What is Coccidioidomycosis? | Medical News Bulletin

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Wondering if you might have coccidioidomycosis?  Look no further! Learn what it is, who gets it, and how it’s treated with Medical News Bulletin’s guide to Valley fever.

What is Coccidioidomycosis?

Coccidioidomycosis, also known as Valley Fever, is a lung infection caused by inhaling a fungus that lives in desert soils.1 This fungus is mostly found in specific regions of the Southwestern part of the United States such as California, Arizona and Texas, as well as in Mexico and parts of Central and South America.2

Is Valley Fever common?

Valley fever/Coccidomycosis is a rare diagnosis, but it’s actually more common than most people realize. According to the CDC, over 20,000 cases were reported in the US in 2019 alone,3 though experts believe the number should be higher given that many people never get tested or are misdiagnosed.

One reason it flies under the radar, despite the thousands of cases reported each year, is that many people infected with this fungus don’t feel sick. In fact, around 60% of people who are infected don’t show symptoms and are unaware they’ve been exposed to the fungus.2 

For the remaining 30% of people who develop a symptomatic infection, it usually looks like pneumonia or a really bad case of the flu.2 Patients often show up at clinics with a cough, fever, chest pain and feeling exhausted. As you can imagine, these symptoms are easily mistaken for other more common respiratory illnesses, making Valley Fever harder to spot. 

 Even though it doesn’t get talked about much, Valley Fever isn’t a new disease by any means; in fact, it has actually been around for more than 130 years! The first known case was reported way back in 1892, long before scientists figured out what was behind the symptoms. It was these early dust detectives who eventually figured out that the culprit lay beneath their feet the whole time. By studying California soil, they discovered a fungus that could settle in the lungs and colonise them, leading to what we now know as Coccidiodomycosis.4 

Who gets Valley Fever?

The most important takeaway here is that Valley Fever isn’t contagious. In other words, you can’t catch it from another person or from animals. The only way to get the disease is by directly breathing in Coccidioides spores from the air, so if you haven’t been around the fungus, you’re not at risk.

Some people are more likely to pick up a Coccidioides infection than others, and not everybody who develops an infection will get very sick. The type of job someone works can definitely put them more at risk, especially when the job involves disturbing dirt. Jobs such as construction, farming, archaeology or military training put people in situations that increase their chances of an infection. 

Where does Coccidioides live?

This fungus likes dry, dusty, desert-like soil, which we typically see in places like Arizona, California, New Mexico, Texas, as well as Mexico. Sometimes microbiologists even find it further afield, extending to some parts of Central and South America.5 Living in or visiting any of these areas can increase your chance of breathing in the spores and eventually getting Valley Fever. It also tends to pop up more during dry months or windy weather, because, as you can imagine, the dust makes it easier for the spores to get into the air. Other factors, such as big dust storms, construction, farming, and even earthquakes, can launch the spores from the soil into the air. 

Who is more likely to get really sick?

Your overall health is a factor that can determine the severity of the disease. If you are in good health with a strong immune system, you can pick up Coccidioides and not even notice. Your body is naturally able to beat the pathogen. On the other hand, people with weakened immune systems, such as those living with HIV/AIDS, cancer or who recently had an organ transplant, have a harder time fighting off the fungus.

Pregnant people are also vulnerable to Valley Fever.  Pregnancy affects the immune system, especially during the last few months when the birthing parent’s immune system is most suppressed, making it harder to fight off infections. 

Racial and ethnic factors have a part to play. Research shows that people of African American or Filipino descent have a much higher risk. People from these backgrounds are about 10 to 127 times more likely to develop the severe form of the disease, which in turn leads to higher hospitalization rates.6 

What are the Symptoms of Coccidioidomycosis?

The symptoms of Coccidiodomycosis vary widely from person to person. Some people don’t develop any symptoms at all, which is why they may never know they were infected. Those those who do get sick, usually exhibit symptoms about one to three weeks after breathing in the fungal spores.1

The most common signs and symptoms of valley fever include:

  • Fever and fatigue
  • Cough and chest pain
  • Headache and body aches
  • Night sweats
  • Skin rash
  • Shortness of breath

You may be wondering, how is this disease even diagnosed when the majority of people don’t show any symptoms, and for those who do resemble the flu? In fact, doctors almost never diagnose Valley Fever based on symptoms alone.  Instead, they use a combination of patient history, such as geographical location, blood tests for antibodies, imaging and more. 

How is Coccidioidomycosis  Diagnosed?

