Viswanathan K's Thoughts

What is it about Chinese markets that seems to unleash viruses on mankind? SARS, bird-flu, now COVID-19. No, this isn’t China-bashing. Spillover , David Quammen’s awesome book on inter-species disease transfer, looks into this question in the spirit of genuine curiosity. He cites a (true) point: “Southern Chinese have always noshed more widely through the animal kingdom than virtually any other peoples on earth.”   Quammen then cites major changes in those “wet markets” (animals for eating are alive in the market, killed only when you buy) between 1993 and 2003: The volume of wild-animal trade had increased enormously; Cross-border trade of animals with Southeast Asian countries had shot up; Commercial breeders had sprung up for species like snakes, civets etc. You can see where this is going. Like all such places across the developing/poor world, wet markets cram these animals in tiny spaces. Crates, one on top of the other. And remember, the animals are alive, whi...

In the age of COVID-19, David Quammen’s 2012 book Spillover is beginning to be viewed as almost prophetic. The book is about the, er, spillover of diseases from animals to humans. The technical term for such inter-species diseases transfer is “zoonotic” . Such occurrences shouldn’t be surprising, he says: “Just as a lion might occasionally depart from its normal behaviour – to kill a cow instead of a wildebeest, a human instead of a zebra – so can a pathogen shift to a new target.” It’s just how nature operates. There are no rules: whatever works will happen.   The significance of zoonotic v/s non-zoonotic diseases in humans is this: “Zoonotic pathogens can hide (in other species).” Ergo, even if you eliminate it in all humans, it’s still out there (in other species). And so it can always come back, either as-is or with some mutation. This explains why we could eliminate smallpox: it is not a zoonotic pathogen. In other words, it had nowhere else (no other species) to...