The consequences of climate change on animal diseases

The work of ANSES

Does global warming risk inducing the emergence or development of animal diseases? Asked to address this issue, the Agency sought to identify and rank the animal diseases, in particular those that can be transmitted to humans, whose development in mainland France in the coming years may be affected by a possible rise in global temperatures. Six diseases were identified for special monitoring.

Over time, climate change, including global warming, has become a reality that is increasingly difficult to contest. Even if pathogen cycles are generally highly complex, it is easy to assume that they may be affected by climate change. This is especially true for diseases whose agent goes through a phase in the environment, with or without a specific vector. Without holding climate change responsible for every unusual incident, the possible impacts should not be overlooked and the risks should be assessed. This is why, in September 2003, the French Ministry of Agriculture asked the Agency to identify the various animal diseases, particularly zoonoses, whose development in mainland France in the coming years may be affected by a possible rise in global temperatures, and to rank them depending on the risks they may present for public health and the farming industry and on the likelihood of their occurrence.

Six diseases to be observed as a priority

Although no-one can claim to be able to predict the exact consequences of climate change on the evolution of known animal diseases, the Agency’s experts, after having ranked these risks, nevertheless identified six diseases that are likely to be the most affected by climate change: Rift Valley fever, West Nile virus infection, visceral leishmaniasis, leptospirosis, bluetongue and African horse sickness. For each of these, the Agency has issued specific measures, in addition to general measures, on improving knowledge about reservoirs and vectors of these diseases.

Developing research and strengthening partnerships

A series of measures to recommend in the fields of health vigilance, ecological vigilance, alerts and active monitoring has also been proposed depending on the existence of these diseases in France or the risk of their introduction, establishment and spread.

The Agency also recommends setting up a network of research actions so that better consideration is given to these diseases, particularly those that do not exist in France but that pose a considerable risk of introduction (Rift Valley fever, for example). It would also enable discussions to be held between European and third countries on health problems related to the environment.

There are many research areas to be developed. The most important, however, lie in the fields of infectiology, eco-epidemiology (particularly the study of vectors) and the social and human sciences, in particular the study of the behaviour of human populations (cultural resistance during health education to reduce infectious risks, for example). The experts regret the lack of skills in the field of ecology, especially entomology, and have stressed the need for them to be reinforced.

Provide better information on the risks

All of these initiatives must be carried out alongside the development of health education for both the general public and health professionals. Information on the diseases that are developing or have emerged in France must be distributed. This should provide all of the objective elements for the risk to be controlled once it has been assessed correctly. It should also present prevention measures, their effectiveness and possible limitations.