The Australian state government of Victoria said that the rapidly spreading bird flu virus had been detected on a duck farm near Melbourne, close to five poultry farms where the virus had already spread.
This duck farm is located within a quarantine zone imposed by the authorities around other affected farms, and the government said that detecting infections there was not surprising.
Authorities are trying to contain the outbreak of two strains of bird flu near Melbourne: the H7N3 strain, which appeared on four poultry farms and a duck farm, and the H7N9 strain, which appeared on a poultry farm about 130 kilometers to the southwest.
The two strains differ from the H5N1 strain, which has infected billions of wild and farm animals worldwide, caused disruptions to food supply chains, and raised fears of human-to-human transmission.
Federal Agriculture Minister Murray Watt said this week that about one million of the 21 to 22 million egg-laying hens in Australia have been or will be culled on farms with two infections in order to contain the virus.
Coles, the country’s second-largest supermarket chain, introduced restrictions allowing each customer to buy two cartons of eggs in most stores this week, but other retailers did not follow suit.
A body representing the egg trade in Australia said that the outbreak of the virus had caused a disruption in supplies, but there was no general shortage of eggs.
Authorities say there is no danger to individuals from eating duck and chicken eggs and their meat.