The disease of deforestation

Most of us have by now suffered under the consequences of the coronavirus pandemic. Whether we have had personal experience of the disease Covid-19, or felt the effect of the measures that followed. From the impossible combination of homeschooling and working from home, to not being able to spend time with the people we love or exercise the freedom to go wherever we want.

Who is holding the key to the next lockdown? The bats, pangolines, pigs and rats that we will meet later in this article, have only one part of the answer

Diseases from animals

“This sort of pandemic comes as a consequence of how we have capitalised on nature, as well as our frenetic traveling,” says biology professor Dag O. Hessen.

Originally these diseases emerged from keeping livestock close to where humans live, according to Hesssen, but recently they are linked to our overconsumption of nature.

A Malaysian Mystery

Several studies point to encroachment on pristine forests as an underlying and common denominator for many of the zoonoses. According to a report from EcoHealthAlliance, almost a third of new infectious diseases are linked to changes in land use, such as deforestation and resource extraction in previously untouched nature.

In order to better understand how this happens, we will time travel to Malaysia in the late 90s, and look at the mystery of coughing pigs and dead pig farmers. At that time there was a rise in both pig farming and palm oil production with large areas of rainforest in western Malaysia being chopped down.

Bats who previously lived in the forest started eating from the farmer’s fruit trees, and moved in under the roofs of the pigsties that were built on the forest frontiers. Chewed off fruit bits and faeces from the bats fell into the pigsty.

In 1998, some of the pigs developed a bad cough, but they were otherwise fine. After a while their piglets started dying. In order to secure as much income as possible the parent pigs were sold. By the time the first pig farmers started getting ill, the pigs had already been sold and consumed all over the country.

The first outbreak of the Nipah virus was a fact. After a while, the virus spread from human to human with symptoms from fever and vomiting to pneumonia, meningitis and permanent personality disorders. The mortality rate of the Nipah virus is high, from 40 - 75 percent depending on where the outbreak is. Other Nipah virus outbreaks have later emerged in Bangladesh and in India.

The outbreak of the deadly Lassa virus in West Africa is another example of how bad things can go when profit is put before nature. Large areas of forest are cut down to meet the global demand for palm oil, and rodents are pushed out of the forest to find food elsewhere. Rats eating food meant for human consumption transmits the contagion, which presents in humans as a fever and internal bleeding.

Some scientists now wonder whether the real cause of Covid-19 is also linked to the destruction of nature. Professor Thomas Gillespie of Emory University said to the newspaper Mongabay that the development of the Three Gorges Dam, the world’s largest hydroelectric power station, could be a contributing factor. The dam is situated about 400 kilometres from Wuhan, further up the Yangtze river. The dam project has killed off most of the animals that lived there, but bats may have flown out of the area and brought contamination to Wuhan, where the first case was registered.

Forest protection as a health measure

“When we destroy forest, we reduce biodiversity. Healthy ecosystems are made up of a great deal of species diversity and when we lose that, pathogens can invade,” says professor of biology Mary C. Pearl. She is Dean of Macaulay Honors College of the City University of New York and has worked with conservation and ecology since the 80s.

Viral chatter

So, destructive viruses can jump from species to species before transmitting to humans, in a process referred to as viral chatter. After that they may jump back to animals and cause pandemics in animals. Or they may mutate and return to humans in a much more dangerous form.

“The strategy of the virus is to mutate fast and get hold of a population which can give the largest possible spread. Humans are many and they travel at a frenetic pace. Although it is not in the virus’ interest to kill off their hosts, there is an imminent danger of new outbreaks that may cause more severe symptoms than Covid-19. It is really just a question of time,” says biology professor Dag O. Hessen.

He calls for better prevention against future zoonoses and pandemics. And he is not alone. Recently, the UN released a report that not only looks at strategies for identifying, diagnosing and treating new zoonoses, but also looks at what the underlying causes are. The UN calls on authorities the world over to have a unified approach, called One Health, that forges closer ties between experts on human, animal and ecosystem health.

Even to the biology professor, the connection between pandemics and natural loss has been a wake-up call. Had he written his recent book “Verden på vippepunktet” (The world at tipping point) a few months later, he would have added some paragraphs about pandemics.

“We have had our eyes opened to how the economy works and had time to think about where we are going, both in terms of climate and degradation of nature. I sincerely hope that this makes the consequences of cutting rainforest very clear,” he says.