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Arthropoda:
Insecta SIPHONAPTERA (Sucking
Lice) (Contact) Please CLICK on
Images to enlarge & underlined links for details: [Also
See: Siphonaptera Key ] GENERAL CHARACTERISTICS
There are
about 221 genera and over 2,205 species and subspecies of fleas in the
world. The order has five families
with species of medical importance: Hectopsyllidae, Dolichopsyllidae, Pulicidae,
Hystrichopsyllidae and
Ischnopsyllidae. Service (2005)
reported that about 94 percent of species attack mammals while the remaining
species are parasites of birds. Fleas
are also widely distributed all over the world, but the most important
vectors of plague (Yersinia pestis)
occur in the tropics and subtropics.
Medically the most important genera are Ctenocephalides. Leptopsylila.
Nosopsyllus. Pulex. Tunga smfXenopsylla. Their combs and meral
rod can identify them:
Thirteen
species which are of medical importance include: Ctenocephalides canis
(Curtis) [dog flea], Ctenocephalides felis
(Bouche) [cat flea], Cediopsylla simplex (Baker) [rabbit flea], Ceratophyllus
gallinae (Schrank) [chicken or hen flea], Ctenophthalmus pseudargyrtes
Baker [Small mammal flea], Echidnophaga gallinacea (Westwood) [stick tight flea], Hoplopsyllus anomalus Baker [rodent flea], Leptopsylla segnis [European mouse flea], Nosopsyllus fasciatus (Bosc.) [rat flea], Oropsylla montana (Baker) [ground squirrel flea], Pulex irritans L. [flea of humans], Tunga penetrans L. [jigger flea] and Xenopsylla cheopis (Roth.) [Oriental rat flea]. The common names of fleas (e.g. "dog flea") are
misleading as humans may also be attacked by any of these species especially
when in close proximity of the preferred host. New discoveries of medically important species are being made
in South America; e.g., Ectinorus insignis
(Beaucournu et al 2013) and Ctenidiosomus
sp. (Lopez-Berrizbeitia et al. 2015).
to one other order, the Diptera, by certain aspects of
their metamorphosis and somewhat by their mouthparts. The
mouthparts are made up of a pair of long serrated mandibles, a pair of short
triangular maxillae with palps, and a reduced labium with palps. There is a
short hypopharynx and a larger labrum-epipharynx similar to that of the
Diptera. The labial palps, held together, serve to support the other parts, a
function which is performed by the labium in the Diptera. In piercing the
host, the mandibles are most important and blood is drawn up a channel formed
by the two mandibles and the labrum-epipharynx (Borradaile & Potts, 1958). The thoracic
segments are free and wings are absent. Although the eggs are laid on the
host they soon fall off and are afterwards found in little-disturbed parts of
the host's habitat. Therefore, in
houses they reside in dusty carpets and unswept corners of rooms. In a few days the larvae hatch and feed on
organic debris. The legless and
eyeless larvae possess a well-developed head and a 13-segmented body. At the end of the third larval instar a
cocoon is spun and the flea changes into an exarate pupa from which the adult
emerges. The whole life cycle takes
about a month in the case of Pulex
irritans..
Pulex irritans is the
common flea of European houses, but by far the most important economically is
the oriental rat flea, Xenopsylla cheopis,
which transmits Bacillus
pestis, the bacillus of plague, from the rat to humans. This bacillus lives in the gut of the flea
and the faeces deposited on the skin of the host are rubbed into the wound by
the scratching which follows the irritation from the bite. Ceratophyllus fasciatus, the European
rat flea, also transmits the plague organism as can also Pulex irritans, but since the latter
does not live successfully on rats, it is a less dangerous vector (Borradaile
& Potts, 1958). Detailed Habits & Morphology All members
of the Siphonaptera feed exclusively on warm-blooded animals. Their mouthparts lack mandibles and a
siphon is formed of structures of the labrum, labium and maxillae. The labium is an elongated and fleshy covering mechanism. The maxillae are interlocking and a
maxillary sheath is present but not obvious.
A labrum is also present.
Fleas are apterous but their extinct
ancestors are known to have possessed wings, which was deduced from pleural
plates on the thorax. Hair-like
structures called geocomb and corolla comb, are present on the
head. The antennae have three segments
and lie in a groove on the head (see ent159).
