Evaluation of the Epidemiologic and Environmental Health Legionellosis Surveillance System in New York State

BACKGROUND:   Legionellosis encompasses both Legionnaire’s Disease, a severe atypical pneumonia, and Pontiac Fever, a more mild illness with influenza-like symptoms. Patients in hospitals and long-term care (LTC) facilities are often more susceptible to legionellosis due to a variety of co-morbidities and weakened immune systems. Currently, a joint effort exists between epidemiology and environmental health staff during health-care associated (HAI) legionellosis investigations. These investigations include up to 25 New York State Department of Health (DOH) staff from the central and regional offices and local health departments (LHDs). Epidemiological information is reported by LHDs to the New York State Communicable Disease Electronic Surveillance System (CDESS). Voluntary environmental information is gathered via Environmental Assessment Forms (EAFs). The purpose of this surveillance system evaluation is to make recommendations for faster illness detection and response.

METHODS:   Data analysis included CDESS case reports with possible HAI exposures from 2004 to 2013. Data quality was analyzed, which included calculating the percentage of cases with missing information for symptoms, exposures, and clinical information. Timeliness was calculated using the median time between symptom onset, report date, and investigation date. In addition, a questionnaire was administered to DOH staff involved in HAI legionellosis investigations. The questionnaire gathered information on communication barriers and usefulness of current field documents.

RESULTS:   During the period of 2004 to 2013, CDESS reports were missing values for 40% for environmental exposure to aerosolized water variables and between 13-53% of patient symptom variables. Overall, the median time from symptom onset date to report date was eight days. The median time from report date to investigation date was one day. In 2007, facilities and DOH staff began using EAFs. Since then, a total of 145 EAFs have been completed during HAI legionellosis investigations and recorded in a separate database. Overall, the majority of questionnaire respondents reported positive communication between epidemiology and environmental health staff. Multiple staff suggested updating the legionellosis guidance to include specific guides for hospitals and LTC facilities. Staff also suggested to enhance the communication through use of online document sharing tools and monthly calls. 

CONCLUSIONS:   LHDs initiated investigations quickly after receiving possible HAI legionellosis reports. The large amount of missing data in CDESS suggests a need to improve data entry, which require less follow-up and time by epidemiology staff during investigations. Updating current guidance and creating an information sharing protocol between epidemiology and environmental health staff may help to complete investigations more quickly.