Re: Parasites and paleoanthropology

Paul Crowley (
Tue, 23 Jul 96 21:46:16 GMT

In article <4stv8c$> "Nick Maclaren" writes:

> >Fleas jump on for a feed and then jump off. If the host never
> >returns to base they die. So chimps and gorillas don't have them.
> Many birds have fleas, but very few have permanent homes.

I vaguely recall reading that bird fleas are an exception, and are
recent speciations. Certainly mammals which have no permanent
nest or habitation, such as deer, antelopes, and monkeys, are
virtually without fleas, although they are almost invariably
infested with lice.

> >> In fact, the existence of water-borne parasites does not even show
> >> that humans used permanent water-holes. If the parasite can last a
> >> complete dry season in either the human or the dormant phase of the
> >> aquatic host, then it can be transmitted entirely via transient water
> >> holes and streams.
> >
> >You should not be so dogmatic when you are so ignorant. ...
> Please educate me by telling me what is incorrect in the statement
> that I made above.

It's the vast overgeneralisation in the first sentence. Parasites
have such extraordinarily complex lifestyles; they come in such an
extraordinarily wide range (coming from different phyla) that it is
next to impossible to make *any* generalisation. It's also the use
of the phrase "the parasite" in your second sentence; it's like
saying "the element" without indicating which one or which type as
though they were all much of a muchness.

Your second sentence could be true about some parasites, although
I have not encountered an example. Some nematode eggs (e.g
Enterobius - the pinworm) seem to be able to survive long dry
periods, but none I know are water-borne.

Nearly all parasites I come across (and most are not water-borne)
appear to depend on a fairly dense and *resident* population which
does not practise good hygiene as regards children picking up dirt
on their hands or as regards defecation. In nearly all cases of
current human parasites a population made up of small bands that
moved on every day would never suffer infestations. They appear
to be characteristic of dense and resident hominid populations.
The question is "How long ago were such populations established?".