Brevetoxin inhalation alters the pulmonary response to influenza A in the male F344 rat.

Epidemiological studies demonstrated that the number of emergency-room visits for respiratory indications increases during periods of Florida Red Tides. The purpose of this study was to examine whether or not repeated brevetoxin inhalation, as may occur during a Florida Red Tide, affects pulmonary responses to influenza A. Male F344 rats were divided into four groups: (1) sham aerosol/no influenza; (2) sham aerosol/influenza; (3) brevetoxin/no influenza; and (4) brevetoxin/influenza. Animals were exposed by nose-only inhalation to vehicle or 50 μg brevetoxin-3/m3, 2 h/d for 12 d. On d 6 of aerosol exposure, groups 2 and 4 were administered 10,000 plaque-forming units of influenza A, strain HKX-31 (H3N2), by intratracheal instillation. Subgroups were euthanized at 2, 4, and 7 d post influenza treatment. Lungs were evaluated for viral load, cytokine content, and histopathologic changes. Influenza virus was cleared from the lungs over the 7-d period; however, there was significantly more virus remaining in t...