1455. Diagnosis and Testing of Travel-Associated Dengue, Alameda County, California – 2019

Abstract

Abstract Background Dengue is an acute febrile infection with one of the four dengue viruses that are transmitted through the bite of mosquitoes. It is a communicable disease reportable to local health departments under Title 17 of the California Code of Regulations via CalREDIE (California Reportable Disease Information Exchange), which receives positive Electronic Lab Reports or Confidential Morbidity Report forms when Dengue infection is strongly suspected. Alameda County is among the top 5 jurisdictions in California for travel-associated Dengue infection reports. In order to inform best practices for diagnosis and treatment, we explored Dengue reports to Alameda County pre-pandemic. Methods CalREDIE data for possible Dengue infections from 2019 were categorized according to CSTE’s Dengue Virus Infections 2015 Surveillance Case Definition into cases (probable and confirmed) or non-cases (suspect and not a case). Univariate and bivariate analysis were conducted in R. Results In 2019, 83 reports of possible Dengue infections were received; 23 met the case classification criteria for confirmed (n=8) or probable (n=15) cases. Most (61%) of the cases were reported between the months of June and October (Figure 1). All cases were symptomatic after travel to an area where Dengue is endemic, notably India (39%), Mexico (17%) and the Philippines (13%). Of the cases, 70% visited the Emergency Department and 48% were hospitalized due to concerns for severe dengue (Table 1). Cases had > 4 times the odds of being hospitalized (Odds Ratio = 4.89, 95% Confidence Interval = 1.63-14.7, p = 0.01) compared to non-cases. 78% of the cases were tested for Dengue within 1 week from symptom onset, but of those, only 39% had a PCR or antigen test while 83% had an IgM test and 78% had an IgG test (Table 2). Figure 1Table 1:Patient Characteristics by CalREDIE Case Resolution Status of 2019 Dengue ReportsTable 2:Laboratory Testing Practices for 2019 Cases with Labs within 7 days of Symptom Onset Conclusion More outreach efforts are needed to educate health care providers on providing timely and adequate testing to travelers and improve diagnosis of travel-associated Dengue. Based on pre-pandemic surveillance in Alameda County, Dengue should be strongly suspected in patients who present with an acute febrile illness and history of travel to Dengue endemic areas such as India, Mexico, and the Philippines. Health care providers suspecting Dengue should test with either PCR or antigen tests within a week of symptom onset. Disclosures All Authors: No reported disclosures.