Abstract
Background Rabies is a zoonotic viral encephalitis caused by the Lyssavirus. In Australia, there have been two known imported cases, and three cases of Australian bat lyssavirus, all fatal. Until March 2023, New Zealand had never seen a case of rabies.
Methods Review of case notes and literature.
Results A 48-year-old diabetic man, working on a ship from the Philippines, presented with three days of fever, vomiting, anorexia, and paranoia. He was tachycardic, acidotic, and hyperglycaemic, and treated as diabetic ketoacidosis. Collateral history revealed a preoccupation with water. He became agitated, with autonomic instability, alternating tachypnoea and apnoea, and hypoxia. Hypertonia, hypersalivation, and abnormal gagging and gulping were observed. CT and MRI were normal. Electroencephalogram was non-specifically abnormal, without epileptic activity. Cerebrospinal fluid showed lymphocytic pleocytosis, with negative meningoencephalitis and neuronal antibody panels. Initial tests for other infective pathogens were negative, including rabies IgG. After two weeks, saliva and skin samples returned positive results for rabies by polymerase chain reaction, and serum rabies IgG became positive. A second MRI showed diffuse FLAIR signal in the cerebral cortex, basal ganglia, and hypothalamus. Supportive care was withdrawn and the patient died. No exposure history was found.
Conclusion This was the first recorded case of rabies in New Zealand. Rabies is a rare cause of severe encephalitis, which can mimic other causes of infectious or autoimmune encephalitis. The history of hydrophobia was an important clue to this patient’s diagnosis. There is no effective treatment for rabies encephalitis, so post-exposure prophylaxis is crucial.
