FARANGI IN TOWN: Evolutionary dead-ends —Ella Rolfe

In Africa, you are far, far more likely to get bitten by a mosquito that will give you malaria than you are in Pakistan or India. Diamond argues from there — and I see no reason to doubt him — that the scourge of malaria has been one of many factors in Africa’s failure to develop at the same rate as South Asia

How lucky you are. If your mother and father are Pakistani, you may have a couple of chips on your shoulder about your extended family and a certain difficulty in getting a visa for just about anywhere. But you have one huge advantage over me — your immune system.

Jared Diamond, in his great book Guns, germs and steel, describes how different populations in different parts of the world have adapted to local ecological conditions, especially how the disease strains in a particular area have affected and evolved alongside expanding human communities.

Interestingly, many of the diseases that ravage us today (as well as many that we have succeeded in overcoming, such as smallpox) were originally transmitted from animals that we domesticated. Thus, farmers, as Diamond puts it, “tend to breathe out nastier germs” than hunter-gatherers. One reason for the ease with which, from ancient times to just the past few hundred years, ‘civilised’ conquerors have found it surprisingly easy to wipe out populations of strong, hardened hunter-gatherers.

Such simple facts of biology can have enormous social and historical effects. Malaria, for instance, is transmitted through several different types of mosquito. In South Asia, the mosquitoes dislike human blood, and 70 percent of the time or more, they bite cattle instead of humans. The malaria parasite also has a far longer gestation period in the mosquito’s stomach at the lower temperatures experienced by this part of the world for much of the year, during which the short-lived mosquito is more likely to die before the parasite is ready to be passed on.

In Africa, the local mosquitoes bite humans almost 100 percent of the time, and the more steadily tropical climate means that the parasite transforms into its infectious form much quicker. Hey presto — in Africa, you are far, far more likely to get bitten by a mosquito that will give you malaria than you are in Pakistan or India. Diamond argues from there — and I see no reason to doubt him — that the scourge of malaria has been one of many factors in Africa’s failure to develop at the same rate as South Asia.

What all this means for me is that my UK-based (well, ultimately Viking, but as far as I know that was all a long time ago) immune system is good at dealing with the common cold, flu, and probably invisible air pollution, but is more than a little confused by water-borne parasites. Nor is it used to ghee. So, whatever I eat, be it home cooked by me (in which case it’s likely to be either omelette or salad) or desi-style, I am almost always a little bit ill or a bit exhausted.

I heard somewhere recently that around 70 percent of Pakistan’s piped water supply is contaminated in some way or another. Now, I am not so stupid as to drink it (much as I find it annoying when Pakistani friends sip from the tap while I am forced to boil pans manically once a week when my bottled water runs out); but if true this does mean that short of showering in mineral water or having a local immune system, there is no way to protect oneself from a random collection of annoying little beasties eager to colonise one’s gut.

I and foreign friends are rather like the hunter-gatherers of five thousand years ago, or the Neanderthals before them who, according to one argument, were wiped out by the diseases of homo sapiens not their weapons. As far as I can see, anyone with predominantly northern European blood is doomed in Pakistan to being exhausted by heat three or four months of the year, and mildly diseased for the rest.

Basically, we’re evolutionary dead-ends here.

The writer is a staff member at The Friday Times

http://www.dailytimes.com.pk/default.asp?page=2008\08\18\story_18-8-2008_pg3_3

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