Valley Fever Risk Factors

Unless you have already had Valley Fever, you are at risk of getting this disease by living, working, playing, or passing through an area where the fungus is growing. For all residents of Kern County, it has been estimated that you have a 1% – 3% chance per year of acquiring Valley Fever.

Many factors such as region of the county that you live or work in matters, risk changes by month, leisure or work activity near undeveloped land, and weather conditions (temperature, wind and rain) all can influence the risk of acquiring Valley Fever.

Factors which increase the chance of catching Valley Fever include:


  • Length of time that you have been living in Kern County-longer times increase risk
  • Duration of time spent in dusty conditions-longer the exposure the greater the risk
  • Being caught in a dust storm
  • Activities that involve intensive contact with undisturbed soils
  • Duration of time spent outdoors
  • In Kern County, June through December are the months that the majority of cases of Valley Fever are reported from.  On average, the risk of catching Valley Fever during these months is 2 times greater that the months between January through May.  Typically, the risk of catching Valley Fever begins to increase in June and continues an upward trend until it peaks during the months of August, September and October. Following October, there is typically a decline in cases (
  • Risk for men is 1.4 times higher than for females
  • Risk for persons 15 to 44 is 1.6 times higher than for all other age groups combined
  • Area of the county that you live, work or play in. The West side of Kern County (I-5 corridor) which includes Taft, Mc Kitrick, Maricopa, Buttonwillow has the highest risk for acquiring Valley Fever.  When compared to the Mountain or Desert regions of the County, West Valley residents are at 5.4 times the risk of getting Valley Fever.  Similarly, residents of the Valley North and Central have a 4.4 and 3.2 times higher risk of getting Valley Fever than residents of the Mountain and Desert regions ( .