Coccidioidomycosis

Coccidioidomycosis is a mammalian fungal disease caused by the dimorphic saprophytic fungi Coccidioides immitis or Coccidioides posadasii, which grow as mold in soil and convert to a spherule form within a host organism ^[1]. The fungi reside in arid desert soils of the southwestern United States, most notably California and Arizona, as well as in parts of northern Mexico, Central America, and South America ^[1][2][5].

Approximately 60% of infected individuals have minimal or no symptoms, while around 40% develop clinical manifestations, most often a respiratory illness resembling bronchitis or pneumonia that resolves over several weeks ^[1][2]. In endemic areas, coccidioidomycosis accounts for roughly 20% of community-acquired pneumonia cases ^[1]. Prominent signs and symptoms include profound fatigue, fever, cough, headaches, rash, muscle and joint pain, and loss of smell and taste, with fatigue sometimes persisting for months ^[1]. A minority of cases (estimated 0.5–2%) progress to disseminated disease involving the skin, bones and joints, central nervous system, or other extrapulmonary sites, which is most frequently observed in immunocompromised patients and certain ethnic groups ^[2]. In immunocompromised hosts, severe pneumonia with respiratory failure and bronchopleural fistulas may also occur ^[1].

Coccidioidomycosis is endemic in areas of Arizona, California, Nevada, New Mexico, Texas, and Utah in the United States, as well as in northern Mexico and parts of Central and South America ^[1][2][4][5]. The recognized geographic distribution of Coccidioides species is expanding, with cases increasingly diagnosed in areas such as eastern Washington, Oregon, and Utah ^[2]. Incidence has risen over time in regions such as California's Central Valley, attributed to both climatic and population changes, and the disease is a common cause of community-acquired pneumonia in endemic U.S. regions ^[1][2][4]. Epidemics have been documented far outside endemic areas following dust-generating events, including a December 1977 windstorm originating near Arvin, California, that produced several hundred cases and deaths in distant non-endemic locations ^[1]. Globally, the burden of endemic mycoses including coccidioidomycosis continues to rise yearly, contributing substantially to morbidity and mortality worldwide ^[3].

Human infection results from inhalation of arthroconidia, the airborne spores produced when soil-dwelling Coccidioides mold is disturbed ^[1][2]. Spore release is triggered by environmental disruption of soil during natural events such as windstorms, earthquakes, and fires, as well as human activities including construction, farming, military maneuvers, and recreation ^[1][2]. The fungus remains dormant in soil during long dry spells and proliferates as a mold with long filaments when rains occur, generating spores that become airborne with subsequent soil disturbance ^[1]. The disease is not contagious and does not spread directly between humans or animals ^[1].

Preventing coccidioidomycosis is challenging because it is difficult to avoid inhaling arthroconidia when the fungus is present in the environment, and no completely effective preventive measures exist for residents of or travelers to endemic areas ^[1]. Recommended approaches focus on reducing exposure to airborne dust and dirt, although such measures do not guarantee protection, and individuals in certain occupations may be advised to wear face masks during dust-generating activities ^[1]. Strengthening surveillance for coccidioidomycosis is regarded as essential for preparedness and for improving early diagnosis in endemic regions ^[1].

1. 1Wikipedia contributors. Coccidioidomycosis - Wikipedia [Internet]. Wikipedia. cited 3 Sept 2026.Available from: https://en.wikipedia.org/wiki/Coccidioidomycosis
2. 2Crum NF et al. Coccidioidomycosis: A Contemporary Review. Infect Dis Ther. 2022 Apr. PMID: 35233706. doi: 10.1007/s40121-022-00606-y.PubMed: https://pubmed.ncbi.nlm.nih.gov/35233706/
3. 3Thompson GR 3rd et al. Global guideline for the diagnosis and management of the endemic mycoses: an initiative of the European Confederation of Medical Mycology in cooperation with the International Society for Human and Animal Mycology. Lancet Infect Dis. 2021 Dec. PMID: 34364529. doi: 10.1016/S1473-3099(21)00191-2.PubMed: https://pubmed.ncbi.nlm.nih.gov/34364529/
4. 4Bays DJ et al. Coccidioidomycosis. Infect Dis Clin North Am. 2021 Jun. PMID: 34016286. doi: 10.1016/j.idc.2021.03.010.PubMed: https://pubmed.ncbi.nlm.nih.gov/34016286/
5. 5Johnson RH et al. Coccidioidomycosis: a review. J Investig Med. 2021 Feb. PMID: 33495302. doi: 10.1136/jim-2020-001655.PubMed: https://pubmed.ncbi.nlm.nih.gov/33495302/