A 32-year-old male construction worker presents to urgent care with a 2-week history of fever (38.5°C), nonproductive cough, and progressive dyspnea. He works on a new housing development in central Arizona. Vital signs show HR 104, RR 24, BP 130/78, SpO2 93% on room air. Physical examination reveals scattered fine crackles at bilateral lung bases. Chest X-ray shows bilateral hilar lymphadenopathy with right lower lobe infiltrates. Laboratory studies reveal WBC 6.8 (normal differential), hemoglobin 13.2 g/dL, and platelet count 245,000/μL. Serology demonstrates positive complement fixation antibodies to Coccidioides immitis. The patient reports no recent travel outside Arizona, no sick contacts, and no history of immunosuppression. Which of the following best explains the mechanism of transmission of this pathogen to this patient?

1. A)Inhalation of sporangia containing endospores from contaminated dust and soilGABARITO
2. B)Penetration of intact skin by motile larvae during soil exposure
3. C)Direct person-to-person transmission via respiratory droplets
4. D)Ingestion of fungal spores present in contaminated food products
5. E)Inoculation through puncture wounds or traumatic skin injury