2 Zoonoses: Malaria, Measles

Surprised with the title ?

It is now established that we have contracted these two from animals as a price when we left the hunting and gathering and settled down to a pastoral life by the great rivers.

“There is a thin line between Zoonoses and all the Non-Zoonotic diseases. It’s actually a dimension of time. For example: Measles, Malaria.“

-R.K.Mahapatra

60% of our infective diseases today have jumped upon us from an animal reservoir in the past. Most of the present pandemics and all those epidemics of the last century ( be it the Bird flu, Swine flu, Horse flu, Ebola, Hendra, Zica or AIDS) have their origin from animals. Some of them are domestic, some are of sylvan origin. 

Here are two examples: Measles , Malaria.

Measles

A virus phylogenetically similar to measles occurs among cattle: the Rinderpest virus among cattle and Canine Distemper Disease among the dogs. We have a molecular biology term called molecular clock which tells us that both the Rinderpest virus and the Canine Distemper viruses are phylogenetically million years older than human measles. Most likely it has jumped upon us 10,000 years ago when we domesticated cattle and dogs. The first adult man who drank a cup of milk ( I presume cow’s) got the nourishment as well as  the opportunity to be infected by measles.

We started planting wheat by the river of Tigris some 10,000 years ago. see below.

The Wheat Story- an account of Zoonoses.

Malaria 

We have four varieties of Malaria parasite. While we are more familiar with the Vivax Malaria, the younger Falciparum Malaria has taken more life. Falciparum malaria has jumped on us hardly few thousand years ago. Noted epidemiologist, Theobald smith has proposed that the virulence of any infection will decrease as the organism matures. Death of the host (man) is not in the best interest of the virus. The older Vivax has mellowed, not so is the younger Vivax.

The Virus has Aged.

What is surprising that none of the four malarial parasites that infect us are phylogenetically related. They are more close to various malaria parasites that invade birds and chimps. We have got malaria from birds or apes.

The youngest Falciparum is identical to the much older western Gorillas of Africa. (These Gorillas are found on the West Bank of the great river Congo.) Most likely it has jumped on the sub Saharan tribes of Africa and then has spread to Romans and travelled the world riding along the army of the Alexander the Great.

Any so called non Zoonotic disease can be traced back to one such animal. It’s a matter of time when we lose the track to its animal connection. After all We one such animal.

• We get malaria from the mosquito, Does it qualify as Zoonosis ?”
• What is the difference between a Vector and a Reservoir ?”

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