It was an amazing day. Floral scent was dancing in the air around me, and birds were unstoppable in singing – a long-forgotten sound. It was one of the first this year’s spring days spent in nature, outside the yard. This spring, quite different than the ones before it, showed me how we could cherish little things. As if we became more sensible – in the absence of usual distractions, everyday walks, spending time outside and everlasting hurry, we began to feel the moments in a different, deeper way. The warmth of the sun felt warmer than before. Bird singing seemed more melodious than last spring. Light breeze coming from the stream, that in some other times I probably would not notice, filled my lungs, and relaxed me in a moment. How could anyone stay inside, away from nature, all those sounds and movements and moments of flourishing, and stay calm? Nature is movable, alive and lively, and yet, it fills us with a unique kind of serenity. I just hope that this deepened feeling for nature that we developed in these unusual times will last.
There is a lot of news about the pandemic shared and served in media these days. Perhaps you have already read the headlines saying that biodiversity loss leads to an increased frequency of pandemics on a global scale. Some of the cardinal human threats to biodiversity include overexploitation of species, habitat destruction, exotic species introduction, and global environmental change caused by climate change. Those are the reasons for a strong decrease in population size and range, as well as facing the extinction of various animal species.
Many different animal species serve as viral hosts – in other words, they are a safe place, a place where a certain virus can survive for a long time, often in a dormant state, causing no harm to its host.
Severe acute respiratory syndrome (SARS), caused by the SARS coronavirus (SARS-CoV), was the first global pandemic in the 21st century. SARS coronavirus was transferred from bats, hosts of this type of virus, to civets, catlike carnivores. The most probable place where the virus was transmitted on humans were the overcrowded wildlife markets in China, where people sell wild animals for meat or as pets, and where the pandemic began. Today, COVID-19 is considered to have crossed to people at a wild-animal and seafood market, where most of the people who first became infected worked. In this type of market, different species of wild animals are kept in small cages in conditions suitable for disease development. Ban on poorly managed wildlife markets across the globe could prevent events like these, but could also intensify already well-built illegal trade in wild animals. Some earlier virus outbreaks are believed to be the result of habitat destruction, deforestation, and drought, which led to moving the viral hosts from their natural habitats closer to humans.
Some studies showed that viruses occur at a lower prevalence in the host organism in areas with higher biodiversity. In other words, if biodiversity at a certain area is high, it will lead to a slower, decreased disease transmission among the individuals of the host organisms and, eventually, decreased spillover to mankind. That leads to the conclusion that with biodiversity loss, there is more chance for a viral outbreak. But this situation cannot be generalized – it is not universal but depends on many parameters, for example, host and pathogen ecology and community composition. In fact, increased biodiversity can sometimes lead to an expanded viral transmission. That happens when the pathogen is a generalist, which means that it has the ability to infect many different species, so with increased biodiversity it gains the opportunity to spread more than before. On the contrary, a decrease in disease transmission with larger biodiversity is more probable when a certain virus has the more restricted host range, so it cannot infect many different species.
Too often we give ourselves the right to generalize events. The world is not white or black. Processes happening in nature are as diverse as shades of gray. We cannot predict many natural events. Although some have tried, we cannot predict when, where or how the next virus outbreak will begin. And sometimes, we jump too early to conclusions, represent natural processes as unambiguous, which they are not. Nature does not act in one direction. I think that biodiversity loss is not the main problem in this story, but our seizing the opportunity to have everything changed on this planet, so we could live easygoing.
It seems to me that the right thing to do would be to live accordant to nature. That is a difficult task, having in mind how far from it many of us live today. But looking in the past, many bad things happened with our involvement in nature. If we haven’t destroyed wild natural habitats, some viruses that were naturally occurring in animal organisms without making a fuss would have never come to us. If we haven’t introduced non-native species to certain areas, many viruses wouldn’t have been able to spread far. If we were more humane, we wouldn’t have caged all those wild animals in terrible conditions. Some things are not meant to be ours, and we still don’t understand it.
“We, people, often refuse change. So instead of changing little by little, we force everything around us to change instead. At first, that may seem like a victory for us but, in time, everything around us will have adapted except us. Then we will have to change more than ever. Question is, will we be able to?” D. J.
Although what you have read so far might make you feel bitter, the purpose of these words is but one: to encourage each and every one of us to change. Solving any problems, including the “little” ones, must begin with accepting the problem itself. To do that, we need a bit of courage and a bit of humbleness.
We all carry a certain dose of pride. In order to begin the process of change, we must move the pride aside, starting from that small, but priceless first step.
Literature
Aguirre A. A. (2017): Changing Patterns of Emerging Zoonotic Diseases in Wildlife, Domestic Animals, and Humans Linked to Biodiversity Loss and Globalization. ILAR Journal 58(3): 315-318.
Ceballos G., Ehrlich P. R., Dirzo R. (2017): Biological annihilation via the ongoing sixth mass extinction signaled by vertebrate population losses and declines. Proceedings of the National Academy of Sciences of the United States of America 114(30): 6089-6096.
Gruber K. (2017): Predicting zoonoses. Nature Ecology & Evolution 1, 0098.
Luis A. D., Kuenzi A. J., Mills J. N. (2018): Species diversity concurrently dilutes and amplifies transmission in a zoonotic host-pathogen system through competing mechanisms. Proceedings of the National Academy of Sciences of the United States of America 115(31): 7979-7984.