San Luis Obispo County Health Officials say they have seen a considerable rise in the number of confirmed Valley Fever cases in the county. Officials say diagnosing Valley Fever can be challenging because symptoms, in the early stages, often appear to be flu-like. Untreated, Valley Fever can be life-threatening. While San Luis Obispo County saw 460 diagnosed cases in 2018. According to KSBY, Kern County had 3,000 confirmed cases of Valley Fever. The most in California.