WikiPortallus: Coccidioidomycosis.html

C. immitis resides in the soil in certain parts of the southwestern United States, northern Mexico, and parts of Central and South America [1]. 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 or farming. 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, and the Mayo Clinic estimates that half the population in some affected areas have suffered from the disease. On occasion, those particularly susceptible, including pregnant women, people with weakened immune systems, and those of Asian, Hispanic and African descent, may develop a serious or even fatal illness from valley fever. 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 and abscesses to bone lesions, severe joint pain, heart inflammation, urinary tract problems, meningitis, and death.

It has been known to infect humans, dogs, cattle, livestock, llamas, apes, monkeys, kangaroos, wallabies, tigers, bears, badgers, otters and marine mammals. ³

Symptomatic infection (40% of cases) usually presents as an influenza-like illness with fever, cough, headaches, rash, and myalgia (muscle pain).⁴ 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.⁵ The disease can be fatal.

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.⁶⁷

Occurrence

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.

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

Mild cases often do not require treatment. PO Fluconazole and IV Amphotericin B are used in progressive or disseminated disease, or in which patients are immunocompromised. Alternatively, itraconazole or ketoconazole may be used.

Experimental Treatment in Veterinary Medicine

An experimental immune modulator is being evaluated by IMULAN BioTherapeutics in dogs with chronic, non responsive valley fever. The immune modulator is a T-Cell Receptor Peptide which has been shown to restore cell mediated immunity in a variety of models. Cell mediated immunity is required for appropriate immune surveillance.

It has been known to infect humans, dogs, cattle, livestock, llamas, apes, monkeys, kangaroos, wallabies, tigers, bears, badgers, otters and marine mammals.

Popular culture

The illness is mentioned in episode 3x04 of the TV Show House, as the cause of a young girl's loss of inhibition. The illness does not actually cause loss of inhibition, nor does it cause milky tears.

It is also the center of an episode of Bones (1x09), The Man In the Fallout Shelter. After being exposed to the fungus, the team was quarantined over Christmas to determine whether or not they had become infected. It was erroneously claimed to be contagious from person to person.

It once again appears in the show Bones (2x17); The Priest in the Churchyard. Cam says the infected became exposed to it from graveyard dirt and no quarantine is imposed. They use it to track down a suspected grave robber later on in the episode.

Valley fever is also mentioned in the Pam Muñoz Ryan's 2000 novel Esperanza Rising, wherein the title character's mother contracts the disease following a California dust storm.

Additional images

References

^ 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. (via NCBI Bookshelf) ISBN 0-9631172-1-1.
^ Hector R, Laniado-Laborin R (2005). "Coccidioidomycosis--a fungal disease of the Americas.". PLoS Med 2 (1): e2. doi:10.1371/journal.pmed.0020002. PMID 15696207.
^ Valley Fever Center for Excellence | url = http://www.vfce.arizona.edu/VFID-other.htm
^ Ryan KJ; Ray CG (editors) (2004). Sherris Medical Microbiology, 4th ed., McGraw Hill, pp. 680-83. ISBN 0838585299.
^ Ampel N (2005). "Coccidioidomycosis in persons infected with HIV type 1.". Clin Infect Dis 41 (8): 1174–8. doi:10.1086/444502. PMID 16163637.
^ Chen, Karl T. K. (1993). "Cytodiagnostic pitfalls in pulmonary coccidioidomycosis". Diagn Cytopathol 12 (2): 177–180. doi:10.1002/dc.2840120220.
^ ValleyFeverSurvivor.com FAQ: "My Valley Fever has been misdiagnosed as cancer. Does this happen very often?" | url = http://www.valleyfeversurvivor.com/faq.html

Coccidioidomycosis.html

Contents