*5.2.2 In animals*

Like humans, animals are very sensitive to the effects of climate change, which can be very negative for the health and well-being of livestock. Climate change plays a role in the establishment and geographic expansion of zoonosis [42]. However, according to several studies, the effect may, in some cases, be positive because the increase in air temperature could reduce the risk of death and improve the health and well-being of humans and livestock living in regions with very cold winters. However, extreme variations in climatic parameters such as heat, cold, humidity, and precipitation have an overall negative impact on the health and welfare of animals, resulting in a marked increase in morbidity and mortality. The negative effects of climate change are, as in humans, the consequence of combined changes in air temperature, precipitation, frequency and magnitude of extreme weather events and can also be both direct and indirect.

Heat stress can, depending on its intensity and duration, directly affect the health of animals by causing metabolic disturbances, oxidative stress and a drastic decrease in immune capacity leading to infections and death. Indirect effects are associated with the quantity and quality of feed and drinking water available to animals and the survival and distribution of pathogens and/or their vectors [47]. Indeed, animals are also highly susceptible to certain vector-borne diseases such as those transmitted by ticks like bovine anaplasmosis, piroplasmosis in dogs and cattle, cowdriosis or heartwater, equine encephalitis, African swine fever as well as by insects like Nile Valley fever or by mollusks like liver fluke. Populations of these different vectors tend to increase with climate change.

The issue of climate change, and its impacts on living beings, has become so important and relevant for life on the planet that the World Organization for Animal Health (OIE) has introduced it in recent decades into its strategies. [48, 49]. According to Vallat [48], the impact of climate change on health has often been mentioned, mainly for human health. As regards animal diseases, their relationship with climate change is more rarely mentioned, no doubt because the recent epizootics were mainly linked to highly contagious viral diseases (foot-and-mouth disease, classical and African swine fever, Newcastle disease, influenza avian, etc.) and for which the

#### *Vector-Borne Diseases and Climate Change in the Environmental Context in Haiti DOI: http://dx.doi.org/10.5772/intechopen.96037*

movements of animals and foodstuffs of animal origin, in particular through trade, have played a preponderant role [48].

Oyhantçaba et *al.* [49] note thet the links between animal production and climate change are complex and multi-directional. On the one hand, animal production has an influence on climate change, with mainly ruminants generating emissions of greenhouse gases. In particular, animal production is a very important source of methane and nitrous oxide released into the atmosphere. On the other hand, climate change influences livestock production by affecting the conditions governing animal production, fodder crop production and animal health. The impacts on animal health are increasingly being recognised, and this theme occupies a special section of this document, as we shall see below [49].

With the introduction and very rapid expansion of West Nile fever virus in North America, the role of wildlife has become clear. This episode highlighted the gaps in our knowledge about the ecology of this type of infection, particularly when they emerge in new settings [48].

It is a fact that the environment in which animals live plays an increasingly important role in the manifestation of diseases, particularly vector-borne diseases. Global warming has led to changes in the ecology of vectors, resulting in the disappearance of certain habitats, the appearance of new ones and, more generally, the displacement of the geographical area that hosts the habitats required by a given vector as a result of environmental changes. Such upheavals in ecosystems have had fairly serious consequences for livestock farming. Thus, we have witnessed the migration of vectors of tropical origin, often carriers of pathogenic germs, to milder and even temperate climates. But still, the causes of vector-borne diseases are multifactorial as they are generally associated not only with climate change but also with trade globalization, urbanization and deforestation [47].

In addition to vector-borne diseases, a dynamic of non-vector-borne diseases is developing, which are also subject to the influence of climate change. One example is avian influenza infections that can be influenced by the migration routes of wild waterfowl. It has been observed that some species of wild birds have reduced their migration distance as a result of global warming, which has sometimes contributed to the spread of some infectious fish diseases to areas that were previously free of them. The persistence of viruses in the environment, including in water, is also influenced by changes in temperature [44].

In general, wildlife plays a significant role in the transmission of some major animal diseases such as avian influenza, rabies, swine fever and tuberculosis. As a consequence of climate change, countries with forests or savannahs with important wildlife often face the problem of water scarcity for watering these animals. As a consequence, they are obliged to gather at the same water point, thus favoring the continuous circulation of pathogens, first among themselves and then in domestic herds due to encounters which are becoming less and less fortuitous in some countries as a result of wild deforestation and anarchic urbanization programs.
