Is what is happening in Idaho an anomaly, a statistical fluke? That is possible. But once it exceeds 1.5 or 2 per million, you start asking questions. If they are all confirmed, it could be odd.

One thing is very clear in Idaho — the number seems to be higher than the number reported in previous years. So far, the investigations have not found any evidence of any exposure that might be common among the cases.

For that part of the country, it seems to be an unusual number of cases.