Disease Summary

Alternative Names (Synonyms)

• Tracheal worm infection 
• Cyathastomiasis (Waterfowl)
• Syngamus infection
• Cyathostoma infection (Waterfowl)

Disease Type

Infectious/Non-Infectious Agent associated with the Disease

• Nematode worms:
• Syngamus trachea in most birds.
• Cyathostoma spp. and occasionally Syngamus trachea in waterfowl.

Infective "Taxa"

• Cyathostoma brantae
• Cyathostoma bronchialis
• Syngamus trachea

Non-infective agents

Physical agents

References

Disease Author

Major References / Reviews

Code and Title List

Other References

Code and Title List

Detailed Clinical and Pathological Characteristics

General
WATERFOWL

Clinical Characteristics

• Signs may not be seen with mild infection (B36.30.w30).

• Extent of signs variable depending on the size of the bird and the degree of infection; generally more signs in smaller birds.

• Breathing difficulties:

  • Gaping (open mouth breathing with stretched out neck) due to inability to breath normally as tracheal lumen is obstructed by worms

  • Short whistling sounds.

• Coughing, jerking/shaking of head and sneezing.

• Often develop squatting position with wings drooped and ruffled plumage.

• May cease feeding and cease moving.

• Emaciation may be seen in heavily infected birds.

• May be anaemic

• Presence of red worms in trachea – may be visible in a live bird if the bill is opened, the head and neck held stretched and a strong light shone through the neck.

• Death.

(B36.30.w30, B48.20.w20)

• Moderate burden: thin, lethargic, depressed, soft or sometimes more explosive cough, which may be more apparent after drinking an at night, frequent 'yawning', head-shaking, stretching or rubbing neck, blood-tinged tracheal mucus (P7.1.w2, B10.25.w11, B11.37.w5.,  B11.39.w7, B11.40.w8, B13.46.w1, B37.x.w1, J8.17.w1, P4.1992.w1).
• Heavy burden: respiratory distress - dyspnoea (difficulty breathing), gaping (open-mouthed breathing), throwing head back, loss of ability to vocalise; clear mucus in nostrils, pale oropharynx, anorexia, stunting of growth and weight loss, anaemia, collapse when handled or stressed, death from asphyxiation (J7.30.w2, J13.15.w1, P7.1.w2, B9.6.w1, B10.25.w11, B11.40.w8, B15, J8.17.w1, B18, B78).

Incubation

• After experimental infection: after 1 week cease feeding, cease moving, often develop squatting position with wings drooped and ruffled plumage.

(B48.20.w20)

Incubation

• Clinical disease may be seen by seven days after infection and patent infection by 13 days post infection (P7.1.w2, B11.40.w8, B32.33.w13).

Mortality / Morbidity

• Clinical signs depend on parasite burden and size of host (B12.55.w1).
• Infection common in juveniles, and mortality can be high (B9.6.w1, B10.25.w11, B11.39.w7). 
• Morbidity of 80% and mortality of 20% in domestic goslings has been reported (J13.15.w1). 
• Occasionally fatal in adults (J7.33.w2, J7.34.w1).

Pathology

• General: may be emaciated,  and may be anaemic (B36.30.w30).
• Respiratory tract: Trachea -  red worms present, with head of male worm penetrating deeply into mucosa and pea sized nodule at attachment site where reactive proliferation of cartilaginous material. Also blood clots and abundant mucus in lumen.(B48.20.w20)

• General - Anaemia.
• Respiratory - bronchopneumonia; nematode worms (reddish-yellow, thin walled, transparent, 1-4cm long) in trachea and bronchi, larynx, and occasionally the abdominal air sacs. Trachea may be blocked by reddish mass of worms. Fibrinous plaques in bronchi may occlude lumen. Areas of lung consolidation. May be whitish masses in air sacs.

Histopathology:

• Lymphocytic tracheitis and bronchitis, may be severe, with mucosal hyperplasia. Multifocal pyogranulomatous pneumonia may develop associated with inspired nematode eggs.

(J7.30.w2, P7.1.w2, B10.26.w11, B18, B32.33.w13, B37.x.w1, B78).

