Outbreak Management and Implications of a Nosocomial Norovirus Outbreak

Abstract

Background. Noroviruses are enterically transmitted and are a frequent cause of gastroenteritis, affecting 23 million people annually in the United States. We describe a norovirus outbreak and its control in a tertiary care hospital during February-May 2004.Methods. Patients and health care workers met the case definition if they had new onset of vomiting and/or diarrhea during the outbreak period. Selected stool samples were tested for norovirus RNA. We also determined outbreak costs, including the estimated lost revenue associated with unit closures, sick leave, and cleaning expenses.Results. We identified 355 cases that affected 90 patients and 265 health care workers and that were clustered in the coronary care unit and psychiatry units. Attack rates were 5.3% (7 of 133) for patients and 29.9% (29 of 97) for health care workers in the coronary care unit and 16.7% (39 of 233) for patients and 38.0% (76 of 200) for health care workers in the psychiatry units. Thirteen affected health care workers (4.9%) required emergency department visits or hospitalization. Detected noroviruses had 98%-99% sequence identity with representatives of a new genogroup II.4 variant that emerged during 2002-2004 in the United States (e.g., Farmington Hills and other strains) and Europe. Aggressive infection-control measures, including closure of units and thorough disinfection using sodium hypochlorite, were required to terminate the outbreak. Costs associated with this outbreak were estimated to be $657,644.Conclusions. The significant disruption of patient care and cost of this single nosocomial outbreak support aggressive efforts to prevent transmission of noroviruses in health care settings.

Within-Host Evolution Results in Antigenically Distinct GII.4 Noroviruses

“…Norovirus is spread rapidly in environments where people are found in close proximity, including schools and daycare centers, nursing homes, cruise ships, and hospitals. Importantly, hospital outbreaks can result in significant economic damage, with direct and indirect costs from a single outbreak reaching $650,000 (4).…”

“…Studies of antigenic variation in GII. 4 norovirus have shown that the P2 region is involved in strain-specific antibody recognition (7,11,12) and contains at least three blockade (potential neutralization) epitopes (13)(14)(15). In epidemic strains, genetic variation in P2 is linked to antigenic changes over time, indicating that molecular evolution in the P2 subdomain is likely driven by escape from human herd immunity (12)(13)(14)(15)(16)(17).…”

Multiple Antigenic Sites Are Involved in Blocking the Interaction of GII.4 Norovirus Capsid with ABH Histo-Blood Group Antigens

“…Strain MD2004-3 was identified in 2004 as a causative agent of diarrhea in a Baltimore, MD, hospital outbreak (29). This strain grouped within the Farmington Hills cluster of the GII.4 genotype (Fig.…”

Prevention and control of infections in the home

“…Antimicrobial resistance may also evolve or be acquired in the community and be introduced into a health care facility from the community, where the infection can spread widely. [1][2][3][4][5][6] The suggestions presented in this review provide a basic approach that can be applied to prevent the transmission of current antimicrobial-resistant pathogens and those that may arise in the future.…”

“…Although these suggestions are based on meta-analysis of an extensive number of reports and intervention studies, they are resource intensive and are, thus, impractical and unrealistic in the home. 4,5,12 Within the home, the concern about antimicrobial-resistant microorganisms, such as methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus and Clostridium difficile, in addition to Mycobacterium tuberculosis and respiratory and gastrointestinal viruses, relates to the implications for the patient and other people living with or visiting people infected or colonized with these pathogens, 1,11,12,[21][22][23][24][25][26][27][28] as well as to home-based health care providers. The true prevalence and risk of transmission of MRSA, vancomycin-resistant Enterococcus, extended spectrum β-lactamase-producing gram negative bacteria, Acinetobacter baumanii and C. difficile in the community among patients, their caregivers and family members is not known.…”