Avian Cholera in Waterfowl

Disease Summary

Alternative Names (Synonyms)

• Fowl Cholera
• Avian Pasteurellosis
• Avian Haemorrhagic Septicemia
• Pasteurella multocida Infection.

Disease Type

Infectious/Non-Infectious Agent associated with the Disease

Infective "Taxa"

• Pasteurella multocida

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

• Frequently just found dead. Dead birds may be found sitting in sternal recumbency with head upright or slightly raised. During an outbreak, dead birds are much more numerous than ill birds. Birds may also literally drop dead while flying or feeding, fly upside down and appear to aim to land either above or below the actual surface of the land or water.
• May appear drowsy/lethargic and be closely approachable then often die quickly (seconds to minutes) once caught. Anorexia may be noted. May have convulsions, swim in circles or throw head back before dying.
• Other signs include: mucous discharge from mouth, matting and soiling of feathers around vent, eyes and bill, diarrhoea or pasty and fawn/yellow droppings, sometimes blood-stained.
• May see clear nasal discharge at time of death.
• Occasionally chronic wasting, dyspnoea and diarrhoea in individual older captive birds.
• Carriers occur with no clinical signs.

(J1.13.w9, J4.108.w1, B10.26.w7, B11.34.w2, B11.37.w5, B11.39.w7, B13.46.w1, B15, B36.7.w7, B37.x.w1, B48.8.w8, B10.26.w7)

Incubation

Mortality / Morbidity

Pathology

Acute Disease:

• The most prominent lesions are seen on the heart, liver, and less frequently the gizzard.
• There may be no lesions with peracute disease, or just scattered petechiae, particularly on the heart. Septicaemia and endotoxin release produce fever, systemic hypertension, sometimes disseminated intravascular coagulation, shock and death.
• General - Usually in good condition (depending on season).
• Respiratory - Thick, mucoid nasal discharge.
• Lungs may be congested, occasionally consolidated. Sometimes appear oedematous due to terminal aspiration of water.
• Heart - Petechiae and sometimes ecchymotic haemorrhages over epicardium and at the coronary band.
• Liver - Pinpoint to pinhead white to yellow necrotic foci, also petechiae. With acute rather than peracute disease, may be darkened or copper-toned, swollen and friable and necrotic areas may be larger.
• Spleen - Occasionally swollen, sometimes with necrotic foci.
• Gastro-intestinal tract - Haemorrhages on surface of gizzard, which may contain food. Congested veins. Frequently catarrhal enteritis; thick gelatinous or mucoid clear to yellowish fluid may dilate intestines. Sometimes intestinal haemorrhage. Intestines usually contain no food.
• Musculature - sometimes haemorrhagic areas in pectoral muscles.

Histopathology:

• Non-specific. Numerous bacteria in vasculature. Hyperaemia, necrosis and early inflammatory cell infiltration in many organs, e.g. spleen, liver. Mucosal haemorrhage in intestines. Lung congestion. Multifocal microhaemorrhage and vascular thrombi may be found in the cerebellum, sometimes diffuse fibrinous meningitis.

Chronic Disease:

• Poor general condition.
• Fibrinopurulent pleurisy, pericarditis, airsacculitis; pulmonary consolidation and haemorrhage. Unilateral ocular lesions (corneal opacity, corneal ulceration, lens prolapse) recorded in experimental infection.
• Salpingitis, with or without associated peritonitis has been reported in domestic ducks and geese from which Pasteurella multocida was recovered in pure culture (J6.24.w1)

(J1.13.w9, J4.108.w1, J5.24.w5, B10.26.w7, B15, B36.7.w7, B37.x.w1, B48.8.w8)

