The outbreak of highly pathogenic bird flu in Japan has almost ended after having swept across the country since last November.
This season, bird flu was discovered in 18 prefectures, including Chiba and Ibaraki, which are known for poultry farming.
The number of chickens and ducks that were culled this season in order to prevent the further spread of infections stood at around 9.87 million as of Saturday, up drastically from the previous record high of some 1.83 million such birds put down between the autumn of 2010 and the spring the following year.
The large-scale cullings are also said to be responsible for the recent rises in egg prices.
Chiba Prefecture, one of the country's largest producer of chicken eggs, lifted restrictions on transferring eggs and chickens from farms on April 20.
After a series of infections was found within Chiba from late last year, a third of all egg-laying hens, or some 4.56 million chickens, were culled in the eastern prefecture.
The culling triggered rises in egg prices, which had been known to remain almost at the same level without any major fluctuations.
Japanese egg seller JA.Z-Tamago Co.'s market price of medium-sized chicken eggs in Tokyo came to ¥250 per kilogram on Friday, 50% higher than a year ago.
An official at a major egg dealer said, "Wholesale prices rose as egg supplies fell short due to the spread of avian influenza."
The culling of close to 10 million chickens and ducks reflected the spread of bird flu in the Kanto eastern region and through wide areas west of Kanto, as well as the enlargement of poultry farms mainly due to a shortage in successors.
The average number of egg-laying hens at farms stood at some 67,000 in 2019, up 50% from 2009.
Chiba Prefecture saw three cases this season in which over 1 million chickens and ducks were culled.
Japan's farm ministry is urging poultry farmers to implement thorough measures to prevent the introduction of viruses, in order to prepare for the next season.
The bird flu virus is thought to be brought into the country by migrating birds from the Eurasian Continent and spread by small animals that came into contact with such birds' droppings, as well as by people and vehicles entering and leaving chicken farms.
Many farms, where chickens and ducks were infected with avian influenza, had openings in the facilities that allowed the entry of small animals.
The ministry has repeatedly asked chicken farms to fix such openings, thoroughly disinfect facilities and check all bird nets.
It has launched discussions to require chicken farms to follow hygiene control standards set by the central government as an eligibility condition for receiving subsidies, in order to raise their awareness.
"As wild birds in a flock are possibly giving the virus to one another, it is important for us to stay vigilant," said Hokkaido University professor Yoshihiro Sakoda, an expert of avian influenza.
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