Fruitbats In Australia – Credit Wikipedia
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Rabies - the best known of the Lyssaviruses - is believed responsible for roughly 55,000 deaths each year around the world.
According to the World Health Organization rabies FAQ, ` . . . rabies still poses a significant public health problem in many countries in Asia and Africa where 95% of human deaths occur even though safe, effective vaccines for both human and veterinary use exist’.
In Greek mythology, Lyssa was the Goddess of rage or madness, hence the adoption of name Lyssavirus for the genus that includes rabies, and others including the Australian bat lyssavirus (ABLV), Duvenhage virus, European bat lyssaviruses 1 and 2, and Lagos bat virus.
Australia is somewhat unique in that it is one of the few regions in the world where rabies has never been detected. Others include New Zealand, Iceland, and the Hawaiian islands, while elsewhere rabies has been eliminated in a number of other countries.
Australia does have Australian Bat Lyssavirus (ABLV), which is a close cousin to the rabies virus.
First identified in 1996, ABLV is known to be carried by at least four varieties of flying foxes/fruit bats and one species of insectivore microbat in Australia (see MMWR 1996 Dispatch Encephalitis Caused by a Lyssavirus in Fruit Bats in Australia).
Up until this past week, only two human infections with ABLV have been reported, both fatal, and both in Queensland. In one of those cases, symptoms did not appear until two years after the bat exposure, a phenomenon that has rarely been reported with rabies as well.
This week, we learn of a third case, an 8-year old boy who is in a coma in a Queensland hospital.
Queensland child critical after contracting deadly bat lyssavirus
- From: AAP
- February 15, 2013 3:28PM
AN eight-year-old Queensland boy is critically ill with a bat-borne virus that causes fits, paralysis and death.
According to this article, this latest case, on top of the infrequent outbreaks of Hendra virus (see Queensland: A Hendra Watch & A New Vaccine) has already led to renewed calls for the culling of bats, a highly divisive topic in Australia.
There are many who fear that the indiscriminate culling of bats would simply increase human exposure to bat-borne viruses, and the loss of native bats could upset the ecological balance.
For now, the Australian government advises:
The best protection against being exposed to the virus is for members of the community to avoid handling any bat or flying fox.
The Australian Government’s Immunization Handbook has some extensive information on ABLV, its prophylaxis, and treatment.
3.1 Australian bat lyssavirus infection and rabies
VirologyAustralian bat lyssavirus (ABL) and rabies virus are members of the family Rhabdoviridae, genus Lyssavirus. There are 7 known genotypes within the genus Lyssavirus; ABL (genotype 7) is more closely related to rabies virus (genotype 1) than any of the other 6 genotypes.
Clinical features
Based on the 2 recognised human cases of ABL infection, it has to be assumed that ABL has the same clinical features as rabies. The incubation period of rabies is usually 3 to 8 weeks, but can range from as short as a week to, on rare occasions, several years. The risk of rabies is higher, and the incubation period shorter, after severe and multiple wounds proximate to the central nervous system (such as on the head and neck) and in richly innervated sites (such as the fingers).
Typically, in the prodromal phase of rabies, which lasts up to 10 days, the patient may experience non-specific symptoms such as anorexia, cough, fever, headache, myalgia, nausea, sore throat, tiredness and vomiting. Paraesthesiae and/or fasciculations at or near the site of the wound may be present at this stage. Anxiety, agitation and apprehension may also occur.
Most rabies patients present with the furious or encephalitic form. In the encephalitic phase, objective signs of nervous system involvement include aerophobia, hydrophobia, bizarre behaviour, disorientation and hyperactivity. Signs of autonomic instability such as hypersalivation, hyperthermia and hyperventilation may occur.
The neurological status of the patient deteriorates over a period of up to 12 days, and the patient either dies abruptly from cardiac or respiratory arrest, or lapses into a coma. Rabies is almost invariably fatal.
Epidemiology
Rabies is endemic throughout much of Africa, Asia, the Americas and Europe, where the virus is maintained in certain species of mammals.
Australia, New Zealand, Japan, Papua New Guinea and Pacific Island nations are free of endemic rabies but it must be remembered that this can change at any time. For example in 2008, rabies was reported in dogs on the island of Bali, Indonesia. Prior to this, Bali was considered to be free of rabies although rabies was known to occur in other areas of Indonesia. Human rabies characteristically follows a bite from a rabid animal, most frequently a dog, but in some parts of the world, other animals, such as jackals and bats, are important sources of exposure. In countries where rabies vaccination of domestic animals is widespread (North America and Europe), wild animals such as raccoons and foxes are important reservoirs.
Cases of rabies after animal scratches, the licking of open wounds or saliva contact with intact mucous membranes are very rare. Cases have been recorded after exposure to aerosols in a laboratory and in caves infested with rabid bats, and cases have been reported following tissue transplantation from donors who died with undiagnosed rabies.
(SNIP)
In Australia, 2 cases of a fatal rabies-like illness caused by ABL have been reported, one in 1996 and the other in 1998.6 Both patients had been bitten by bats. Evidence of ABL infection has since been identified in all 4 species of Australian fruit bats (flying foxes) and in several species of Australian insectivorous bats. It should therefore be assumed that all Australian bats have the potential to be infected with ABL.
