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The
control of malaria was vital for the construction of the Panama Canal
The discovery by Major Ronald Ross that malaria was transmitted by mosquitoes
had tremendous impact on developmental programs in the tropics. One of
the first of these was the construction of the Panama Canal which began
within a few years after Dr. Ross's discovery. During the American occupation
of Havana, Cuba, regulations were put into effect by the United States
Army for the control of yellow fever that consisted of the screening of
houses and extensive drainage to reduce breeding of mosquitoes. Not only
was yellow fever eliminated, but malaria transmission was also greatly
reduced. Work in Havana was under the direction of Surgeon Major W. C.
Gorgas.
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William
Crawford Gorgas
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In
1904, the Isthmian Canal Commission, accompanied by Col. W. C. Gorgas,
Medical Corps, U. S. Army, John W. Ross, Medical Director, U. S. Navy,
Capt. C. E. Gillette, Corps of Engineers, U. S. Army, and Maj. Louis A.
LaGarde, Medical Corps, U. S. Army, as experts on sanitation inspected
the potential site of construction. These experts prepared a plan for
the sanitation of the Canal Zone and the cities of Panama and Colon. On
June 30, 1904, the Sanitary Department was formed with Colonel Gorgas
as its head.
The
Isthmus of Panama was an ideal environment for mosquitoes. The high temperature
varies little during the year. The rainy season lasts for nine months
and the interior of the Isthmus is tropical jungle, ideal for mosquito
breeding. The Panama Canal extends diagonally across the Isthmus of
Panama from south-east to north-west, a distance of 42 miles from shore
to shore. At Panama, the anti-malarial work was principally rural, located
for 47 miles along the line of the railroad between Panama and Colon.
The population was about 80,000 living within half a mile of the railroad
and occupying some 30 villages and camps or isolated houses. Malaria
was so abundant that in Colon, it was estimated that one-sixth of the
population was suffering from malarial attacks during each week.
An integrated program of mosquito control was initiated that involved
seven basic programs that were strictly enforced. These were, in order
of importance:
- Drainage: All pools within 200 yards of all villages
and 100 yards of all individual houses were drained. Subsoil drainage
was preferred followed by concrete ditches. Lastly, open ditches were
constructed. Paid inspectors made sure ditches remained free of obstructions.
- Brush and grass cutting: All brush and grass was cut and maintained
at less than one foot high within 200 yards of villages and 100 yards
of individual houses. The rationale was that mosquitoes would not
cross open areas over 100 yards.
- Oiling: When drainage was not possible along the grassy edges of
ponds and swamps, oil was added to kill mosquito larvae.
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Joseph
Augustin LePrince
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Samuel
T. Darling
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- Larviciding: When oiling was not sufficient, larvaciding was done.
At the time, there were no commercial insecticides. Joseph Augustin
LePrince, Chief Sanitary Inspector for the Canal Zone developed a larvacide
mixture of carbolic acid, resin and caustic soda that was spread in
great quantity.
- Prophylactic quinine: Quinine was provided freely to all workers
along the construction line at 21 dispensaries. In addition, quinine
dispensers were on all hotel and mess tables. On average, half of the
work force took a prophylactic dose of quinine each day.
- Screening: Following the great success in Havana, all governmental
buildings and quarters were screened against mosquitoes.
- Adult killing: Because the mosquitoes usually stayed in the tent or the
house after feeding, collectors were hired to gather the adult mosquitoes
that remained in the houses during the daytime. This proved to be very
effective. Mosquitoes that were collect in tents were examined by Dr.
Samuel T. Darling, Chief of the Board of Health Laboratory. Cost of adult
mosquito killing was $3.50/per capita/per year for whole population of
the strip.
The
results of this malaria program were such that yellow fever was totally
eradicated. Death rate due to malaria in employees dropped from 11.59
per 1,000 in November 1906 to 1.23 per 1,000 in December 1909. It reduced
the deaths from malaria in the total population from a maximum of 16.21
per 1,000 in July 1906 to 2.58 per 1,000 in December 1909.
Among the work force, the percentage of employees hospitalized due to
malaria was 9.6% in December 1905, 5.7% in 1906, 1.8% in 1907, 3.0% in
1908, and 1.6% in 1909. Malaria continued to be a challenge throughout
the entire construction program.
The Panama Canal was the construction miracle of the beginning of the
20th century. It also was a great demonstration of malaria control based
on an integrated mosquito control program enforced by the military. Malaria
was not eliminated. However, under these most trying conditions, the disease
was controlled to the extent that the construction work could be completed.
Drs.
Gorgas, LePrince, and Darling are remembered as pioneers for their leadership
in the control of malaria during this period. The Gorgas Memorial Laboratory
in Panama, named after Col. Gorgas remained a leading research center
for tropical disease research throughout the 20th century. The American
Society of Tropical Medicine and Hygiene every 3 years awards the Joseph
Augustin LePrince Medal in recognition of outstanding work in the field
of malariology. Professor Darling is honored by the Darling medal and
prize, which is awarded by the Darling Foundation for outstanding achievements
in the pathology, etiology, epidemiology, therapy, prophylaxis, or control
of malaria. An examination of references 2, 3, and 5 will give details
of the work of these pioneer malariologists in the control of malaria
in the construction of the Panama Canal.
References
1. Marshall, L. 1913. The story of the Panama Canal. L.
T. Myers. Pp. 1-358.
2. Gorgas, W. C., 1910. Malaria prevention on the Isthmus of Panama.
In The Prevention of Malaria by R. Ross. Sect. 42. pp. 346-352.
E. P. Dutton & Co., New York.
3. Le Prince, J. A., 1910. Anti-malarial work on the Isthmus of
Panama. In The Prevention of Malaria by R. Ross. Sect. 43., 43.
pp. 353-368. E. P. Dutton & Co. New York.
4. Darling, S. T. 1910. Factors in the transmission and prevention
of malaria in the Canal Zone. Ann. Trop. Med. Parasitol.
4: 179-223.
5. Darling, S. T. 1910. Studies in relation to malaria. Isthmian
Canal Commission, Laboratory of the Board of Health. Pp. 1-42.
2nd Edition.
Page last modified : April 23, 2004
Content source: Division of Parasitic Diseases
National Center for Zoonotic, Vector-Borne, and Enteric Diseases (ZVED)
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