Valley fever cases are rising in SLO County. What is causing the spike?

COVID-19 is not the only flu-like illness spiking in San Luis Obispo County this summer.

According to public health officials, the area has seen its highest rate of cases of valley fever in the last ten years, and they expected the numbers to keep going up.

Coccidioidomycosis — more commonly known as valley fever or cocci for short — is a lung infection caused by inhaling the coccidioides fungus found primarily in soil. While it is not contagious via human contact, rising infection rates have raised flags for public health officials.

During the last decade, SLO County has averaged 220 cases of valley fever each year. As of this September, the county has already surpassed that average with 240 cases and growing, according to County Public Health Department epidemiologist Jessie Burmester.

“We do expect for this 240 cases to continue to rise as we come into fall and winter,” Burmester said.

She said while people typically contract the disease during summer, symptoms can take weeks or even months before they present themselves, delaying the time frame within which people are tested and diagnosed and leading to more cases in the later seasons.

“While the exposure to the fungus happens in the summer months, we don’t actually see people typically diagnosed until the fall and winter,“ Burmester said. “We’re actually coming into the months right now — meaning September, October, November, December and January — where we have locally the highest amount of diagnoses of valley fever.”

Valley fever cases are on the rise in California. Here’s what to know about symptoms, causes

Who is most at risk?

Exposure can take place when dust and dirt is disturbed, causing fungal spores to become airborne, according to Burmester.

For that reason, construction and agricultural workers — especially those working with roots and bulb vegetables very close to the ground — are at higher occupational risk to valley fever, she said.

Other at-risk populations include adults older than 60 years old, people with underlying health conditions and pregnant individuals, she said.

What is causing the rise in valley fever cases?

Burmester said the cause of this spike is likely environmental.

“The kind of environmental relationship of valley fever is being heavily investigated nationwide,” she said.

A recent study in California found a correlation between periods of drought followed by wet winters and subsequent fungal blooms of coccidioides, which can lead to higher cases of valley fever.

This is not the first year California has battled increased instances of the disease.

Cases spiked dramatically in 2016 locally and statewide, and have more or less risen steadily every year since.

In 2023, California saw the largest number of valley fever patients to date at 9,280 cases, which was predicted to carry into 2024 due to the heavy rainfalls of the previous 2022-23 winter after years of drought.

San Luis Obispo is not the only county in California that has become a hotbed for valley fever this year.

Kern and Tulare counties are also seeing more cases than normal, as well as neighboring Santa Barbara and Monterey counties that have historically had very low numbers, she said.

What to look out for

The symptoms of valley fever mimic that of the flu or common cold and include fatigue, headache, shortness of breath and coughing, but Burmester said that 6 in 10 people will be asymptomatic.

Valley fever is considered a self-limiting disease — meaning that it will often go away on its own and will not require medical intervention — but anti-fungal treatment is needed in some cases, she said.

“That’s kind of worst-case scenario,” Burmester said. “What we want people to be aware of is that it does exist in the county, and pretty much anyone is at risk of getting it.”

In extremely rare cases, the fungal infection can spread to other organs, requiring life-long treatment and a risk of death, but Burmester said there was maybe a 1% chance of that happening.

Burmester recommended taking preventative measures like rolling up your car windows when driving through windy rural areas.

Due to the symptomatic similarity to other respiratory diseases, it can be difficult to distinguish valley fever from other illnesses like COVID-19 or the flu without a test.

While 60% of patients will not experience any symptoms, Burmester encouraged those whose symptoms develop and persist to see a medical professional for a blood test or chest X-ray.

“It’s really important that people are just aware of valley fever so if they do develop symptoms — if they need to get tested — that they feel empowered to request a test for valley fever,” Burmester said.