Vanessa Vila López: Covid and Monkeypox What is zoonosis and what effect does climate change have on the appearance of new pandemics?

With COVID still causing periodic surges due to the emergence of new variants, a new international health problem has emerged in recent months: monkeypox. On July 23, the WHO declared the contagious disease a public health emergency of international importance, the institution’s highest alert level. In both cases, these are zoonotic diseases, that is to say, they have passed from an animal vector to a human being. To better understand this process and how climate change influences the appearance of this type of disease, we contacted Vanessa Vila LopezProfessor of Official Master in Epidemiology and Public Health of VIU, where he teaches the subject “Environment and public health. Environmental risks”. Vila López holds a degree in biology, a degree in food science and technology, and a degree in veterinary medicine. He has developed various surveys in epidemiology and in the field of nutrition and health.

Following the pandemic, there is a lot of talk about zoonoses and how the loss of habitat or the invasion by people in hitherto unexploited territories, favors the appearance of this type of disease, can you explain to us what consists this phenomenon and how the climate crisis facilitates it?

Man’s action on the environment, to his advantage, causes alterations in ecosystems, breaking the balance that kept them stable.

Typical examples of these actions can be found, for example, in deforestation or changes in land use and urban expansion towards natural areas.

In these cases, we will witness irreparable damage to the wild flora and fauna of these territories, either due to the loss of biodiversity, and therefore, to a decrease in the number of individuals of species essential to maintaining the balance of ecosystems. , either because these individuals they are forced to change their behavior and move to other areas to feed, seek appropriate environmental conditions, shelter, etc.

These migrations will favor an approach towards human settlements. This is where this wild fauna (often carrying pathogens) can come into contact with our domestic fauna and/or with ourselves and promote the spread of zoonotic infections.

On other occasions, man, in his desire to dominate nature, often enters these ecosystems to seize wildlife for food, medicine or illegal trafficking, with the consequent risk of disease transmission. and possible crossing of the species barrier by the pathogens they carry. .

If to these facts we add the effect of climate change on the planet, we will see that the increase in temperatures, torrential rains, floods, changes in air quality, etc. they can create environments and conditions conducive to the development and proliferation of certain vectors, crucial in the transmission mechanism of zoonoses, such as certain species of mosquitoes or ticks.

If not, how does the climate crisis influence the appearance of new diseases or the worsening of existing epidemics?

The climate crisis in which we are immersed becomes evident, among other examples, with the global increase in temperature or with the appearance of certain extreme atmospheric phenomena that cause the loss of habitats and, consequently, of food, which obliges, in many countries of opportunity, to carry out migrations of populations, both human and wildlife, in search of better living conditions. This increases the likelihood of contact between species and the appearance of new pathogenic pathogens.

In turn, this contact between species (animal-animal or human-animal) can be favorable to the production of zoonotic diseases due to the barrier jump between pathogenic species.

On the other hand, phenomena such as floods due to torrential rains, tidal waves, increased sea water temperature and phenomena such as El Niño or La Niña, cause alterations and contaminations water and food (other sources of transmission of infectious diseases in addition to vectors) which are also the cause of diseases or even the aggravation of certain epidemics that may already exist.

What other health risks does climate change and desertification pose to our species?

The degradation and loss of soil fertility is one of the many consequences of climate change but also of human action in these territories.

Man, by acting on the environment with the overexploitation of natural resources, by carrying out bad farming and agricultural practices and by encouraging deforestation with illegal cutting or arson, favors the desertification of soils in the medium and long term.

These actions, added to the increase in temperature, the alterations in the cycles of rains and the drought, also strongly favor these processes of soil degradation in the drier zones.

In these cases we are going to see an obvious decrease and loss of animal and plant biodiversity, the onset of drought and a decrease in the quantity and quality of water, becoming one of the most important health risks. important.

The lack of quality water due to its poor filtration through the soil, and its quantity prevents the development of any agricultural activity and, therefore, livestock, leaving these areas in lack of food security, which will favor the appearance of diseases infections, dehydration, lack of adequate food and the resulting malnutrition, among others.

Does the climate crisis and its consequences make it more difficult to control epidemics or other contagious diseases? Are the chances of a new pandemic increasing?

Of course, as we mentioned earlier, the consequences of climate change on the human, animal and plant population will have a direct impact on the development and spread of certain diseases, including contagious diseases.

Environmental changes such as extreme temperature variations, rising sea temperatures, droughts or desertification force people to migrate in search of better conditions, and foster conditions of extreme poverty, especially among the poor. vulnerable populations where access to health resources is less.

These consequences of the climate crisis cause food insecurity and nutritional problems that favor the aggravation and severity of diseases, which increases the mortality rate in many cases. Under these conditions, it is difficult to control epidemic diseases due to poor access to quality health care.

It is easy to understand that with these conditions the probability of the appearance of new diseases is much more likely.

Currently, in addition to COVID, what infectious diseases with active foci do you consider to be of particular concern?

It is clear that the Covid-19 has given us a lot of work in recent years and it seems that there is still a lot to do against it. These days we are experiencing new epidemics in our country, with a high rate of contagion, but it is true that there are other infectious diseases that should not be overlooked.

The recent appearance of cases of monkeypox is an example of this. In this case, the rapid increase in cases and their spread in practically the whole world is evident. It will be necessary to be attentive to the behavior and the evolution of this disease to act accordingly.

These two diseases are a clear example of how globalization can influence the development and spread of infectious pathologies, since international travel is what has facilitated its expansion.

Other diseases with recent outbreaks that have been reported are, for example, the increasing cases of measles in the African and Eastern Mediterranean area, it is necessary to be attentive to possible outbreaks of zoonotic diseases in the coming months due to the summer season, increase in temperature and possible increase in the population of vectors that transmit pathogens such as Nile fever virus.

What we need to be aware of is the importance of the relationship between the environment, animal health and human health. The One Health approach is what can help us control this type of disease and epidemic in the future.

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