eBook: Safe and Effective Research in the Vivarium - 6

avoid potential contamination of animals with microorganisms from vivarium workers. If using an
open cage, one option is to cover the cage with a
closed filtertop. Typically, a Remay filter is used in
these tops, preventing dust particles that can " fall "
into the cage but allow some exchange of gases (oxygen, CO2, ammonia) via passive diffusion. However,
the ventilation is limited, resulting in an earlier rise
of higher ammonia and humidity levels. As a consequence, these filtertop cages should be changed
more frequently compared to open cages.

lab's exhaust system, further removing allergens and
odor from the room. Because the HEPA filtration of
the in- and out-going air of the animal cages filter
out microorganisms, the infection risk (of airborne
microorganisms) is significantly reduced when cages are closed. During cage changing and procedures
with animals, cages must be opened, stacked, transported, emptied and cleaned in the cage wash area
only. Unless adequate protection measures are applied (both equipment and working procedures),
open handling of animals and used cages will result
in a temporary increase of animal and cage dust in
the air, again implying higher levels of allergens and
microorganisms (higher infection risk of animals/
cages/personnel).

Individual Ventilated Cages
To overcome the poor ventilation in static filtertops,
a few decades ago, the Individual Ventilated Cages
(IVC) concept was introduced. IVC systems are cages
with closed lids and a filter at the top. Each cage has
its own air supply and exhaust. The inlet and exhaust
air of the system is HEPA-filtered. The result is much
better air quality with significantly lower allergen
levels. Additionally, an IVC can be connected to the

Animal Transfer Stations (ATS) & Class II
Biosafety Cabinets (BSC)
Several primary engineering controls have been developed to protect vivarium technicians during the
handling of animals and cages. The Animal Transfer
Station (ATS) and Class II Biosafety Cabinet (BSC)
are used for this purpose. Sometimes fume hoods
and backdraft cabinets are also applied to protect

NuAire's AllerGard™ ES (Energy Saver) model NU-620 Animal Transfer
Station offers product and improved allergen protection during sensitive
cage changing procedures, while maintaining mobility in the vivarium
environment.

Innovive's Innorack® IVC Mouse 3.5 dynamically maintains settings on
both supply and exhaust blowers.

eBook: Safe and Effective Research in the Vivarium

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