Hypothetical examples of emergency animal diseases :
• A known exotic disease agent enters a susceptible population e . g . Taura syndrome virus in Queensland ( QLD ) prawns
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• A new or emerging disease agent e . g . a new variant of a current endemic disease Yellow head virus 7 causing disease signs in QLD prawns
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• An endemic disease agent enters a previously unexposed population e . g . abalone viral ganglioneuritis ( AVG ) in the South Australian ( SA ) wild abalone population ( where the disease is not known to occur ).
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2 . Observe the pattern of cases
How is the disease occurring in the population ? There are three terms used to describe disease patterns and these terms are illustrated with “ epidemic curves ”.
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Endemic disease pattern Cases occur regularly at a reasonably constant level e . g . Amoebic gill disease in Tasmanian salmon ( Figure 2 ).
Number of new aquatic cases
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Months
Figure 2 . Epidemic curve of an endemic disease
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