From the mayo clinic:
Valley fever is a fungal infection caused by coccidioides (kok-sid-ee-OI-deze) organisms. It can cause fever, chest pain and coughing, among other signs and symptoms.

The coccidioides species of fungi that cause valley fever are commonly found in the soil in certain areas. These fungi can be stirred into the air by anything that disrupts the soil, such as farming, construction and wind. The fungi can then be breathed into the lungs and cause valley fever, also known as acute coccidioidomycosis (kok-sid-e-oi-doh-mi-KOH-sis).

Mild cases of valley fever usually go away on their own. In more severe cases of valley fever, doctors prescribe antifungal medications that can treat the underlying infection.

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The poster hanging at the vet's office says symptoms in pets are:
Asymptomatic coughing - check
"Flu" like symptoms - not so much
lameness - check
neurological signs - not so much
limping - check
weight loss - check - 15.6 lbs on 2/20 - 12.0 lbs today
decreased appetite - check

As far as Valley Fever in humans - a man I used to work with spent 3 months recovering from it - he nearly died. Both of his lungs collapsed, it was terrible.