (n = 10). Most (82%) of the 1,723 outbreaks caused by norovirus or an unknown etiology occurred during the winter months, and outbreaks caused by Shigella or another suspected or confirmed etiology most often occurred during the spring or summer months (62%, N = 53 and 60%, N = 38, respectively). A setting was reported for 1,187 (53%) of total outbreaks. Among these reported settings, nursing homes and other long-term-care facilities were most common (80%), followed by childcare centers (6%), hospitals (5%), and schools (5%). Interpretation: NORS provides the first national data on AGE outbreaks spread primarily through person-to-person transmission and describes the frequency of this mode of transmission. Norovirus is the most commonly reported cause of these outbreaks and, on the basis of epidemiologic characteristics, likely accounts for a substantial portion of the reported outbreaks of unknown etiology. In the United States, sporadic and outbreak-associated norovirus causes an estimated 800 deaths and 70,000 hospitalizations annually, which could increase by an additional 50% during epidemic years. During 2009-2010, norovirus outbreaks accounted for the majority of deaths and health-care visits in person-to-person AGE outbreaks reported to NORS. Public Health Action: Prevention and control of person-to-person AGE outbreaks depend primarily on appropriate hand hygiene and isolation of ill persons. NORS surveillance data can help identify the etiologic agents, settings, and populations most often involved in AGE outbreaks resulting primarily from person-to-person transmission and guide development of targeted interventions to avert these outbreaks or mitigate the spread of infection. Surveillance for person-to-person AGE outbreaks via NORS also might be important in clarifying the epidemiology and role of certain pathogens (e.g., STEC) that have been traditionally considered foodborne but can also be transmitted person-to-person. As ongoing improvements and enhancements to NORS are introduced, participation in NORS has the potential to increase, allowing for improved estimation of epidemic person-to-person AGE and its relative importance among other modes of transmission.

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    • "However, infections also occur through person person-to-person transmission, especially among members of the same household or in crowded places where hygiene is often compromised, such as day care centers and nursing homes. In these conditions, transmission can sometimes cause large outbreaks in the community and even in hospital settings.1-3 Successful prevention of spreading of infectious diarrhea in the community depends largely on adequate control measures such as rapid and accurate microbiological diagnosis among the populations at risk, reporting of specific communicable diseases to the appropriate public health authorities, adequate follow-up strategies to monitor fecal shedding after treatment in groups at risk, patient isolation and preventative education.4 "
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    ABSTRACT: Purpose This study was performed to evaluate the compliance with, and adequacy of, the Korean national guidelines which had been recommended until 2011 for isolation of patients with group 1 nationally notifiable infectious diseases (NNIDs), namely cholera, typhoid fever, paratyphoid fever, shigellosis, and enterohemorrhagic Escherichia coli (EHEC) infection. Materials and Methods We evaluated the clinical and microbiological characteristics of confirmed cases of group 1 NNIDs and compliance with the guidelines in 20 Korean hospitals nationwide in 2000-2010. We also compared the Korean guidelines with international guidelines. Results Among 528 confirmed cases (8 cases of cholera, 232 of typhoid fever, 81 of paratyphoid fever, 175 of shigellosis, and 32 EHEC infections), strict compliance with the Korean guideline was achieved in only 2.6% to 50.0%, depending on the disease. While the Korean guidelines recommend isolation of all patients with group 1 NNIDs, international guidelines recommend selective patient isolation and screening for fecal shedding, depending on the type of disease and patient status. Conclusion Compliance with the previous national guidelines for group 1 NNIDs in Korea was generally very low. Further studies are needed to evaluate whether compliance was improved after implementation of the new guideline in 2012.
    Yonsei medical journal 03/2014; 55(2):435-41. DOI:10.3349/ymj.2014.55.2.435 · 1.29 Impact Factor
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    • "Monthly norovirus outbreak counts were based on reports of suspected and confirmed norovirus outbreaks elicited from 30 states during January 2007–April 2010 (12); these monthly data were used as the main comparison for the BioSense data. For a separate analysis, weekly norovirus outbreak surveillance data were obtained from the National Outbreak Reporting System (NORS), a national-level, Internet-based reporting platform established in 2009 (10). These weekly data were based on suspected and confirmed norovirus outbreaks as reported by 47 state and territory health departments during January 2009–December 2011. "
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    ABSTRACT: 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.
    Emerging Infectious Diseases 08/2013; 19(8):1214-21. DOI:10.3201/eid1908.130483 · 6.75 Impact Factor
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    • "NV is spread through a number of pathways with the occurrence of both fecal-oral and vomit-oral transmission. Direct person-to-person transmission is a primary mode of transmission in most outbreaks [7] and sporadic diseases [8]. Furthermore, NV disease outbreaks are reported year-round. "
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    ABSTRACT: The human norovirus (NV) circulates worldwide and is a major cause of epidemics, which have increased in Taiwan since 2002. NV in acute gastroenteritis (AGE) and non-acute gastroenteritis (asymptomatic) patients, including children and adults, have not been previously examined in Taiwan; therefore, we examined the epidemiology and phylogeny of NV in AGE and asymptomatic patients of all ages. 253 stool samples were collected from August 2011 to July 2012 (including 155 AGE and 98 asymptomatic samples in Taiwan) and analyzed using reverse transcription-polymerase chain reaction (RT-PCR) for NV. Primers targeting the RNA-polymerase gene were used for RT-PCR to allow DNA sequencing of Taiwan NV strains and phylogenetic analyses. NV was detected in 24 (9.5%) of 253 stool specimens using RT-PCR. NV was isolated from all age groups (1 to 86 y) and those NV-positive samples were major identified from inpatients (79.2%, 19/24). Statistical analysis showed that the NV infectious rate of AGE patients was statistically significant (P < 0.05) for age, season and water type, respectively. Phylogenetic analyses of the RdRp region sequence showed that 24 NV isolates belonged to Genogroup II Genotype 4 (GII.4). They were closely related to the epidemic strain in Taiwan in 2006, the GII.4-2006b pandemic strain in 2006, and the GII.4-New Orleans strain in 2010. This study is the first to examine NV in sporadic AGE and asymptomatic patients in Taiwan. Furthermore, epidemic strains of isolated GII.4 were predominant in Taiwan during 2011 and 2012.
    BMC Infectious Diseases 07/2013; 13(1):338. DOI:10.1186/1471-2334-13-338 · 2.61 Impact Factor
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