Shigellosis outbreaks at summer camps for the mentally retarded in New York State

Illness and injury among children attending summer camp in the United States, 2005

OBJECTIVES

The purpose of this work was to describe illnesses and injuries sustained by campers at summer camps, calculate illness and injury rates, and identify risk factors for camp-related illness and injury.

METHODS

A convenience sample of camps selected from the US summer camp population participated in this pilot illness and injury surveillance study. Camps completed weekly reports detailing the number of campers on site and the number of adverse events sustained and provided specific information about each adverse event.

RESULTS

A total of 177 camper illnesses and injuries occurred during 122,379 camper-days, with a median rate of 1.15 adverse events per 1000 camper-days. The majority of reported events were illnesses (68.0%), 11.8% of which were communicable and seen in multiple individuals at camp. Of the injury events (32.0%), cut/scratch/scrape were the most common diagnoses (33.3%), followed by fracture (14.6%) and sprain/strain (10.4%); horseback riding and capture the flag were identified as injury-producing activities.

CONCLUSIONS

Internet- and telephone-based surveillance systems can be successfully used to conduct illness and injury surveillance among children attending summer camp. Data collected via such systems can be used to calculate illness and injury rates, to describe patterns of illness and injury, and to identify risk factors for camper-related illness and injury. Given the millions of children attending summer camp yearly, a surveillance system such as this can provide the data needed to develop evidence-based prevention interventions to decrease the number of youth whose camp experiences are negatively affected by illness and injury.

Use of a prospective space-time scan statistic to prioritize shigellosis case investigations in an urban jurisdiction

OBJECTIVE

A prospective space-time scan statistic was applied to Chicago's 2002 shigellosis surveillance data to evaluate its utility in objectively describing clusters and assisting in the prioritization of investigations.

METHODS

The prospective space-time module of SaTScan, a free software available online, was used to identify "live" clusters of disease, meaning cases that were current as of the date of the analysis and strongly associated in place and time. Fifty-two separate space-time analyses were run; one simulation for each week of 2002. Identified clusters were described in terms of space, time, risk factors reported by involved case-patients, and cases' links to venue-associated outbreaks.

RESULTS

Twelve live clusters were detected at the p < 0.05 significance level: two single-household clusters and 10 community clusters. The community clusters ranged in size from 194 to 367 census tracts (median = 294), and in disease burden from 21 to 41 cases (median = 29). Geographically, all of the community clusters were located in the west-central part of the city and had a temporal span of 28 days. Within the 10 community clusters, 15 different day care centers were identified as potential exposure settings for case-patients or their close contacts.

CONCLUSIONS

The prospective space-time scan statistic offers local health departments an objective way of describing clusters of shigellosis cases. The method used in this study could help prioritize the assignment and investigation of cases, particularly when overall shigellosis incidence exceeds expected numbers or when an agency's resources are stressed by other events, such as outbreaks.

Application of a geographic information system to the tracking and control of an outbreak of shigellosis

A personal computer-based commercial geographic information system (GIS) was applied to an outbreak of Shigella sonnei infection at Fort Bragg, North Carolina. We used a database consisting of demographic, temporal, and home-address information for all recognized cases of S. sonnei that occurred among health care beneficiaries from 23 May 1997 through 14 August 1997. We imported this database into the GIS, which contained a digitized basemap of the local community. Through simultaneous examination of temporal and spatial distribution of the 59 identified cases of S. sonnei, a focus of infection in a single housing area was identified. Targeted education among residents of the neighborhood in which there was intense transmission was associated with prompt extinction of the epidemic. A GIS offers an efficient and practical way to directly visualize the dynamics of transmission of infectious diseases in the setting of a community outbreak.