Coccidioidomycosis is often a diagnosis of exclusion. Valley Fever often looks a lot like other respiratory illnesses, such as the flu or pneumonia, so when doctors first interact with patients, they don’t usually jump to diagnosing it right away. In most cases, they rule out the most common causes first, such as pneumonia, tuberculosis, bronchitis, viral infections and even COVID-19. As the doctor continues to collect information, such as the patient’s symptoms, medical history and travel history, they will order specific tests to narrow down the condition. These tests include:

Blood tests: These tests look for antibodies that show the immune system is responding to the Coccidioides fungus. Elevated levels of inflammatory markers, such as C-reactive protein or increased globulins (hyperglobulinemia), may also support the diagnosis.

Imaging studies: A chest X-ray or CT scan may show signs of infection such as inflammation, lung nodules, or cavities.

Sputum or tissue samples: Samples of mucus, lung tissue, or other fluids may be collected and examined under a microscope or grown in a laboratory culture to identify the fungus visually. In certain cases, more advanced methods such as polymerase chain reaction (PCR) testing can be used to detect the fungal DNA more quickly.

Physical examination: A healthcare provider may check for rashes, swollen lymph nodes or other visible signs of infection that sometimes accompany Valley Fever. In more severe cases, imaging of other organs with CT or MRI scans might be recommended if the infection is suspected to have spread beyond the lungs.

Is there a cure for Coccidioidomycosis?

Most mild cases of Valley Fever resolve naturally without any medical treatment. Resting, staying hydrated and eating well gives your body the support it needs as your immune system clears the infection. If symptoms such as fever or pain persist, they can be managed with over-the-counter medications and supportive care. When the infection is moderate or severe, or when it spreads beyond the lungs, doctors can prescribe antifungal medications. The goal of these drugs is to slow or stop the growth of the fungus and prevent complications.

The FDA-approved treatments for Valley Fever include amphotericin B and ketoconazole. While effective, these medications can cause significant side effects, so their use is often limited to serious infections or patients who cannot tolerate other drugs. Newer antifungal medications are being used more often, even though they’re technically off-label. These include isavuconazole, posaconazole, voriconazole, fluconazole, and itraconazole. These medicines have the fewest side effects and are safe to use for as long as several months, depending on how the infection responds to treatment.7

People with chronic or disseminated disease often need long-term therapy and close medical monitoring. Some may require hospital care, especially if the infection affects the brain, bones or other vital organs. In rare cases, surgical intervention may be necessary to remove infected tissue or drain abscesses.8 

Does Coccidioidomycosis have complications?

Chronic Coccidioidomycosis

If symptoms last for a long time or worsen, the infection may have entered the chronic stage. This can happen when the immune system is unable to completely eliminate the fungus.2

Symptoms may include:

  • Persistent cough that produces mucus
  • Weight loss and ongoing fatigue
  • Night sweats and chest discomfort
  • Lung nodules or cavities that may show up on imaging tests such as X-rays or CT scans

Disseminated Coccidioidomycosis

In very rare cases, the fungus spreads beyond the lungs to other areas of the body. This is called disseminated coccidioidomycosis, which is the most serious form of the disease and can be life-threatening. It can affect the skin, bones, joints or the central nervous system. Symptoms depend on which part of the body is involved.9

  • Skin infections.
  • Bone and joint infections can cause pain, swelling, and stiffness.
  • If the infection reaches the brain, it can lead to meningitis, a dangerous inflammation of the tissues around the brain and spinal cord.

What causes Valley Fever?

Coccidioidomycosis begins when a person breathes in the tiny fungal spores that live in dry soil. These spores, known as arthroconidia, are the infectious form of the fungus. In the soil, the fungus grows in thin, thread-like strands called hyphae. The hyphae break apart into tiny, dusty spores when the ground is disturbed by wind, farming or construction. Once inhaled, the spores travel deep into the lungs, and they transform into larger, round structures known as spherules. Spherules are filled with many smaller particles called endospores. When a spherule bursts, it releases the endospores into nearby lung tissue. These endospores can then grow into new spherules, continuing the infection cycle.10,13 

There are three main stages of the disease.

  1. Initial (Acute) stage: During this stage, the fungi begin to multiply inside the lungs. This triggers inflammation and leads to symptoms that resemble the flu, such as fever, cough, chest pain and fatigue.11
  2. Resolution or Recovery Stage: In most healthy people, the body’s immune system is able to control the infection within a few weeks or months. Many people recover without needing any medical treatment and may develop immunity that protects them from future infections.11
  3. Chronic or Disseminated Phase: In some people, especially those with weakened immune systems, the infection does not completely go away. Instead, it can remain in the lungs for a long time or spread to other parts of the body, such as the skin, bones, or even the brain. This advanced stage is more serious and may require long-term antifungal treatment.12

How can I avoid Valley fever?