Human Health Considerations

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

• N.B. Outbreaks may affect tens of thousands of wild waterfowl (J1.13.w9, B15, B36.7.w7, B48.8.w8).
• Wild white-fronted geese Anser albifrons, Canada geese Branta canadensis, snow geese Anser caerulescens(Chen hyperborea), mallard, Anas platyrhynchos, (northern) pintail Anas acuta, American wigeon Anas americana, gadwall Anas strepera, northern shoveler Anas clypeata, green-winged teal Anas crecca carolinensis, blue-winged teal Anas discors, wood duck Aix sponsa, lesser scaup Aythya affinis, redhead Aythya americana, canvasback Aythya valisineria, ring-necked duck Aythya collaris, bufflehead Bucephala albeola, North American ruddy duck Oxyura jamaicensis (J1.13.w9).
• Captive giant Canada geese Branta canadensis maxima in Nebraska, USA (J1.13.w10).
• Wild whistling (tundra) swan Cygnus columbianus, Ruddy duck Oxyura jamaicensis, (northern) shoveler Anas (Spatula) clypeata, bufflehead Bucephala albeola, greater scaup Aythya marila, lesser scaup Aythya affinis, canvasback Aythya valisineria, ring-necked ducks Aythya collaris, pintail Anas acuta, American wigeon (widgeon) Anas americana, green-winged teal Anas (crecca) carolinensis in winter in Humboldt County, California, USA (J1.14.w3).
• Wild common eiders Somateria mollissima dresseri in Maine, USA in early summer, among densely-nesting breeding birds (mainly females affected) (J1.14.w4).
• Wild whistling (tundra swan Cygnus columbianus, pintail Anas acuta, American widgeon (wigeon) Anas americana, northern shoveler Anas clypeata, mallard Anas platyrhynchos, gadwall Anas strepera, American green-winged teal Anas crecca carolinensis) in in Humboldt County, California, USA in January (J1.14.w5).
• Wild lesser snow goose Anser caerulescens caerulescens, Ross's goose Anser rossii, also few Canada goose Branta canadensis, redhead Aythya americana, American wigeon Anas americana, possibly gadwall Anas strepera in Saskatchewan, Canada, during spring migration (J1.15.w6).
• Wild Canada geese Branta canadensis wintering in the Mississippi Valley, USA (J1.19.w4).
• Whistling swan Cygnus columbianus, white-fronted goose Anser albifrons, snow goose Anser caerulescens, Ross's goose Anser rossii, Canada goose Branta canadensis, green-winged teal Anas crecca, mallard Anas platyrhynchos, northern pintail Anas acuta, blue-winged teal Anas discors, northern shoveler Anas clypeata, gadwall Anas strepera, American wigeon Anas americana, canvasback Aythya valisineria, redhead Aythya americana, ring-necked duck Aythya collaris, common eider Somateria mollissima, long-tailed duck (Oldsquaw) Clangula hyemalis, white-winged scoter Melanitta fusca, common merganser Mergus merganser, ruddy duck Oxyura jamaicensis (mostly free-living, a few captive) (J1.19.w8).
• Canada goose Branta canadensis, canvasback Aythya valisineria, green-winged teal Anas crecca, lesser scaup Aythya affinis, mallard Anas platyrhynchos, pintail Anas acuta, ring-necked duck Aythya collaris, Ross's goose Anser rossii (Chen rossi), ruddy duck Oxyura jamaicensis, shoveler Anas clypeata, whistling swan Cygnus columbianus, swan Cygnus sp., white-fronted goose Anser albifrons, (American) wigeon, Anas americana in California, USA (J1.26.w3).
• Wild mallard Anas platyrhynchos and northern pintails Anas acuta in Texas, USA (J4.108.w1).
• Wild lesser snow geese and blue geese Anser caerulescens (Chen hyperborea hyperborea, Chen caerulescens), mallard Anas platyrhynchos, Canada goose Branta canadensis in Missouri, USA (J40.31.w1).
• Wild common eiders Somateria mollissima on their breeding grounds in The Netherlands (J7.42.w1).
• Mallard Anas platyrhynchos and a few northern pintail Anas acuta and American wigeon Anas americana in Nebraska (J5.32.w2).
• Muscovy ducks Cairina moschata in Japan (J27.54.w1).
• Whistling (Tundra) swan Cygnus (Olor) columbianus, trumpeter swan Cygnus (Olor) buccinator, Canada goose Branta canadensis, white-fronted goose Anser albifrons, Blue and snow goose Anser (Chen) caerulescens, Ross's goose Anser (Chen) rossii, mallard Anas platyrhynchos, (American) black duck Anas rubripes, gadwall Anas strepera, pintail Anas acuta, green-winged teal Anas crecca, cinnamon teal Anas cyanoptera, American wigeon (widgeon) Anas (Mareca) americana, (northern) shoveler Anas (Spatula) clypeata, wood duck Aix sponsa, canvasback Aythya valisineria, greater scaup Aythya marila, lesser scaup Aythya affinis, common eider Somateria mollissima, ruddy duck Oxyura jamaicensis in the USA, Egyptian goose Alopochen aegyptiacus, spur-winged goose Plectropterus gambensis in Kenya (B48.8.w8).
• Wild tundra swan Cygnus columbianus, trumpeter swan Cygnus buccinator, mute swan Cygnus olor, white-fronted goose Anser albifrons, snow goose Anser (Chen) caerulescens, Ross's goose Anser (Chen) rossii, Canada goose Branta canadensis, Egyptian goose Alopochen aegyptiacus, spur-winged goose Plectropterus gambensis, wood duck Aix sponsa, green-winged teal Anas crecca, American black duck Anas rubripes, mallard Anas platyrhynchos, northern pintail Anas acuta, blue-winged teal Anas discors, cinnamon teal Anas cyanoptera, northern shoveler Anas clypeata, gadwall Anas strepera, American wigeon Anas americana, rosy-billed pochard (Rosybill) Netta peposaca, canvasback Aythya valisineria, redhead Aythya americana, ring-necked duck Aythya collaris, greater scaup Aythya marila, lesser scaup Aythya affinis, common eider Somateria mollissima, long-tailed duck (Oldsquaw) Clangula hyemalis, black (common) scoter Melanitta nigra, surf scoter Melanitta perspicillata, white-winged scoter Melanitta fusca, common goldeneye Bucephala clangula, bufflehead Bucephala albeola, common merganser Mergus merganser, red-breasted merganser Mergus serrator, North American ruddy duck Oxyura jamaicensis (J1.27.w3).
• Whistling swans Cygnus columbianus wintering in California, wild trumpeter swan Cygnus buccinator, and also a mute swan Cygnus olor in the UK (B6.9.w1).
• Domestic ducks and geese in the UK (J3.104.w1).
• Pasteurella multocida multocida recovered in pure culture from domestic ducks and geese with chronic salpingitis, and from the cloaca/penis of apparently normal geese from the same flocks in Denmark (J6.24.w1).

