The Australian Immunisation Handbook 10th Edition 2013

4.16.3 Epidemiology
The epidemiology of rabies varies depending on the lyssavirus species and the
animal host. Lyssaviruses have been found in all continents, except Antarctica. 11
Rabies that is due to the classical rabies virus and occurs in land dwelling
(terrestrial) mammals is present throughout much of Africa, Asia, the Americas
and Europe, where the virus is maintained in certain species of mammals,
particularly dogs. In countries where rabies vaccination of domestic animals is
widespread (North America and Europe), wild animals such as raccoons and
foxes are important reservoirs. The continual maintenance of rabies in animal
populations in these countries is referred to as enzootic rabies. Australia, New
Zealand, Japan, Papua New Guinea and Pacific island nations are currently free
of rabies in terrestrial mammals. However, a country’s status can change at any
time. For example, in 2008 on the island of Bali, Indonesia, rabies was reported
in dogs, with cases later reported in humans. 12 Prior to this, Bali had been
considered free of rabies, although rabies was known to occur in other areas of
Indonesia. 13
In some parts of the world, bats are important reservoirs of classical rabies
as well as other lyssaviruses, with bat lyssaviruses found in areas that are
considered free from terrestrial rabies. ABLV was first reported in bats in 1996;
since then, two cases of fatal encephalitis caused by ABLV have been reported
in Australians, one in 1996 and the other in 1998. 2,14 Both patients had been
bitten by bats. Evidence of ABLV infection has since been identified in all four
species of Australian fruit bats (flying foxes) and in several species of Australian
insectivorous bats. 4,15-17 It should therefore be assumed that all Australian bats
have the potential to be infected with ABLV. Different regions in Australia have
reported higher risk of potential ABLV exposures. 18,19 ABLV has not been isolated
from bats outside Australia. However, closely related lyssaviruses are found in
bats in other countries. For example, European bat lyssavirus 1 and European
bat lyssavirus 2 have been isolated in bats in some parts of Europe. Four human
deaths from European bat lyssavirus variants have been reported in Europe, all
with no record of prophylactic rabies immunisation. 3,5 As such, bats anywhere in
the world should be considered a potential source of lyssaviruses and a potential
risk for acquiring rabies, depending on the exposure.
Information on the global occurrence of rabies can be obtained from reputable
international authorities. 11,20,21 In addition, advice on potential lyssavirus
exposures and their management should be obtained by contacting the relevant
Australian state/territory health authorities (see 4.16.12 Public health management
of lyssavirus infections below).
354 The Australian Immunisation Handbook 10th edition