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

January 1, 2003

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 inthe Midwest consisting of four distinctive units. Unit 1 is a securedAlzheimer's unit (Medicaid certified) with a capacity of 30 residents. Unit 2has 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-bedMedicaid certified unit. The characteristics of the residents on each unit aresomewhat different. On Unit 1, the Alzheimer's residents are in the mid-laterstages of the disease process and often demonstrate problem behaviors. Unit 2 isa higher acuity unit and often has residents that stay for a short time toconvalesce after a hospitalization. Many of the residents on Unit 3 came to thefacility following hospitalization and were unable to return home. This unit hasresidents that have resided in the facility for a range of one month to 25years. Unit 4 has residents who were hospitalized but were unable to return homeafter convalescence also, however, several of these residents have early-to-midstages of Alzheimer disease or some other form of dementia.


The infection control practitioner (ICP) became aware of a cluster of illresidents on Feb. 21, 2002, as eight residents were identified withgastrointestinal symptoms (nausea, vomiting, diarrhea); there were five cases onUnit 1 and three on Unit 3. The administrator was informed of the cases of whatappeared to be an infectious gastroenteritis. A decision was made to inform thelocal health department (HD) of the possible outbreak of gastrointestinalinfection. During conversation with the nurse manager of the local HD, immediateprevention and control measures and the need for additional data wereidentified. The following immediate actions were taken: immediate re-training ofall personnel on proper handwashing technique; handwashing reminders were postedby every sink in the common-use areas; residents experiencing gastrointestinalsymptoms were asked to remain in their rooms; department heads were instructednot to allow personnel with GI symptoms to work; a line listing of residents andpersonnel with symptoms was initiated; and the rules of operation were given toall 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 fromadministrative reports, interviews with employees, alert charting logs and abrief chart review. From this initial review there were residents identified ashaving symptoms as early as Feb.12, 2002.

Within a couple hours the local HD had communicated with the state HD and haddelivered specimen collection containers so stool samples could be sent to thestate HD laboratory. A centralized stool specimen collection refrigerator wasidentified for the facility (the specimens are usually placed in a cooler with abiohazard marking). During this initial visit the staff nurse from the local HDrequested further information: three days of menus, resident census and thetotal number of facility employees. The line listing for personnel includedtheir name, unit assigned, home address, home telephone number, date of theonset of symptoms, specific symptoms and frequency of the symptoms. It was morechallenging to develop the employee line listing from the attendance logs but aninitial list was prepared that first day.


The next morning the representative from the local HD returned to thefacility 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 forstrict handwashing for everyone entering the building. Instructions were givento the receptionist directing visitors to speak with a nurse prior to visitingresidents. All residents were restricted to the unit where they reside, all unithallway doors were closed, meals were served in the residents' rooms, the beautyshops were closed, planned group activities were cancelled and individualactivities were substituted.

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


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


Three more residents developed symptoms on Units 1, 2 and 4. One certifiednursing assistant (CNA) from Unit 3 was sent home ill. A nurse from Unit 1called in sick and a housekeeper from Unit 1 was sent home ill. Two surveyorsfrom the state HD came to the facility in response to an outbreak-associatedcomplaint. The surveyors reviewed the line listing of residents and employees,the restrictions in place and interviewed a number of residents. There were nosuggestions from the surveyors regarding additional precautions or relaxation ofthe precautions that were in place. One surveyor did indicate that that it wouldbe a good idea not to admit new residents until no new cases were identified for30 to 36 hours. The complaint was unsubstantiated and unverified.


The local HD representative picked up two additional stool specimens. Contactwith the local health department's educator was made by the training coordinatorto 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 thebeauty shops the next day to asymptomatic residents with the followingrestrictions: Residents had to be asymptomatic for 24 hours prior to visitingthe beauty shop; one resident could be in the shop at a time; beauticians had tobe asymptomatic for 24 hours prior to caring for the residents; beauticianswould wash their hands and disinfect the chairs and surfaces between residents;and residents' hands would be washed before leaving their unit and upon returnto the unit where they reside.


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


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

Confirmation was received from the state HD that the causative agent for thisoutbreak was Norwalk virus. Instructions were given that stringent preventionand control measures must be maintained until there were no new cases reportedfor four days. An outbreak of Norwalk virus in a nursing home can last two tosix 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 bythe state HD.

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


Due to the number of employees affected by the outbreak two exceptionsregarding floating employees were made to meet residents' needs on Unit 3; twoqualified medication aides were selected to float between Units 3 and 4. Theunit director instructed these individuals on handwashing and other preventionmeasures.


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 fromUnit 2, who also is a local college student, reported that a number of herfellow students and instructors had been ill with gastroenteritis. Two nursescalled in sick with vomiting and diarrhea. The department managers were updatedon 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 weretransferred to Unit 3 to allow the renovation of Unit 4 to continue. Theresidents being transferred did not have any symptoms of gastroenteritis nor didthe 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 totheir unit, disinfect ion of common surfaces, etc. Each student was providedwith alcohol hand gel before leaving the training room. Two hours later one ofthe nursing assistant students was sent home due to diarrhea. The individual wasinstructed to collect the next diarrhea stool specimen because it wasquestionable whether the student was really ill. Keeping with the restrictionsthe student was instructed not to return to the facility until asymptomatic for24 hours. No specimen was collected from this student. An update of the outbreakwas given to the local HD. Two residents were moved into the newly renovatedprivate 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 illchild. Employee questionnaires were faxed to the local HD.


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

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


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


Twelve days after the HD inservice there was a reoccurrence of diarrhea onUnit 1 involving residents and employees. The residents were restricted to theunit for one week while the employees continued to be restricted from work ifsymptomatic. By the end of the week there were no further cases among residentsor employees.


Norwalk virus is an RNA genome of the Calcivirus family that causes an activeinfection that is usually self-limiting. The reservoir for this virus is humansand is distributed worldwide. An infection can occur with exposure to as littleas 10 viral particles. These viral particles are transmitted via a fecal-oralroute or from contaminated fomites. On average, the incubation period is 30 to36 hours but may range from 12 to 60 hours. Clinical symptoms of nausea,vomiting, diarrhea, abdominal pain, myalgia, headache, malaise and low-gradetemperature generally last for 24 to 48 hours. Re-infection may occur becausethe 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 fecalmatter of food handlers. In Louisiana in 1993 there was a community outbreaksecondary to infected oysters contaminated from a malfunctioning sewage system.

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


Approximately 38 residents and 34 staff members became ill withgastrointestinal symptoms between January 30, 2002 and March 1, 2002. Thecomprehensive care facility includes approximately 175 residents and 210 staffmembers. Symptoms reported by the 72 cases included diarrhea (94 percent),nausea (84 percent), vomiting (80 percent), abdominal cramps (55 percent), bodyaches (52 percent), and fever (50 percent). The temperature range reported was99-102 degree F with an average of 100.5 F. The median duration of illness was22 hours with a range of 5.5 to 111.5 hours. Eight residents and five employeessought medical attention. Ten specimens from residents were submitted foranalysis; all tested negative for Salmonella, Shigella, Camptobacter and E. coli0157. Four of 10 specimens tested positive for Norwalk virus. Although sixspecimens tested negative for viral pathogens, it is possible that thoseresidents were no longer shedding virus at the time the specimen was collected.

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

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