Host Species List

• Aix sponsa - Wood duck
• Alopochen aegyptiacus - Egyptian goose
• Anas acuta - Northern pintail
• Anas americana - American wigeon
• Anas clypeata - Northern shoveler
• Anas crecca - Common teal
• Anas cyanoptera - Cinnamon teal
• Anas discors - Blue-winged teal
• Anas platyrhynchos - Mallard
• Anas platyrhynchos domesticus - Domestic duck
• Anas rubripes - American black duck
• Anas strepera - Gadwall
• Anser albifrons - Greater white-fronted goose
• Anser anser domesticus - Domestic goose
• Anser caerulescens - Snow goose
• Anser rossii - Ross's goose
• Aythya affinis - Lesser scaup
• Aythya americana - Redhead
• Aythya collaris - Ring-necked duck
• Aythya marila - Greater scaup
• Aythya valisineria - Canvasback
• Branta canadensis - Canada goose
• Bucephala albeola - Bufflehead
• Bucephala clangula - Common goldeneye
• Cairina moschata - Muscovy duck
• Clangula hyemalis - Long-tailed duck
• Cygnus buccinator - Trumpeter swan
• Cygnus columbianus - Tundra swan
• Cygnus olor - Mute swan
• Melanitta fusca - White-winged scoter
• Melanitta perspicillata - Surf scoter
• Melanitta nigra - Black scoter
• Mergus merganser - Common merganser
• Mergus serrator - Red-breasted merganser
• Netta peposaca - Rosy-billed pochard
• Oxyura jamaicensis - Ruddy duck
• Plectropterus gambensis - Spur-winged goose

