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National update
According to state-level estimates compiled by FOI Clinical, cumulative cyclosporiasis reports now exceed 3,300 nationwide (year-to-date, not confirmed outbreak-related). For context, a typical year sees 3,000 to 4,000 cyclosporiasis cases reported to the National Notifiable Disease Surveillance System. No source has been identified yet.
Michigan remains most affected at 1,562, followed by New York (470) and Ohio (364). At least 500 additional cases have been reported in the last day, including more than 300 in Michigan. Data from the Michigan Department of Health & Human Services show that outbreak signals began in late June and have accelerated steadily since.
According to CDC, which shows lower overall case counts due to reporting delays, patients ranged in age from 5 to 88 (median 44) and 59% were female. Of 843 patients with available information, 86 were hospitalized.
Surveillance considerations
As we reported earlier in the week, standard diagnostic workups do not detect cyclospora, so clinical awareness is especially influential in case detection and reporting. Part of the recent acceleration in states like Michigan may reflect increased testing rather than increased infection. Conversely, states with no recognized increase may be underascertained. The true burden is almost certainly higher, and more widely distributed, than current numbers suggest.
Related
- Cyclospora cayetanensis: Multistate Outbreak with Midwest Epicenter. Comprehensive update on the outbreak, including diagnostic considerations and links to treatment recommendations. July 8 from FOI Clinical.
- A large cyclosporiasis outbreak is underway. An overview of the outbreak for a general audience. July 8 from Force of Infection.
- Clinical Guidance for Cyclosporiasis. CDC