346 
created much misery to _ peoples 
throughout the world. Even today 
plague rages in certain parts of the 
world and is of potential importance 
in the United States. Endemic ty- 
phus can be transmitted by fleas and 
is one of our common diseases. This 
insect was therefore also included 
among those investigated at the Or- 
lando laboratory. Under the super- 
vision of A. W. Lindquist, A. H. 
Madden, and others, we tried various 
repellents and insecticides. Although 
dimethyl phthalate and other mos- 
quito repellents afforded some pro- 
tection to individuals, a material 
which would kill fleas was more 
urgently needed. 
When DDT proved so highly effec- 
tive to a number of other insects, we 
naturally investigated this material 
for flea control. It was shown that 
fleas could be eliminated completely 
from infested areas by applying DDT 
sprays or dusts. Although slow in 
action, DDT was also useful for killing 
fleas on persons already infested or 
those subject to infestation. Its effec- 
tiveness as an all-purpose flea insecti- 
cide compared favorably with that as 
a louse killer or for mosquito and fly 
control. 
Bedbugs.—Bedbugs have not been 
incriminated as disease carriers, but 
they are important from the stand- 
point of annoyance. In permanent 
military establishments, and of course 
among a high percentage of civilian 
homes and institutions, bedbugs con- 
stituted a major insect pest problem. 
Ordinary household type of sprays, 
heat, and fumigation were methods 
employed for controlling bedbugs. 
These treatments, however, were far 
from satisfactory. 
The bedbug problem was under- 
taken in 1942 by A. W. Lindquist and 
A. H. Madden, the same men men- 
tioned in connection with the research 
on mosquitoes, flies, mites, and other 
arthropods. Many insecticides were 
tested against bedbugs. Pyrethrum 
properly used and in sufficient amount 
was good, but we could not recom- 
ANNUAL REPORT SMITHSONIAN INSTITUTION, 1948 
mend that it be used because all 
available supplies were required for 
the disease-carrying insects. 
When DDT became available, labo- 
ratory tests demonstrated that this 
insecticide when used as a residual 
spray remained effective for many 
weeks. Practical tests were then con- 
ducted in naturally infested homes. 
A thorough treatment of the walls, 
bedsteads, springs, and mattresses 
completely eradicated the bugs pres- 
ent. In order to determine how long 
the treatment would prevent rein- 
festations, 25 bugs from the labora- 
tory colony were added to a bed in 
one of the treated homes at intervals 
of a week to a month. This test was 
continued for 16 months. Bedbugs 
failed to become established, and 
finally Mr. Madden gave up, even 
though bugs placed on the bed were 
still being killed after this period of 
time. 
The next problem was to give DDT 
a thorough test under military condi- 
tions. The Orlando Air Base under 
the direction of Lt. Col. J 3@ar 
Daniels carried out investigations 
along this line. A total of 6,000 beds 
and the quarters were treated, and 
during 6 months of checking no bed- 
bugs were found. The Corps of Engi- 
neers obtained equally spectacular 
results in practical tests. We now say 
that DDT is the perfect answer to the 
bedbug problem for the military as 
well as for civilians. 
Scabies investigations—The human 
itch mite is widespread in distribution 
and is an important military problem. 
It is also important among civilians, 
especially among school children. The 
studies on itch mites, which were un- 
dertaken by G. W. Eddy, were greatly 
handicapped by a lack of sufficient 
cases for treatment. No method of 
colonizing this parasite is known. A 
treatment for scabies generally re- 
quires the application of materials to 
the entire body. It was necessary 
therefore to exercise extreme caution 
from a _ toxicological - viewpoint in 
choosing materials for test purposes. 
