“Clenched Claw” Syndrome:  A Paralysis-Paresis Condition of Rainbow Lorikeets, Trichoglossus Haemadotus

J.J. McKee, R.J. Booth and W.J. Hartley

Wild rainbow lorikeets make up a 9% the 4500 yearly admissions to Currumbin Sanctuary Wildlife Clinic.  Approximately 10% of lorikeet admissions present with a paresis - paralysis condition primarily affecting their ability to fly and perch.  The most dramatic sign is ataxia with one or both claws rigidly clenched.   This condition was previously reported as being caused Vitamin E deficiency leading to muscle disease.  Between 1995 - 1997, thirty five rainbow lorikeets presenting with unilateral or bilateral hind limb paresis and inability to fly were subject to a standardised clinical, serological, pathological and histopathological examination. Results indicate that vitamin E deficiency is not an important cause of this syndrome.  Twenty eight birds had pathology consistent with either acute spinal trauma or a suspected viral encephalomalacia.  Three had demonstrable protozoan infection in flight muscles but it was uncertain whether these lesions were sufficient to explain the clinical presentation. No causative lesions were detected in three birds. Two birds only had low serum vitamin E concentrations but had no signs of vitamin E related muscle disease.  Diagnosis and treatment options are discussed. At this stage there appears to be no association between clench-claw syndrome and the widespread practice of public feeding of wild rainbow lorikeets. Further investigation to confirm and isolate the virus suspected of causing the polioencephalomalacia is warranted.