Diary Of An Outbreak Of Norwalk Virus In Long-term Care

Diary Of An Outbreak Of Norwalk Virus In Long-term Care

By Brenda Breivogel RN, BS, MHSA

The facility in which this outbreak occurred is a 200-plus bed facility in the Midwest consisting of four distinctive units. Unit 1 is a secured Alzheimer's unit (Medicaid certified) with a capacity of 30 residents. Unit 2 has about 20 certified Medicaid/ Medicare beds and 40 Medicaid certified beds. Unit 3 is the largest with 84 Medicaid certified beds. Unit 4 is a 37-bed Medicaid certified unit. The characteristics of the residents on each unit are somewhat different. On Unit 1, the Alzheimer's residents are in the mid-later stages of the disease process and often demonstrate problem behaviors. Unit 2 is a higher acuity unit and often has residents that stay for a short time to convalesce after a hospitalization. Many of the residents on Unit 3 came to the facility following hospitalization and were unable to return home. This unit has residents that have resided in the facility for a range of one month to 25 years. Unit 4 has residents who were hospitalized but were unable to return home after convalescence also, however, several of these residents have early-to-mid stages of Alzheimer disease or some other form of dementia.


The infection control practitioner (ICP) became aware of a cluster of ill residents on Feb. 21, 2002, as eight residents were identified with gastrointestinal symptoms (nausea, vomiting, diarrhea); there were five cases on Unit 1 and three on Unit 3. The administrator was informed of the cases of what appeared to be an infectious gastroenteritis. A decision was made to inform the local health department (HD) of the possible outbreak of gastrointestinal infection. During conversation with the nurse manager of the local HD, immediate prevention and control measures and the need for additional data were identified. The following immediate actions were taken: immediate re-training of all personnel on proper handwashing technique; handwashing reminders were posted by every sink in the common-use areas; residents experiencing gastrointestinal symptoms were asked to remain in their rooms; department heads were instructed not to allow personnel with GI symptoms to work; a line listing of residents and personnel with symptoms was initiated; and the rules of operation were given to all department heads and posted at the nurses' stations.

Included in the resident line listing were the resident's name, room number, date of onset of symptoms, specific symptoms and the frequency of the symptoms. The data for the resident line listing were gathered from notes taken from administrative reports, interviews with employees, alert charting logs and a brief chart review. From this initial review there were residents identified as having symptoms as early as Feb.12, 2002.

Within a couple hours the local HD had communicated with the state HD and had delivered specimen collection containers so stool samples could be sent to the state HD laboratory. A centralized stool specimen collection refrigerator was identified for the facility (the specimens are usually placed in a cooler with a biohazard marking). During this initial visit the staff nurse from the local HD requested further information: three days of menus, resident census and the total number of facility employees. The line listing for personnel included their name, unit assigned, home address, home telephone number, date of the onset of symptoms, specific symptoms and frequency of the symptoms. It was more challenging to develop the employee line listing from the attendance logs but an initial list was prepared that first day.


The next morning the representative from the local HD returned to the facility to perform a chart review based on the line listing prepared by the ICP. Signs were posted on each of the facility's entry doors emphasizing the need for strict handwashing for everyone entering the building. Instructions were given to the receptionist directing visitors to speak with a nurse prior to visiting residents. All residents were restricted to the unit where they reside, all unit hallway doors were closed, meals were served in the residents' rooms, the beauty shops were closed, planned group activities were cancelled and individual activities were substituted.

The sanitation officer from the local HD inspected the dietary department, observed food preparation and distribution and concluded that food was being stored, prepared and distributed in accordance with all sanitation guidelines. Four stool specimens were collected, and an additional seven containers were left at the facility for future use. That same day the nurse manager of the local HD called to share what the state agency suspected was the cause of the outbreak: Norwalk virus. The state epidemiologist said several other nursing homes had experienced outbreaks caused by this virus.


New cases among the residents included two cases from Unit 3 and two cases from Unit 2. One more employee was identified from Unit 3.


