An Outbreak of Gastroenteritis in a Child Care Center, 1999

On 21st of March 1999 (4/12/1419) nine children were referred from a Child Care Center (CCC) and admitted to the Maternity and children hospital in Makkah. All suffered from diarrhea, vomiting, and one child had fever. They were all diagnosed as gastroenteritis on admission. One of these children died. The objectives of this study was to determine the magnitude of the outbreak, identify the source of infection, limit extent of gastroenteritis in the CCC and recommend suitable preventive measures.

The team from the Preventive Medicine Department in Makkah and the FETP visited the hospital on the same day. Stool and blood samples were obtained from the cases. Medical registers of the hospital were reviewed for the past year and no similar event was recognized. Accordingly, an investigation was initiated. Cases were defined as any child from the CCC complaining of diarrhea and/or vomiting, with or without fever, during the period of 4/12/1419 to 7/12/1419.

At the time of the outbreak, there were 106 children living at the center; 57 males (53.8 %) and 49 females (46.2 %), with ages ranging from 2 months to 7 years. There were 43 baby-sitters and 10 servants; 3 of whom worked in the kitchen. All the children were examined for signs of gastroenteritis, and the baby-sitters interviewed about history of diarrhea and vomiting in the last two weeks. A standard questionnaire containing data related to the clinical picture of gastroenteritis, onset of symptoms, age, sex, food consumed during the last 48 hours, and child-care during the last 48 hours, was completed for each child. Another questionnaire was filled by each baby-sitter, inquiring about methods of food preparation, bottle cleaning, child bathing, diaper changing, and whether any other person helped with child care. Nasal, throat, nail, and rectal swabs were obtained from every child-minder and servant. Two samples of water and residues of milk in bottles, food remains, and swabs from utensils and baby dummies were sent for chemical and bacteriological analysis.

Revision of the hospital register revealed that 9 cases of diarrhea and vomiting were admitted within a 21 hour time period, from 2 a.m. to 11.15 p.m. on 4/12/1419. Their ages ranged from 2 to 15 months (Mean 8.9 months ± 4.4), 6 were males (66.6%) and 3 were females (33.3%), 8 were discharged, and one died. The dead infant was a 6 months old male, who had been complaining of diarrhea and vomiting but no fever, and he died of dehydration as a result of gastroenteritis

All the affected cases lived in one apartment in the CCC, consisting of 3 rooms. The first room was occupied by 6 children, 2 of whom were affected (Attack rate (AR) 33.3%), the second room was occupied by 9 children, 4 were affected (AR 44.4%), and the third room was occupied by 5 children, 3 were affected (AR 60%).

The epidemic curve showed that the median case occurred at 11.00 a.m., the first case at 2.00 a.m., while the last case at 11.15 p.m., all on 4/12/1419. The clinical picture of the disease manifested as diarrhea and vomiting, with or without fever.

With regards to the children€™s' food consumption during the previous week and the 48 hours before the outbreak, all were found to have eaten the same food items at the same time. No association was found between any food item and the occurrence of gastroenteritis.

Results of the rectal swabs and the blood samples were negative for bacteriological growth. Enterobacter.sp. was isolated from milk residues, but was not pathogenic. These findings suggest that this outbreak was neither due to food poisoning, nor was it bacterial in origin. It was most likely viral gastroenteritis.

The epidemic curve indicated that the most likely day of exposure was 3/12/1419 H. The minimum incubation period was 18 hours and the maximum was 39 hours (median 27 hours), which indicated Rotavirus etiology.

On reviewing medical records of the CCC, it was found that during the last week of Thul-Qaeda, one of the servants had suffered from diarrhea, nausea and vomiting, had received treatment, and was on leave since 1/12/1419 H. As reported by the other baby-sitters, this servant had shared in child care in the affected apartment and therefore might have been the source of infection of the first affected child (index case). Subtraction of the median incubation period from the onset of median case indicated that the date of exposure was most likely 3/12/19 H.

Revision of a baby-sitter's practice showed that she was responsible for bathing and diaper changing, in addition to food preparation and feeding the children. On reviewing the baby sitters' work schedules, it was found that baby sitter no. 2 had the highest attack rate, such that all the children under her care were affected. Table 1 demonstrates the percentage of ill Children under each baby sitter's care in the CCC.

The incubation period for rotavirus is known to range between 24 to 48 hours [1]. Rotavirus is a known cause of about half the cases of acute diarrhea in children under 3 years of age worldwide [2]. Furthermore, it has been reported that 50% of children in day care population infected with rotavirus excrete the virus without symptoms [3].

This outbreak may be explained by the hypothesis that the hands of the sick baby sitter (no. 2) might have been contaminated while changing the diaper of the index case, after which she prepared milk bottles or food for the other children. It was recommended to increase the number of baby-sitters and to specify duties, having one assigned for changing of diapers, and another for food preparation and feeding, with emphasis on personal hygiene.