Summary
Report type: immediate notification
Started: 16 Jan 2023
Confirmed: 19 Jan 2023
Reported: 20 Jan 2023
Reason for notification: new strain in the country
Causal agent: highly pathogenic avian influenza virus
Serotype: H5N2
Nature of diagnosis: clinical, laboratory
This event pertains to a defined zone within the country.

Outbreak location: Saiki-City 1, Saiki, Oita
Started: 16 Jan 2023
Epidemiological unit: farm
Animals affected:
Species / Susceptible / Cases / Deaths / Killed and disposed of /
Slaughtered or killed for commercial use / Vaccinated
Birds / 55 400 / 160 / 160 / 55 240 / 0 / 0

Epidemiology
Source of the outbreak(s) or origin of infection: unknown or
inconclusive
Epidemiological comments: The outbreak of Saiki-City1 (H5N2 Case
1/HPAI Case 60): On 16 Jan 2023, a livestock hygiene service centre
(LHSC) in Oita Prefecture received a notification from a domestic
broiler farm on an increase in the number of dead birds. The samples
were collected from dead birds in the farm by prefectural veterinary
officers and tested positive for influenza A virus by viral antigen
rapid test. On 17 Jan 2023, the LHSC conducted RT-PCR and RRT-PCR
tests and confirmed that the subtype was H5. On the same day, stamping
out of all birds in the affected farm (12 900 birds) and 2
epidemiologically linked farms (42 500 birds) was completed. On 18 Jan
2023, relevant control measures were completed. On 19 Jan 2023, the
National Institute of Animal Health (NIAH) conducted the sequencing
and confirmed that the subtype of the virus was H5N2 and the causative
virus was determined as high pathogenicity avian influenza. Movement
restriction and shipment restriction are imposed on farms within a
radius of 3 km (1.86 mi) and 10 km (6.21 mi) of the affected farms,
respectively.

Control measures at event level
Domestic control measures applied: screening, stamping out,
traceability, quarantine, official disposal of carcasses, by-products,
and waste, movement control, disinfection, ante and post mortem
inspections
Wild control measures applied: screening

Diagnostic test results
Laboratory name and type / Species / Outbreaks / Test / Test date /
Result
National Institute of Animal Health, National Agriculture and Food
Research Organization / birds / 1 / gene sequencing / 19 Jan 2023 /
positive
Livestock Hygiene Service Centre / birds / 1 / real-time reverse
transcription polymerase chain reaction (rRT-PCR) / 17 Jan 2023 /
positive
Livestock Hygiene Service Centre / birds / 1 / reverse
transcription-polymerase chain reaction (RT-PCR) / 17 Jan 2023 /
positive