The use of a decision tree based on the rabies diagnosis scenario, to assist the implementation of alternatives to laboratory animals.

Brazilian federal legislation makes the use of alternatives mandatory, when there are validated methods to replace the use of laboratory animals. The objective of this paper is to introduce a novel decision tree (DT)-based approach, which can be used to assist the replacement of laboratory animal procedures in Brazil. This project is based on a previous analysis of the rabies diagnosis scenario, in which we identified certain barriers that hinder replacement, such as: a) the perceived higher costs of alternative methods; b) the availability of staff qualified in these methods; c) resistance to change by laboratory staff; d) regulatory obstacles, including incompatibilities between the Federal Environmental Crimes Act and specific norms and working practices relating to the use of laboratory animals; and e) the lack of government incentives. The DT represents a highly promising means to overcome these reported barriers to the replacement of laboratory animal use in Brazil. It provides guidance to address the main obstacles, and, followed step-by-step, would lead to the implementation of validated alternative methods (VAMs), or their development when such alternatives do not exist. The DT appears suitable for application to laboratory animal use scenarios where alternative methods already exist, such as in the case of rabies diagnosis, and could contribute to increase compliance with the Three Rs principles in science and with the current legal requirements in Brazil.