Emerging animal diseases pose significant threats to animal and public health. It appears impossible to predict the next emerging animal disease with an acceptable degree of uncertainty. Emerging animal diseases are driven by specificrisk factors.
This study was designed to identify and rank risk factors based on their influence on the risk of emergence of infectious animal diseases.
The effect of 33 risk factors on the risk of emergence of 34 (potentially) (re-)emerging infectious animal diseases was evaluated via a Delphi survey conducted by 50 experts. The consensus expert opinions obtained were transformed into scores.The risk factors were then ranked according to their impact on the risk of emergence ofthe animal diseases studied, either considered as one overall group, or subdivided into different subgroups (zoonotic diseases, vectorial diseases or exotic diseases).
When emerging animal infectious diseases were considered as as one group, seven risk factors were judged as having an important impact (mean score > 2): the problems of detection of emergences, the existence of an animal reservoir for the disease, the difficulties in controlling the disease by vaccination, the geographical expansion of the pathogen, the asymptomatic carriage, the increase in incidence of the disease in other countries and epidemiological role of wildlife. These seven risk factors had also an important influence (mean score ≥ 2) in the three other scenarios considering specific subgroups. For zoonotic diseases, one additional risk factor had an important impact (mean score ≥ 2): the increase in density and/or distribution of wildlifepopulations. Forexotic diseases, two additional risk factors concerning globalisation had an important impact (mean score > 2): increases in trade and in transport. For vector-borne diseases, seventeen risk factors, of which the presence of the vector and the changes in climate and meteorology which scored very high (mean score > 3), had an important impact (mean score > 2), constituting an alert on the importance of the risk of emergence of vector-borne diseases. The legislation/sanitary policy and the intensive production systems appeared to be protective factors.
This study allowed to identify key risk factors of emergence on which risk managers could act in terms of surveillance and mitigation. Also, it could serve as a tool for the inclusion of measurable risk factors in a still to be developed emerging risk forecasting system designed to identify early conditions favouring the emergence of certain diseases