That may be purely an artifact of changing definitions, improved testing and expanded testing. It's only an increase of 57% over the previous values. The "percentage game" is abused by writers of this kind of article. Going from 10 baseline cases to 15 cases is a 50% increase. It sounds alarming if you don't know the actual numbers used to calculate the percentage. Check the details before becoming "alarmed".
I see, that makes sense then. Still I prey for those families affected.