Coccidioidomycosis

Coccidioidomycosis
Classification and external resources
Histopathological changes in a case of coccidioidomycosis of the lung showing a large fibrocaseous nodule.
ICD-10	B38
ICD-9	114
MedlinePlus	001322
eMedicine	med/103 ped/423
MeSH	D003047

Coccidioidomycosis (also known as "California disease",^[1] "Desert rheumatism",^[1] "San Joaquin valley fever",^[1] and "Valley fever"^[1]) is a fungal disease caused by Coccidioides immitis or C. posadasii.^[2] It is endemic in certain parts of Arizona, California, Nevada, New Mexico, Texas, Utah and northwestern Mexico.^[3]

C. immitis resides in the soil in certain parts of the southwestern United States, northern Mexico, and parts of Central and South America.^[4] It is dormant during long dry spells, then develops as a mold with long filaments that break off into airborne spores when the rains come. The spores, known as arthroconidia, are swept into the air by disruption of the soil, such as during construction, farming, or an earthquake.^[5] Infection is caused by inhalation of the particles. The disease is not transmitted from person to person. C. immitis is a dimorphic saprophytic organism that grows as a mycelium in the soil and produces a spherule form in the host organism.

Presentation

The disease is usually mild, with flu-like symptoms and rashes. The Mayo Clinic estimates that half the population in some affected areas have suffered from the disease. On occasion, those particularly susceptible may develop a serious or even fatal illness. Serious complications include severe pneumonia, lung nodules, and disseminated disease, where the fungus spreads throughout the body. The disseminated form of valley fever can devastate the body, causing skin ulcers, abscesses, bone lesions, severe joint pain, heart inflammation, urinary tract problems, meningitis, and often death. In order of decreasing risk, people of Filipino, African, Native American, Hispanic, and Asian descent are susceptible to the disseminated form of the disease.^[6] Men and pregnant women, and people with weakened immune systems (as from AIDS) are more susceptible than non-pregnant women.

It has been known to infect humans, cattle, deer, dogs, elk, fish, mules, livestock, apes, kangaroos, wallabies, tigers, bears, badgers, otters and marine mammals.^[7]

Symptomatic infection (40% of cases) usually presents as an influenza-like illness with fever, cough, headaches, rash, and myalgia (muscle pain).^[8] Some patients fail to recover and develop chronic pulmonary infection or widespread disseminated infection (affecting meninges, soft tissues, joints, and bone). Severe pulmonary disease may develop in HIV-infected persons.^[9]

An additional risk is that health care providers who are unfamiliar with it or are unaware that the patient has been exposed to it may misdiagnose it as cancer and subject the patient to unnecessary surgery.^[10]

Geographic distribution of coccidioidomycosis.

Types

Coccidioidomycosis may be divided into the following types:^[11]:314-316

• Primary pulmonary coccidioidomycosis
• Disseminated coccidioidomycosis
• Primary cutaneous coccidioidomycosis

Incidence (North America)

California state prisons, as far back as 1919, have been particularly affected by Coccidioidomycosis. In 2005 and 2006, the Pleasant Valley State Prison near Coalinga and Avenal State Prison near Avenal on the western side of the San Joaquin Valley had the highest incidence in 2005, of at least 3,000 per 100,000.^[12]

Incidence varies widely across the west and southwest. In Arizona, for instance, in 2007, there were 3,450 cases in Maricopa County, which in 2007 had an estimated population of 3,880,181^[13] for an incidence of approximately 1 in 1,125.^[14] In contrast, though southern New Mexico is considered an endemic region, there were 35 cases in the entire state in 2008, and 23 in 2007,^[14] in a region that had an estimated 2008 population of 1,984,356^[15] for an incidence of approximately 1 in 56,695. Infection rates vary greatly by county, and although population density is important, so are other factors that have not been proven yet. Greater construction activity may disturb spores in the soil. In addition, the effect of altitude on fungi growth and morphology has not been studied, and altitude can range from sea level to 10,000 feet or higher across California, Arizona, Texas and New Mexico.