The larvae are eruciform (wormlike)
with a distinct head capsule. They do
not possess legs but leg-like setae instead.
Larvae are not parasitic.
There is an exarate pupa formed in a cocoon (see ent160).
Their general
pest status of humans and domestic animals and their ability to vector
diseases makes them of great economic importance. Role as Parasites. -- Fleas are well adapted to the parasitic
habit by being laterally compressed.
They also have a very hard exoskeleton, their legs are developed for
leaping and the hairs on their body are directed backward. Service
(2008) pointed out that the role fleas have in transmitting plague involves
certain important characteristics as follows: Saliva, with
anticoagulants, is passed to the host during feeding, and the blood enters
the pharynx, esophagus and proventriculus, where there are a lot of spines
that are pointed to the rear. These
spines may prevent blood regurgitation of t blood into the esophagus. The proventriculus is important in the
mechanism of plague transmission." Then the blood passes into a large
stomach for digestion. The posterior intestines form a small widened rectum
with rectal glands that remove water so that the faeces are dry. Both male and female fleas suck blood and
can serve as vectors of plague. ----------------------------------------------- Diseases Transmitted by Siphonaptera Bubonic Plague. -- The vector of Pasteurilla pestis is the rat flea. This bacillus wiped out one quarter of the
population of London, England. The
fleas search out other hosts as soon as the rat dies. Transfer is accomplished by (1) defecation
on the body and the inoculum is scratched into the wounds, and (2) the flea
cannot digest the bacillus, so it regurgitates into the wound made by its
mouthparts. Cat-Scratch Disease. -- Bartonella henselae
occurs in cat fleas and can infect humans through a cat's claws if
contaminated. Chigger Infection. -- The
fertilized female flea burrows under the skin and becomes extremely
distended. A serious tropical form is
known as Tunga penetrans. Murine Typhus. -- This
typhus is caused by Rickettsia typhi.
It is transmitted when infected faeces come into contact with
abrasions or mucous membranes. Faeces
retain infectivity of months or years.
The disease primarily affects rodents, especially rats. It is spread by species of Xenopsylla, Nosopsyllus
and Leptopsylla. Different species of Rickettsia may also cause typhus in
humans. Sylvanic Plague. -- The vectors are fleas that live on rodent hosts. This is actually mild type of bubonic
plague, which is found in Western North America. However, humans may also die from infection. Tapeworms. -- The
tapeworm, Dipylidium
caninum, affecting dogs and cats, can also be transmitted by fleas
to humans. Transmission from animals
can occur through handling. Tularaemia. --
Sometimes Francisella
tularensis may be transmitted to humans by fleas even though ticks
are the principal vectors. CONTROL OF SIPHONAPTERA The problem
of controlling fleas involves several distinct measures as advised by
Matheson (1950): (1) control on
domestic pets and in the home; (2) control of fleas on poultry and domestic
animals and in their living areas; (3) control of fleas on rats and other
wild rodents that are sources of plague; (4) prevention of the spread of
plague by restricting the movement of flea carriers. In buildings cleanliness is very
important. Unclean carpets, crevices,
kitchens, bathrooms, closets, cellars, etc. are all places where fleas may
breed. The commercial treatment with
insecticides may be required to reduce flea numbers, or even the fumigation
of an entire building could be necessary. (See Hinkle et al. in References for new
control approaches). = = = = = = = = = = = = = = = = = = = = Key References: <medvet.ref.htm> <Hexapoda> Azad, A. F. 1990.
Epidemiology of murine typhus.
Ann. Rev. Ent. 35: 553-69. Azad, A. F. & C. B.
Beard. 1998. Rickettsial pathogens and their arthropod
vectors. Emerging Infectious Diseases
4: 179-86. Beaucournu, J.-C.
2013. A new flea, Ectinorus insignis n. sp. (Siphonaptera,
Rhopalopsyllidae, Parapsyllinae), with notes on the subgenus Ectinorus
in Chile and comments on unciform sclerotization in the superfamily
Malacopsylloidea. Parasite 20(35). Bishopp, F. C. 1931.
Fleas and their control. U.S.
Dept. Agr., Farmers' Bull. 897. Bossard, R L; Hinkle, N
C; Rust, M K. 1998. Review of insecticide resistance in cat
fleas (Siphonaptera: Pulicidae). J. Medical Entomol.
