COCCIDIOIDES IMMITIS is a pathogenic fungus that resides in the soil
in certain parts of the southwestern
* 1 Epidemiology * 2 Clinical manifestation
* 3 Treatment
* 3.1 Azoles * 3.2 Amphotericin * 3.3 Duration of therapy and costs
* 4 HHS select agents listing * 5 References * 6 External links
C. immitis, along with its relative C. posadasii , is most commonly
seen in the desert regions of the southwestern United States,
including certain areas of Arizona, California, New Mexico, Nevada,
Texas, and Utah; and in Central and South America in Argentina,
Brazil, Colombia, Guatemala, Honduras, Mexico, Nicaragua, Paraguay,
and Venezuela. C. immitis is largely found in California, while C.
posadasii is regularly found in Texas, northern
C. immitis can cause a disease called coccidioidomycosis (valley
fever). Its incubation period varies from 7 to 21 days.
* Commonly used indicators to judge the severity of illness include:
* Continuous fever for longer than 1 month * Body-weight loss of more than 10% * Intense night sweats that persist for more than 3 weeks * Infiltrates that involve more than half of one lung or portions of both lungs * Prominent or persistent hilar adenopathy * Anticoccidioidal complement fixation IgG titers of 1:16 or higher * Absence of dermal hypersensitivity to coccidioidal antigens * Inability to work * Symptoms that persist for more than 2 months
* Risk factors for dissemination (for which treatment should be initiated):
* Primary infection during infancy * Primary infection during pregnancy, especially in the third trimester or immediately post partum * Immunosuppression (e.g., patients with HIV/AIDS, transplant recipients, patients receiving high-dose corticosteroids, those receiving antitumor necrosis factor medications) * Chronic debilitation or underlying disease, including diabetes mellitus or preexisting cardiopulmonary disease * High inoculum exposures * Certain ethnicities, such as Filipino, Black, or Hispanic * Age greater than 55 years
The introduction of azoles revolutionized treatment for coccidioidomycosis, and these agents are usually the first line of therapy. However, none of the azoles is safe to use in pregnancy and lactation because they have shown teratogenicity in animal studies.
Of the azoles , ketoconazole is the only one approved by the U.S.
Food and Drug Administration
For patients who are unresponsive to fluconazole, options are
limited. Several case reports have studied the efficacy of three newer
antifungal agents in the treatment of disease that is refractory to
first-line therapy: posaconazole and voriconazole (triazole compounds
similar in structure to fluconazole) and caspofungin (glucan synthesis
inhibitor of the echinocandin structural class). However, these drugs
have not been FDA approved, and clinical trials are lacking.
Susceptibility testing of
In very severe cases, combination therapy with amphotericin B and an azole have been postulated, although no trials have been conducted. Caspofungin in combination with fluconazole has been cited as beneficial in a case report of a 31-year-old Asian patient with coccidioidal pneumonia. In a case report of a 23-year-old Black male with HIV and coccidioidal meningitis, combination therapy of amphotericin B and posaconazole led to clinical improvement.
Posaconazole has been approved by the European Commission as a salvage therapy for refractory coccidioidomycosis. Clinical trials are now ongoing for further evaluation. Voriconazole is also being studied in salvage therapy for refractory cases. A case report indicated that voriconazole in combination with amphotericin B as salvage therapy for disseminated coccidioidomycosis was successful.
Several case reports have studied caspofungin , with differing results. Caspofungin 50 mg/day following administration of amphotericin B in a patient with acute pulmonary coccidioidomycosis who had undergone transplantation showed promising results. In a patient with disseminated coccidioidomycosis, first-line therapy with amphotericin B and caspofungin alone failed to elicit a response, but the patient was then given caspofungin combined with fluconazole, with good results. A published report described a patient with disseminated and meningeal coccidioidomycosis in whom conventional therapy with fluconazole, voriconazole, and amphotericin B failed; caspofungin 50 mg/day after a loading dose of 70 mg intravenously was also unsuccessful.
DURATION OF THERAPY AND COSTS
The objectives of treatment are resolution of infection, decrease of antibody titers, return of function of involved organs, and prevention of relapse. The duration of therapy is dictated by the clinical course of the illness, but it should be at least 6 months in all patients and often a year or longer in others. Therapy is tailored based on a combination of resolution of symptoms, regression of radiographic abnormalities, and changes in CF IgG titers. Immunocompromised patients and patients with a history of meningeal involvement require lifelong treatment.
The cost of antifungal therapy is high, from $5,000 to $20,000 per year. These costs increase for critical patients in need of intensive care. Arizona spent an average of $33,762 per patient with coccidioidomycosis between 1998 and 2001.
HHS SELECT AGENTS LISTING
Along with C. posadasii, C. immitis was featured on the select agents
and toxins list compiled by the U.S. Department of Health and Human
Services (HHS), as evident from the
Code of Federal Regulations
* ^ "GSD Species Synonymy:
* ^ "