In California from 2000 to 2007, there were 16,970 reported cases (5.9 per 100,000 people) and 752 deaths (0.26 per 100,000 people) with the highest incidence in the San Joaquin Valley (44.1 per 100,000).^[16]

Biological warfare

C. immitis was investigated by the United States during the 1950s and 1960s as a potential biological weapon.^{[citation needed]} The Cash strain received the military symbol OC, and original hopes were for its use as an incapacitant. As medical epidemiology later made clear, OC would have lethal effects on several segments of the population, so it was later considered a lethal agent. It was never standardized, and beyond a few field trials, it was never weaponized. Most military work on OC was on vaccines by the mid-1960s. It is still on the CDC's list of select agents however.^[17]

Diagnostic test

The fungal infection can be demonstrated by microscopic detection of diagnostic cells in body fluids, exudates, sputum and biopsy-tissue. With specific nucleotide primers C.immitis DNA can be amplified by PCR. It can also be detected in culture by morphological identification or by using molecular probes that hybridize with C.immitis RNA. An indirect demonstration of fungal infection can be achieved also by serologic analysis detecting fungal antigen or host antibody produced against the fungus.

Treatment

There are no published prospective studies that examine optimal antifungal therapy for coccidioidomycosis. Mild cases often do not require treatment. Oral Fluconazole and intravenous Amphotericin B are used in progressive or disseminated disease, or in which patients are immunocompromised. Alternatively, itraconazole or ketoconazole may be used.^[18] Posaconazole and voriconazole have also been used.

Additional images

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See also

• Medical geology
• List of cutaneous conditions

References

1. ^ ^{a b c d} Rapini, Ronald P.; Bolognia, Jean L.; Jorizzo, Joseph L. (2007). Dermatology: 2-Volume Set. St. Louis: Mosby. ISBN 1-4160-2999-0. 
2. ^ Walsh TJ, Dixon DM (1996). Spectrum of Mycoses. In: Baron's Medical Microbiology (Baron S et al., eds.) (4th ed.). Univ of Texas Medical Branch. ISBN 0-9631172-1-1. (via NCBI Bookshelf). 
3. ^ Hector R, Laniado-Laborin R (2005). "Coccidioidomycosis—A Fungal Disease of the Americas". PLoS Med 2 (1): e2. doi:10.1371/journal.pmed.0020002. PMC 545195. PMID 15696207. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=545195. 
4. ^ http://www.mayoclinic.com/print/valley-fever/DS00695/DSECTION=all&METHOD=print
5. ^ Schneider E, Hajjeh RA, Spiegel RA, et al. (1997). "A coccidioidomycosis outbreak following the Northridge, Calif, earthquake". JAMA 277 (11): 904–8. doi:10.1001/jama.277.11.904. PMID 9062329 
6. ^ http://www.merck.com/mmpe/sec14/ch180/ch180f.html
7. ^ Valley Fever Center for Excellence | url = http://www.vfce.arizona.edu/VFID-other.htm
8. ^ Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology (4th ed.). McGraw Hill. pp. 680–83. ISBN 0838585299. 
9. ^ Ampel N (2005). "Coccidioidomycosis in persons infected with HIV type 1". Clin Infect Dis 41 (8): 1174–8. doi:10.1086/444502. PMID 16163637. 
10. ^ Chen, Karl T. K. (1993). "Cytodiagnostic pitfalls in pulmonary coccidioidomycosis". Diagn Cytopathol 12 (2): 177–180. doi:10.1002/dc.2840120220. PMID 7774502. 
11. ^ James, William D.; Berger, Timothy G.; et al. (2006). Andrews' Diseases of the Skin: clinical Dermatology. Saunders Elsevier. ISBN 0-7216-2921-0. 
12. ^ http://www.blackwell-synergy.com/doi/abs/10.1196/annals.1406.011
13. ^ U.S. Census Bureau, State & County QuickFacts
14. ^ ^{a b} http://www.azdhs.gov/phs/oids/pdf/countycases2007.pdf
15. ^ New Mexico Intercensal Population Estimates from the U.S. Census Bureau [1]
16. ^ Morbidity and Mortality Weekly Report 58;5 105-109
17. ^ http://www.cdc.gov/od/sap/docs/salist.pdf
18. ^ Barron MA and Madinger NE (November 18, 2008). "Opportunistic Fungal Infections, Part 3: Cryptococcosis, Histoplasmosis, Coccidioidomycosis, and Emerging Mould Infections". Infections in Medicine. http://www.consultantlive.com/infection/article/1145625/1404367. 

External links

• U.S. Centers for Disease Control and Prevention page on Coccidioidomycosis
• Medline Plus Entry for Coccidioidomycosis