Thursday 24 September 2026 · Edition of the day

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The Skeptic's Daily

The day's biggest stories, taken apart. For each one: what is actually established, what is only asserted, the questions worth asking — and a plausibility score for the central claim, given everything currently known.

Stories
1
Average plausibility
70%
How to read the score
It rates how well the core claim is evidenced — not how important the story is, nor whether it is good or bad news.
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01ScienceNorth America

Bird flu strain circulated undetected for months in North America, study finds

A surveillance gap let the D1.1 H5N1 variant spread unnoticed before its first confirmed detection.

A study led by Arizona State University's Matthew Scotch, with the Arizona Game and Fish Department, compared Arizona H5N1 D1.1 sequences with thousands of public samples. It concluded the lineage likely began expanding around summer 2024, months before its first recognized US detection. D1.1 has infected humans, including a fatal case in Louisiana in early 2025.

What holds up

  • ✓The study was carried out by ASU with the state wildlife department.
  • ✓D1.1 is a variant of the H5N1 clade driving the global outbreak.

What doesn't yet

  • ?The start date and origin of hidden spread are inferred from genetic modeling.
  • ?Whether this reflects an ongoing national surveillance failure is the authors' assertion.

Ask before you share

  • →How much of the wild bird population goes unsampled?
  • →What surveillance changes are planned before the next migration?
  • →What does this imply about current risk to humans?

Sources & original reporting

  1. [1]ASU News · Published 23 Sept 2026 · news.asu.edu