Temples, Monkeys and Pandemic Equations

I talked of the why-China is the origin of so many zoonotic diseases in recent times (SARS, bird flu,  COVID-19). The key point in those wet markets is the presence of live animals of multiple species, giving viruses opportunities to make the multiple hops across different species.

 

On the other hand, we haven’t seen zoonotic disease transfer from the temples of India and Buddhist countries, where monkeys are all over the place. They are so numerous, and come close to humans all the time. In his awesome book, Spillover, David Quammen writes of one such temple:

“Thousands of bites, thousands of scratches, thousands of opportunities, and zero cases (anyway, zero reported cases) of humans sickened.”

So why have no zoonotic diseases started off from those temples? Is it because there aren’t other species in close proximity (just monkeys and humans), which means the multiple hops can’t be made? Or is it because the monkeys aren’t under threat around these temples, which in turn means there’s no evolutionary pressure for viruses to jump host?

 

Maybe, maybe not.

 

Let’s switch to a different topic next. We have all those equations for how an epidemic can spread. Susceptible count, infectious count, recovered count, threshold density, are all part of the equation. Quammen admits he likes the English (descriptive) version of equations, not the maths (numerical) version:

“Mathematics to me is like a language I don’t speak though I admire its literature in translation. It’s Dostoyevsky’s Russian, or the German of Kafka.”

 

Unfortunately, the maths only helps up to a point. As Quammen wrote of malaria, and we see all too well with COVID-19:

“It’s such an intricate disease, deeply entangled with human social and economic considerations, as well as ecological ones, and therefore a problem more complicated than even differential calculus can express.”

 

Quammen was bang on target about what would happen when the Next Big One hit us:

“Whatever happens after that will depend on science, politics, social mores, public opinion, public will, and other forms of human behaviour. It will depend on how we citizens respond… either calmly or hysterically, either intelligently or doltishly.”

 

What nobody could have predicted though was which countries would deal better with the Next Big One. That China would get it under control. That India would appreciate the seriousness before it hit the land and learn new habits like wearing masks overnight. That the US would refuse to wear masks 6-9 months after the outbreak. Human behaviour: the unpredictable element that derails equations.