Fleas and Flea Management - Urban Insect Pests: Sustainable Management Strategies - page 95

differently from the control of fl eas
responsible for domestic nuisance. The
World Health Organization has prepared a
Plague Control Manual (Dennis et al. , 1999)
for use in affected countries. Plague control
work is typically carried out by local or
national governmental organizations,
although in some areas local residents may
also become involved, e.g. in rodent control.
Prevention and control of plague may be
divided into a series of separate but
interlinked activities:
• Plague vector surveillance . In areas
where plague transmission occurs or
may occur, it is important to be aware of
the current status of the disease in the
area. This requires a detailed under-
standing of the ecological conditions in
which transmission is likely to occur,
together with routine surveillance of fl ea
vectors and their rodent hosts.
• Flea control . The usual strategy in
plague control is to reduce fl ea numbers
before any attempt is made to control the
rodent hosts. This avoids the widespread
death of fl ea-infested rodents, which
would result in large numbers of poten-
tially infective fl eas seeking alternative
hosts, such as humans. A variety of tech-
niques are used to control the fl eas, with
insecticide dusts being the most common
(Gratz, 1999). These may be applied
directly into rodent burrows, along
rodent runs or deployed within rodent
bait stations. Formerly, DDT dust was
widely used, but now a range of organo-
phosphate, carbamate or synthetic pyre-
throid dusts are used (Mian et al. , 2004).
In India, indoor house spraying for
malaria control also achieved control of
the fl eas responsible for plague transmis-
sion (Renapurkar, 1990).
• Rodent control . Once fl ea populations
have been controlled, the rodent reser-
voir of plague is reduced, normally
through the use of anti-coagulant roden-
ticides. These are typically used as baits,
which are deployed either directly into
burrows or contained within bait stations
to prevent exposure to the weather and
non-target animals. Dead rodents are

collected at regular intervals, to avoid
secondary poisoning of scavenging
animals.

Insecticide Resistance in Fleas

Repeated treatment of insects with a
particular insecticide will favour the
survival of strains carrying genes that
confer resistance to that insecticide.
Insecticide resistance is documented in a
broad range of insect pests, including fl eas.
Bossard et al. (2002) tested 11 strains of C.
felis from across the USA and found varying
levels of resistance to organophosphates,
carbamates and pyrethrins. Bossard et al.
(1998) suggest that, as with other insects,
prolonged exposure of the fl ea to insecticide
residues, such as may occur through use of
fl ea collars and some other treatment
techniques, may increase the selection
pressure for resistance. Hinkle et al. (1997)
emphasize the role of non-chemical control
techniques in reducing the selection
pressure for resistance. The fl ea vectors of
plague (principally X. cheopis ) have also
developed resistance to several insecticides,
which would make control more chal-
lenging in the event of a plague outbreak
(Ratovonjato, 2000). In India, however,
Renapurkar (1990) has suggested that the
absence of fl ea resistance in urban centres,
and its occurrence in rural areas, shows
that the resistance has arisen through
collateral exposure to insecticides from
malaria control programmes, not through
fl ea control itself.
A couple of case studies are presented
below to show how successful fl ea control
has been achieved in different areas.

Shopping mall fl eas

A shopping mall had a problem with a
population of feral cats that found harbour-
age in engineering plant rooms, ducting and
service areas but freely roamed through
some of the indoor and public areas. The
cats obtained food by foraging in waste bins,