FDA对密歇根州环孢子虫疫情的溯源快速锁定单一供应商，受访病例中90%食用过生菜，Taco Bell单一连锁餐厅的供应链记录提供了关键帮助。CDC对患者粪便样本采用八标记基因分型而非全基因组测序，产品检测对该寄生虫也困难且不可靠。召回生菜于6月29日至7月16日发货，但多数病例的发病时间在数周前，此次召回主要是前瞻性预防。
📝FDA seems to have relied on a strong epidemiological case here: Michigan’s ingredient-level analysis had 90% of interviewed cases eating iceberg lettuce. FDA’s traceback then quickly converged on a single supplier, all things considered. Strong supply chain records at a single restaurant chain (Taco Bell) likely helped a lot; most Cyclospora outbreaks never get a source at all.
Detection remains the hard part. CDC genotypes stool specimens from patients, but it's an eight-marker panel, not the whole genome sequencing CDC relies on through PulseNet for bacterial pathogens like E. coli. Product testing is separately difficult and unreliable with this parasite.
Expect the national case count to include a substantial number of non-outbreak background cases. CDC and FDA both say as much. But the Midwest cluster looks almost certainly single-source.
The recalled lettuce shipped June 29–July 16. Illness onsets started May 13. Any recall at this stage is mostly prospective — to prevent additional illnesses if contaminated product is still in stores or in people's homes. But the product that caused most of the reported cases was eaten weeks ago.
To clarify, this false-positive lab sample DOES NOT change the basis for FDA’s ongoing outbreak investigation or the overwhelming epidemiological data supporting the current voluntary recall by Taylor Farms. Over the weekend, FDA alerted Taylor Farms that a new sample of shredded lettuce from Taylor Farms de Mexico tested positive for Cyclospora during import examination at the Southern Border. This ended up being a false positive, and Taylor Farms was alerted to the corrective test result Sunday. FDA’s traceback investigation and outbreak data continue to converge on shredded iceberg lettuce from Taylor Farms locations in central Mexico. FDA will continue to work with federal and state partners to investigate this multistate outbreak and ensure products implicated in this outbreak have been removed from the market. Protecting the American public remains our highest priority. We encourage the public to continue to avoid all products listed in Taylor Farms’ voluntary recall. https://www.fda.gov/safety/recalls-market-withdrawals-safety-alerts/taylor-fresh-foods-recalls-iceberg-lettuce-central-mexico-because-possible-health-risk在 X 查看被引用的帖子
来源：Scott Gottlieb, MD 🇺🇸 · x.com