 To evaluate six intensively studied patients admitted to medical intensive care with pulmonary blastomycosis requiring mechanical ventilation. Interventionally, all patients will receive continuously infused amphotericin-B 1 mgkgd; and then stepped down to oral or i.v. voriconazole once clinically responding. Blood will be sampled for amphotericin-B concentrations for the 3 first days i.e. one blood sample per day; and when eventually changed over to voriconazole i.e. generally after a total dose of 1 g has been reached of Amphotericin-B; as per usual practice. Once switched to oral or intravenous voriconazole, at the treating physicians discretion, then blood would once again be sampled for the next 3 days for voriconazole concentrations. MICs of the infecting blastomyces would also be analyzed. The fungal isolate would be sent off to the Fungus Testing Laboratory at the University of Texas in San Antonio for susceptibility testing. 