Avian Medicine PDF

Avian Medicine Marie Kubiak BVSc CertAVP(ZM) CertAqV DZooMed MRCVS RCVS Recognised Specialist in Zoo and Wildlife Medicine  Over 9000 different species  Anseriformes: ducks, geese and swans  Falconiformes: eagles, hawks, falcons and vultures  Galliformes: grouse, quail, pheasants, chicken, tur...

Avian Medicine Marie Kubiak BVSc CertAVP(ZM) CertAqV DZooMed MRCVS RCVS Recognised Specialist in Zoo and Wildlife Medicine  Over 9000 different species  Anseriformes: ducks, geese and swans  Falconiformes: eagles, hawks, falcons and vultures  Galliformes: grouse, quail, pheasants, chicken, turkey  Columbiformes: pigeons, doves  Psittaciformes: parrots, including budgies  Passeriformes: canaries and finches Identifying sick or deteriorating animals  Birds hide symptoms  Illness makes them a target to potential predators  A bird that looks sick is VERY sick  Rapid metabolic rate can lead to rapid change in condition  Always be alert for minor changes  Monitor weight, demeanour, activity  Be proactive with management Signs of ill health  Fluffed up.  Loss of appetite, weight or condition  Alteration in faeces  Loss or change of voice / vocalisation  Changed behaviour, less active  Sleeping more  Standing on 2 legs / abnormal stance  Reduced performance  Change in height of perching / on floor  Change of balance (tail up or down)  Tail bobbing  Abnormal bodily discharges  Vomition / regurgitation  Wings hanging down  Hanging onto perch / cage with beak Raptors  Harris Hawks common in captivity  Often the choice of new falconers  Falcon species also common but require more skill  Buzzards, kestrels, sparrowhawks and owls often seen as wildlife casualties  Eagles, condors and other large species rarely present to non-specialist facilities How to handle raptors  Falconry birds used to handling and tolerate more intervention than parrots  Assisted by equipment such as jesses and hoods  Always restrain the feet  Casting very useful for complete examination  Wild birds and stressed animals are better anaesthetised for complete examination What not to do  Damage feathers  Raptors usually moult annually  Damaged feathers will affect flight until the next moult  Tail guards can be easily placed  Be complacent  Injuries from footing can be severe Diagnostics  Due to the non-specific signs and advanced nature of many lesions on presentation, immediate investigation is warranted  A standard starting protocol is:  Haematology  Biochemistry  Lateral and ventrodorsal radiographs Blood sampling  Manual haematology necessary  Jugular  Apterium on right side of neck  Align vessel with vertebrae before sampling to allow application of pressure for haemostasis  Superficial ulnar vein  Often used for catheterisation  Blood sampling can be done from catheter  Haematoma formation often greater than jugular Radiography  Familiarity with normal anatomy is essential  Right lateral  Extend wings dorsally and legs caudally  Ventrodorsal  Extend wings laterally and legs caudally Kubiak, M., 2020. Grey Parrots, pp.165-187, In Kubiak, M. ed., 2020. Handbook of Exotic Pet Medicine. John Wiley & Sons. Kubiak, M., 2020. Grey Parrots, pp.165-187, In Kubiak, M. ed., 2020. Handbook of Exotic Pet Medicine. John Wiley & Sons. Common conditions  Sour crop  Fractures  Squirrel bites  Bumblefoot  Wing tip oedema  Aspergillosis Wing tip oedema  Typically affects raptors from warm climates  Harris hawks, Lanner falcons  First year birds predisposed  Occurs in winter when temperatures drop  Blood supply to the wing tip is compromised  Oedema of the metacarpi develops  Dry gangrene follows with loss of the wing tip  Loss of primary feathers leads to permanent flight compromise  Presenting signs  Dropped/abducted wings  Swollen metacarpi  Loss of one or both wing tips  Treatment  Gentle warming  Physiotherapy (manual/flight if possible)  Sterile draining of any vesicles  Isoxuprine (Navilox)/Propentofylline (Vivitonin)  Topical Preparation H  Covering antibiotic