Valley Fever (cont.)

Coccidioidomycosis is caused by two species of fungi, Coccidioides immitis and Coccidioides posadasii. Both are dimorphic (having mycelial and spore phases), almost always acquired through the respiratory tract by inhalation. When viewed microscopically, the mycelial form found in the soil has arthroconidia (barrel-shaped asexual spores) attached to non-spore-forming rectangular mycelium cells, usually alternating in a line. Once the arthroconidia are inhaled, the fungus develops into 30-60 micron diameter spherules that are filled with 3-5 micron diameter endospores. The large spherules then release the endospores that continue the infection; microscopic identification of these endospores in pus or tissue confirms the diagnosis.

Pictures of Coccidioides immitis and lung X-rays can be seen in the first and third Web sites listed below.

About 60% of all infected people (without immunosuppression) have no symptoms and do not seek medical care. About 30%-35% of people who develop symptoms have flu-like symptoms (fever, cough, malaise, and chills) that resolve over about two to six weeks without treatment. Some may develop additional symptoms such as shortness of breath, night sweats, headaches, sputum production, and joint and muscle pains (symptoms resembling pneumonia). Women, more often than men, may develop erythema nodosum (reddish, painful, tender lumps, usually on the legs) or erythema multiforme (an allergic reaction similar to erythema nodosum in multiple body sites with rash). Usually these symptoms resolve in about two to six weeks.

Chronic coccidioidomycosis occurs in about 8% of patients and is characterized by the above symptoms but may spread from the lungs to other parts of the body. People develop lung cavities that may disappear in about two years or become calcified.

Progressive pulmonary coccidioidomycosis includes the above symptoms but progresses to lung volume loss, fibrosis (scarring), and inflammation.

Disseminated coccidioidomycosis (about 1% of cases) can be characterized by the above symptoms, but they may occur over weeks to years. The fungi may be found in any body organ but are most frequently seen in the skin, meninges, and bones. In a few cases, the disease is rapidly fatal. Disseminated disease occurs most often in immunosuppressed individuals, males, and pregnant females.

Source: MedicineNet.com
http://www.medicinenet.com/valley_fever/article.htm