144 INFECTIONS CAUSED BY MOLDS 



"Dissolve asparagine in about 300 cc of hot distilled water, 50 degrees C. Dis- 

 solve each of the organic salts in 25 cc of water, ferric citrate being dissolved 

 in hot water. Add each salt in order, starting with K2HPO4 to the hot aspara- 

 gine solution and mix well each time the salt is added. Then add dextrose 

 and glycerine [glycerol] and finally make up to volume. Fill 1500 cc to each 3 

 liter Fernbach culture flask. Then sterilize at 115 degrees for 25 minutes. Incu- 

 bate." 



After the culture has grown for 2 months at room temperature or 

 30° C. the broth is filtered, made up to the original volume, tested 

 for sterility, a preservative is added, and the product is tested for 

 potency and specificity by skin-testing persons whose degree of sensi- 

 tivity is known. Many lots of coccidioidin fail to meet the latter 

 tests and must be discarded. A suitable lot is stable over ^a pe- 

 riod of several years. The skin test is performed by injecting 

 0.1 ml. of a dilution of 1:1000 of the filtrate intracutaneously. The 

 test is read after 48 hours as a tuberculin test would be read. Indi- 

 viduals failing to react to the first dose can be retested by a dilution 

 of 1 : 10. Those who have had primary coccidioidomycosis even in 

 an inapparent form and recovered from it retain the skin sensitivity 

 for many years, perhaps for life in many cases. Some individuals 

 appear to lose their skin sensitivity gradually. A coccidioidin skin 

 test may not be informative in the diagnosis of a present condition 

 in an individual who has previously been within the endemic area of 

 coccidioidomycosis for even a few hours since it may merely reflect 

 an early infection from which the patient has recovered. Aronson, 

 Saylor, and Parr ^ in a study of calcified pulmonary nodules in 

 tuberculin negative persons living within endemic areas concluded 

 that some of these nodules may be due to a previous coccidioidomy- 

 cosis. They found a high percentage of reactions to coccidioidin in 

 persons living within the endemic areas of this disease and few or 

 no reactions in other groups. It was shown that there was no cross 

 reaction with tuberculin. 



Coccidioidin can be used as an antigen in precipitin and comple- 

 ment fixation tests which give some indication of the extent and 

 probable course of the disease. According to Smith, a high antibody 

 titer follows spread of the infection and, conversely, a fall in titer 

 indicates a good prognosis. Skin sensitivity is retained after recov- 

 ery, but in cases of fatal infection it is greatly decreased during the 

 terminal stages. 



Demonstration of the fungus by direct examination or by culture 

 may be difficult in initial coccidioidomycosis where sputum is often 

 scanty or is not produced. In the disseminated form the fungus can 



