My question is twofold.
1. What is the evolution in the number of pandemics in history? Is there an increase? What are the causes?
2 Is there a link with habitat loss and loss of biodiversity? Some biologists argue that the risk of a pandemic increases as the natural habitat (undisturbed by humans) declines? And since habitat loss is also linked to biodiversity loss, I suspect there is a link between the two. But is there a scientific basis for that?
3 Is livestock farming also a cause? And to what extent does livestock farming contribute to the outbreak of pandemics?
Answer
Epidemics and pandemics result from highly infectious germs invading a population that is not immune. Smallpox was a classic example of this. Plague may have been too. Due to the decline in measles vaccination, there have been quite a few outbreaks of measles in recent years, probably resulting in 60,000 deaths. Not a pandemic, but it’s still something to think about. An epidemic/pandemic can therefore only come about under those conditions. That’s why so many Native Americans died in South America: They weren’t immune to diseases that Europeans were immune to (of course, that wasn’t the only reason, but that’s another discussion).
Note that a pandemic is an epidemic on several continents. With the surge in travel behaviour, a pandemic can develop in weeks, which used to take years. You cannot compare the current situation with the past in that respect.
The loss of a natural habitat – or more precisely, the intrusion of humans into a habitat of certain animal species (which may carry viruses without becoming ill themselves) opens up potential contacts that were not there before. . Ebola is an example. Bats are possible virus carriers. That way an epidemic can start. Covid-19 is also said to have started this way (“wet market” in Wuhan – however, there are unconfirmed rumors that the virus may have escaped from a lab, but the Chinese government is not known for its transparency, so we won’t know immediately) .
The flu pandemic of 1919-1920 (the so-called Spanish flu) is probably a very different story. The classical theory is that bringing together many people, poultry and pigs (possibly also cattle and horses) enables a flu virus to reorganize itself genetically so that relatively mild variants suddenly become much more dangerous. Such a situation withstands on the frontline in WW I, in France. After all, millions of soldiers have to be fed and the wounded nursed. However, it is not so easy to reconstruct events from 100 years ago.
Monocultures are also more susceptible to plant diseases than natural areas. Large-scale livestock farming is also vulnerable. This is also something to think about: the loss of biodiversity is bad for the survivors, plants, animals and humans. But in different ways. It doesn’t have to be a pandemic.
Answered by
Dr Mistiaen Wilhelm
Prinsstraat 13 2000 Antwerp
http://www.uantwerpen.be
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