Echidnophaga gallinacea

 

Taxonomic classification

Phylum: Arthropoda

Class: Insecta

Order: Siphonaptera

Genus: Echidnophaga gallinacea (sticktight flea)

 

Echidnophaga gallinacea is an international sticktight flea, which may infest a wide variety of birds and mammals. Echidnophaga gallinacea is the only species in the genus found in North America and mainly found in the southern United States. The flea was introduced accidentally due to humans and their domesticated animals.  Echidnophaga gallinacea may infest an extremely wide range of hosts.  It may become a serious pest of poultry and cause irritation to cats, dogs, rabbits, rodents, horses and humans.  Poultry may develop clusters of the fleas around the eyes, comb, wattles, and other bare spots. Echidnophaga gallinacea are difficult to remove because their heads are embedded in the host's flesh and they cannot be brushed off.  The fleas may easily infest dogs and cats that frequently come in contact with barnyard fowl. Dog and cat infestations with sticktight fleas will usually be found around the margin of the outer ear or occasionally between the toe pads.

 

Host spectrum

Poultry, rodents, rabbits, canids, felids, horses, and occasionally humans may all become infested.

 

Geographic distribution

 Echidnophaga gallinacea is found in the tropics, subtropics, and also in the United States as far north as Kansas and Virginia.

 

Morphology

Adults – The adults are approximately 1.5 to 4 mm in length and laterally flattened.  They are dark brown in color, wingless, and have mouthparts that aid in both the piercing of the skin and sucking of the host’s blood.  Neither genal nor pronotal combs are present.   The adult fleas have heads that are flattened and angled acutely (not curved or rounded).  The sticktight flea is one of the smallest fleas found on domestic animals.

 

 

Eggs – The eggs are approximately 0.5 mm in length.  They are oval shaped and pearly white in color.  Nonfertile females will produce eggs just as fertile females do, however, the eggs will be nonviable.

Larvae – The larvae are approximately 6 mm in length.  They are maggot-like, creamy/yellow in color, and have thirteen segments with bristles on each segment. 

Pupae - The pupa, with a loosely woven debris-collecting cocoon, is approximately 4 x 2 mm.

 

Life cycle (stages)

Before mating occurs both sexes will hop around freely.  The life cycle is similar to that of Pulex irritans, except upon fertilization the females will remain attached to the host and lay their eggs in ulcers that have formed.   The larvae will then fall off and feed on organic debris including the adult flea feces.  After many weeks the larvae will spin silken cocoons, becoming covered with dust and dirt, in which they pupate. An adult may emerge within days, weeks or even months depending on environmental conditions. The newly emerged adult fleas will seek a host, mate, and the females will attach to the host to produce another generation. The lifecycle requires approximately thirty to sixty days.  Female sticktight fleas attach and feed at one site on their hosts for prolonged periods.  These periods may range from four to nineteen days.  During these feeding sessions, the surrounding tissue becomes swollen and ulcerated. Males will feed for shorter periods and look to mate around the same time.

Site of infestation

 Echidnophaga gallinacea will attach to the skin (especially bare spots), around the eyes, comb, wattles, and anus

 

Pathogenesis/clinical signs

Echidnophaga gallinacea primarily cause problems in outdoor birds.  The attached fleas will cause both swelling and ulceration.  Young birds may die from infestation, due to anemia produced by the fleas' feeding.  The sheer numbers that may be present can make the eyes of the host swell shut, causing the host to starve to death.

 

Diagnosis

Diagnosis of Echidnophaga gallinacea is accomplished by finding the fleas on the host.

 

Treatment

Treatment of Echidnophaga gallinacea is difficult because the fleas are attached to the host.  Sticktight fleas can be removed with tweezers by grasping and pulling firmly. In order to prevent infection, an antibiotic ointment should be applied to the area.  If there are to many fleas to remove individually, a flea product registered for on-animal use should be applied according to label instructions. When applying the product, be careful not to come in contact with the host’s/animal's eyes. 5% malathion dust has also been effectively used for treatment. 

Other control measures

Keep other hosts out of chicken pens, which can be a high area of flea infestation.  To prevent reinfestation, treat the area to eliminate flea larval development. There are several insecticides registered for treatment of outdoor areas for fleas. Burning of infested organic material, such as animal bedding and poultry litter has also been a recommended form of treatment.

 

Public health significance

Echidnophaga gallinacea can infest humans.  Although sticktight fleas are not known to transmit any diseases, their attachment can lead to problems such as secondary infections.

 

References Cited

http://www.cvm.missouri.edu/cvm/courses/vm556/Arthropods/Fleas/Fleas.htm#STICKTIGHT

http://216.239.33.100/search?q=cache:y0JLWP6M49UC:home.cc.umanitoba.ca/~fieldspg/pdf/gallow00.pdf+Echidnophaga+gallinacea+&hl=en&ie=UTF-8

http://edis.ifas.ufl.edu/MG236