Concomitant neurocysticercosis and brucellosis. A young Mexican woman had headache and left arm weakness develop shortly after immigrating to the United States. A solitary cerebral cysticercus was found at surgery, but, instead of the expected finding of clear fluid, the cyst contained pus from which Brucella melitensis was cultured. Although the patient had no signs or symptoms suggestive of brucellosis, agglutination studies revealed IgM and IgG antibodies consistent with active brucellosis. Clinicians should be alert to the possibility of multiple infections in immigrants from countries where parasites and bacteria that are uncommon in the United States are endemic. 