DISEASE SUMMARY PAGE

Keel Lesions

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Summary Information
Diseases / List of Physical / Traumatic Diseases / Disease summary
Alternative Names
  • Keel Sores
  • Sternal ulceration
  • Decubital ulcers
  • Pressure sores.
Disease Agents Physical trauma - pressure.
Infectious Agent(s) --
Non-infectious Agent(s) --
Physical Agent(s)
General Description Summary: Sores, involving discontinuity of the skin and often of deeper tissues, which develop on the keel (sternum) due to prolonged contact between the keel and solid surfaces.

Causes/predisposing factors:

  • Excessive/prolonged pressure on the tissues over the keel
  • Off-water housing of species which normally spend little time on land.
  • Also birds crash-landing on hard surfaces or repeatedly flying into e.g. walls.

(B188, D16, B197.15.w15, B198.6.w6, B364.10.w10)

Incubation:

  • N.B. Lesions may develop in just 3-10 days of off-water housing. (P4.1990.w1)
  • Even with net-bottom cages the lesions can start to form within as little as five days. (P14.7.w16)

Clinical signs:

  • Early signs include of pressure on the keel bone include feather thinning and skin erythema (reddening). (P24.327.w26)
  • The thin layer of soft tissue over the keel becomes bruised, followed by tissue necrosis along the line of the keel. The affected tissue splits open with the blood and serum which drain from this lesion contaminating the abdominal feathers; this serum is difficult to clean from the feathers. (P14.7.w16)
  • A wound over the sternum (keel, breastbone), involving the skin and usually also the muscle.
  • The keel bone may be exposed. (P24.327.w26)
  • The skin edges are separated and underlying tissue is necrotic. (J29.8.w1)
  • The wound may be quite small, e.g. one to 1.5 inches (2.5-3.75cm) long and 1/4 inch (0.6cm) wide.
  • Since the wound weeps serum, the lesion and feathers surrounding the area are not waterproof. (D16) Affected birds become hypothermic if placed on cold water. (P14.7.w16)
  • This can become a chronic open wound with associated fibrosis and infection, or a chronic ulcerative lesion with granulating tissue around the edges.

(B197.15.w15, B198.6.w6, P4.1990.w1, D16).

Further Information

CAUSES AND SUSCEPTIBLE SPECIES

Keel lesions may develop in a variety of bird species for different reasons.

1) Repeated or continuous low-grade trauma. This is seen in species which normally spend their lives on water / in the air, and are being maintained on a solid substrate, for example during rehabilitation following Oiling:

  • Diving ducks such as pochards (Aythya spp.).
  • Stiff-tailed ducks (Oxyura spp. and related species)
  • Seaducks (J29.8.w1) such as scoters. (D214.2.w2)
  • Loons (divers) (Gaviidae - Loons (Family))(B23.38.w2, D214.2.w2, J29.8.w1)
  • Grebes (Podicipedidae - Grebes (Family)) (J29.8.w1)
  • Gannets, shearwaters, petrels (B23.38.w2)
  • Guillemots/murres (alcids). (J29.8.w1)
  • Other pelagic birds
  • Very weak birds, and those with foot problems, may also spend long periods resting on the breast, and therefore be predisposed to development of keel lesions. (B188)
  • Individuals which are very thin or emaciated, and therefore have little soft tissue covering the keel, are particularly susceptible to the development of keel lesions. (D16)
    • Weak and emaciated birds of other species, such as raptors, spending long periods lying on their sternum, are also susceptible. (B11.14.w21)
2) Collision-associated

3) Due to self-mutilation

PREVENTION:

Prevention in water birds undergoing rehabilitation:

  • This condition should be prevented if at all possible as treatment is difficult and time consuming, delaying release of the affected bird. 
  • House seaducks, other diving ducks and pelagic birds which would normally rarely stand on water whenever possible.
    • Water birds with early signs of keel pressure should be housed on warm water pools. (P24.327.w26)
  • Use padded surface or net-bottomed cage if housing on water is not possible (e.g. prior to washing oiled birds). (B23.38.w2, B363.9.9, P14.7.w16, P24.335.w21, J29.8.w1, J311.11.w1)
    • Net-bottomed cages are preferred as, in addition to having a "give" in their surface, they allow droppings to fall away from the bird, reducing contact of feathers with urates and thus the risk of Feather Rot. (B23.38.w2, J29.8.w1, J311.11.w1, P4.1990.w1, P14.7.w16)
    • Note: net-bottom cages may slow the development of keel lesions but do not prevent them. (P14.7.w16)
  • In oil-spill treatment centres, prioritise susceptible species to be washed and placed onto water as soon as possible. (D60.7.w7, D214.2.w2)
  • "Donuts" may be used on thin/emaciated birds which are not standing well, or on individuals with very limited mobility on land, to protect the keel. These are soft rings (e.g. a rolled up cloth) which are attached to the bird around the keel such that when the bird sits/lies down the edges of the donut, not the keel, is against the ground. (D16, D133.5.w5, B363.9.9)
    • The "donut" is "U" shaped and the bird's weight rests against the pectoral muscles. (P14.7.w16)
    • Skill is required to fit the "donut" correctly; it is held onto the bird using "figure of eight" strapping across the bird's back, leaving the neck, wings and legs free to move. (P14.7.w16)
    • Note: Donuts are useful but are not a complete solution. If left in place these for long periods, some bruising of the pectoral muscles occurs. (P14.7.w16)
    • Inflatable "donuts" may be used. (J312.16.w1)

