Development of a quality identification system for laboratory animals. Identification of the level of barriers (Post 1)

This article reviews the historically established categories of laboratory animals — Specific pathogen free and Conventional — whose main difference in housing was considered to be the presence of barriers. In modern laboratories all animals are kept in barrier systems, regardless of their category, which may allow to unify the approach to quality assessment of laboratory animals used in biomedical research. Barriers can be diverse in design and fulfil different functions depending on their purpose. This article considers primary, secondary and hygienic barriers, the totality of which allows to maintain the health and well-being of laboratory animals. A set of requirements for each type of barrier ensures adequate protection and quality assurance of laboratory animals. Based on the reviewed barriers and their requirements, we propose to classify barriers into several levels: BC (barrier class) 1, 2, 3, 4 and 5. The proposed system can help research organisations to assess their own conditions for keeping laboratory animals and think about opportunities for improvement. In the future, this division of barriers in animal housing can provide an objective division of animal categories according to their health status and protection from pathogens.