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

• N.B. Outbreaks may affect tens of thousands of wild waterfowl (J1.13.w9, B15, B36.7.w7, B48.8.w8).
• Wild white-fronted geese Anser albifrons, Canada geese Branta canadensis, snow geese Anser caerulescens(Chen hyperborea), mallard, Anas platyrhynchos, (northern) pintail Anas acuta, American wigeon Anas americana, gadwall Anas strepera, northern shoveler Anas clypeata, green-winged teal Anas crecca carolinensis, blue-winged teal Anas discors, wood duck Aix sponsa, lesser scaup Aythya affinis, redhead Aythya americana, canvasback Aythya valisineria, ring-necked duck Aythya collaris, bufflehead Bucephala albeola, North American ruddy duck Oxyura jamaicensis (J1.13.w9).
• Wild whistling (tundra) swan Cygnus columbianus, Ruddy duck Oxyura jamaicensis, (northern) shoveler Anas (Spatula) clypeata, bufflehead Bucephala albeola, greater scaup Aythya marila, lesser scaup Aythya affinis, canvasback Aythya valisineria, ring-necked ducks Aythya collaris, pintail Anas acuta, American wigeon (widgeon) Anas americana, green-winged teal Anas (crecca) carolinensis in winter in Humboldt County, California, USA (J1.14.w3).
• Wild common eiders Somateria mollissima dresseri in Maine, USA in early summer, among densely-nesting breeding birds (mainly females affected) (J1.14.w4).
• Wild whistling (tundra swan Cygnus columbianus, pintail Anas acuta, American widgeon (wigeon) Anas americana, northern shoveler Anas clypeata, mallard Anas platyrhynchos, gadwall Anas strepera, American green-winged teal Anas crecca carolinensis) in in Humboldt County, California, USA in January (J1.14.w5).
• Wild lesser snow goose Anser caerulescens caerulescens, Ross's goose Anser rossii, also few Canada goose Branta canadensis, redhead Aythya americana, American wigeon Anas americana, possibly gadwall Anas strepera in Saskatchewan, Canada, during spring migration (J1.15.w6).
• Wild Canada geese Branta canadensis wintering in the Mississippi Valley, USA (J1.19.w4).
• Whistling swan Cygnus columbianus, white-fronted goose Anser albifrons, snow goose Anser caerulescens, Ross's goose Anser rossii, Canada goose Branta canadensis, green-winged teal Anas crecca, mallard Anas platyrhynchos, northern pintail Anas acuta, blue-winged teal Anas discors, northern shoveler Anas clypeata, gadwall Anas strepera, American wigeon Anas americana, canvasback Aythya valisineria, redhead Aythya americana, ring-necked duck Aythya collaris, common eider Somateria mollissima, long-tailed duck (Oldsquaw) Clangula hyemalis, white-winged scoter Melanitta fusca, common merganser Mergus merganser, ruddy duck Oxyura (J1.19.w8).
• Canada goose Branta canadensis, canvasback Aythya valisineria, green-winged teal Anas crecca, lesser scaup Aythya affinis, mallard Anas platyrhynchos, pintail Anas acuta, ring-necked duck Aythya collaris, Ross's goose Anser rossii (Chen rossi), ruddy duck Oxyura jamaicensis, shoveler Anas clypeata, whistling swan Cygnus columbianus, swan Cygnus sp., white-fronted goose Anser albifrons, (American) wigeon, Anas americana in California, USA (J1.26.w3).
• Wild mallard Anas platyrhynchos and northern pintails Anas acuta in Texas, USA (J4.108.w1).
• Wild lesser snow geese and blue geese Anser caerulescens (Chen hyperborea hyperborea, Chen caerulescens), mallard Anas platyrhynchos, Canada goose Branta canadensis in Missouri, USA (J40.31.w1).
• Wild common eiders Somateria mollissima on their breeding grounds in The Netherlands (J7.42.w1).
• Mallard Anas platyrhynchos and a few northern pintail Anas acuta and American wigeon Anas americana in Nebraska (J5.32.w2).
• Wild whistling (Tundra) swan Cygnus (Olor) columbianus, trumpeter swan Cygnus (Olor) buccinator, Canada goose Branta canadensis, white-fronted goose Anser albifrons, Blue and snow goose Anser (Chen) caerulescens, Ross's goose Anser (Chen) rossii, mallard Anas platyrhynchos, (American) black duck Anas rubripes, gadwall Anas strepera, pintail Anas acuta, green-winged teal Anas crecca, cinnamon teal Anas cyanoptera, American wigeon (widgeon) Anas (Mareca) americana, (northern) shoveler Anas (Spatula) clypeata, wood duck Aix sponsa, canvasback Aythya valisineria, greater scaup Aythya marila, lesser scaup Aythya affinis, common eider Somateria mollissima, ruddy duck Oxyura jamaicensis in the USA, Egyptian goose Alopochen aegyptiacus, spur-winged goose Plectropterus gambensis in Kenya (B48.8.w8).
• Wild tundra swan Cygnus columbianus, trumpeter swan Cygnus buccinator, mute swan Cygnus olor, white-fronted goose Anser albifrons, snow goose Anser (Chen) caerulescens, Ross's goose Anser (Chen) rossii, Canada goose Branta canadensis, Egyptian goose Alopochen aegyptiacus, spur-winged goose Plectropterus gaminess, wood duck Aix sponsa, green-winged teal Anas crecca, American black duck Anas rubripes, mallard Anas platyrhynchos, northern pintail Anas acuta, blue-winged teal Anas discors, cinnamon teal Anas cyanoptera, northern shoveler Anas clypeata, gadwall Anas strepera, American wigeon Anas americana, rosy-billed pochard (Rosybill) Netta peposaca, canvasback Aythya valisineria, redhead Aythya americana, ring-necked duck Aythya collaris, greater scaup Aythya marila, lesser scaup Aythya affinis, common eider Somateria mollissima, long-tailed duck (Oldsquaw) Clangula hyemalis, black (common) scoter Melanitta nigra, surf scoter Melanitta perspicillata, white-winged scoter Melanitta fusca, common goldeneye Bucephala clangula, bufflehead Bucephala albeola, common merganser Mergus merganser, red-breasted merganser Mergus serrator, North American ruddy duck Oxyura jamaicensis (J1.27.w3).
• Whistling swans Cygnus columbianus wintering in California, wild trumpeter swan Cygnus buccinator (B6.9.w1).

