The bedbug: its relation to public health

TREASURY DEPARTMENT

UNITED STATES PUBLIC HEALTH SERVICE

HUGH S. CUMMING, Surgeon General

THE BEDBUG

ITS RELATION TO PUBLIC HEALTH, ITS HABITS AND
LIFE HISTORY, AND METHODS OF CONTROL

REPRINT No. 626

FROM THE

PUBLIC HEALTH REPORTS

December 10, 1920
(Pages 2964-2970)

[Revised edition, 1924]

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WASHINGTON

GOVERNMENT PRINTING OFFICE
1924

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THE BEDBUG.1

Its Relation to Public Health, its Habits and Life History, and Methods of Control.

The bedbug is one of the numerous insects which have been sus¬
pected of conveying disease to man. Compared with such insect
pests as mosquitoes, lice, and fleas, however, its r61e is decidedly a
minor one. It has been claimed that the bedbug can take up the
microparasites of European relapsing fever, plague, and possibly
leprosy, along with the blood of men or animals suffering from these
diseases. It is also possible that in rare instances the bedbug may
transmit plague or European relapsing fever to man. On the other
hand, there is no convincing evidence that the bedbug is the usual and
ordinary insect transmitter of these or any other diseases at present
known to us.

If the bedbug acts as a transmitter of disease, it apparently does
so by the accidental carriage of disease elements on the mouth parts;
but this occurs only under the most favorable conditions. These
would require, first, the presence of great numbers of microparasites
on the skin or in the blood of a man or animal sick with some disease
transmissible to man by subcutaneous inoculation; second, it would
probably be necessary that there should be many bugs biting in
order that one or more of them should bite some healthy person
within a rather short space of time after these insects had fed on the
infected individual.

In actual practice these conditions would be found only in the
most filthy and insanitary surroundings and would call for drastic
measures to exterminate all vermin. It is, of course, possible that
under unsettled conditions where sick and well are crowded together
with no facilities for cleanliness, bedbugs might act as transmitters
of septicemic diseases. Experience has shown that under such
grossly insanitary conditions such insects as fleas and lice appear to
be and are far more dangerous as carriers of disease. Special meas¬
ures for their extermination should be taken. Added precautions
for the examination of bedbugs under these conditions would
probably not be justified by the results.

Notwithstanding the minor r61e which must be assigned the bed¬
bug as a carrier of disease, its presence is an offense against sanitary
decency. Its bites are quite poisonous to some people and its odor
is most disagreeable; and every effort should be made to keep all

i Reprint from the Public Health Reports, vol. 86, No. 50, December 10, 1920, pp. 2964-2970.

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»OoU-B THE BEDBUG. 3

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<2 dwellings, hospitals, ships, and other premises free from these dis-

5 gusting insects.

Dr. L. O. Howard, Chief of the Bureau of Entomology, United
States Department of Agriculture, and consultant United States
Public Health Service, has permitted the quotation of the following
passages from Farmer’s Bulletin No. 754, by C. L. Marlatt, which
gives an authoritative account of the habits, life history, and the
means of control of these insects.

“General Characteristics.

“The bedbug belongs to the order Hemiptera, which includes the
true bugs or piercing insects, characterized by possessing a piercing
and sucking beak. The bedbug is to man what the chinch bug is
to grains or the squash bug to cucurbs. Like nearly all the insects
parasitic on animals, however, it is degraded structurally, its para¬
sitic nature and the slight necessity for extensive locomotion having
resulted, after many ages doubtless, in the loss of wings and the
assumption of a comparatively simple structure. Before feeding, the
adult is much flattened, oval, and in color is rust red, with the abdo¬
men more or less tinged with black. When engorged, the body
becomes much bloated and elongated and brightly colored from the
ingested blood. The wings are represented by the merest rudiments,
barely recognizable pads, and the simple eyes or ocelli of most other
true bugs are lacking. The absence of wings is a most fortunate
circumstance, since otherwise there would be no safety from it even
for the most careful of housekeepers. Some slight variation in
length of wing pads has been observed, but none with wings showing
any considerable development has ever been found.

