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After unusual July spike in Valley fever cases, Arizona heads into peak season

By Nicholas Gerbis
Published: Friday, November 10, 2023 - 3:05pm

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Valley fever coccidioides fungus
Pooja Gandhi/Centers for Disease Control and Prevention
Medical illustration of coccidioides, the fungus that causes Valley fever (coccidioidomycosis).

Arizona is entering peak Valley fever season.

The state has seen some unusual patterns in the fungal disease over the past few years, including a spike in late July.

Valley fever cases dropped by 17% in 2022, to just over 9,500, with about 700 hospitalizations and 75 deaths.

That still far exceeds the typical annual toll prior to 2020 and 2021, when cases spiked to 11,500 for two consecutive years.

The state health department could not explain the variations, but cited weather patterns, health care-seeking behavior and testing practices as possible factors.

In any case, it’s not just due to population growth: Incident rates per 100,000 have risen over the past decade from around 90 to more than 128.

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