The spread of Zika virus disease throughout South and Central America, as well as the Caribbean islands, poses a threat to the southeastern portion of the United States where Aedes aegypti mosquitoes are present. While most infected people have no or mild rash illness, epidemiologic evidence points to maternal Zika virus infection being associated with birth defects, including microcephaly. In Florida, preventing autochthonous transmission of Zika virus disease is paramount.
Syndromic surveillance (SyS), with its near real-time data, has shown value responding to emerging infectious pathogens. The Florida Department of Health (DOH) utilizes the Electronic Surveillance System for the Early Notification of Community-Based Epidemics (ESSENCE-FL) as its SyS-system; there are five data sources in ESSENCE-FL including emergency department (ED)/urgent care center (UCC) and poison control (PC) call data.
METHODS:
In February 2016, a letter was issued to all EDs requesting that they ask then record, in the chief complaint field, recent patient travel history and pregnancy status. Zika queries were run against the ESSENCE-FL ED chief complaint and discharge diagnosis data and separate queries were used to review the PC data. The ED query was
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An ESSENCE-FL foreign travel query was utilized to search ED chief complaints for country names. ESSENCE-FL was adapted to make the triage note a searchable field. When Zika visits were identified, an email was sent to county health departments (CHDs) for follow-up. Results were tabulated; Within DOH’s reportable disease system, county epidemiologists noted when a case was first identified via ESSENCE-FL queries.
RESULTS:
From February 1 – March 23, 2016, the Zika query resulted in 37 flagged ED/UCC visits sent to the CHDs for further investigation. The foreign travel queried flagged 29 ED/UCC visits that were sent to the counties. Five of Florida’s 73 imported Zika virus disease cases were identified using ESSENCE-FL ED/UCC queries. A total of 363 Zika-related PC calls were identified, none of which were determined to be cases.
CONCLUSIONS:
Active case finding using SyS is an important function of these systems. Having rich, real-time data (increasingly available from electronic health records) will only increase the potential for this type of surveillance. Florida’s comprehensive and flexible SyS infrastructure, including designated ESSENCE-FL users in each of the 67 counties, facilitated additional identification of Zika virus disease cases. With appropriate precautions provided to these cases and rapid response from local mosquito control, the risk of local transmission in Florida is reduced.