Coccidioides immitis, the fungus that causes Valley Fever, is sensitive to climate conditions due to its response to changes in moisture and temperature conditions. Moisture is necessary for the growth of the fungus in the soil, while a dry period is required for the fungus to become airborne and infections to occur.
Temperature is also an important variable in understanding the fungus.
Previous research shows that very high temperatures may partially sterilize the soil, allowing C. immitis to grow in an environment relatively free of competing microorganisms. The general climate conditions in both the Central Valley of California and central Arizona are characterized by seasonal shifts in precipitation, as well as high summer temperatures, and these two areas are therefore regions of high valley fever incidence. Given this background, our research aims to first understand how climate affects incidence, and secondly to develop monthly predictive models based on climate information. Basic relationships between climate conditions and valley fever are complex, and they vary over different time lags. We have developed monthly predictive models using multivariate regression.