Synthesis

The preceding chapters have described in detail specific examples of viruses that have emerged or re-emerged from animal sources. Most, although not all, are zoonotic and have caused significant human morbidity and mortality. This final chapter will attempt to bring together a number of the common themes raised by these examples. These include the role of historical events in shaping the emergence of viruses in the present, the ability to retrospectively test samples to trace the emergence of disease and the technologies used to detect viruses. Technologies such as the polymerase chain reaction and mass sequencing have revolutionized virus detection and enabled the rapid identification and characterization of viruses. The application of these methods has led to the identification of new groups of viruses in samples obtained from a range of animal species without the need for invasive sampling or the recovery of live virus. However, with the detection of such a large range of viruses that exist asymptomatically with other species, the challenge now becomes the identification of those with the potential to become pathogenic for humans.