Diagnosis of coccidioidomycosis in a non-endemic area: Inference of the probable geographic area of an infection.

Background: Coccidioidomycosis is one of the most important endemic mycoses in Northern Mexico. However, diagnosing this disease can be challenging, particularly in patients who do not reside in endemic areas.

Case Report: The case of a Mexican HIV+ patient who developed fever, general malaise, a severe cough, and dyspnea during a stay in Acapulco, Guerrero, Mexico, is presented. Since various diseases are endemic to the state of Guerrero, the doctors originally suspected that the patient had contracted influenza A (H1N1), Q fever, or tuberculosis. All the diagnostic tests for those diseases were negative. The patient had received numerous mosquito bites while staying in Acapulco, and a nodule had appeared on his right cheek. Therefore, malaria, cryptococcosis, and histoplasmosis were also suspected, but those infections were also ruled out through diagnostic tests. A direct microscopic examination was performed using KOH on a sample taken from the cheek nodule. The observation of spherules suggested the presence of a species of Coccidioides. The fungus was isolated, and its identity was confirmed by phenotypic and molecular methods. The geographic area in which the infection was likely acquired was identified by random amplified polymorphic DNA (RAPD) analysis. The results suggested a probable endogenous reactivation.

Conclusions: This clinical case illustrates the difficulties associated with diagnosing coccidioidomycosis in non-endemic areas.