Fleas and Flea Management - Urban Insect Pests: Sustainable Management Strategies - page 87

control of fl eas during disease outbreaks is
more typically addressed by regional or
national public health organizations.

Fleas can also act as intermediate hosts
and vectors of the tapeworm Dipylidium
caninum (Pugh, 1987) of dogs, cats and
rarely children (Table 6.1) (Dryden and
Rust, 1994). There is also a possibility that
fl eas may be involved in the transmission of
feline leukaemia virus (Vobis et al ., 2003).

Veterinary signifi cance

Flea bites vary in their effects on the host
animal, depending on its sensitivity. The
typical reaction to fl ea bites is the formation
of a small, central red spot surrounded by a
red halo. Heavy and repeated infestations
will result in more serious skin reactions,
together with the risk of secondary infection.
The host animal typically becomes restless,
irritable, loses weight, develops a ruffl ed
coat, and will be repeatedly biting and
scratching itself. Fleas on dogs and cats
seem to prefer the head and neck to other
parts of the body. The fewest fl eas are
typically found on the legs and tail (Hsu et
al ., 2002). Repeated fl ea bites can sensitize
the host animal to the allergens in fl ea
saliva, causing fl ea-bite allergy, leading to a
fl ea allergy dermatitis (FAD), the most
common skin disease of dogs and one of the
most common causes of dermatitis in cats
(Carlotti and Jacobs, 2000).
Where livestock are particularly heavily
infested, anaemia may develop, which in
extreme cases may result in the death of the
host animal (Yeruham et al. , 1989).

Medical signifi cance

In developed countries, the most common
medical problem caused by fl eas is simple
nuisance biting. Most nuisance biting is
caused by young adults of cat fl eas ( C. felis ).
The fl ea bites can occur anywhere on the
body, but occur most commonly on the
lower leg and arms. Bites are characterized
by localized and very irritating papules,
although a few people may develop severe
allergic reactions, even to a single bite. Bites
are often in rows, as though the fl ea made a
succession of attempts to fi nd a suitable
point at which to feed (Fig. 6.1). Although
the bites heal spontaneously, repeated
scratching may lead to secondary infection.
Bubonic plague, caused by Yersinia
pestis , is the most signifi cant disease known
involving fl eas. Plague is a disease of
rodents, particularly of rats (e.g. Rattus

Table 6.1. Transmission of pathogens by fl eas.
Species Hosts Main pathogens and other impacts

Ctenocephalides canis Dogs, humans Larvae of tapeworms - Dipylidium and

Hymenolepis

Ctenocephalides felis Cats, humans Larvae of tapeworms - Dipylidium and

Hymenolepis

Pulex irritans Humans, pigs, goats, domestic

animals

Yersinia pestis , larvae of tapeworms

Ceratophyllus gallinae Chickens, turkeys, humans Many pathogens: mechanical

transmission

Echidnophaga gallinacea Chickens, dogs, humans Bacteria

Leptopsylla segnis Mice Many pathogens: mechanical

transmission

Nosophyllus segnis Rats, humans Yersinia pestis , other bacteria

Spilopsyllus cuniculi Rabbits, humans Myxomatosis virus, Franciscella

tularensis

Xenopsylla cheopis Rats, rodents, humans Yersinia pestis , Rickettsiae, larvae of

tapeworms

Tunga penetrans Humans, many animals Secondary infection of lesion