A new UC Berkeley study reveals that California's shifting climate patterns, particularly longer and drier summers, are extending the transmission season of Valley fever - a fungal disease spreading across the southwestern United States.
Valley fever cases in California typically peak in late summer before declining in winter. However, research published in the Journal of the Royal Society Interface indicates that changing rainfall patterns associated with climate change are causing earlier onset and longer duration of the transmission season.
The disease, also known as coccidioidomycosis, occurs when people inhale spores from the Coccidioides fungus found in arid southwestern soils. These spores can become airborne through wind, construction work, or soil disturbance. Symptoms range from fever and cough to severe complications like pneumonia and meningitis in some cases.
"Climate change in California is expected to bring drier spring and fall seasons with heavier winter rains. Our research shows these extended dry periods can lengthen the timeframe of high Valley fever risk," explained Simon Camponuri, lead researcher and doctoral student at UC Berkeley.
By analyzing historical disease data and climate records, researchers discovered that drier springs trigger earlier transmission seasons while dry falls delay their conclusion. California has recently experienced record-breaking Valley fever cases, raising concerns about climate change's role in disease proliferation.
"Understanding how seasonal rainfall affects Valley fever helps us target interventions and improve testing during peak transmission times," said Justin Remais, professor at UC Berkeley School of Public Health and study leader. He advised healthcare providers to be particularly alert during extended dry periods when disease transmission may increase.
The research team emphasized developing proactive public health strategies as California's climate continues changing. Their findings will help inform public awareness campaigns and medical responses during high-risk periods.