Leyte Normal UniversityTacloban City

Presented by:Jenelyn P. Cadion

BS Biology 3

Syngamus trachea(Gapeworms in fowl)

Kingdom: Animalia Phylum: Nematoda

Class: Secernentea Order: Strongylida

Family: Syngamidae Genus:

Syngamus Species: S. trachea

Taxonomy

•Parasite of the upper respiratory tract of non-aquatic birds, commonly known as the “gapeworm”

•Sometimes designated as "redworm" or “forked worm”

•The resulting disease is known as gape

Syngamus trachea

Morphology•males and females are joined together in a state of permanent copulation forming a Y shape • female 20mm long; male 6mm long

Syngamus trachea

 Operculated Egg, Thick-Shelled EggLength: 78-100  ; Width: 43-60

•Definitive hosts of Syngamus trachea are chickens, turkeys, geese, guinea fowl, pheasants, peafowl, quail, and other birds of all ages

•Intermediate or paratenic hosts include earthworms, snails, (Planorbarius corneus, Bithynia tentaculata), or slugs, where it encysted.

Hosts

•Has preparasitic and parasitic phases

• In preparasitic phase, L3s develop inside the eggs at which time they may hatch.

•The parasitic phase involves substantial migration in the definitive host to reach the predilection site.

Life cycle

Life cycleInfection may occur

in one of three ways.

1. By ingestion of an egg containing an L3 (A).2. By ingestion of the hatched L3 (B). 3. By ingestion of a transport host containing encapsulated L3s (C). 

•Following ingestion, the L3s will be in the duodenum (D) of the final host, molt, and pair off. 

• They penetrate the intestine and travel  first to the liver and then to the lungs (E) via the bloodstream. 

•Adult males and females pair off move up to the trachea  and begin copulation  in the bronchi and trachea (F).•Eggs escape from the vulva under the bursa of the permanently attached male and are carried up the trachea in the excess mucus produced in response to infection. 

•Eggs are passed in the feces of infected birds.  Unlike other strongyloids, S. trachea larva develops within the egg until it reaches the L3 stage. 

•They are then swallowed and passed in the feces, completing the cycle.

•The prepatent period is approximately two weeks with a range of 12-17 days.

•Various reports have shown that adults may survive for

• 23-147 days in chickens•48-224 days in turkeys •approximately 98 days in guinea fowl.

Prepatent period

Pathogenesis

•causes catarrhal tracheitis, asphyxiation and pneumonia•lymphoid nodules form at the point of attachment of the worms in the bronchi and trachea. •Birds infected with gapeworms show signs of weakness and emaciation, usually spend much of their time with eyes closed and head drawn back against the body

Diagnosis•Necropsy by finding copulating  adults worms, 10 to 20 mm long, in the trachea and also by finding the characteristic eggs in the feces of infected birds.

•Fecal flotation - egg 90 X 50 microns with small, thick bipolar end plugs, unembryonated in fresh feces.

Epidemiology•Earthworm transport hosts are important factors in the transmission of Syngamus trachea.•Other invertebrates may also serve as paratenic hosts and these include terrestrial snails and slugs as well as the larvae of Musca domestica (the common house fly) and Lucilia sericata (the green bottle fly responsible for cutaneous myiasis).

Treatment of Syngamus

trachea•Ivermectin•Thiabendazole (Tresaderm)-pheasants•Methyl 5-benzoyl-2-benzimidazole•5-isopropoxycarbonylamino-2-

(4-thizolyl)-benzimidazole•Cambendazole-chickens and turkeys•Levamisole (Ergamisol)-game birds•Fenbendazole (Panacur)

• Treatment of the soil or litter to kill intermediate hosts may be beneficial.

•Insecticides suitable for litter treatment include carbaryl, tetrachlorvinphos (stirofos).

•For most nematodes, control measures consist of sanitation and breaking the life cycle rather than chemotherapy

References•Parasites and Parasitic Diseases of

Domestic AnimalsDr. Colin Johnstone (principal author)Copyright © 1998 University of Pennsylvania •http://cal.vet.upenn.edu/projects/merial/Strongls/strong_4.htm

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