TOPICS: Zoonotic diseases
Ironically the countries that have contributed least to global warming, mainly the developing countries, are the most vulnerable to its impacts especially from the diseases that higher temperatures can bring.
Globalization and climate change have had an unprecedented worldwide impact on emerging and re-emerging animal diseases and zoonosis.
Climate change is harming the natural ecosystem by providing more suitable environments for infectious diseases allowing disease causing bacteria, viruses and fungi to move into new areas where they may harm wildlife and domestic species as well as humans.
Zoonotic diseases are those which can be passed between vertebrate animals and humans. However, ecological change and climate events can promote epidemic expansion of the host.
Different zoonosis are transmitted to humans in different ways and the disease may be directly infectious. It may be transmitted by vectors or by food or water.
Emerging diseases have been newly discovered and have recently increased in prevalence, jumping from the animal population into humans.
Re-emerging diseases are diseases that have been discovered previously in a species and are often at enzootic levels in that species but for some reason have significantly increased in incidence at a given point of time or in a specific geographic region.
The poorest communities are the most disadvantaged. The increased incidence in deadly infectious diseases on wildlife, livestock and people may be one of the most important immediate consequences of global warming.
Climate change affects the modes by which diseases are passed from animals to humans. The direct link between climate and diseases is relatively easy to identify. More difficult to discern, however, are the complex indirect effects of climate variability.
These include effect on the organisms that transmit diseases. Climate change variability affects population dynamics of wild animals and domestic animals and these dynamics affect the transmission of diseases within the animal populations as well as the transmission to other animals or people.
Climate can affect the reproductive success and population densities of some species and hence it can increase the probability that a zoonotic disease will spread.
The greater the number of the affected animals the greater are the chances of transmission within and between species.