Mass airflow cabinet for control of airborne infection of laboratory rodents.
A mass airflow cabinet for handling and housing of laboratory rodents has been developed and tested. The unit consists of a high-efficiency particulate air filter and uniform distribution of air at a vertical velocity of 19 cm per s. Animals are maintained without bedding in mesh-bottomed cages that rest on rollers for rotation inside the cabinet. There is an air barrier of 90 cm per s separating the cabinet air from room air. Sampling for airborne bacteria yielded an average of 0.03 colony-forming units (CFU) per ft(3) of air inside the cabinet, whereas 28.8 CFU per ft(3) was simultaneously detected outside the cabinet during housekeeping, a reduction of almost three logs. The efficiency of the air barrier was tested by aerosolization of T3 phage. When phage was aerosolized 5 cm outside the cabinet, no phage could be detected 5 cm inside when the fans were operating; with the fans off an average of 1.6 x 10(4) plaque-forming units (PFU) per ft(3) was detected in six tests. Aerosolization of phage inside the cabinet yielded an average of 9 x 10 PFU per ft(3) outside; an average of 4.1 x 10(6) PFU per ft(3) were detected with the fans not in operation, a reduction of more than four logs. In-use studies on effectiveness showed that the cabinet significantly reduced the incidence of mice originally titer-free to Reo-3 virus. Hemagglutination inhibition antibodies to Reo-3 were detected in 9/22 (42%) mice housed in a conventionally ventilated animal laboratory while no seroconversion was detected in any of 22 mice housed in the mass air flow cabinet in the same laboratory.
D000336:Aerosols; D000391:Air Microbiology; D000392:Air Movements; D000818:Animals; D000830:Animals, Laboratory; D000914:Antibodies, Viral / Q000032:analysis; D001419:Bacteria / Q000302:isolation & purification; D003090:Coliphages / Q000302:isolation & purification; D005069:Evaluation Studies as Topic; D005374:Filtration; D005856:Germ-Free Life; D006385:Hemagglutination Inhibition Tests; D006799:Housing, Animal; D051379:Mice; D011120:Polyomavirus / Q000276:immunology; D012087:Reoviridae / Q000276:immunology; D012376:Rodent Diseases / Q000517:prevention & control*
D000336:Aerosols; D000914:Antibodies, Viral