Australian bat lyssavirus investigation in East Gippsland

Jo Cunningham, DVO Bairnsdale

Veterinarians, nurses, wildlife carers or others who anticipate handling bats or flying foxes are at risk of becoming infected with Australian bat lyssavirus (ABLV) and should consider pre-exposure vaccination.

In November 2016, a male grey-headed flying fox (Pteropus poliocephalus) from a colony of 6000 at Bairnsdale, was presented to an East Gippsland wildlife shelter with hemiparesis (muscular weakness or partial paralysis restricted to one side of the body). Physical injury to the limbs and wings was not apparent.

The flying fox was euthanised and the carcass submitted to the laboratory for exclusion of Australian bat lyssavirus (ABLV). Necropsy revealed trauma to the caudal skull with discolouration of subcutaneous tissue and a cranial fracture. Histologically there were multifocal haemorrhages within the meninges with an infiltration of neutrophils.

Samples were negative for ABLV.

In a separate presentation, a second grey-headed flying fox that scratched a member of the public after becoming caught in fruit tree netting was also ABLV negative.

ABLV is a potentially fatal zoonotic disease related to, but distinct from Rabies (genus Lyssavirus, family Rhabdoviridae). It was first recognised in 1996 in Queensland and has been found in several species of Australian flying foxes (megabats) and insectivorous bats (microbats). There have been cases in Victoria and all bats should be regarded as capable of being infected.

Zoonotic spread may occur following bites or scratches. The best protection against being exposed is to avoid handling bats.

• Staff (veterinarians, nurses, wildlife carers) who anticipate handling bats should consider pre-exposure vaccination. Rabies vaccination is used in both humans and animals following potential (or confirmed) exposed to ABLV.
• Always use personal protective equipment when handling bats even if they appear healthy (Refer to the AVA Guidelines for veterinary personal biosecurity.)
• DO NOT allow bats of any age, whether healthy or sick, to be handled or touched by children or other people who do not have a current rabies vaccination.
• Beware of the exposure of pets to bats.

Reminder: Cases similar to those described above should be routinely investigated because of the zoonotic potential of ABLV.

For more information visit the Wildlife Health Australia (WHA) website or download the most current WHA fact sheet (under 'Mammals').