therapy  Hopeless if wing tip already lost Aspergillosis “The commonest respiratory disease of captive birds”, Redig (1993) Fungal mycelium in human HIV patient  Multiple species capable of disease  A. flavus, A. niger, A. fumigatus, A terreus  Non-contagious but can appear to cause outbreaks with group exposure to spores  Opportunistic infection  Immunosuppression: concurrent disease/stress/malnutrition  Marked predisposition in Goshawk, Golden Eagle, Gyr falcon and Snowy owls  Overwhelming challenge: housing close to compost/hay/wood  Aflatoxins cause hepatic pathology  Marked leucocytosis Syringeal aspergilloma       Fungal granulomas form on the syringeal mucosal folds Progressive air flow obstruction develops Early signs include changes in vocalisation Acute dyspnoea occurs as granulomas grow Diagnosis: tracheoscopy Treatment:  Stabilisation: air sac tube, supportive care  Debridement (surgical/endoscopic)  Systemic antifungal therapy  Itraconazole (?toxic in AGPs), Voriconazole, Amphotericin B  Nebulisation  Dietary and environmental improvement Air sac aspergilloma  Caudal air sacs generally affected  Natural deposition of spores as air flow slows  No respiratory signs  General malaise  Hepatic dysfunction  Surgical/endoscopic debridement  Antifungal therapy  Nebulisation  Less favourable prognosis Lung aspergilloma  Severe necrotising fungal pneumonia  Dyspnoea  Poor prognosis Aspergillus flavus Parrots  There are around 400 species of parrots  They are all complicated animals not necessarily suited to captivity  Intelligent and easily bored or stressed  Require much exercise and interaction  Messy and destructive  Require a balanced, complex diet  Heating and ultraviolet light necessary for most species  Long-lived  Most behavioural and health problems are associated with inappropriate husbandry African Grey Parrot  Found in forests of Central and West Africa  Feeds on semi-ripe African fruits and nuts  Basks in sunlight in the upper canopy of trees  Forms social flocks of hundreds of birds Maintained indoors in small cages  Fed sunflower seed mixes  No access to sunlight  Kept alone Handling parrots  Few are tame and will allow complete examination or medication without restraint  Towel restraint safest  Approach with open towel to limit avoidance  Grasp around the back of the neck  Wrap towel around wings to prevent injury  Beak is the major risk but nails can be sharp  Always consider anaesthesia in a stressed animal Crop Tube Feeding  Vital procedure  Support bird in a towel  Restrain head/jaw  Pass tube into side of mouth on birds left  Over the tongue and down the birds right side – avoiding the glottis  Palpate the tube tip in the crop before feeding Common conditions  Beak overgrowth  Wing clipping  Respiratory compromise  Feather plucking Beak overgrowth An apparently simple problem But…. A parrot’s beak should be worn effectively with appropriate management conditions So, there is a problem somewhere  Inappropriate wear  Wrong diet  Lack of chewing material  Parrots are naturally destructive and will readily chew branches, toys, furniture…  Infectious pathology  Knemidokoptes mite infestation  Circovirus (Psittacine Beak and Feather Disease)  Cockatoos appear most likely to develop severe beak and nail changes  Previous trauma  Malocclusion results and even wear is compromised  Hand-feeding of juveniles is a common cause  Abnormal growth  Liver pathology  Can be secondary to malnutrition, hormonal irregularities, chlamydophila etc.  