The imperative to develop a human vaccine for the Hendra virus in Australia

Zahoor, Bilal A.; Mudie, Lucy I.

It is widely believed that disease transmission of HeV by equines, to humans, occurs via spread of droplets via aerosolization in the respiratory tract of the equine, during the final stages of the infection (8) . However, one index case of human infection was acquired during the necropsy of an HeV-infected equine (3, 9) . Another case was noted when a human acquired HeV from an otherwise asymptomatic HeV-infected equine (7) . Clinical syndromes in human cases usually present initially with non-descript respiratory symptoms followed by fulminant encephalitis occurring many months later. This contributes to the high mortality and morbidity associated with the disease. Not surprisingly, this pattern is changing; a recent human case documented a primary cerebral insult post-HeV infection (1, 4, 7) . HeV infection demonstrates a high case fatality rate in humans, estimated around 60% (4). Currently, no curative treatment exists apart from the off-label use of monoclonal antibodies, which at best are only supportive and anecdotal in application (1, 3, 10) . Current treatment strategies center around prophylactic and preventative strategies, endorsed by Biosecurity Queensland (4, 6, 11) . This involves culling of suspect and/or infected equines, regardless of symptom status, and contact isolation by humans concerning any potential equine HeV cases and/ or use of personal protective equipment (6) . Other strategies to contain the spread of the virus, targeting the bats, are futile given the wide and changing geographical habitats that bats use in their migratory patterns. Furthermore, tertiary control options that have proven successful in the reduction of Ross River virus spread cannot be enforced with HeV.