General information
Report type: Immediate notification
Reason for notification: Recurrence of an eradicated strain
Reported: 9 Dec 2023
Confirmation date: 8 Dec 2023
Started: 6 Dec 2023
Date of last occurrence: 5 Dec 2022
Disease: Influenza A viruses of high pathogenicity (Infection with)
(non-poultry including wild birds) (2017-)
Causal agent: Highly pathogenic avian influenza virus
Genotype/serotype/subtype: H5N1
Nature of diagnosis: Laboratory test
Animal type: Terrestrial
Disease category: WOAH(OIE) listed disease
Report status: Validated
Event status: Ongoing
Outbreak locations: Hong Kong, Yuen Long

Affected animals
Reported date: 9 Dec 2023
Species / Susceptible / Cases / Deaths / Killed and disposed of /
Slaughtered or killed for commercial use / Vaccinated
Wildlife (species unspecified) (wild) / - / 1 / - / - / - / -

Affected population description
An intensive surveillance system is in place for avian influenza virus
including screening at Mai Po Nature Reserve in Hong Kong. One
environmental sample (wild bird fecal dropping) collected by the
University of Hong Kong on 6 Dec 2023 was tested positive for H5N1.

Epidemiology
Source of event or origin of infection: Unknown or inconclusive
Epidemiological unit: Natural park
Epidemiological comments: An intensive surveillance system is in place
for avian influenza virus including screening at Mai Po Nature Reserve
in Hong Kong. Among the environmental samples collected by the
University of Hong Kong on 6 Dec 2023, a sample of wild bird fecal
dropping has been confirmed to be positive for H5N1. The organization
managing the reserve has stepped up cleaning and disinfection of
visitor facilities. The government is closely monitoring the situation
of the birds in the reserve. There are no poultry farm within 3 km
(1.86 mi) of the reserve. The government has closely monitored the
situation of the local poultry farms and wholesale market. Poultry
farmers, pet bird shop owners and licensed holders of pet poultry and
racing pigeons are reminded from time to time to ensure that proper
precaution against avian influenza have been implemented.

Control measures at event level
Wild animals, applied: Disinfection, screening

Diagnostic test result
Test name / Laboratory / Species sampled / Number of outbreaks sampled
/ First result date / Latest result date / Result
Gene sequencing / Centre of Influenza Research, School of Public
Health, Li Ka Shing Faculty of Medicine, University of Hong Kong /
Wildlife (species unspecified) / 1 / 8 Dec 2023 / 8 Dec 2023 /
Positive
Real-time reverse transcription polymerase chain reaction (rRT-PCR) /
Centre of Influenza Research, School of Public Health, Li Ka Shing
Faculty of Medicine, University of Hong Kong / Wildlife (species
unspecified) / 1 / 8 Dec 2023 / 8 Dec 2023 / Positive