Neoplasia rarely reported Chondrosarcoma in a Scarlet Macaw  A rotating abrasive tool or burr is used  Comprehensive trimming requires anaesthesia  This minimises stress  The beak can be reshaped properly  The intraoral beak surfaces can be accessed  An endotracheal tube can be placed to prevent dust inhalation Wing clipping √ Allows socialisation ₓ Prevents normal behaviour √ Outdoor activity ₓ √ Reduces contact with hazards Doesn’t necessarily prevent flight completely √ Improved owner confidence and interaction ₓ Can give false confidence in security ₓ Can trigger aggression ₓ Factor in feather trauma ₓ Risks crash landing ₓ Inactivity leads to health problems  Rarely indicated  Not consistent with Animal Welfare Act 2006  Can be a temporary measure to allow training of an aggressive bird  Trim inner feathers, with ends under coverts  Trim both wings  Gives better balance  Warn owners that flight may still be possible and feathers will regrow Respiratory compromise  A dyspnoeic bird is a severely ill bird  Stabilise in oxygen chamber while taking history  Investigation under anaesthesia may need to be attempted even in an unstable case  Warn owners that prognosis is guarded  Investigation crucial as many causes can present as respiratory compromise and all have different approaches needed Causes  Respiratory disease  Aspergillosis  Chlamydophila psittaci (Psittacosis/ornithosis)  Inhaled foreign body (usually cockatiels)  Tracheal stricture  Tracheal trauma  Pneumonia  Tracheal parasitism (Syngamus spp.)  Cardiovascular  Congestive heart failure  Common in older owls  Associated with atherosclerosis in psittacines  Anaemia  Usually due to acute haemorrhage/chronic disease  IMHA reported in raptors  Toxic  Teflon inhalation  Respiratory irritants e.g. smoke, aerosols  Coelomic compression (NO DIAPHRAGM)  Coelomitis (often reproductive in origin)  Ascites  Hepatomegaly  Neoplasia Feather plucking  Common presentation and many causes  Internal discomfort including:  Air sacculitis (always check for Chlamydophila)  Renal pathology  Metabolic bone disease  Chronic enteritis (beware proventricular dilation syndrome)  Osteoarthritis  Angina  Dermatological factors  Preen gland impaction/infection  Secondary to malnutrition (lack of Vitamin A) and leads to dry, brittle feathers  Quill mites in kakarikis  Polyfolliculitis in love birds  Abnormal feathers  Beware PBFD if distorted/abnormal coloured feathers  Altered smell or texture e.g. smoke, triggers removal  Behavioural  Displaced aggression/frustration  Stressors in environment  Alteration or lack of a routine  Sexual/breeder frustration in imprinted birds  Lack of stimulation and ‘boredom’ associated  Physiological  Mate preening in Macaws  No one treatment fits all  A comprehensive medical investigation is necessary to identify health factors  Haematology and biochemistry  Radiography  Chlamydophila serology  Other tests as indicated  Diet and management invariably need improvement even if not yet causing problems Pet poultry  Ex-battery hybrid hens  Pedigree chickens  Waterfowl  Turkey  Peafowl  Guineafowl  Ratites Egg peritonitis  A broad term used indiscriminately for inflammation of a bird’s reproductive tract and coelomic cavity  The most common reason for presentation of chickens  Ectopic follicle/yolk causing severe coelomic ‘foreign body’ reaction Aetiopathogenesis 1  Failure of a follicle to move into the infundibulum.  The yolk instead is ovulated into the coelom  A single episode causes mild inflammation  Usually self-limiting  Adhesions can lead to secondary problems Aetiopathogenesis 2  Follicle ovulates normally but external trauma leads to oviduct rupture and leakage  Scarring and inflammation of oviduct likely to predispose to ongoing problems  Difficult to identify as trauma usually unseen and little external indication Aetiopathogenesis 3  Accumulated oviductal damage leads to narrowing  High output hens accumulate damage faster  Infectious salpingitis increases risk dramatically  Narrowing intermittently prevents normal egg progression  Reflux of oviductal contents occurs leading to marked and repeated inflammation  Appears to be common Clinical signs  None in early disease  Lethargy  Anorexia  Weight loss  Ascites  Predisposition to other pathogens  Reduced frequency of laying  Shell abnormalities  Palpably warm ventral skin  Self-trauma  Dyspnoea Diagnosis  Clinical examination is highly suggestive  Radiography rarely of diagnostic use  