The cultivation of viruses in non-natural hosts was initially performed by means of experimental infection of living animals, and progress in virology was dependent on the use of laboratory animals. This practice has become less acceptable today as a result of concerns about animal welfare. The use of animals is now restricted to the growth of fastidious viruses and the preparation of laboratory reagents.

Globally various Research Councils have issued guidelines for the effective management of laboratory animal use in biomedical research, in particular the most commonly used laboratory animals namely rats, mice, rabbits and guinea pigs. These animals are used for various tests and propagation of viruses by means of different inoculation routes. The advantages and disadvantages of these procedures are discussed in this module.

Handling and preparation of tissues and inocula are described, including precautions that must be taken. The six possible routes of inoculation are explained and decisions to be taken in terms of the species and age of the animals, dose, needle gauge and the methods of restraint are addressed. The use of laboratory animals for the isolation of viruses of veterinary importance is included with an explanation of those factors influencing the outcome of inoculations. Precautions when handling animals are emphasized as well as post inoculation observations. Clinical signs both general and specific are given and clinical signs associated with specific viruses are mentioned.

Finally, harvesting after euthanasia or death is described for both organs and blood/serum, and confirmatory tests for the presence of viruses are briefly mentioned.