Patient 1 was a previously healthy, 26-year-old Peruvian man who was evaluated in July 1985 for a 3-month history of periorbital pain, headaches, and periodic generalized tonic-clonic seizures. The initial neurologic examination was nonfocal, but subsequent computerized tomography scan showed a 5x5-cm enhancing mass in the left frontoparietal region associated with midline shift.
At the time of surgical biopsy, frozen section histology raised the possibility of a high-grade astrocytoma or lymphoma, prompting resection of a 3x3-cm well-circumscribed left frontal lobe mass. Final examination of pathologic specimens showed granulomas with multinucleated giant cells (Figure 1). Bacterial, fungal, and acid-fast bacilli stains were negative. Based on these pathologic findings and concern that the patient may have had tuberculosis, treatment with isoniazid, rifampin, and ethambutol was begun. Serologic tests for Histoplasma capsulatum, Blastomyces dermatidis, Coccidioides immitis, and Paracoccidioides brasiliensis were negative. Toxoplasma gondii serologic titers were weakly positive at 1:64.
On postoperative day 39, fungal tissue cultures became positive for a Brucella spp., preliminarily identified as B. melitensis. The patient's antimicrobial treatment was changed to tetracycline and rifampin and was continued for 2 months. An initial serologic titer for Brucella was positive at 1:160 by tube agglutination assay. A follow-up serologic titer obtained in January 1986 was negative (<1:20).
Three months before his initial evaluation, the patient had immigrated to the United States from Lima, Peru. His diet included regular consumption of unpasteurized cow or goat cheese (queso fresco) and occasional consumption of raw shellfish (ceviche). He denied eating other raw or significantly undercooked meat. He had frequently swum in the Pacific Ocean from December through March but recalled no direct contact with marine mammals.