Ultrasonography recommended  Easy to carry out  Assess oviduct  Demonstrates severity of ascites  Check for adhesions  Allow safer aspiration  Differentials:  Egg binding  Inspissated oviduct  Aspiration  Clear to orange fluid  High protein (>30g/l) and cellularity  Cytology to check for secondary infection  Surprisingly low incidence of infection  Relieves pressure on respiratory and cardiovascular system  Temporary measure Differentials  Ascites  Bacterial coelomitis  Congestive heart failure  Hepatopathy  Reduced laying/shell changes  Mycoplasma gallisepticum  Infectious bronchitis  Nutritional secondary hyperparathyroidism  Systemic disease Management  Initial stabilisation  Oxygen therapy  Subcutaneous fluids  Drainage Conservative management  Anti-inflammatories  Meloxicam @0.5mg/kg bid  Prophylactic antibiotic therapy if infection component  Ongoing fluids and assist feeding if required  Likely to recur when egg laying resumes  Many owners are happy to treat intermittently  Repeat episodes exacerbate oviductal damage Longer term control  Cessation of reproductive activity is key  Euthanasia  Salpingectomy  High risk, technically demanding surgery  Significant haemorrhage common  Difficult to eliminate post-op infection risk  Expensive  Endocrine manipulation  Leuprolide  Deslorelin (Suprelorin, Virbac)  Should we be really using these in food producing species?  Lack of withdrawal times for advising owners Preventative measures  Optimise husbandry  Quarantine and vaccination protocols  Control infectious factors e.g. Mycoplasma  Provide shelter to reduce trauma likelihood  Select lower production breeds  Culling controversial with pet birds Marek’s Disease  Oncogenic Gallid herpesvirus  Virus is ubiquitous and persists for >1 year  Chicks will be infected from environment  Disease progression is highly variable  Infected birds may be asymptomatic shedders  Typically develops at 12-20 weeks  Neurotrophic  Sciatic nerve most commonly affected  Progressive leg weakness and paralysis  Neck weakness and opisthotonus also seen  Dermal and visceral nodules can occur  Iridial changes may be seen  Blue/grey discolouration  Diagnosis  Elimination of other causes of neuropathy  Heavy metal toxicity  Hypovitaminosis B  Trauma  Egg binding  Serology may be used  Definitive diagnosis involves sciatic nerve histopathology  Euthanasia advisable for infected birds  Recovery rare  Prevention  Vaccination readily available (Poulvac-MD)  All chicks should be vaccinated Mycoplasma  Two species of importance:  Mycoplasma gallisepticum  Respiratory and reproductive infections  Mycoplasma synoviae  Musculoskeletal infections  Mycoplasma meleagridis  Respiratory infection in turkeys Mycoplasma gallisepticum  Common inhabitant of URT  Immunosuppression leads to shedding  Often seen after introduction of new birds  Potentiation of/by IB and E.coli Co-infections lead to severe disease  Clinical appearance often diagnostic  Serology available  Treatment  Lincospectin (lincomycin/spectomycin combination)  Tylan (tylosin)  Reduces clinical signs but birds likely to remain carriers Prevention  ?Cull clinical cases  ?Isolate suspected infected birds  Vaccinate new stock Internal parasites  Coccidia  Seven species of Eimeria  Most pathogenic species are E. necatrix and E.tenella  Also most common!  Cause caecal inflammation, necrosis and secondary bacterial infection  Diarrhoea, weight loss, ill thrift  Lethargy, fluffed appearance  Rarely cause ‘pathognomonic’ haematochezia  Young birds more severely affected with high mortality  Diagnosis  Identification of oocysts on faecal smear/flotation  Treatment  Baycox (Toltrazuril)  7mg/kg sid for two days  Environmental hygiene Nematodes  Most have low pathogenicity  Ascarids can affect food conversion efficiency Flubenvet in food effective  Capillaria high pathogenicity Oesophageal lesions in turkeys and game birds Intestinal pathology in chickens Resistance common  Flubendazole licensed with zero egg withdrawal