In Homer there is a disputed reference to malaria, but it is not possible
to ascertain whether the disease was present during the rise of Greek
civilisation, and there are no references to this disease in the literature
from 700 B.C. to 550 B.C. [58] From this date references to malaria
gradually become more frequent, and Hippocrates stated that "those who live
in low, moist, hot districts, and drink the stagnant water, of necessity
suffer from enlarged spleen. They are stunted and ill-shaped, fleshy and
dark, bilious rather than phlegmatic. Their nature is to be cowardly and
adverse from hardship; but good discipline can improve their character in
this respect." [59] After an exhaustive study of the literature, Mr. Jones
concludes "that malaria was endemic throughout the greater part of the
Greek world by 400 B.C."

Concerning the causes of a malarial epidemic, Sir Ronald Ross writes: [60]
"Suppose that the Anophelines have been present from the first, but that
the number of infected immigrants has been few. Then, possibly, some of
these people have happened to take up their abode in places where the
mosquitoes are rare; others may have recovered quickly; others may not have
chanced to possess parasites in suitable stages when they have been bitten.
Thus, the probability of their spreading infection would be very small. Or,
supposing even that some few new infections have been caused, yet, by our
rough calculations in section 12, _unless the mosquitoes are sufficiently
numerous_ in the locality, the little epidemic may die out after a
while--for instance, during the cool season." The italics are mine, because
some writers have suggested that the decline of Greece was _due_ to
malaria, whereas I submit, as the more logical interpretation of the facts,
that a moral catastrophe led to the neglect of agriculture, whereby the
area of marshy land became more extensive, mosquitoes more numerous, and
the fever more prevalent.