Three more residents developed symptoms on Units 1, 2 and 4. One certified nursing assistant (CNA) from Unit 3 was sent home ill. A nurse from Unit 1 called in sick and a housekeeper from Unit 1 was sent home ill. Two surveyors from the state HD came to the facility in response to an outbreak-associated complaint. The surveyors reviewed the line listing of residents and employees, the restrictions in place and interviewed a number of residents. There were no suggestions from the surveyors regarding additional precautions or relaxation of the precautions that were in place. One surveyor did indicate that that it would be a good idea not to admit new residents until no new cases were identified for 30 to 36 hours. The complaint was unsubstantiated and unverified.


The local HD representative picked up two additional stool specimens. Contact with the local health department's educator was made by the training coordinator to schedule a handwashing inservice.


On this day there was only one additional case identified among residents (Unit 4) and none among the employees. Consideration was given to re-opening the beauty shops the next day to asymptomatic residents with the following restrictions: Residents had to be asymptomatic for 24 hours prior to visiting the beauty shop; one resident could be in the shop at a time; beauticians had to be asymptomatic for 24 hours prior to caring for the residents; beauticians would wash their hands and disinfect the chairs and surfaces between residents; and residents' hands would be washed before leaving their unit and upon return to the unit where they reside.


During the first morning round one new case among the residents was reported on Unit 4. Two hours later, a resident on Unit 1 was reported to have diarrhea and Unit 2 had a resident with vomiting. An employee from Unit 2 was sent home ill. Another employee with nausea, vomiting and diarrhea on Unit 3 was reported as ill and sent home.


The nurse manager from the HD toured the facility and discussed lifting restrictions in two days if there were no new cases identified among residents and employees. Applesauce utilized to administer medications was discussed as a possible source for the virus. It was reported that a number of local schools had also experienced multiple cases that were similar in description. That evening two CNAs from Unit 3 were sent home ill; later on, a CNA from Unit 1 called in sick and stated that her child was also ill.

Confirmation was received from the state HD that the causative agent for this outbreak was Norwalk virus. Instructions were given that stringent prevention and control measures must be maintained until there were no new cases reported for four days. An outbreak of Norwalk virus in a nursing home can last two to six weeks depending on how well prevention and control measures are maintained. The key prevention and control measure is proper handwashing of employees, residents and visitors. Disinfection of common surfaces was also emphasized by the state HD.

Department managers were updated on the status of the outbreak and the given information on the causative agent. An inservice was given to department managers on viral gastroenteritis, and materials from the Centers for Disease Control and Prevention (CDC) and state HD Web sites were provided to the managers who then inserviced their personnel.


Due to the number of employees affected by the outbreak two exceptions regarding floating employees were made to meet residents' needs on Unit 3; two qualified medication aides were selected to float between Units 3 and 4. The unit director instructed these individuals on handwashing and other prevention measures.


Unit 3 reported one new resident case with vomiting as the main symptom. Three CNAs were symptomatic: two from Unit 1 and one from Unit 2. The CNA from Unit 2, who also is a local college student, reported that a number of her fellow students and instructors had been ill with gastroenteritis. Two nurses called in sick with vomiting and diarrhea. The department managers were updated on the outbreak during the regular department head meeting.


One CNA from Unit 3 was sent home due to nausea, vomiting and diarrhea.


The only new case was a resident on Unit 1. Four residents from Unit 4 were transferred to Unit 3 to allow the renovation of Unit 4 to continue. The residents being transferred did not have any symptoms of gastroenteritis nor did the new roommate.


A new class of nursing assistants arrived for their clinical experience. These students were informed of the precautions in place: strict handwashing, exclusion of all employees experiencing symptoms, restriction of residents to their unit, disinfect ion of common surfaces, etc. Each student was provided with alcohol hand gel before leaving the training room. Two hours later one of the nursing assistant students was sent home due to diarrhea. The individual was instructed to collect the next diarrhea stool specimen because it was questionable whether the student was really ill. Keeping with the restrictions the student was instructed not to return to the facility until asymptomatic for 24 hours. No specimen was collected from this student. An update of the outbreak was given to the local HD. Two residents were moved into the newly renovated private rooms on Unit 4, and three residents from Unit 3 were transferred.


