Bed Bugs 101: Basics of Cimex lectularius.

Bed Bugs 101:
the Basics of Cimex lectularius.
Harold J. Harlan

100 American Entomologist • Summer 2006
in public shelters in the last half, as
compared with the first half, of the
year (Hwang et al. 2005). In Great
Britain, reported infestations more
than quadrupled each year from
1998 to 2002 (Burgess 2002). In
Berlin, Germany, a 10-fold increase
in bed bug infestations has been
reported, rising from 5 reported
cases in the 1992 to 76 cases in 2004
(Bauer-Dubau 2004). An Australian
government public health agency
reported a 400% increase in bed
bugs submitted in 2001–2004
compared with 1997-2000. They
also reported increased interceptions of bed bugs
in luggage by quarantine inspectors from 1986 to
2003, with 74% of those occurring from 1999 to
2003 (Doggett et al. 2004). The continued spread
and increased problems due to bed bugs seem to
be inevitable.
Public Health Aspects
Bed bugs consume only blood from mammals
(e.g., humans) or birds. Adults need at least one
blood meal of adequate volume for nutrition and
reproduction. Each active instar may feed multiple
times if hosts are readily available. Adults may
feed every 3–5 d throughout their typical 6–12-
mo life span.
Vector Potential
Although 28 human pathogens have been found
naturally occurring in common bed bugs, they have
never been proven to biologically or mechanically
transmit any of them (Usinger 1966, Jupp et al.
1991, Blow et al. 2001).
Health Effects of Bites
Bed bug bites can cause physical and psychological
discomfort. Although their feeding usually
is never felt, the saliva contains biologically active
proteins, which may cause progressive, allergenic,
visible symptomatic skin reactions to repeated
bites. Typical symptoms include a raised, inflamed,
reddish weal at each bite site, which may itch intensely
for several days. Immediate reactions may
appear from 1 to 24 h after a bite and may last
1–2 d; delayed reactions usually appear 1–3 d (or
more) after a bite and may last 2–5 d (Feingold et
al. 1968). There can also be a social stigma attached
with having a bed bug infestation (Usinger 1966,
Krinsky 2002). There is no current requirement to
report bed bug infestations to any public health or
government agency.
Importance as Pests
Bed bugs are often hard to control because
they are nocturnal, seek cryptic harborages, are
very small and elusive, and can detect and avoid
many chemicals, including cleaning agents. They
are easily transported on or in luggage, furniture,
boxes, and clothes. Because they are very thin,
except just after a blood meal, they can fit through
or hide in very narrow cracks. Adults can live for
several months (some more than a whole year), and
nymphs can survive for 3 mo or longer without
feeding. Complete elimination of an established
infestation is almost impossible to accomplish in
a single service visit by most PMPs. The bed bug’s
importance as a pest has increased because of its
biting and associated effects, its characteristic odor,
and the public fear of them.
Conditions in which bed bugs thrive include
an adequate supply of available hosts, abundant
cracks or harborages within about 1.5 m of a
host, and ambient temperatures between 28 and
32 ºC and 75–80% RH. Currently occupied, cluttered
bedrooms with little air movement are ideal.
Although sanitation alone will not eliminate an
infestation, eliminating clutter, removing accumulated
dirt and debris, and sealing cracks and
crevices reduce available harborages, make it easier
to detect remaining bug populations, and increase
the probability of successful treatment.
Detailed inspection is essential to any effective
control effort. The bugs must be found promptly
and correctly identified; and their harborage sites
and extent of infestation, including a rough estimate
of the population size, must be determined as
rapidly as possible.