Disease Summary

Alternative Names (Synonyms)

• Sarconema eurycerca infection
• Filariasis

Disease Type

Infectious/Non-Infectious Agent associated with the Disease

VECTOR: Trinoton anserinum (Feather louse)

Infective "Taxa"

• Sarconema eurycerca
• Trinoton anserinum (Vector)

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

Clinical Characteristics

• Usually subclinical.
• Reduced body weight may be noted (J7.30.w3).
• Acute depression and death have been reported.

(J4.96.w1, B13.46.w1, B15, B16.19.w1).

Incubation

Mortality / Morbidity

• Prevalence of infection with microfilariae has been reported as high as 22.4% (J7.30.w3).
• Low mortality but occasionally considered the primary cause of death (J4.99.1, B15).

Pathology

• Adult nematode(s) visible under epicardium or within myocardium (heart muscle).
• Usually small number of adult worms per host (e.g. 2-3), but as many as 52 have been reported in a single individual.
• Heart may be enlarged, myocardium may be generally pale and flabby or have pale foci.

Histopathology:

• Focal myocardial necrosis, haemorrhage and inflammation, to fibrosis; may be severe. Focal myocarditis and fibrosis may be noted even in cases where the nematode was considered an incidental finding.

(J1.11.w4, J14.16.w1, B13.46.w1, B15, B16.19.w1, B36.31.w31).

Human Health Considerations

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

• Whistling (Tundra) swan Cygnus (Olor) columbianus, British Columbia, Canada (J14.16.w1).
• Whistling (Tundra) swan Cygnus (Olor) columbianus, Idaho (J4.96.w1, J4.99.w1).
• Whistling (Tundra) swan Cygnus (Olor) columbianus, Ontario (J1.11.w4).
• Whistling swan Cygnus (Olor) columbianus and trumpeter swans Cygnus (Olor) buccinator in British Columbia, Canada (J14.19.w1).
• Mute swan Cygnus olor, Whistling (Tundra) swan Cygnus columbianus columbianus, Trumpeter swan Cygnus buccinator (B9.6.w1).
• Mute swan Cygnus olor and Bewick's (Tundra) swan Cygnus columbianus, in the UK; also Mute Cygnus olor, Trumpeter Cygnus (cygnus) buccinator, Bewick's Cygnus columbianus bewickii, Whistling Cygnus columbianus columbianus and Whooper swan Cygnus (cygnus) cygnus, Canada goose, Branta canadensis, white-fronted goose Anser albifrons and bean goose Anser fabalis (J7.30.w3).
• Swans, Canada geese Branta canadensis, white-fronted geese Anser albifrons, bean geese Anser fabalis, also apparently lesser snow geese Anser caerulescens (grossly visible myocardial nematodes, Sarconema sp.) (B15).
• Mute swan Cygnus olor, Trumpeter swan Cygnus (cygnus) buccinator, Bewick's swan Cygnus columbianus bewickii, Whistling swan Cygnus columbianus columbianus, Canada goose, Branta canadensis, white-fronted goose Anser albifrons and bean goose Anser fabalis (B36.31.w31).
• Whooper swan Cygnus cygnus, probable incidental finding in Scotland (J36.44.w1).
• Anser albifrons - Greater white-fronted goose, Anser fabalis - Bean goose, Branta canadensis - Canada goose, Cygnus columbianus - Tundra swan, Cygnus cygnus buccinator - Trumpeter swan, Cygnus olor - Mute swan. (B91)

WATERFOWL Host Species List

• Anser albifrons - Greater white-fronted goose
• Anser fabalis - Bean goose
• Anser caerulescens - Snow goose
• Branta canadensis - Canada goose
• Cygnus buccinator - Trumpeter swan
• Cygnus columbianus - Tundra swan
• Cygnus cygnus - Whooper swan
• Cygnus olor - Mute swan

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

• Whistling (Tundra) swan Cygnus (Olor) columbianus columbianus, British Columbia, Canada (J14.16.w1).
• Whistling swan Cygnus (Olor) columbianus and trumpeter swans Cygnus (Olor) buccinator in British Columbia, Canada (J14.19.w1).
• Whistling (Tundra) swan Cygnus (Olor) columbianus columbianus, Idaho (J4.99.w1).
• Whistling (Tundra) swan Cygnus (Olor) columbianus, Ontario (J1.11.w4).
• Mute swan Cygnus olor, Whistling (Tundra) swan Cygnus columbianus columbianus, Trumpeter swan Cygnus buccinator (B9.6.w1).
• Mute swan Cygnus olor and Bewick's (Tundra) swan Cygnus columbianus, in the UK; also Mute swan Cygnus olor, Trumpeter swan Cygnus (cygnus) buccinator, Bewick's swan Cygnus columbianus bewickii ,Whistling swan Cygnus columbianus columbianus and Whooper swan Cygnus (cygnus) cygnus, Canada goose, Branta canadensis, white-fronted goose Anser albifrons and bean goose Anser fabalis (J7.30.w3).
• Anser caerulescens caerulescens - Lesser snow goose (grossly visible myocardial nematodes, Sarconema sp.) (B15)
• Whooper swan Cygnus cygnus, probable incidental finding in Scotland (J36.44.w1).

WATERFOWL Host Species List

• Anser caerulescens - Snow goose
• Cygnus buccinator - Trumpeter swan
• Cygnus columbianus - Tundra swan
• Cygnus cygnus - Whooper swan
• Cygnus olor - Mute swan

• Transmission thought to occur primarily on the breeding grounds where louse infestation may be prevalent (B36.31.w31).
• Larvae concentrate in peripheral circulation at night (0100-0400), at least in Whistling (Tundra) swan Cygnus columbianus (J7.30.w3).

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

• Infection may be diagnosed in a live bird by the presence of microfilariae in the blood. False negatives may be found if the sample is too small, the infection is pre-patent, worms of only on sex are present or the concentration of microfilariae in the blood is lower than the sensitivity level of the test used to detect them. Repeated sampling, or sampling at night (peak in peripheral circulation at 0100-0400hrs) may increase the chance of detecting infection. Capillary tube test may be most sensitive technique to detect microfilariae in blood (J7.30.w3, B13.46.w1, B15, B16.19.w1).
• Infection in a dead bird is diagnosed on the presence of adult worms (white, thread-like) in the myocardium at post mortem examination.
• In order to diagnose disease associated with the infection, the presence of Sarconema eurycerca in the myocardium must be in association with histological evidence of myocardial damage (B15, B36.31.w31).

• 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

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General Nursing and Surgical Techniques

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Preventative Measures

WATERFOWL

• Preventative Medicine for Birds - General

Environmental and Population  Control Measures

WATERFOWL

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