​Infectious Diseases and Microbiology -Coccidioidomycosis (Coccidioides immitis)

​Infectious Diseases and Microbiology -Coccidioidomycosis (Coccidioides immitis) 
The coccidioidomycosis
 Coccidioides immitis is the causative agent of coccidioidomycosis, which is inhaled after contaminated soil is disturbed by humans (excavation) or natural events (dust storms, earthquakes). In arid areas of the southwestern United States, portions of Mexico, and South America, occoccidioidomycosis is endemic. Immunocompromised people, Blacks and Asians, and pregnant women in the third trimester are among the groups most at risk for infection.
Most cases of infection are asymptomatic, however 40% of cases result in self-limited lung illness. About 5% of instances of disseminated extrapulmonary coccidioidomycosis result in meningitis and damage to the skin, bones, and central nervous system. 50% of cases of disseminated illness die without treatment.
Endospore-filled spherules are formed in the lung by the germination of inhaled arthroconidia. Neutrophils and macrophages phagocytize organisms. The virulence factor is influenced by proteases and spherule outer wall components. Resolving disease is mostly dependent on cell-mediated immunity.
Upon closely examining clinical materials (tissue, sputum) in a KOH preparation, distinctive spherules are visible. An acute infection is indicated by an IgM response specific to C immitis. In order to diagnose exposure to infection, a skin test's reactivity to fungal extracts (coccidioidin and spherulin) may become negative in cases of widespread illness. It has been observed that eosinophilia is a helpful laboratory indicator of coccidioidomycosis.

Coccidiomycosis is treated with amphotericin B, fluconazole, and itraconazole. Fluconazole's enhanced CNS penetration makes it useful for treating disease-associated meningitis. Preventive methods include avoiding travel to endemic areas and engaging in activities that expose people to dust there.