“Habits and Life History.

“•The bedbug is normally nocturnal in habits and displays a certain
degree of wariness, caution, and intelligence in its efforts at conceal¬
ment during the day. Under the stress of hunger, however, it will
emerge from its place of concealment in a well-lighted room at night,
so that under such circumstances keeping the gas or electric light
burning is not a complete protection. It has been known under
similar conditions to attack human beings voraciously in broad
daylight. It usually leaves its victim as soon as it has become
engorged with blood and retires to its normal place of concealment,
either in cracks in the bedstead, especially if the latter be one of the
wooden variety, or behind wainscoting, or under loose wall paper;
and in these and similar places it manifests its gregarious habit by
collecting in masses. It thrives particularly in filthy apartments
and in old houses which are full of cracks and crevices, in which it

4

THE BEDBUG.

can conceal itself beyond easy reach. As just noted, the old-
fashioned, heavy, wooden-slatted bedsteads afford especially favorable
situations for the concealment and multiplication of this insect,
and the general use in later years of iron and brass bedsteads has very
greatly facilitated its eradication. Such beds, however, do not insure
safety, as the insects are able to find places of concealment even about
such beds, or get to them readily from their other hiding places.

“The bedbug takes from 5 to 10 minutes to become bloated with
blood, and then retires to its place of concealment for 6 to 10 days
for the quiet digestion of its enormous meal, and for subsequent
molting, or reproduction if in the adult stage.”

“The eggs hatch in a week or 10 days in the hot weather of mid¬
summer, but cold may lengthen or even double this incubation
period or check development altogether. The young escape by push¬
ing up the lid-like top with its projecting rim. When first emerged,
they are yellowish white and nearly transparent, the brown color of
the more mature insect increasing with the later molts.”

“Unfavorable conditions of temperature and food will necessarily
result in great variation in the number of generations annually and
in the rate of multiplication, but allowing for reasonable checks on
development, there may be at least four successive broods in a year
in houses kept well heated in winter.”

“Food and Longevity.

“Under normal conditions the food of the common bedbug is
obtained from human beings only, and no other unforced feeding
habit has been reported. It is easily possible, however, to force the
bedbug to feed on mice, rats, birds, etc., and probably it may do so
occasionally in nature in the absence of its normal host. The
abundance of this insect in houses which have long been untenanted
may occasionally be accounted for by such other sources of food;but
probably normally such infestation can be explained by the natural
longevity of the insect and its ability to survive for practically a
year, and perhaps more, without food.”

“Influence of Temperature.

“As a messmate of human beings in dwelling houses, the bedbug is
normally protected from extreme cold and is known to be an
abundant and serious pest far north. In fact, it is often more
troublesome in north temperate latitudes than farther south. This
may be accounted for partly by the fact that the bedbug is very
sensitive to high temperatures, and a temperature of 96° to 100° F.
or more, accompanied with a fairly high degree of humidity, results
in the death of large numbers of the bugs. The mature or partly
mature bedbugs can stand comparatively low temperatures, even

THE BEDBUG.

5

below freezing, for a considerable period. The eggs and newly
hatched larvae, however, succumb to a temperature below freezing,
if this condition is prolonged for from 15 days to a month. The
feeding and developing activity of the insect practically ceases at
60° F., the insect remaining quiescent and in semihibernation at
temperatures below this point. The most favorable temperatures
for activity are between 60° and 98° F. The activity of the insect
is controlled entirely by temperature and food supply, and, there¬
fore, in heated houses the insect may remain active throughout the
winter. There is some protection in winter, therefore, in sleeping in
cold bedrooms.”

“The Bite of the Bedbug.

“The bite of the bedbug is decidedly poisonous to some individuals,
resulting in a slight swelling and disagreeable inflammation. To such
persons the presence of bedbugs is sufficient to cause the greatest
uneasiness, if not to put sleep and rest entirely out of the question.
With others, however, who are less sensitive, the presence of the bugs
may not be recognized at all, and, except for the occasional staining
of the linen by a crushed individual, their presence might be entirely
overlooked. The inflammation experienced by sensitive persons
seems to result chiefly from the puncture of the skin by the sharp
piercing setse which constitute the puncturing element of the mouth
parts, as there seems to be no secretion of poison other than the
natural fluids of the mouth.

