Norovirus is the most frequent cause of acute gastroenteritis outbreaks. The Kaplan criteria used for prompt recognition include: vomiting, short incubation and illness duration, and absence of bacterial pathogens. We report the results of an outbreak investigation that occurred in a Veterans Affairs long-term care facility (LTCF).
An outbreak of norovirus cases occurred over a 26-day period from 3/24/2016 - 4/18/2016 on a 19 bed LTCF ward. Case definition included any person with vomiting and/or diarrhea on the affected ward (or an epidemiological link to the ward) during this time period. Norovirus PCR (a send-out test), Clostridium difficile PCR, bacterial stool culture, and rotovirus testing were requested on all suspected cases.
The index case was a patient transferred from an acute care hospital 2 days prior. He developed fever, vomiting, and diarrhea. Isolation was started on day 3 of symptoms. 12 of 19 (63%) patients and 9 staff met the case definition (figure 1). Among patients, 7 (58%) tested positive for norovirus. Only 4 patients had vomiting (33.3%). The initial positive norovirus test resulted on outbreak day 6. The strain was genotyped by the local health department and found to be GII.4 untypeable. Additionally, 2 (16.7%) patients tested positive for C. difficile. One of these patients was positive for both norovirus and C. difficile.
Among employees 7 (77.8%) had vomiting. Testing was performed on 4 staff members. Additional pathogens identified among staff members included 3 (33%) with C. difficile, 1 (11%) with Campylobacter jejuni, and 1 (11%) with Aeromonas.
Aggressive infection control measures were implemented to control the outbreak, including education, strict hand washing, contact isolation of cases, restriction of ward admissions, enhanced cleaning with bleach, and cancelation of group activities. Additionally, the unit and common areas were terminally cleaned with bleach and all patient clothing was bagged and contracted out for laundering.
Norovirus can cause a rapid widespread outbreak in a LTCF. The recognition of outbreaks is hampered by lack of rapid in-house diagnostics, and the detection of other co-pathogens. Therefore, high suspicion should be maintained for norovirus.
J. Johnson, None
V. Nelson, None
B. Siepierski, None
S. Dhar, None