1609. Using a Novel Rapid Test to Investigate a Multistate Outbreak of Coccidioidomycosis Among US Residents Returning From Mission Trips in Baja California, Mexico, June–July, 2018

BACKGROUND: In August 2018, New York City health authorities notified CDC of two students with pneumonia and rash following mission trips to Mexico. Send-out Coccidioides serology tests took 7 days for results to return. Both students and five additional travelers from four states were diagnosed with coccidioidomycosis. A seroepidemiologic survey implicated soil-disturbing activities at a single site as a likely source. Given the time to diagnosis observed, we examined the use of a novel one-hour lateral flow assay (LFA). METHODS: We interviewed and collected sera from people who traveled with seven case-patients during June‒July 2018 and performed LFA, enzyme immunoassay (EIA), and immunodiffusion (ID). We asked travelers about exposures and symptoms and compared test results with reports of ≥1 coccidioidomycosis symptom(s) within 6 weeks of travel. RESULTS: Of 133 travelers, we interviewed 108 (81%) and collected sera from 75 (56%). Majority were male teenagers. One-third (34%, 37/108) reported symptoms, and of those, 43% (16/37) sought healthcare. Four were hospitalized, including one in intensive care, for a median of 7 days (range 3–12). Only six (6%) had previously heard of coccidioidomycosis. One-third (32%, 24/75) tested LFA positive, 10 (13%, 10/75) EIA positive, and eight (11%, 8/75) ID positive. Seventy-one percent (17/24) with positive LFA reported symptoms, compared with 83% (10/12) with positive EIA, 100% with positive ID (8/8), and 31% (16/51) with negative LFA. Of 51 travelers with negative LFA, we observed one positive EIA and no positive ID. CONCLUSION: In this outbreak that resulted in a high attack rate and prolonged hospitalizations, the rapid one-hour LFA appeared as a useful screening tool compared with send-out testing, which took at least 7 days to return. The proportion of symptomatic LFA-positive travelers was nearly as high as for those with positive EIA, and we observed agreement with EIA and ID-negative results. Whether 12 people with positive LFA but negative EIA and ID truly had infection is unclear. Further evaluation to examine sensitivity and specificity of LFA are needed. Additionally, greater education is needed for groups traveling to coccidioidomycosis-endemic areas. DISCLOSURES: All authors: No reported disclosures.