Correction of a Hyperflexed Hallux in a Saker Falcon (Falco cherrug) by Hemisectioning the Deep Digital Flexor Tendon

A 3-year-old male saker falcon (Falco cherrug) was presented with a history of hyperflexion of the first digit of the left pelvic limb with what appeared to be a hypercontracted distal end of the deep digital flexor tendon (m. flexor hallucis longus). Conservative treatment, bandaging, and splinting techniques failed to resolve the hypercontraction of the deep digital flexor tendon and improve digit function. Intraoperatively, the deep digital flexor tendon was found to have formed adhesions with the tendon sheath as well as the bone and soft tissue structures underneath it, impeding its ability to move freely within the tendon sheath. The adhesions were surgically resolved, and the tendon was lengthened by hemisectioning the deep digital flexor tendon at its distal end. Postsurgically, the digit was maintained in an extended position by bandaging. Mild physiotherapy was provided at 5-day intervals to retain function and prevent adhesions. Digit extensibility and function were restored to nearly normal levels after 4 weeks.

Management of Knuckling in an Ostrich (Struthio camelus) Using a Custom-Made Orthotic Shoe

A 4-year-old female ostrich (Struthio camelus) developed knuckling on its left foot after a traumatic event. Conservative treatment, rest, and traditional splinting methods failed to resolve the gait abnormality or improve mobility. A dynamic multicomponent orthotic shoe was then custom designed and fabricated with an ultra-high-molecular weight, low-pressure polyethylene polymer (St 1000 DIN16972 TG2) to correct the foot malposition. The affected foot and leg were wrapped with soft padding and the orthosis was attached and secured by nylon belts (Nylon PA [polyamide] 6, a semicrystalline polyamide polymer) with self-locking modified wrench straps. The orthosis immediately prevented knuckling and improved ambulation. After 2 weeks, this shoe was replaced with a modified orthotic shoe of lighter weight to improve kinetics and ease of use by the bird. The modified orthosis dramatically improved ambulation and was left attached to the affected leg for 7 more weeks. Thereafter, the bird was able to ambulate comfortably without the aid of the shoe, even though permanent anatomical changes to the affected leg seemed to restrict its speed of locomotion. The ostrich had another unfortunate traumatic event 10 weeks later, the result of which was knuckling on the contralateral (right) foot. After routine medical and supportive care, the orthosis was then applied to the right foot for a period of 9 weeks. During this period the bird was able to ambulate well, despite having to support the bulk of its weight on the previously affected left limb. At the end of 9 weeks, the orthosis was removed, and the bird was able to ambulate without aid, although the bird's speed of locomotion was considerably reduced. After recovery of its leg problems, the ostrich was confined to a relatively small paddock for the rest of its life.

Inclusion Body Herpesvirus Hepatitis in Captive Falcons in the Middle East: A Review of Clinical and Pathologic Findings

Inclusion body hepatitis in falcons is caused by a herpesvirus designated Falconid HV-1. This herpesvirus and other herpesviruses affecting birds of prey have not been assigned to a genus and include inclusion body herpesvirus hepatitis in eagles (Accipitrid HV-1) and inclusion body herpesvirus hepatitis in owls (Strigid HV-1). Herpesvirus infections have been diagnosed in both captive and free-living raptors across Europe, North America, and Asia in different species of the family Falconidae. Herpesviruses affecting owls and falcons have been found to be antigenically similar to pigeon herpesvirus (Columbid HV-1) and distinct from other avian herpesviruses. When the herpesvirus isolates from owls, falcons, and pigeons were compared by sequencing a fragment of the herpes viral DNA polymerase gene from those birds naturally infected with the virus, the sequences from these 3 sources were found to be nearly identical. The authors of this study concluded that the Falconid HV-1, Strigid HV-1, and Columbid HV-1 were the same virus. Furthermore, the authors also proposed that the virus therefore be referred to as Columbid HV-1 (CoHV-1), because pigeons may be responsible for the transmission of the virus to birds of prey. Pigeons are often carriers of the virus without showing any clinical signs. It has long been suspected that raptors may contract the infection by the ingestion of infected pigeons. Some studies have suggested that falcons may not contract the infection through the oral route by ingesting carrier pigeons, but through the ocular or nasal route. Inclusion body herpesvirus hepatitis is a frequently diagnosed disease in the captive falcon population used for falconry, racing, and breeding in the Middle East, and it seems to be associated with the extensive use of pigeons for training and as a food item. This paper reviews the clinical and pathological findings in falcons affected by inclusion body herpesvirus hepatitis in the Middle East.

Detection of Avian bornavirus in multiple tissues of infected psittacine birds using real-time reverse transcription polymerase chain reaction

Avian bornavirus (ABV), the cause of proventricular dilation disease in psittacine birds, has been detected in multiple tissues of infected birds using immunohistochemical staining (IHC) and reverse transcription polymerase chain reaction (RT-PCR). In the current study, real-time RT-PCR, using primers targeting the ABV matrix gene, was used to detect ABV in 146 tissues from 7 ABV-infected psittacine birds. Eighty-six percent of the samples tested positive, with crossing point values ranging from 13.82 to 37.82 and a mean of 22.3. These results were compared to the findings of a previous study using gel-based RT-PCR and IHC on the same samples. The agreement between the 2 RT-PCR techniques was 91%; when tests disagreed it was because samples were negative using gel-based RT-PCR but positive on real-time RT-PCR. Agreement with IHC was 77%; 16 out of 74 samples were negative using IHC but positive on real-time RT-PCR. The results suggest that real-time RT-PCR is a more sensitive technique than gel-based RT-PCR and IHC to detect ABV in tissues. The tissues that were ranked most frequently as having a high amount of viral RNA were proventriculus, kidney, colon, cerebrum, and cerebellum. Skeletal muscle, on the other hand, was found to have a consistently low amount of viral RNA.

Potassium chloride as a euthanasia agent in psittacine birds: Clinical aspects and consequences for histopathologic assessment

Twelve parrots anesthetized with isoflurane were euthanized intravenously (IV) with 3 or 10 mEq/kg body weight (BW) of potassium chloride (KCl) resulting in ventricular asystole at 68.0 s and 32.8 s, respectively. Mild vocalization (1/6 birds, 3 mEq/kg BW) and involuntary muscle tremors (5/6 birds, 10 mEq/kg BW) were noted. Unlike barbiturates or T-61 no histologic artefacts resulted from this technique.

Avian bornavirus is present in many tissues of psittacine birds with histopathologic evidence of proventricular dilatation disease

Proventricular dilatation disease (PDD) is a neurologic disease of psittacine birds suspected to be caused by a recently identified Avian bornavirus (ABV). In the current report, data supporting the causal association of ABV with PDD are presented. Immunohistochemistry (IHC) with rabbit polyclonal antiserum raised against ABV nucleocapsid protein was used to identify cell and organ distribution of viral antigen. The ABV antigen was most consistently detected in brain, spinal cord, adrenal gland, pancreas, and kidney. Histopathologic evaluation was correlated with ABV-specific polymerase chain reaction (PCR) and immunohistochemical tests in multiple tissues from 16 psittacine birds with and without PDD. Using histopathologic diagnosis as the gold standard, the sensitivity and specificity of IHC for ABV antigens were found to be 100% and 100%, respectively. Many more tissues were positive for ABV RNA by reverse transcription PCR than were positive for pathologic changes or viral antigens by IHC, indicating the presence of subclinical or asymptomatic infection at many sites.