Effect of Ventilated Caging on Water Intake and Loss in 4 Strains of Laboratory Mice.

Food availability, temperature, humidity, strain, and caging type all affect water consumption by mice. Measurement of transepidermal water loss (TEWL) is a new technique for the quantification of water turnover in mice. To understand water turnover in common strains of adult mice, male and female SCID, SKH, C57BL/6, and FVB mice were housed in same-sex groups of 5 animals in static cages or IVC. Body weight, TEWL, urine osmolality, and water consumption of mice and intracage temperature and humidity were measured every 48 h for comparison. Static cages were monitored for 7 d and IVC for 14 d before cage change. Female SCID, FVB, and C57 mice drank less water than did their male counterparts. Male and female SCID, SKH, and FVB mice in IVC drank less water and had higher urine osmolality than did those in static cages. In SCID and SKH mice, TEWL paralleled water consumption. C57 mice in static cages drank less water, had lower urine osmolality, and had less TEWL than did those in IVC. Temperature and humidity within the cage was higher than the macroenvironmental levels for all housing conditions, mouse strains, and sexes. Temperatures within IVC ranged from 76.6 to 81.4 °F compared with 69±0.4 °F in the room. Humidity within IVC ranged from 68% to 79% compared with 27.o%±2.7% within the room. These data demonstrate that mouse strain and housing conditions significantly influence water balance and indicate that macroenvironmental measurements do not always reflect the intracage environment.

Effectiveness of shoe covers for bioexclusion within an animal facility.

The personal protective equipment (PPE) required for entry into rodent barrier rooms often includes a hair bonnet, face mask, disposable gown, gloves, and shoe covers. Traditionally, shoe covers have been considered essential PPE for maintaining a 'clean' animal room. The introduction of microisolation caging and ventilated rack housing prompted us to reevaluate the contribution of shoe covers to bioexclusion. Contamination powder that fluoresces under black light was to track particle dispersal on the floor and personnel. The test mouse room contained a ventilated microisolation rack and biosafety cabinet. Powder was applied directly inside or outside the animal room doorway. PPE with or without shoe covers was donned outside of the animal room doorway and discarded on exiting. Participants either were scanned on entry into the room for the presence of florescence or asked to complete a simulated standard animal room activity while wearing full PPE. Animal rooms were scanned for florescence after exit of participants. All participants donning shoe covers fluoresced in multiple areas, primarily on gloves and gowns. Shoe covers had no effect on the spread of powder in normal traffic patterns, with no powder detected within caging. Powder also was used to determine the distance substances could be carried on the floor from building entry points. Results indicate that shoe covers do not improve (and actually may compromise) bioexclusion. Donning of shoe covers offers a potential for contamination of personnel from contact with shoe bottoms.