Abstract: An animal isolation cage ward has upper and lower confinement units positioned within a housing and mounted on wheels for mobility. The units are heated for animal comfort and have exhaust ports in each connecting to a plenum within the housing. An exhaust blower draws air inwardly through the units, through the exhaust port, and out through a duct for routing contaminated air outwardly. The cages are fitted with doors of transparent material which are slightly smaller than the door opening, so that a gap is maintained about the periphery of each of the doors for airflow into the unit. The size relationships are designed so that a slight negative pressure is maintained within each of the cage units for inward airflow. The housing is designed so that air from one unit does not contaminate the other unit. A high efficiency particulate matter filter can be installed in the exhaust duct.