A fifth poultry farm near Melbourne has been infected with a highly pathogenic strain of bird flu. The farm is close to three others where an H7N3 strain of avian influenza had already spread and all 600 thousand chickens at the farms will be culled. Another farm in Victoria has had an outbreak of a different strain, neither is the same as the H5N1 type that has spread globally through bird and mammal populations and even into humans.
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00:00 We have learned that in previous outbreaks in poultry that these viruses do sometimes
00:07 spread.
00:08 And if you look at the approach that was taken by Agriculture Victoria, rather than only
00:12 quarantine one farm, they actually set out quite a large control area in anticipation
00:17 of something like this happening.
00:19 How has it got into the chicken population?
00:22 So this virus is probably coming from Australian wild birds.
00:26 So in our wild bird population we actually have quite a lot of avian influenzas, but
00:31 the strains that we have are benign.
00:34 Sometimes these benign strains go from wild birds into chicken populations and there they
00:38 evolve or mutate to become these very deadly viruses.
00:43 And that's most likely what has occurred here.
00:45 So it's not come from migratory birds then bringing it from other parts of the world?
00:50 No, it is not.
00:51 It is most closely related to viruses that are circulating in Australian wild birds.
00:55 Okay, as I mentioned, it's not the strain that has caused so many problems and in fact
01:02 the first person has died in Mexico from that.
01:06 So what does this strain or these two strains do to birds?
01:12 So these highly virulent strains, these strains that are quite nasty, are actually really
01:16 terrible for birds.
01:18 And this includes both poultry as well as wild birds.
01:21 It can make them really sick and it can cause a lot of mortality, so it can kill them.
01:25 Okay, so what is the biosecurity that goes with locking down a chicken farm?
01:34 So it's not just one chicken farm, it's actually quite a large area that is now under biosecurity
01:40 measures.
01:41 So Agriculture Victoria has put in a housing order that means poultry in certain parts
01:46 of the state must now be kept inside, so you can't have free-range chickens outside anymore.
01:52 There are also movement restrictions and control, that means you can't move any chickens around,
01:58 you also can't move around things like feed or equipment between farms to try to prevent
02:04 the spread.
02:05 And what about the workers?
02:06 We saw some putting on biohazard suits, they have to fully suit up, do they, all the time?
02:11 So it's really important for any workers that may be exposed to this virus to wear appropriate
02:16 PPE.
02:17 While these Australian lineage viruses of the H7 have not caused human infections, we
02:22 do know that H7 has caused human infections overseas, so it's very important that all
02:27 poultry workers who are dealing with infected farms be wearing PPE.
02:31 As I mentioned, something like 600,000 chickens will be culled at these farms.
02:36 What does the farm do then?
02:37 Does it have to wait for a period before it can restock?
02:41 So all the poultry will need to be culled and the premises will need to be cleaned,
02:47 and only once the farm passes the OK from Agriculture Victoria can they potentially
02:52 start restocking again.
02:55 Would you, given the evidence of other outbreaks in other countries, would you think that this
03:02 can be locked down and stopped in its tracks, or is it something that we will be dealing
03:07 with over the coming months and years?
03:10 So Australia has a really good record of eradicating these homegrown domestic variants of avian
03:16 influenza in poultry.
03:17 You may remember that in 2020 we actually had quite a significant outbreak of avian
03:22 influenza around Lethbridge, also caused by these homegrown H7 viruses, and these viruses
03:29 were eradicated from poultry population.
03:31 And so I have great confidence that Agriculture Victoria will lead a really effective response.
03:37 There is of course concern about the viruses that are circulating overseas.
03:42 Those viruses, that strain H5N1, is much more difficult to control because it actually replicates
03:49 and spreads quite well in wildlife, so that's wild birds and mammals, and is not so sort
03:54 of adapted to poultry as these H7 viruses are likely to be.
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