“ The biting organ of the bedbug is similar to that of other insects
of its order. It consists of a rather heavy, fleshy under lip (the only
part ordinarily seen in examining the insect), within which lie four
thread-like hard filaments or setae which glide over one another with
an alternating motion and pierce the flesh. The blood is drawn up
through the beak, which is closely applied to the point of puncture,
and the alternating motion of the setae in the flesh causes the blood
to flow more freely.

“To allay the irritation set up by the bite of the bedbug, peroxide
of hydrogen or dioxygen may be used with good results.

“Tincture of iodine either at ordinary or double strength is also a
good counter irritant for use in cases of flea, mosquito, bedbug, and
other insect bites, but should be used with caution on the tender
skin of small children and on those who are affected with or disposed
to eczemic disorders.”

“Natural Enemies of the Bedbug.

“Living always in houses as it does and being well concealed, the
bedbug is not normally subject to much if any control by natural
enemies. Certain other household insects, however, do occasionally
prey upon the bedbug, as, for example, the house centipede and the

THE BEDBUG.

common little red house ant. Such enemies, however, are of very
small importance and yield little, if any, effective control except
under very exceptional circumstances.”

“Remedies.

“ Undoubtedly the most efficient remedy for the bedbug is to fumi¬
gate the infested house or rooms with hydrocyanic-acid gas. This
gas will penetrate into every crevice in the house or room where the
bedbugs conceal themselves and has an immediate effectiveness
which gives it an important recommendation, especially when the
infestation is considerable or of long standing. This method of
fumigation should be intelligently employed, as the gas is deadly
poisonous.” Five ounces of potassium cyanide per 1,000 cubic feet
of space should be employed; exposure, one hour.2 Ten ounces per
1,000 cubic feet would be better.

“ The fumes of burning sulphur are also a very efficient means of
control where the conditions are such that this method can be used,
readily destroying the insect in all stages, including the egg. The
treatment is inexpensive compared with the use of hydrocyanic-
acid gas and offers much less risk of danger to human beings. There
is, however, a considerable risk of injury to household fabrics, furnish¬
ings, and wall papers from the strong bleaching quality of sulphur
fumes. This danger will be somewhat diminished if the fumigation
can be done at a time when the room or house is thoroughly dried out,
as in winter by a furnace or other heating system. Further precau¬
tions should be taken by removing all metallic surfaces from the
room or building, or by protecting them with a coating of vaseline.”

. Four pounds of sulphur are recommended for each 1,000 cubic feet
of space, and the building should be closed for the treatment for at
least five or six hours. “ Sulphur candles may be used where avail¬
able, or the sulphurous gas or fumes can be generated by burning
the sulphur in a dish placed in the center of the room, and for pro¬
tection set within a larger vessel. Thoroughgoing precautions must
be taken to prevent accidental overflowing or the starting of a fire,
and after the fumigation the house should be given a thorough airing.

“ Other gases have been experimented with, such as formalin and
the vapors of benzine, naphthalene, and camphor, but these gases are
of little value. Similarly, insect powders are of little value, largely
from the difficulty of getting them into the crevices and other places
of concealment of the insects.

“The old-fashioned household remedies referred to below are effec¬
tive enough, though at a greater cost of time and personal effort.
They will, however, be often of much service in the case of slight or

* Creel, R. H., and Faget, F. M., Cyanide Gas for the Destruction of Insects, with Special Reference
to Mosquitoes, Fleas, Body Lice, and Bedbugs: Publio Health Reports, June 9, 1916, pp. 1464-1475;
Reprint No. 343.

THE BEDBUG.

