image of dust storm coming to depict environment that may be at risk to valley fever

Valley Fever: Taking Precautions if You Work Outdoors

Cases of Valley fever have been increasing, but many are not aware of this fungal agent and that it can be quite dangerous.

What is Valley Fever?

Valley fever (Coccidioidomycosis) is caused by inhalation of the spores of Coccidioides immitis fungus. The fungus is commonly found in the soil of southwestern states of the United States, and more likely to be present in undisturbed soils, compared with cultivated/irrigated soils. Exposure typically comes from inhalation of spore-laden dust and wind bound soil. Valley fever is also known as desert rheumatism, San Joaquin Valley fever and as one form of desert fever.

Very often, affected individuals do not realize they have been infected with the coccidioides immitis fungus. Symptoms may be mild and slow to appear. When common Valley fever symptoms such as fatigue, cough, chest pain, fever and joint pain do present, they may be mistaken for bronchitis or pneumonia.

It is important to note that Valley fever is not contagious. Many people often believe it is contagious because the symptoms are like those of the flu. People also think that Valley fever, because it is a fungus, might be able to spread like athlete’s foot. This is not the case.

Where is Valley Fever Found?

Cases of Valley fever are most common in the arid southwest region of the United States.

Known and suspected areas where the fungus that causes Valley fever lives in the United States
Known and suspected areas where the fungus that causes Valley fever lives in the United States. Image provided by CDC.

However, cases in other states have also been reported. The Centers for Disease Control (CDC) estimates 30-60% of the population in these areas will be exposed to this fungus during some time of their lives. The highest risk times for infection are June to July and October to November in Arizona, as well as June to November in California.

Cases of Valley Fever Have Been Increasing over Recent Decades

The number of Valley fever cases has increased over recent decades reportedly due to natural disaster events including drought conditions, wildfires and massive flooding/mudslides where the spores of the fungus are pushed up out of the ground and into the air. According to the CDC, the number of cases increased 850% between 1998 and 2011.

Between 2012 and 2016, there were more than 58,000 cases reported in the United States. Of those infected, 60 percent show no symptoms; 38-39% demonstrate mild to moderate symptoms. For most people, the body fights off the disease with no medical intervention. Valley fever presents the most danger in the 0.5 – 2% of the population who have a secondary infection or dissemination of the fungus to other organ systems. This progression causes a severe form of Valley fever. Dissemination of the fungus throughout the body can cause severe effects, including pneumonia, meningitis, or bone and joint infection. If this is left untreated it can be fatal. Even though it is difficult to diagnosis, there are tests and treatments available for Valley fever.

Who is at Risk?

Exposure to fungal spores and Valley fever can put workers involved in outdoor activities at risk, particularly if the work involves disturbing soil. Occupations at risk of Valley fever include any that disturb the soil, such as road and construction workers, archeologists, geologists, wildland firefighters, mining workers, solar panel installation workers, gas and oil extraction workers, and agricultural workers.

Although it is not known why—genetics may play a factor— some African Americans and certain people of Asian descent are more likely to develop the severe form of Valley fever or develop an infection that spreads beyond the lungs. Additionally, pregnant women who are in the third trimester and people who have weakened immune systems may also be at a higher risk for contracting the more severe form resulting from dissemination to other organ systems.

Precautionary Measures to Help Avoid Contracting Valley Fever

Here are some suggested control measures to help limit contracting Valley fever:

  • Avoid areas that may harbor the fungus
  • Restrict high-risk workers from contaminated areas if possible
  • Implement a dust control plan (e.g. soil watering) to minimize airborne soil and spores
  • Install HEPA air filters on enclosed equipment cabs
  • Provide personal hygiene (washing) facilities
  • Minimize work on unusually windy days
  • Wash prior to eating, smoking, or drinking and at the end of the shift

Personal Protective Equipment (PPE) Recommendations

Because of the pervasive nature of the fungus in the soil, engineering exposure controls may not be feasible in many cases. Using the following PPE precautions in dusty work areas may help workers prevent exposure to Valley fever fungal spores:

All PPE should be used per Occupational Safety and Health Administration (OSHA) regulations and manufacturer user instructions. The use of NIOSH-certified respirators in workplace environments must be accompanied by a full respiratory protection program as specified by OSHA in 29 CFR 1910.134. Components of a respiratory protection program include several items, such as written standard operating procedures, medical evaluation, fit testing of any tight-fitting respirator, user training, respirator cleaning and maintenance, and cartridge/filter change-out schedules.

In fact, Cal/OSHA saw a spike in Valley fever cases in 2017, and even fined employers who failed to control employee exposure and ensure workers were using appropriate respiratory protection.

It is important to train workers on the health hazards of Valley fever and its symptoms, proper work procedures and how to use PPE. All workers on a site should understand the need to inform the supervisor of suspected symptoms of work-related Valley fever. In fact, California  required training on this by May 1, 2020

Contractors may also want to consider recruiting only local workers for dusty operations in areas where Valley fever is common. Workers native to the area are more likely to have already had exposure to the fungus and developed immunity to it.

To learn more about Valley fever, we invite you to review our Technical Bulletin #216: Valley Fever and Precautions for Outdoor Workers or talk to our health and safety specialists who can help you by calling 1-800-243-4630 today.