Prevention in pet birds, falconry or aviculture:

  • Prevention of collision-associated keel lesions in wing-clipped pet birds requires ensuring that incorrect wing-clipping is not carried out. (V.w5)
  • Padding of the walls or fences of aviaries or enclosures may be useful to reduce injury due to repeated crashing into such structures. (V.w5)

TREATMENT:

  • Treatment is easier and more likely to be successful if the problem is detected early. (B188)
  • Birds with early signs of lesions developing - reddening of the skin and thinning of the feathers - should be placed on a warm water pool, thereby removing the source of the pressure. (P24.327.w26)
  • It is vitally important to remove any pressure from the site of the lesion. (D16)
  • Affected birds with keel lesions due to prolonged contact with inappropriate substrates must be provided with a more appropriate substrate. (P24.355.w14) (see prevention)
  • Ideally, affected water birds should be kept entirely on water, heated to about 80 to 95 F, to remove pressure from the wound and allow it to heal. (D16)
    • Cold water pools cannot be used since the lack of waterproofing means that the water will reach the skin, which leads to hypothermia, and to attempts to leave the water, which may result in further trauma. (D16)
    • Prophylactic treatment to prevent aspergillosis (Aspergillosis in Birds) may be required, as the warm moist atmosphere of a warm water pool may provide ideal conditions for the development of this disease. (D16)
  • The affected area should be cleaned and flushed with antiseptic (e.g. 1% iodine), followed by application of wound dressings. (P24.355.w14)
  • Given time (several weeks), lesions may heal through granulation and secondary intention healing.
  • Thorough cleaning is required before suturing. (J29.8.w1)
  • Keel sores often do not respond well to suturing. (P14.7.w16)
  • Surgical treatment:
    • Anaesthetise; (B197.15.w15)
    • Pluck the minimum possible number of feathers from the edge of the wound: the remaining feathers should completely cover the wound once the skin edges are re-apposed; (B197.15.w15)
    • Disinfect the skin using a non-detergent skin disinfectant; (B197.15.w15)
    • Debride and remove necrotic tissue; (B197.15.w15, B198.6.w6, P24.327.w26))
      • It may be necessary to bluntly dissect the pectoral muscles and partially resect the bone in severe cases, such as self-inflicted ulcerated wounds in psittacines, (B198.6.w6) or if the bone has become infected. (B11.14.w21)
    • Close the wound (P24.327.w26) with absorbable sutures and/or tissue glue; (B197.15.w15)
      • Interrupted horizontal mattress sutures are recommended for suturing the muscle. (B198.6.w6)
      • Interrupted horizontal mattress sutures secured to a gauze swab (to minimise tension over wound edges) may also be used to close the skin defect. (B198.6.w6)
    • Reintroduce water birds to water as soon as possible to prevent recurrence of damage. (B197.15.w15)
    • Suturing of an appropriate wound dressing (e.g. Granuflex) over the wound may be useful; this provides additional protection for the keel bone during healing. This may be left in place for two weeks [in raptors].(B11.14.w21)
    • Water birds may be placed on warm water pools following surgery; sufficient seclusion is important to ensure that the bird feels secure and remains on the water. (P24.327.w26)
    • Provide appropriate antibiotics. (P24.327.w26)
  • N.B. Birds which have developed keel lesions while undergoing rehabilitation are not fit for release until tests show the plumage over the healed wound site (and elsewhere) to be totally waterproof. 
    • Keel lesions may be slow to heal. (P24.327.w26)
    • The time to return of normal feathering may be prolonged. (P24.327.w26)

(B23.38.w2, B197.15.w15, B198.6.w6, P4.1990.w1, D16, D32)

Associated Techniques
Host taxa groups /species

[N.B. Miscellaneous / Traumatic Diseases tend to be under-reported and the majority are likely to affect all species, given exposure to the related disease agents/factors.]

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