35(4): 415-422. Eisle, M. , J. Heukelbach &
van Marck, E. et al. 2003. Investigations on the biology, edpidemiology, pathology and
control of Tunga penetrans in Brazil: I. Natural history in man.
Parasitology Res. 49: 557-65. Ewing, H. E. 1924.
Notes on the taxonomy and natural relationships of fleas, with
descriptions of four new species.
Parasitology 16: 341-254. Ewing, H. E. & I.
Fox. 1943. The fleas of North America.
U.S. Dept. Agr. Misc. Pub. 500. Fox, Irving. 1940.
Fleas of the eastern United States.
Ames, Iowa Press Gage, K. L. & Y.
Kosoy. 2005. Natural history of plague: perspectives
from more than a century of research.
Ann. Rev. Ent. 50: 505-28. Gratz, N. G. 1999.
Control of plague transmission:
Plague Manual: Epidemiology, Distribution, Surveillance & Control. WHO, Geneva. pp. 97-134 Hechemy, K. E. & A. F. Azad. 2001. Endemic
typhus, and epidemic typhus. IN: The Encyclopedia of Arthropod-Transmitted
Infections of Man and Domesticated Animals. CABI, pp. 165-69 & 170-74. Heukelbach, J., A. M. L. Costa, T. Wilcke & N.
Mencke. 2004. The animal reservoir of Tunga penetrans in severely affected
communities of north-east Brazil. Med. & Vet. Ent.
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Feldmeier. 2004. High attack rate of Tunga penetrans (L. 1758) infestations
in an impoverished Brazilian community. Trans. Roy
Soc. Trop. Med. & Hyg. 98: 43-44. Hinkle, N. C., P. G.
Koehler, W. H. Kern & R. S. Patterson.
1991. Hematophagous
strategies of the cat flea (Siphonaptera: Pulicidae). Florida Ent. 73: 377-85. Hinkle, N. C., P. G. Koehler & R.
S. Patterson.1995. Residual effectiveness
of insect growth regulators applied to carpet for control of cat flea (Siphonaptera: Pulicidae) larvae. J. Econ. Ent. 88: 903-6. Hinkle, N C; Koehler, P G; Patterson,
R S. 1998. Host grooming efficiency
for regulation of cat flea (Siphonaptera: Pulicidae) populations. J. Med. Ent. 35(3: 266-69. Hinkle, N.C., M.K. Rust and D.A.
Reierson. 1997. Biorational approaches to flea
(Siphonaptera: Pulicidae) suppression: present and future. J. Agric. Entomol. 14(3): 309-321. Hubbard, C. A. 1947.
Fleas of western North America.
Ames, Iowa Press. Lopez-Berrizbeitia,
M. F. et al. 2015. A new flea of the genus Ctenidiosomus (Siphonaptera, Pygiopsyllidae) from Salta
Province, Argentina. Zoo Keys
512: 109-20. Matheson, R. 1950. Medical Entomology. Comstock Publ. Co, Inc. 610 p. Pugh, R. E.
1987. Effects on the
development of Dipylidium caninum
and on the host reaction to this parasite in the adult flea (Ctenocephalides felis felis).
Parasitol. Res. 73: 171-77. Rothschild, N. C. 1910.
A synopsis of the fleas found on Mus
norvegicus, Mus rattus
and Mus musculus. Bull. Ent. Res. 1: 89-98. Rust, M. K. 2005.
Advances in the control of Ctenocephalides
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Dryden. 1977. The biology, ecology and management of the
cat flea. Ann. Rev. Ent. 42: 451-73. Rust, M.K., I. Denholm, M.W. Dryden,
P. Payne, B.L. Blagburn, D.E. Jacobs, N. Mencke, I. Schroeder, M. Vaughn, H.
Mehlhorn, N.C. Hinkle, and M. J. Med. Entomol. 42(4): 631-636. Rust, M.K., I. Denholm, M.W. Dryden, P. Payne, B.L.
Blagburn, D.E. Jacobs, N. Mencke, I. Schroeder, M. Vaughn, H. Mehlhorn, N.C.
Hinkle, and M.
Williamson. 2005. Determining a diagnostic dose for
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Higgins & A. F. Azad. 1994. Murine typhus: updated roles of multiple
organ components and a second
typhus like rickettsia. J.
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Conf. on Fleas, Ashton Wold, Peterborough, UK, 21-25 Jun 1977. Rotterdam: Balkema. |
