As our planet gets increasingly warmer, we’re seeing in real-time the myriad of ways our climate is changing: unbearably hot summers, extreme cold snaps, and more dangerous natural disasters. And when our environment changes, so do we — especially in regards to our health. Valley fever, a fungal disease that invades our lungs, is one of these not-so-obvious public health concerns. The fungus, which is typically present in the western United States, is projected to spread to new frontiers across the country, my former colleague Keren Landman reported back in 2023.

We knew then that climate change had played some kind of role in the spread of Valley fever. Now, more evidence is coming in about this looming public health threat. Last week, the Journal of the American Medical Association (JAMA) published a brief aimed at practicing doctors that drove home just how neglected Valley fever — and by proxy, other diseases like it — can be.

According to the brief on Valley fever, California’s Department of Public Health recorded over 9,000 cases of Valley fever in 2023, the highest number of recorded cases on record. That same year, California had multiple storms that drenched the state over the course of a few weeks, after a long period of drought starting in 2020. These conditions — long spells of extremely dry weather followed by intense rain — are just right for Valley fever growth and in turn, infections.

The earliest recorded case of Valley fever dates back to the 1890s. For some people, it’s totally asymptomatic. But for others, Valley fever can cause symptoms for weeks or months. And then there’s the unlucky few whose infection travels outside of the lungs and into the skin, bones, or brain. Severe cases can be life-changing and even fatal.

According to the brief, Valley fever is pretty significantly underdiagnosed — cases may be up to 10 to 18 times higher than the 10,000 to 20,000 cases reported to the CDC annually. Doctors can miss the signs because the symptoms are similar to other respiratory infections: a cough, fever, feeling tired. That ends up delaying treatment for people who end up really needing it.

Read the full article about Valley fever and climate change by Sam Delgado at Vox.