Information received on 12/12/2008 from Dr Thomas Sit, Assistant Director , Inspection & Quarantine, Agriculture, Fisheries and Conservation Department, Cheung Sha Wan , Hon Kong , Hong Kong (P.R. China)

Summary

Report type Immediate notification
Start date 08/12/2008
Date of first confirmation of the event 08/12/2008
Report date 12/12/2008
Date submitted to OIE 12/12/2008
Reason for notification Reoccurrence of a listed disease
Date of previous occurrence 10/2008
Causal agent Highly pathogenic avian influenza virus
Serotype H5N1
Nature of diagnosis Suspicion, Clinical, Laboratory (basic), Laboratory (advanced), Necropsy
This event pertains to the whole country

New outbreaksSummary of outbreaks Total outbreaks: 1
Outbreak Location and Affected population HONG KONG (Yuen Long) : There were 67,968 chickens and 25,680 fertilized eggs on this index farm with compulsory avian influenza vaccination program and strict biosecurity measures in place. Unusual mortality was first noted in the sentinel chickens on 8 December. Clinical signs observed included rales, dyspnoea, cyanosis and oedema of the comb and wattle with yellow creamy nasal discharge. Cloacae swabs and chicken carcasses were collected on the same day for laboratory testing. Culling of the chickens and eggs began on 9 December and finished on 10 December.

Total animals affected Species Susceptible Cases Deaths Destroyed Slaughtered
Birds 67968 285 285 67683 0

Outbreak statistics Species Apparent morbidity rate Apparent mortality rate Apparent case fatality rate Proportion susceptible animals lost*
Birds 0.42% 0.42% 100.00% 100.00%

* Removed from the susceptible population through death, destruction and/or slaughter


EpidemiologySource of the outbreak(s) or origin of infection Under investigation

Epidemiological comments On 11 December 2008, 17,960 chickens were also culled in a chicken farm within the 3-km-radius infected zone. Poultry in the wholesale market (10,704 chickens, 2900 pigeons, 1,420 pheasants, 3,100 silky chickens and 370 chukars) were also culled on 11 December 2008. Initial surveillance using PCR did not detect any H5 in all the other poultry farms in Hong Kong (virus isolation pending). Advice was given to these unaffected chicken farms to administer a booster vaccine immediately. Importation of live poultry was banned and movement of poultry, eggs, fodder and other things in local farms is prohibited for 21 days as from 09 December 2008.


Control measuresMeasures applied Stamping out
Quarantine
Movement control inside the country
Screening
Zoning
Vaccination in response to the outbreak (s)
Disinfection of infected premises/establishment(s)
No treatment of affected animals

Measures to be applied No other measures



Diagnostic test resultsLaboratory name and type Tai Lung Veterinary Laboratory, Agriculture, Fisheries and Conservation Department (National laboratory)
Tests and results Species Test Test date Result
Birds immunohistochemical test 08/12/2008 Positive
Birds polymerase chain reaction (PCR) 08/12/2008 Positive
Birds virus isolation 11/12/2008 Positive



Future ReportingThe event is continuing. Weekly follow-up reports will be submitted.