Host Species List

• Aix sponsa - Wood duck
• Alopochen aegyptiacus - Egyptian goose
• Anas acuta - Northern pintail
• Anas americana - American wigeon
• Anas clypeata - Northern shoveler
• Anas crecca - Common teal
• Anas cyanoptera - Cinnamon teal
• Anas discors - Blue-winged teal
• Anas platyrhynchos - Mallard
• Anas rubripes - American black duck
• Anas strepera - Gadwall
• Anser albifrons - Greater white-fronted goose
• Anser caerulescens - Snow goose
• Anser rossii - Ross's goose
• Aythya affinis - Lesser scaup
• Aythya americana - Redhead
• Aythya collaris - Ring-necked duck
• Aythya marila - Greater scaup
• Aythya valisineria - Canvasback
• Branta canadensis - Canada goose
• Bucephala albeola - Bufflehead
• Bucephala clangula - Common goldeneye
• Clangula hyemalis - Long-tailed duck
• Cygnus buccinator - Trumpeter swan
• Cygnus columbianus - Tundra swan
• Cygnus olor - Mute swan
• Melanitta fusca - White-winged scoter
• Melanitta perspicillata - Surf scoter
• Melanitta nigra - Black scoter
• Mergus merganser - Common merganser
• Mergus serrator - Red-breasted merganser
• Netta peposaca - Rosy-billed pochard
• Oxyura jamaicensis - Ruddy duck
• Plectropterus gambensis - Spur-winged goose

• Initially described mainly as a winter disease in North America. More recently reported to occur year round but frequently linked to particular seasons in given areas. For example, as a winter to early spring disease in California, in spring further north along migratory paths, in early summer on nesting grounds.
• Outbreaks may be linked to inclement weather (as a general stressor, increased transmission due to crowding or changes in feeding patterns), low water levels or freezing weather (therefore fewer open water areas), possibly seasonal nutritional deficiencies, and to seasonal aggregations (e.g. on wintering grounds, migratory staging areas, in one outbreak among moulting birds and in some species such as common eiders Somateria mollissima, lesser snow geese Anser caerulescens caerulescens and Ross's geese Anser rossii, in breeding colonies).
• Salinity, presence of organic matter (e.g. carcasses), presence of other microorganisms and increased temperature (e.g. 18-20ºC versus 4ºC) may all increase survival of Pasteurella multocida in water.