Currently, there is no vaccine available for Valley Fever.3 Researchers are working to develop one, but for now, the best way to avoid getting sick is to limit how much dust you breathe in- especially if you live in or travel to high-risk areas.

Simple things like avoiding outdoor activities during dust storms, keeping doors and windows closed on windy days, and wearing a mask if you have to work outside can make a huge difference to one’s health.

Employers and job site managers in fields like construction, agriculture and landscaping also have a responsibility to protect workers and people who live nearby. According to the United States’ Occupational Safety and Health Administration (OSHA), some tips they recommend include wetting down the soil before digging to keep dust from flying everywhere, using enclosed or air-conditioned vehicles with good air filters and keeping all equipment filters clean and well-maintained.

Workers should also get proper training on Coccidioides so they know the risks, the symptoms to watch for and when to speak up. 

Reference List

  1. Zaheri, S. C., Field, E., Orvin, C. A., Perilloux, D. M., Klapper, R. J., Shelvan, A., Ahmadzadeh, S., Shekoohi, S., Kaye, A. D., & Varrassi, G. (2023). Valley fever: Pathogenesis and evolving treatment options. Cureus, 15(12), e50260. https://doi.org/10.7759/cureus.50260
  2. Donovan, F. M., Fernández, O. M., Bains, G., & DiPompo, L. (2025). Coccidioidomycosis: A growing global concern. Journal of Antimicrobial Chemotherapy, 80(Suppl_1), i40–i49. https://doi.org/10.1093/jac/dkaf002
  3. CDC. Valley Fever. Valley Fever (Coccidioidomycosis). April 11, 2025. Accessed January 12, 2026. https://www.cdc.gov/valley-fever/index.html
  4. Deresinski, S., & Mirels, L. F. (2019). Coccidioidomycosis: What a long strange trip it’s been. Medical Mycology, 57(Supplement 1), S3–S15. https://doi.org/10.1093/mmy/myy123
  5. Brown, J., Benedict, K., Park, B. J., & Thompson, G. R. III. (2013). Coccidioidomycosis: Epidemiology. Clinical Epidemiology, 5, 185–197. https://doi.org/10.2147/CLEP.S34434
  6. Johnson, R. H., Sharma, R., Kuran, R., Fong, I., & Heidari, A. (2021). Coccidioidomycosis: A review. Journal of Investigative Medicine, 69(2), 316–323. https://doi.org/10.1136/jim-2020-001655
  7. Crum, N. F. (2022). Coccidioidomycosis: A contemporary review. Infectious Diseases and Therapy, 11(2), 713–742. https://doi.org/10.1007/s40121-022-00606-y
  8. Johnson, L., Gaab, E. M., Sanchez, J., Bui, P. Q., Nobile, C. J., Hoyer, K. K., Peterson, M. W., & Ojcius, D. M. (2014). Valley Fever: Danger lurking in a dust cloud. Microbes and Infection, 16(8), 591–600.https://doi.org/10.1016/j.micinf.2014.06.011
  9. Harvey, E., Clegg, J., Bresnik, M., Blatt, E., Hughes, S., Umanzor-Figueroa, C., Purdie, R., Thompson, G. R., & Symonds, T. (2025, March). Development of a novel patient-reported outcome measure for disseminated coccidioidomycosis (Valley Fever). Journal of Antimicrobial Chemotherapy, 80(3), 657–665. https://doi.org/10.1093/jac/dkae453
  10. Nosanchuk JD, Snedeker J, Nosanchuk JS. Arthroconidia in coccidioidoma: case report and literature review. Int J Infect Dis. 1998;3(1):32-35. doi:10.1016/s1201-9712(98)90092-3
  11. García García, S. C., Salas Alanis, J. C., Flores, M. G., González González, S. E., Vera Cabrera, L., & Ocampo Candiani, J. (2015). Coccidioidomycosis and the skin: A comprehensive review. Anais Brasileiros de Dermatologia, 90(5), 610–619. https://doi.org/10.1590/abd1806-4841.20153805
  12. Akram, S. M., & Koirala, J. (2023, February 25). Coccidioidomycosis. In StatPearls [Internet]. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK448161/
  13. Kollath, D. R., Miller, K. J., & Barker, B. M. (2019). The mysterious desert dwellers: Coccidioides immitis and Coccidioides posadasii, causative fungal agents of coccidioidomycosis. Virulence, 10(1), 222–233. https://doi.org/10.1080/21505594.2019.1589363
  14. Williams, S. L., & Chiller, T. (2022). Update on the epidemiology, diagnosis, and treatment of coccidioidomycosis. Journal of Fungi, 8(7), 666. https://doi.org/10.3390/jof8070666