A SUMMARY OF TEN YEARS OF OBSERVATIONS 
ON MALARIA IN PANAMA WITH REFERENCE 
TO CONTROL WITH QUININE, ATABRINE, 
AND PLASMOCHIN, WITHOUT ANTI¬ 
MOSQUITO MEASURES 
By HERBERT C. CLARK 
GORGAS MEMORIAL LABORATORY, APARTADO 1252, PANAMA CITY, R. P. 
WILLIAM H. W. KOMP 
UNITED STATES PUBLIC HEALTH SERVICE, GORGAS MEMORIAL LABORATORY, PANAMA CITY, R. P. 
It is probably true that anti-mosquito 
measures are the most efficient methods of 
malaria control, but in many instances their 
cost has been prohibitive, particularly if it 
is necessary to apply them in rural areas in 
the tropics, where economic resources are 
low, and the cost per capita of the measures 
would be high. Considerable work in at¬ 
tempting to control malaria in rural native 
populations has been done by British work¬ 
ers in India, Malaya, and other parts of the 
East, and by the Italians in Italy, using 
anti-malarial drugs alone, or in combination 
with anti-mosquito measures. We have 
been interested in the possibilities of drug 
control of malaria, without the use of anti¬ 
mosquito measures for two reasons: it seems 
logical to assume that a great reduction in 
the number of infected mosquitoes might 
follow a reduction in the malarial parasite 
rate by means of drugs administered to a 
given population; and we wished to investi¬ 
gate the possibilities of the newer synthetic 
anti-malarial drugs, under conditions which 
made outlays for mosquito control measures 
impossible. 
In 1929 the Republic of Panama granted 
us the privilege for an indefinite period of 
using some villages located near the middle 
of the Chagres River basin for an experi¬ 
ment in drug control of malaria. At the 
beginning of our investigations the towns 
selected had no means of communication 
with the outside world except by small dug- 
out canoes propelled by paddle and pole. 
The houses of the villagers were of the usual 
type common in the tropics, with thatched 
roof, side-walls of cane, and dirt floor. The 
villages were located along the river banks, 
just above flood level. There was no sani¬ 
tation ; water for drinking and cooking was 
obtained from the river, which was also 
used for bathing and laundering. There 
was no local medical attention and no drugs 
were available in any of the towns. The 
river with its small branches and many 
shallow lagoons, filled with aquatic vegeta¬ 
tion, provided large breeding areas for the 
larvae of anopheline mosquitoes. These vil¬ 
lages could be reached from our laboratory 
in Panama City in about one and one-half 
hours, by automobile and outboard motor- 
boat. 
At the beginning of our experiment, we 
knew that two large-scale construction proj¬ 
ects would soon be under way near the vil¬ 
lages, one of which was the Madden Dam 
across the Chagres River, some few miles 
above the villages, and the other of which 
was the Madden Highway from Panama 
City to Madden Dam, a distance of about 
24 miles. The imminence of these projects 
and the probability that other changes 
would take place in the towns themselves, 
such as the installation of latrines, better 
schools, and the introduction of our own 
medical service, made them especially suit¬ 
able for long-continued observation. We 
have limited our experiment to 10 succes¬ 
sive years of observations. The towns se- 