(J1.20.w3, J1.27.w3, J1.28.w3, J5.32.w2, J40.31.w1, B15)

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

• Widespread disease, with records of outbreaks in Africa, Europe, South America and Japan, but important for wild waterfowl die-offs primarily in North America, in all major flyways (J1.27.w3, B15). Occasional outbreaks in domestic waterfowl and poultry in the UK (J3.104.w1).
• Repeated outbreaks occur in the Central Valley of California, the Tulare Lake and Klamath Basins (northern California and southern Oregon), Texas Panhandle and the rainwater Basin below the Platte River in Nebraska (B36.7.w7).

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

• USA, Canada, Chile, Netherlands, Kenya, probably Mexico (J1.27.w3, J7.42.w1, B36.7.w7, B48.8.w8).
• Repeated outbreaks occur in the Central Valley of California, the Tulare Lake and Klamath Basins (northern California and southern Oregon), Texas Panhandle and the rainwater Basin below the Platte River in Nebraska (B36.7.w7).

General Information on Investigation / Diagnosis

• History of acute mortality with few sick birds but many dead birds, plus gross post mortem lesions (petechiae on heart and on serous membranes, necrotic foci on the liver), is highly suggestive.
• Bacteria with bipolar staining (using methylene blue, Wright's stain, Giemsa or Gram stain) in heart blood smears allows presumptive diagnosis.
• Definitive diagnosis depends on bacterial isolation and identification.
• The whole carcass should be sent for diagnosis if possible. Alternatively, heart blood (collect whole heart) and liver (at least half): keep cool preferably refrigerated. Freeze if tissues will be in transit for more than24hrs.
• If scavenged or decomposed collect wings: P. multocida persists several weeks to several months in bone marrow.

(J1.20.w8, J1.27.w3., B10.26.w7, B11.37.w5, B11.39.w7, B15, B36.7.w7, B37.x.w1, B48.8.w8)

• Physical Examination - General
• Necropsy - General
• Treatment and Care - 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

• Treatment and Care - General

General Nursing and Surgical Techniques

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Preventative Measures

WATERFOWL

• Preventative Medicine for Birds - General

Environmental and Population Control Measures

WATERFOWL

• Early detection is important. Aim is to minimize environmental exposure and direct contact.
• Carcass pick-up is essential – pick up head first, preferably by bill to reduce loss of contaminated fluids from nose and mouth, immediately place in bag. Double bagging of carcasses is recommended. Incineration is preferred for carcass removal, burial or liming otherwise.
• Draining a contaminated site (e.g. into a river sufficiently large to adequately dilute the contaminated water), or adding large volumes of water to dilute the concentration of bacteria may be useful.
• Disinfection of a wetland may be used where a large number of birds have died in a short time: the possible environmental impact should be assessed first.

(J1.13.w9, B10.26.w7, B11.37.w5, B11.39.w7, B13.46.w1,B15, B36.7.w7, B37.x.w1, B48.8.w8)

• Isolate affected birds.
• Hazing may be used to keep birds from moving into the site of an outbreak (particularly in the case of birds of conservation importance), and feeding and protection from disturbance may be used to keep waterfowl at a specific location (e.g. to stop spread to other areas). Dispersing birds during an outbreak may decrease population concentration and therefore disease transmission, but risks spreading the disease to other sites
• Control of scavenging birds may help prevent dispersal of disease.
• Destruction of a population has been undertaken. The useful effect of this was not clear. Such action could only be justified in special circumstances and conditions:
  

"(1) The outbreak must be discreet and localized rather than generalized and widespread;
(2) Techniques must be available that will allow complete eradication without causing widespread dispersal of potentially infected birds;
(3) The methods used must be specific for target species and pose no significant risk for nontarget species;
(4) Eradication must be justified on the basis of risk to other populations if the outbreak is allowed to continue; and
(5) The outbreak represents a new geographic extension of avian cholera into an important migratory bird population." (B36.7.w7).

(J1.13.w9, B10.26.w7, B11.37.w5, B13.46.w1, B15, B36.7.w7).

• Preventative Medicine for Birds - General
• Environmental and Population Management - General
• Treatment and Care - Euthanasia
• Chapter 4 - B36 Field Manual of Wildlife Diseases - Disease Control Operations
• Chapter 5 - B36 Field Manual of Wildlife Diseases - Euthanasia