208 An Introduction to Medical Mycology 



of 105 rodents trapped in the desert around San Carlos, Arizona. Definite 

 identification of C. immitis was made in two animals. No instance has been 

 recorded of transmission of the disease from one human being to another. 

 It is thought that most infections occur through inhalation of dust laden 

 with organisms. In a laboratory worker, observed by us, the infection was 

 acquired from the inhalation of spores from an old culture. An injury to 

 the skin may sometimes provide a portal of entry for the fungus. Most of 

 the patients are laboring men, usually engaged in farming, and a high per- 

 centage are Mexicans. The epidemiology of acute coccidioidomycosis has 

 been carefully studied by Smith. 



(c) Clinical characteristics.— The primary lesion may be situated on 

 an exposed part of the skin, but the condition more commonly develops 

 first in the lungs, resulting from inhalation of dust containing the fungus. 

 So-called primary involvement of the pelvis, of the meninges or of the 

 bones is probably the first manifestation of systemic dissemination. The 

 primary invasion of the lungs may be accompanied by a febrile state simu- 

 lating influenza or bronchopneumonia. According to Dickson most of these 

 patients recover completely. In a scientific exhibit at the annual meeting of 

 the American Medical Association in 1938 he showed roentgen views of 

 chests in which the process had resolved, in patients whose sputum con- 

 tained the fungus. The roentgenogram of the chest reveals dense shadows 

 in the hilar regions and scattered densities throughout the lungs, indicating 

 parenchymatous involvement. The pulmonary involvement may occur with- 

 out much fever and with only slight cough. Headaches and backache may 

 occur and blood-tinged sputum may be noted. Pleuritic involvement may 

 cause pain to be a prominent symptom. In cases in which the course is un- 

 favorable, evidences of a spreading infection such as loss of weight, night 

 sweats and fever are observed, and signs of lesions in other locations become 

 evident. The acute infection has been reported only from the San Joaquin 

 Valley, where it is known as valley fever or desert fever. A person of any 

 age and either sex may be affected. In 354 instances of the acute illness, 

 there was only a single death, from coccidioidal meningitis (Dickson). 

 Commonly, from eight to 15 days after the onset nodules of erythema no- 

 dosum develop on the shins or in other areas, disappearing spontaneously 

 in four or five days. Recovery from the acute infection usually occurs in 

 three to six weeks. 



The manifestations of Coccidioides are various, and the course of the 

 disease is unpredictable. Thus the patient with a systemic infection may 

 succumb within a lew weeks, or a chronic locus may remain localized 

 lor years. 



The primary cutaneous lesions develop as granulomas, which eventually 



