So, Who Is King of the Jungle?

Trey Smith

As the Abrahamic religions tell us, humankind is the species created in the image of the creator. It's not just those religions either; a good deal of belief systems posit the very same thing. And why not? From our perspective, we're the smartest, most innovative species this world has ever known. We have harnessed technology to better our lives and no one yet has found a tree or a butterfly who can recite poetry!

Yes, we must be the kings of the jungle. No other organism is as powerful as human beings...

...except pathogens! Every time we think we have vanquished one, scores more take their place. While a pathogen never built a skyscraper, there's a better than even chance that, at the end of the day, the pathogens will live on and Homo Sapiens will become just another extinct and forgotten species!

Just as predators have their accustomed prey, so do pathogens. And just as a lion might occasionally depart from its normal behaviour – to kill a cow instead of a wildebeest, or a human instead of a zebra – so a pathogen can shift to a new target. Aberrations occur. When a pathogen leaps from an animal into a person, and succeeds in establishing itself as an infectious presence, sometimes causing illness or death, the result is a zoonosis.

It's a mildly technical term, zoonosis, unfamiliar to most people, but it helps clarify the biological complexities behind the ominous headlines about swine flu, bird flu, Sars, emerging diseases in general, and the threat of a global pandemic. It's a word of the future, destined for heavy use in the 21st century.

Ebola and Marburg are zoonoses. So is bubonic plague. So was the so-called Spanish influenza of 1918–1919, which had its source in a wild aquatic bird and emerged to kill as many as 50 million people. All of the human influenzas are zoonoses. As are monkeypox, bovine tuberculosis, Lyme disease, West Nile fever, rabies and a strange new affliction called Nipah encephalitis, which has killed pigs and pig farmers in Malaysia. Each of these zoonoses reflects the action of a pathogen that can "spillover", crossing into people from other animals.

Hmm. Who looks to be the king of the jungle now?