Apparently it's not that simple. They don't say so in the article, but the trouble with identifying the causal agent is that the suspect strains have an incide

Apparently it's not that simple. They don't say so in the article, but the trouble with identifying the causal agent is that the suspect strains have an incidence rate which is multiple orders of magnitude higher than the number of AFM cases. But as far as I know those virus species are not routinely tested for or differentiated that far. It's mostly "just a cold". I think there are more specific causes for the GBS cases, so that may explain a local clustering.