METHODS: Data from the Merlin reportable disease reporting system were used to analyze the timing of symptom onset, sample collection, laboratory reporting, CHD notification, and MC notification for CHIK cases from 2014-2015 and DEN cases from 2009-2015.
RESULTS: From 2014-2015, 579 cases of imported CHIK and 12 locally acquired CHIK cases were reported. From 2009-2015, 673 imported cases of DEN and 130 locally acquired DEN cases were reported. The CHDs were notified of CHIK cases an average of 29.5 days after onset of symptoms, over a week longer than for DEN cases. Similarly, the timing of onset to sample collection for CHIK cases (17.24 days) was also longer than for DEN cases (7.15 days). However, initial case notification through laboratory reports (56% of all cases), took longer for commercial laboratories compared with the state public health laboratories. The greatest difference was seen with CHIK cases, with commercial laboratories taking an average of 8.19 days longer than the state laboratories for positive result reports to reach CHDs. Many commercial laboratories reported CHIK test results via paper laboratory reports vs. electronic lab reports, which differed from other arbovirus testing. The average amount of time from CHD notification to MC notification could only be calculated for 2014-2015, and was 2.1 days for CHIK, and 3 days for DEN.
CONCLUSIONS: Reporting to the CHD and MC was delayed for both arboviruses. The delay seen in CHIK reporting compared to DEN could be due in part to CHIK being an unfamiliar disease for many clinicians, as well as the less efficient reporting methods used by commercial laboratories. Ways to improve timeliness of reporting to CHDs and MC should be investigated further.