A laundry employee went home ill with vomiting; the employee also had an ill child. Employee questionnaires were faxed to the local HD.


A night shift qualified medication aide from Unit 1 was reported as having vomiting and diarrhea. Unit 3's social worker experienced vomiting and her children were also ill. Following consultation with the local HD a decision was made to lift the restriction on residents that required them to remain on the assigned units. Residents would be required to wash their hands before leaving their unit and upon return. Personnel would be required to disinfect all common surfaces after the resident contact, after group activities or dining, etc. Only residents with nausea, vomiting or diarrhea would be restricted to their rooms (24 hours after no further symptoms). A department head meeting was held to review how the precautions would be lifted.

The following information was given to the department managers: Strict handwashing would remain a priority for residents, employees and visitors; residents would be allowed to go to the dining room and participate in group activities if asymptomatic; residents should wash their hands before leaving the unit and upon return to the unit; symptomatic residents would remain in their rooms until asymptomatic for 24 hours; beauty shops would open to more than one (asymptomatic) resident; hallway doors would be opened; visitors would continue to be instructed to wash their hands; and all restrictions on employees remained unchanged.


The local HD educator held well-attended handwashing inservices for employees and residents.


Twelve days after the HD inservice there was a reoccurrence of diarrhea on Unit 1 involving residents and employees. The residents were restricted to the unit for one week while the employees continued to be restricted from work if symptomatic. By the end of the week there were no further cases among residents or employees.


Norwalk virus is an RNA genome of the Calcivirus family that causes an active infection that is usually self-limiting. The reservoir for this virus is humans and is distributed worldwide. An infection can occur with exposure to as little as 10 viral particles. These viral particles are transmitted via a fecal-oral route or from contaminated fomites. On average, the incubation period is 30 to 36 hours but may range from 12 to 60 hours. Clinical symptoms of nausea, vomiting, diarrhea, abdominal pain, myalgia, headache, malaise and low-grade temperature generally last for 24 to 48 hours. Re-infection may occur because the viral particles may be present in the stool for up to two weeks.

It is estimated that 181,000 cases occur annually in the United States. Shellfish have been implicated in outbreaks after being contaminated via fecal matter of food handlers. In Louisiana in 1993 there was a community outbreak secondary to infected oysters contaminated from a malfunctioning sewage system.

In 1992 Norwalk virus was discovered in stool specimens collected during an outbreak at an elementary school. Until a new method of identification was developed in 1995 it was difficult to determine the importance of this virus as a pathogen. The method used for identification of this virus is reverse transcription polymerase chain reaction abbreviated RT-PCR.


Approximately 38 residents and 34 staff members became ill with gastrointestinal symptoms between January 30, 2002 and March 1, 2002. The comprehensive care facility includes approximately 175 residents and 210 staff members. Symptoms reported by the 72 cases included diarrhea (94 percent), nausea (84 percent), vomiting (80 percent), abdominal cramps (55 percent), body aches (52 percent), and fever (50 percent). The temperature range reported was 99-102 degree F with an average of 100.5 F. The median duration of illness was 22 hours with a range of 5.5 to 111.5 hours. Eight residents and five employees sought medical attention. Ten specimens from residents were submitted for analysis; all tested negative for Salmonella, Shigella, Camptobacter and E. coli 0157. Four of 10 specimens tested positive for Norwalk virus. Although six specimens tested negative for viral pathogens, it is possible that those residents were no longer shedding virus at the time the specimen was collected.

The epidemic curve indicates that this outbreak was most likely transmitted person-to-person. An asymptomatic person or an unidentified symptomatic person, such as a visitor, may have introduced illness into the facility. At least two staff members reported having contact with an ill family member before becoming ill. This would indicate that a similar infection was circulating in the community at the same time as the outbreak. The state and local HDs commended the facility for its prompt control measures and cooperation during the investigation.

Brenda Breivogel, RN, BSN, MHSA, has been a member of the Association for Professionals in Infection Control and Epidemiology (APIC) for more than 20 years and has worked in acute care, critical care, long-term acute care and long-term care. She currently serves as regional co-director for the APIC-IN region 9.

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