Seasonal Statistical Analysis of Valley Fever in Kern County, California

• Activity Number: 375
• Type: Contributed
• Date/Time: Tuesday, August 2, 2016 : 10:30 AM to 12:20 PM
• Sponsor: Section on Statistics in Epidemiology
• Author(s): Bilin Zeng* and Jessica Struck and Samantha Alaniz and Alondra Valenzuela and Carlos Romero
• Companies: California State University at Bakersfield and California State University at Bakersfield and California State University at Bakersfield and California State University at Bakersfield and California State University at Bakersfield
• Keywords: Coccidioides immitis ; Valley Fever incidence rate ; Time series analysis ; Poisson modeling

Abstract

Coccidioides immitis is a naturally occurring fungus that thrives in the southern part of California and through Arizona. When the fungus dries, it releases spores that are sent airborne through soil disruption. When these spores are inhaled, it can often lead to the development of Coccidioidomycosis, an infection known as Valley Fever, which can in rare cases lead to death. In our study, we examine the association between the monthly incidence rate per 100,000 populations in Kern County, California to palmer drought severity index (PDSI), precipitation, wind speed, temperature, dew point temperature, gust wind speed, fine particulate matter 2.5 (PM 2.5) and PM 10.0 from the year of 2001 to 2014. Due to the lagged environmental effect, a component of time series analysis is taken into account. We also test the assumption of Poisson distribution which is commonly used to model the valley fever incidence rate in most existing literature but its validity is rarely evaluated. A final model is developed to further investigate the effect of the above environmental factors on the valley fever incidence rate in Kern County, California.