Eradication of transboundary animal diseases: can the rinderpest success story be repeated?
A matrix system was developed to aid in the evaluation of the technical amenability to eradication, through mass vaccination, of transboundary animal diseases (TADs). The system involved evaluation of three basic criteria - disease management efficiency, surveillance and epidemiological factors - each in turn comprised of a number of elements (17 in all). On that basis, 25 TADs that have occurred or do occur in southern Africa and for which vaccines are available, in addition to rinderpest (incorporated as a yardstick because it has been eradicated worldwide), were ranked. Cluster analysis was also applied using the same criteria to the 26 diseases, creating division into three groups. One cluster contained only diseases transmitted by arthropods (e.g. African horse sickness and Rift Valley fever) and considered difficult to eradicate because technologies for managing parasitic arthropods on a large scale are unavailable, while a second cluster contained diseases that have been widely considered to be eradicable [rinderpest, canine rabies, the Eurasian serotypes of foot and mouth disease virus (O, A, C & Asia 1) and peste des petits ruminants] as well classical swine fever, Newcastle disease and lumpy skin disease. The third cluster contained all the other TADs evaluated with the implication that these constitute TADs that would be more difficult to eradicate. However, it is acknowledged that the scores assigned in the course of this study may be biased. The point is that the system proposed offers an objective method for assessment of the technical eradicability of TADs; the rankings and groupings derived during this study are less important than the provision of a systematic approach for further development and evaluation.