How does climate change affect epidemics

Those who see climate change as the most serious and impending catastrophe tend to blame this phenomenon in whatever direction it is getting worse in the most diverse sectors. An example of this is the prediction that due to global warming we will be more affected by pathogens and therefore the number of epidemics we can expect will increase, even beyond what is caused by mere numerical increase and our invasions of natural environments. But is it really possible to predict such an effect of continued global warming?

Try to answer this question a secent work published in Nature in April of this year. The authors of this work first attempted to model the change in distribution caused by the projected rise in temperature for 3,139 species of land mammals. The heat, predictably, will in fact lead all species to move in search of the climate best suited to their ecological niche, given the effect of temperature on the survival of many species; The authors attempted to model these changes, along with corresponding changes in land use by humans, between now and 2070..

The scenarios derived from this analysis allow us to highlight the clustering of the considered species into new groups at high altitudes, in new biodiversity hotspots and, above all, in densely populated regions, both in Asia as an effect of high temperature Heat .. than in Africa. In contrast, the researchers write, this would result in interspecific transmission of viruses that had never previously been in close contact, for a total of approximately 4,000 excess transmission events in the time period considered by the analysis.

Moreover, due to their ability to spread rapidly over very long distances, bats in typical scenarios represent the source of most species whose virus jumps, and are likely to guide viruses along evolutionary paths that will facilitate their future. in humans. Finally, the researchers cautioned that, from what can be inferred from their models, an ecological and epidemiological transition caused by global warming is already underway and that keeping warming below 2 °C by the 21st century will not significantly reduce viral involvement in the future.

At this point, some considerations must be made. First of all, as always in this type of study, the details of the prediction – the number of indirect events, for example, as well as the speed with which they will increase – are closely related to the variables whose estimation, well, suffers greatly: Distribution of new ecological niches, for example, is critical, as is correct modeling of virus sharing between compatible host species or prediction of future land use by humans.. After this precautionary consideration has been made, however, there is still a trend finding that is difficult to dispute: a general reduction of many species’ habitats will lead to increased overlap between and among non-human species and the area with a higher density of organisms. population.
Whatever the rate of spillage produced, it will inevitably increase to a greater extent than would have already occurred due to human overpopulation and environmental invasion: So yes, the prediction of who will lead to global warming is also correct.

There is also more to consider. The work focuses on looking at human dispersal events starting with land mammals; But first of all, there are other classes of vertebrates that are able to infect us, starting with birds, secondly viruses can also take care of species of domestic mammals that are very important to us, and finally there are not only viral pathogens, but also bacterial pathogens or true nucleus. In all cases, the same influences and the same type of considerations that are present in the work cited by the authors apply; Thus, the risks are generally greater than those discussed in that article, and can be further expanded to consider pathogens in our native plants. What conclusion should be drawn? As stated by the researchers: The findings highlight the urgent need to link emerging pathogen surveillance with biodiversity investigations, taking into account changes in the distribution and density of species, particularly in the tropics that contain the most potentially zoonotic pathogens and suffer. rapid warming; Only this surveillance is capable of allowing a possible mitigating reaction; Because climate change has already arrived, and the expected impacts have begun.