Australian bat lyssavirus

Australian bat lyssavirus
Virus classification
Group:	Group V ((−)ssRNA)
Order:	Mononegavirales
Family:	Rhabdoviridae
Genus:	Lyssavirus
Species:	Australian bat lyssavirus

Australian bat lyssavirus (ABLV) (initially named pteropid lyssavirus PLV) is a zoonotic virus closely related to rabies virus. It was first identified in a 5-month-old juvenile Black Flying Fox (Pteropus alecto) collected near Ballina in northern New South Wales, Australia in January 1995 during a national surveillance program for the recently identified Hendra virus. ABLV is the seventh member of the lyssavirus genus (which includes rabies virus) and the only lyssavirus family member present in Australia.

Prevalence

ABLV is distributed throughout Australia in a variety of bat species which are believed to be the primary reservoir for the virus.

"Surveillance initiatives also confirmed the presence of lyssavirus in both Pteropid (Gould et al., 1998) and insectivorous bats (Gould et al., 2002; Hooper et al., 1997), and later, human infections were reported following encounters with both fruit and insectivorous bats (Allworth et al., 1996; Hanna et al., 2000; Warrilow, 2005; Warrilow et al., 2002). Indeed, ABLV has now been isolated from five different bat species, all four species of Pteropodidae in Australia and from an insectivorous bat species, the yellow-bellied sheath-tailed bat (Saccolaimus flaviventris), with two distinct lineages apparently circulating in insectivorous and frugivorous bats (Fraser et al., 1996; Gould et al., 1998, 2002; Guyatt et al., 2003). Phylogenetically and serologically, ABLV isolates appear to be more closely related to RABV than any of the other Old World lyssaviruses (Fig. 2). Although the black flying fox is a native fruit bat to Australia and is present on islands to the north, ABLV has only been isolated in Australia. However, serosurveillance of bat populations in the Philippines has suggested that lyssavirus infection of bats might be more widespread than previously thought (Arguin et al., 2002)."

Bat lyssavirus and human health

There have been three confirmed cases of ABLV in humans, all of them fatal. The first occurred in November 1996 when an animal carer was scratched by a Yellow-bellied Sheath-tailed Bat. Onset of a rabies-like illness occurred 4–5 weeks following the incident, with death twenty days later. ABLV was identified from brain tissue by PCR and immunohistochemistry.

In August 1996, a woman in Queensland was bitten on the finger by a flying fox while attempting to remove it from a child it had landed on. Six months later, following heightened public attention from the first ABLV death, she consulted a GP regarding testing for the virus. Post exposure treatment was advised but for an unknown reason did not occur. After a 27-month incubation a rabies-like illness developed. The condition worsened after hospital admission and she died 19 days after the onset of illness. On the day the woman was hospitalised cerebrospinal fluid (CSF), serum and saliva were submitted for testing. On the fourth day of her hospital admission these tests were returned with results of probable ABLV infection. Post-mortem tests were all strongly positive for ABLV. The length of incubation is unusual as classical rabies has typical incubation periods of less than 90 days.

In December 2012 an eight-year-old boy was bitten or scratched by a bat in north Queensland. He became ill three weeks later, and died on 22 February 2013. Rabies vaccine and immunoglobulin are effective in prophylactic and therapeutic protection from ABLV infection. Since the emergence of the virus, rabies vaccine is administered to individuals with a heightened risk of exposure and vaccine and immunoglobulin are provided for post exposure treatment.

ABLV is one of four zoonotic viruses discovered in Pteropid bats since 1994, the others being Hendra virus, Nipah virus and Menangle virus. Of these, ABLV is the only virus known to be transmissible to humans directly from bats without an intermediate host.

"Dr John Carnie [Victoria's Chief Health Officer] said Australian bat lyssavirus was a rare but fatal disease that could be transmitted to humans or pets bitten or scratched by bats. But he said only two cases have ever been recorded, both in Queensland. No animal or person in Victoria has ever contracted the disease, Dr Carnie said. Nine Victorian flying foxes have been found with the virus since 1996. "Under no circumstances should people handle flying foxes on their property as some diseases they carry, such as Australian bat lyssavirus, are transmissible to humans," Dr Carnie said in a statement. Only trained volunteers or workers should handle bats. Anyone who encounters a sick or injured flying fox should not try to catch it but call the DSE Customer Service Centre on 136 186."

ABLV was detected in a bat found in the Melbourne suburb of Kew in July 2011. The discovery prompted health authorities to issue warnings to Melbourne residents not to touch the creatures.[1]

ABLV was found in a horse on Queensland's Darling Downs on 10 May 2013, the horse was put down immediately. The property was then quarantined and 6 people that were believed to have been in contact with the horse were given an immediate dose of rabies vaccine and immunoglobulin.

See also

• European Bat lyssavirus 1