Gastro Enteritis Outbreak in A Residential Complex for the Elderly

? First Case Peak State/Local dept. Involved Prelim Norvo CDC

23rd 24th 29th 30 31 2 3 6 7 8 9 10 1 1 12 17 18 19 25 26

Jan Feb JunB. Party B. Party Env. Dept Lab samples Phone survey sent yes/no

Contact Frankfort: Lab report

(Forms filled) Bact –ve Fwd. CDC

Staff Meeting

In house Training

Legend

OP Hosp Visit First Case

In house Training

CDC confirms

BACKGROUND

Residential Complex for Elderly is 3 tiered

Independent Living 61 Occupants

Assisted Living 82 Occupants

Nursing Home 27 Occupants

Study Objective:

•Identify Source and Risk Factors and for the outbreak.

•With Emphasis on food-borne disease factors.

ASSISTED LIVING FACILITY

RESIDENTS (N = 82)

AFFECTED NOT AFFECTED

(N= 23) (N= 59)

STAFF (N = 35)

AFFECTED NOT AFFECTED

(N= 13) (N= 22)]

STUDY DESIGN: 1:1 Unmatched Case-Control Study.

Study Tools :

Questionnaire Based Study.

Face to face group interview.

Telephone survey

Study Setting:

• Assisted Living Facility AND some Inputs from

• Nursing Home

• Independent Living

Main Outcome Measures:

1. Attack rates at the 3 living facilities for residents

2. Attack rates for the staff at the assisted living facility

3. Specific food items related attack rates for the staff

Age of Participants

RESIDENTS (N = 82)

AFFECTED NOT AFFECTED

Mean age 85 Mean age 85

(N= 23) (N= 59)

STAFF (N = 35)

AFFECTED NOT AFFECTED

Mean age 37 Mean age 43

(N= 13) (N= 22)

Results:

Figure 1: Common Symptoms

Illness: Symptoms Reported in Residents and Staff

0

20

40

60

80

100

120

Symptoms

% R

epor

t

Residents (%) N=16Staff (%) N=13

Results:

Fig 2 Date of Onset of Illness

0

2

4

6

8

Date of Onset

Staff

Residents

Results: Table No. 1

Some Variables Studied for Association in the Assisted Living Facility (Data is only for the Staff)

 

 1. Social Event Gathering No Association.

 

2. Travel No Association.

 

3. Child care exposure No Association

 

4. Drinking water source No Association

 

5. Spatial clustering No Association

Results

Table No 2 (a) Attack Rates

Level Total subjects

Data Sample

Number ill Attack rate

Level 1: Independent Living*

61 36 8 25% (8/36)

Level 2: Assisted Living**

82 ?82 23 28%(23/82)

Level 3: Nursing Home***

27 27 7 26%(7/27)

Assited Living Staff

35 ?35 15 42%(15/35)

 * Telephone survey to ascertain GI illness in 3-week time frame ** Resident data forms and staff interviews*** Interview with management of Nursing Home

Staff Breakdown

Total subjects

Data Sample

Number ill

Attack rate

Kitchen 10 10 8 80% (8/10)

Other Staff 25 19 5 26%(5/19)

Results

Table No 2 (b) Attack Rates : Staff

Results Table No 3 Risk of GE Associated with Eating of Particular Food amongst staff of a Residential FacilitySN

Food OR P-Value 95% CI

1. 

Tomato and Lettuce 0.85 0.83 0.19-3.7 

2. Rolls 4.3 0.1 0.8-27.9

3. Soup 0.4 0.3 0.06-2.52

4. Green Beans 0.9 0.6 0.2-4.7

5. Roast Turkey 0.5 0.3 0.09-2.5

6. Cheese 0.6 0.2 0.15-2.9

7. Meat Combo 0.3 0.3 0.03-3.9

None of these foods were shown to be associated with the illness.

Laboratory ConfirmationLab Specimen sent on: 11th Feb

Number & type of specimen: One emesis, one stool

Preliminary reports State and CDC: Frankfort Excluded bacteria, forwarded to CDC, CDC reported probable noro virus

Final report CDC: June 7th

Both samples were tested for norovirus (RT-PCR) When using the Region B primer set, 1 of the 2 samples was positive for norovirus.  When using the Region C primer set, 2 out of 2 samples were positive for norovirus.

 In conclusion, this outbreak of gastroenteritis was associated with multiple strains of norovirus belonging to genogroup II.

Conclusion1. The source of outbreak was not likely to be food borne.

2. The likely spread was person to person.

3. Clinical, Epidemiological and Preliminary Lab findings are suggestive of Noro virus outbreak.

4. About half of all GE outbreak in US are Noro Virus

Note: Similar outbreaks were being reported throughout US (Virginia, Nevada, Alaska, California) and also in Europe.Europe (Netherlands, Germany, England) reports emergence of a new noro virus variant, a geno group II 4 virus . Lancet 2004;363:682-8.

Lessons Learnt

Functional Aspects

• The Hospitals and the HD need to work together.

• Establish contact with KY DPH Epidemiology early.

• Daily update with Director of the MCHD.

Investigational aspects

4 Talk to as many people in the facility as possible.

5 Check tool for appropriateness: large font for elderly.

6. Notify health providers: They assist in case finding.

7. Take and specimen containers on initial visit & make specimen collection a top priority

Lessons Learnt

a. Some useful tools for investigation could be:

                        i.      Large calendar of time frame involved with significant events of the time to help staff and residents be oriented to dates.

ii Group meetings help in standardizing the information people receive and ascertains memories that are agreed upon by the staff. New sources of documented evidence can be unearthed, such as “communication book.”

Shortcomings

Shortcomings of this investigation: 1.   1)  1/3 of residents have some memory loss2) Working through management to obtain individual data has

significant limitations. 3) Delay in obtaining information from staff.