Human Health Considerations

Disease / Agent has been reported in either the wild or in captivity in:

• Affects a variety of species of birds in a wide range of orders. (B24, B91)
• Gapeworm is particularly prevalent in Galliformes - Pheasants, Quails & Turkeys (Order) and Passeriformes - Wrens, Crows, Tits & Sparrows (Order) and is seen less frequently in Anseriformes - Ducks, Geese & Swans (Order), Piciformes - Honey Guides, Barbets & Toucans (Order), and Gruiformes - Cranes, Bustards, Seriemas & Rails(Order) (B48.20.w20)
• Goslings and cygnets (B10.25.w11, B11.40.w8, B37.x.w1).
• Snow goose Anser caerulescens, Canada goose Branta canadensis, bean goose Anser fabalis, 'swan' (no species information), domestic goose (Anser anser) (J13.15.w1).
• Canada goose Branta canadensis, blue goose (lesser snow goose) Anser (Chen) caerulescens, bean goose Anser fabalis) (J37.13.w1).
• Snow goose Anser caerulescens, Canada goose Branta canadensis, bean goose Anser fabalis, Hawaiian goose (Nene) Branta sandvicensis, mandarin duck Aix galericulata (B15).
• Coscoroba swan Coscoroba coscoroba, black-necked swan Cygnus melanocoryphus and 'European swans' (B9.6.w1).
• European eider Somateria mollissima adults, hooded merganser Lophodytes cucullatus adult, goosander (common merganser) Mergus merganser juvenile in captivity in the UK (J7.30.w2).
• Black-bellied (red-billed) whistling-duck Dendrocygna autumnalis, Plumed (Eyton's) whistling-duck Dendrocygna eytoni, Fulvous whistling-duck Dendrocygna bicolor (J7.33.w2)
• Common in juvenile lesser white-fronted goose Anser erythropus, emperor goose Anser canagicus in collection in UK (J7.34.w1)
• Grey-breasted (Black-bellied) whistling-duck Dendrocygna autumnalis (J7.6.w1).
• Hawaiian goose Branta sandvicensis goslings and adults (P7.1.w2).
• Anser anser domesticus - Domestic goose (Syngamus trachea, Cyathostoma bronchialis), Tadorna ferruginea - Ruddy shelduck (Cyathostoma bronchialis), Tadorna tadornoides - Australian shelduck (Syngamus trachea), Anas platyrhynchos - Mallard (Syngamus trachea, Cyathostoma bronchialis), Anas platyrhynchos domesticus - Domestic duck (Syngamus trachea, Cyathostoma bronchialis), Anser caerulescens - Snow goose(Cyathostoma brantae, Cyathostoma bronchialis), Anser fabalis - Bean goose ( Bean goose (Cyathostoma bronchialis), Branta canadensis - Canada goose (Cyathostoma brantae), Aix galericulata - Mandarin duck (Cyathostoma brantae),
• Starlings, jackdaws, rooks, gamebirds including turkeys (B36.30.w30).

Further information on Host species has only been incorporated for  species groups for which a full Wildpro "Health and Management" module has been completed (i.e. for which a comprehensive literature review has been undertaken).

Host species with further information available are listed below:

WATERFOWL Host Species List

• Aix galericulata - Mandarin duck
• Anas platyrhynchos - Mallard
• Anas platyrhynchos domesticus - Domestic duck
• Anser anser domesticus - Domestic goose
• Anser canagica - Emperor goose
• Anser caerulescens - Snow goose
• Anser erythropus - Lesser white-fronted goose
• Anser fabalis - Bean goose
• Branta canadensis - Canada goose
• Branta sandvicensis - Nene
• Coscoroba coscoroba - Coscoroba swan
• Cygnus melanocorypha - Black-necked swan
• Lophodytes cucullatus - Hooded merganser
• Dendrocygna autumnalis - Black-bellied whistling-duck
• Dendrocygna bicolor - Fulvous whistling-duck
• Dendrocygna eytoni - Plumed whistling-duck
• Mergus merganser - Common merganser
• Somateria mollissima - Common eider
• Tadorna ferruginea - Ruddy shelduck
• Tadorna tadornoides - Australian shelduck

Disease / Agent has been specifically reported in Free-ranging populations of:

• Starlings, jackdaws, rooks, gamebirds including turkeys (B36.30.w30).

Further information on Host species has only been incorporated for  species groups for which a full Wildpro "Health and Management" module has been completed (i.e. for which a comprehensive literature review has been undertaken).

