PULMONARY RESPONSES OF CONSCIOUS STRAIN-13 GUINEA-PIGS TO PICHINDE VIRAL-INFECTION

A laboratory animal model for studying pulmonary responses to arenaviral infection was established with advanced technologies. Tidal volume (TV), respiratory rate (RR), minute volume (MV), expiratory time (TE), inspiratory time (TI), peak expiratory flow (PEF), and specific pulmonary airway resistance (RES) were measured with a double plethysmograph and a computer data-acquisition system in six conscious, strain 13 guinea pigs. Using the same animal, experiments were conducted before and after subcutaneous inoculation with 10(4) plaque-forming units of Pichinde virus. Pulmonary functions were determined for 1 minute every 10 minutes for 2 hours before and at postinoculation days (PID) 3,6, 8, and daily thereafter until shortly before death. The mean time to death was 18 +/- 0.7 days. Tidal volume, RR, MV, PEF, RES, and rectal temperature increased slightly on PED 3 and reached peak values at the midpoint of disease. At 95% of the mean time to death (16.5 +/- 0.5 days), RR, MV, and rectal temperatures suddenly decreased to lower than baseline values; while TV, RES, and PEF values remained high. When TE decreased with the increase in RR, TI did not change. When RR decreased at the terminal stage, both TE and TI increased. Hyperventilation, increased specific pulmonary airway resistance, terminal hypoventilation, and respiratory arrest were noted in strain 13 guinea pigs infected with Pichinde virus.