In addition to the 10%-40% prevalence of the disease in Mexico, approximately 100,000 primary infections occur in humans annually in the United States. In 60% of cases, there are no symptoms, and infection can only be detected by means of a skin test. The other cases can be classified as either acute, chronic, or disseminated. The acute form is rare, found only 3% of the time, and requires little to no treatment. In 5% of cases, the patients will develop a chronic version of coccidioidomycosis, which can occur even 20 years after initial infection. In this form of the disease, lung abscesses form, and when they rupture, the can fill the pleural space with pus, a very dangerous condition. The disseminated form occurs when the infection spreads to other tissues in the body and can cause meningeal infection, the most dangerous form of the disease. This occurs 0.15% to 0.75% of the time, and can often be life-threatening, especially when in concurrence with tuberculosis, as is often the case in areas with high prevalence of the latter. In immunocompromised patients, the disease can progress to these dangerous stages very rapidly.
There are three stages of infection by C. posadasii:
1. Spherule Initiation: In this stage, the arthroconidium is beginning its transformation into a spherule. It becomes rounder as its nucleus divides rapidly, producing a multinucleate cell with an empty central vacuole. These spherules can be visualized in and cultured from the sputum.
2. Spherule Segmentation: At this stage, the spherule begins to form endospores by means of internal segmentation, compartmentalizing each nucleus into its own endospore. This internal segmentation is accomplished by invagination of the spherule wall and incorporation of chitin. Segmentation begins 72 hours after initiation.
3. Endospore Release: The spherule ruptures and releases all 200-300 endospores either back lungs or into the lymphatic system and/or the bloodstream. This usually happens 120 to 132 hours after infection.
Symptoms of coccidioidomycosis include blood-tinged sputum, mental symptoms, mild to sever chest pain, chills, cough, fever, headache, join stiffness, loss of appetite, muscle aches and stiffness, night sweats, erythema nodosum (painful red nodules on the lower legs), sensitivity to light, excessive sweating, weight loss, and weezing. Less common symptoms include swelling of the ankles and feet, arthritis, enlarged or drained lymph nodes, and joint pain and swelling. It takes approximately seven to twenty-one days after initial infection for these symptoms to appear, if they ever do. Diagnosis can occur by means of a CBC blood test, sputum analysis, a coccidioidin skin test, or a chest x-ray. Using the latter, however, it is difficult to tell apart coccidioidomycosis and tuberculosis. For acute infections, bed rest and treatment similar to that of flu symptoms is sufficient. For worse cases, however, antifungals such as amphotericin B, ketoconazole, fluconazole, or itraconazole are used.
Thus, infection by C. posadasii can not only be uncomfortable but also life threatening. Pregnant women, African Americans, Filipinos, patients with HIV, Hodgkin’s disease, lymphoma, or any other immunosuppressing diseases, diabetics, people who have undergone organ transplants, and people undergoing adrenal corticosteroid therapy are all at a much higher risk of infection than average. Because of its potency, C. posadasii has very real capabilities as a biological weapon, and as a result, there are very strict rules set in place internationally governing its possession and use.