Beating the mosquito
VulcanSpirit
Richard & Alison Brunstrom
Mon 19 Mar 2012 02:37
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Yellow fever and malaria are both transmitted by
mosquitoes and played a major role in the building of the Panama Canal - but
we've yet to be bitten here (although we are taking the tablets!).
Why?
The answer is one man, Colonel Dr William Gargas,
US Army Medical Corps.
The Panama Railway completed in 1885 cost at
least 5000 lives. They financed their hospital by selling the corpses of their
workers for medical students to dissect. The failed French attempts to build the
Canal, 1880-1903, cost over 22 000 lives thus making it the
most costly human endeavour ever, other than war. The vast majority of these victims died of yellow fever or
malaria.
The fact that malaria and yellow fever were
transmitted by mosquitoes only became known at the very end of the nineteenth
century. When the USA took over building the canal in 1903 Gargas, as the newly
appointed Chief Medical Officer insisted on a mosquito control programme before
construction work started. He persuaded the President to fund it and the rest is
history - from which we still need to learn.
Mosquito larvae live in stagnant fresh water -
ponds, water butts, puddles, anything will do. Central Panama has 3000mm of rain
a year (that's a lot) so there is a lot of water standing about. Gargas
targetted this. He had water butts sealed, swamps were drained, roads were
surfaced to remove puddles, piped water was supplied to houses and mains
drainage installed, diesel oil was sprayed onto standing water to prevent the
air-breathing larvae from surfacing (including, ingeniously, allowing diesel to
drip into slow moving streams so that it would collect on the surface of any
pools). But this was not all; every house where infected people were found was
fumigated with burning sulphur, all infected people were segregated and kept
behind screens so that they could not pass on the infection (mosquitoes are
themselves infected by biting infected humans, then transmit the disease to
a new human host), and mosquito nets were used for sleeping. Every single house
was visited, several times, and appropriate peventative action
taken.
These measures were stunningly effective. The last
yellow fever victim in the Canal Zone died in November 1906; there were no more.
Malaria took longer, but by June 1910 malaria deaths were down to 1% of what
they had previously been. The Canal Zone remains effectively free of malaria and
yellow fever today. The US-built Canal took about 5000 lives. Horrific by
today's standards, but a fraction of what it might have been without
Gargas.
But did you know that (according to The
Lancet) 1.2 million people worldwide died of malaria in 2010? Gargas
still has a lesson to teach us.
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