Host species with further information available are listed below:

WATERFOWL Host Species List

• Associated with grazing on pastures used by infected birds the previous year (P4.1992.w1, B11.40.w8, B10.25.w11).
• May also be associated with wet conditions; much reduced in long dry seasons (P7.1.w2, B10.25.w11, B37.x.w1).
• Most likely to be a problem in overcrowded captive conditions (B15).

Regions / Countries where the Infectious Agent or Disease has been recorded

Regions / Countries where the Infectious Agent or Disease has been recorded in Free-ranging populations

General Information on Investigation / Diagnosis

• Clinical signs - gaping.

• Presence of red worms in trachea – may be visible on post mortem examination, or in a live bird if the bill is opened, the head and neck held stretched and a strong light shone through the neck.

• Detection of eggs in faeces. With Syngamus trachea irregular oval, about 90u x 50u, with opercula (plugs) at the poles. Thin shelled, usually at 4 or 8-celled cleavage stage when deposited.
• (B36.30.w30, B48.20.w20)

• Clinical signs - coughing, depression, head shaking, blood in tracheal mucus, dyspnoea (B11.37.w5, B11.39.w7, B16.19.w1).
• Bright red worms in bronchi and trachea; visible in trachea on endoscopy (B11.39.w7, B13.46.w1, B16.19.w1, B37.x.w1).
• Worms and/or eggs in faeces. Eggs bi-operculate with Syngamus trachea, no operculum visible with Cyathostoma bronchialis (B37.x.w1, B11.39.w7, B13.46.w1).
• Worms and/or eggs in tracheal mucus (B37.x.w1, B13.46.w1, B16.19.w1).

• Physical Examination - General
• Necropsy - General
• Chapter 2 - B36 Field Manual of Wildlife Diseases - Specimen Collection and Preservation
• Chapter 3 - B36 Field Manual of Wildlife Diseases - Specimen shipment
• Appendix A - B36 Field Manual of Wildlife Diseases - Sample specimen history form

Similar Diseases (Differential Diagnosis)

Specific Medical Treatment

• Anthelmintics: thiabendazole  in feed (B48.20.w20)

• Fenbendazole (Panacur, Hoechst) oral; 50mg/kg bodyweight once (for raptors) (B156.16.w16)

• Ivermectin (Ivomec, MSD) 200µg/kg bodyweight once (for raptors). (B156.16.w16)

N.B. killed worms may remain in the trachea continuing to cause irritation for 5-6 weeks. Suggested supportive treatments include:

• Bromohexine (Bisolvon, Boerhinger). (B156.16.w16)

• Broad-spectrum antibiotics. (B156.16.w16)

• Levamisole hydrochloride, 1ml/kg of 7.5% solution, repeated every ten days in growing goslings (B10.26.w11).
• Levamisole hydrochloride (Nilverm, ICI), 1ml/kg of 1.5% solution (J8.17.w1)
• Levamisole 25-50mg/kg orally (B13.46.w1); 30mg/kg given (P7.1.w2). 20mg/kg for three days (B49)
• Ivermectin 1% solution, 200µg/kg body weight, subcutaneous or oral (P7.1.w2, B13.46.w1).
• Mebendazole 5-15 mg/kg orally for two days (B13.46.w1, B16.19.w1).
• Fenbendazole 20mg/kg orally (B11.39.w7); given for five days (P7.1.w2).
• Mebendazole in feed at 1.2g/tonne for 14 days (B11.39.w7).
• Flubendazole in feed at 2.4g/tonne for seven days (B11.39.w7).
• Ivermectin, fenbendazole, albendazole, (P4.1992.w1)
• Tetramisole 25-50mg/kg (B16.19.w1)

N.B. clinical signs may continue after treatment due to effects of dead worms and debris in the respiratory tract (B11.39.w7).

• Treatment and Care - General

General Nursing and Surgical Techniques

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Preventative Measures

WATERFOWL

For information on routine parasite control see Preventative Medicine for Birds - Parasite screening and Routine Control Measures

• Treatment and Care - General
• Preventative Medicine for Birds - General

Environmental and Population  Control Measures

WATERFOWL

• Preventative Medicine for Birds - General
• Environmental and Population Management - General