7

recent infestations, or where the employment of more poisonous and
troublesome gases is objected to or is impracticable. Of these simple
methods of control perhaps the most efficient is in very liberal appli¬
cations of benzine or kerosene, or any other of the lighter petroleum
oils, introduced with small brushes or feathers, or by injecting with
syringes into all crevices of beds, furniture, or walls where the insects
may have concealed themselves. Corrosive sublimate is also of value,
and oil of^turpentine may be used in the same way. The liberal use
of hot water, wherever it may be employed without danger to furniture,
etc., is also an effectual method of destroying both eggs and active
bugs.3 A 5 per cent solution of compound solution of cresol (liquor
cresolis compositus) in kerosene forcibly applied with a large plant
sprayer is effective if frequently applied.

‘Various bedbug remedies and mixtures are for sale, most of them
containing one or another of the ingredients mentioned, and these
are frequently of value. The great desideratum, however, in a case
of this kind, is a daily inspection of beds and bedding, particularly
the seams and tufting of mattresses, and of all crevices and locations
about the premises where these vermin may have gone for conceal¬
ment. A vigorous campaign should, in the course of a week or so
at the outside, result in the extermination of this very obnoxious and
embarrassing pest.”

/ “ Temperature control. — The possibility of temperature control is

indicated in the discussion elsewhere of the effect of temperature
on this insect. A temperature maintained below freezing for 10 or
15 days destroys the eggs, and this temperature continued for 15
days to a month will destroy the newly hatched young. It may be,
therefore, that if infested houses in cold climates should be opened
up and allowed to remain at a temperature well below freezing for a
considerable period, all eggs and the young, and possibly most if not
all of the adults, would be exterminated. This method of control

* “A remedy for the bedbug has been devised by Mr. R. H. Pettit (‘Notes on two insecticidal agents,’
10th Rpt. Mich. Acad. Sci., p. 159-160, 1908) as a substitute for hydrocyanic-acid gas and sulphur, and
is reported to have proved very successful. The preparation of this insecticide and its application are
described as follows:

“Alcohol is drawn through pyrethrum in a funnel until the powder is well washed and a large part of
the resinous principle extracted. To do this, the powder is placed in a large funnel with filter-plate and
a layer of cotton wool at the bottom. An aspirator is attaohed and the alcohol is at first slowly and later
rapidly sucked through six or eight times, during which operation it becomes highly colored. To this
liquid as a basis , are added several oils to give permanence to the application. Bpth alcohol and pyrethrum
evaporate so quickly that it was thought best to carry in some heavier volatile oils whose effects would
last several days or even weeks. The formula when completed stands as follows:

“To the extract made by washing 400 grams of pyrethrum with 2,000 c. c. of strong alcohol, are added—
50 grams gum camphor.

150 c. o. cedar wood oiL
25 grams oilcitronella.

25 grams oil lavender.

“The application is best made with a large-sized atomizer, one holding a pint or more and working with
a piston instead of a rubber bulb. * * * To obtain the best results, repeat the treatment after about
two weeks. We have tried this mixture repeatedly and with uniformly gratifying results. Usually
one application, if thoroughly made, put a period to the complaints, about eight to ten ounces being
required in an average sleeping room. The odor remains some little time in a room, but is not disagreeable
to the average person.

"‘This remedy can be readily prepared by a pharmacist in any drug store.’

8

THE BEDBUG.

might perhaps he practicable at least in the case of summer houses in
the North which are left un tenanted in the whiter.

“The maintaining of high temperatures may be an even more
efficient method of control. The activity of the bedbug is at its
greatest between 60° and 70° to 75°. As indicated elsewhere, in a
temperature of 96° to 100° F., accompanied with a high degree of
humidity, newly hatched bedbugs perish within a few days, and, if this
temperature is raised to 113° F., in a few minutes.4 A temperature of
113° will also destroy the eggs, and with these higher temperatures
the item of humidity is not apparently important.

* Editorial note. — An account of successful use of live steam to eradicate bedbugs in bunkhouses, as
practiced by a lumber company in Oregon, was published in Public Health Reports, Nov. 28, 1919, pp.
2713-2714. In that instance steam pipes were tapped, after closing all doors and windows, and a tem¬
perature of 160° F. was held for approximately 3 hours. The officials of the company stated that 2 months
after the steaming no signs of bedbugs had been found.

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