Wednesday, November 30, 2016

Korea: Epidemiological Investigation Committee Meeting On H5N6

H5N6 In Korea - Credit Japan's MAFF


Korea's Ministry of Agriculture (MAFRA) has published notes from yesterday's meeting of their AI ​​Subcommittee which met to discuss the epidemiology and changing genetics of their rapidly spreading H5N6 virus, and their response to it.

The committee concluded that the virus was introduced to South Korea via migratory birds - likely from China - bringing in a reassorted virus.
As we've discussed previously, Korea's H5N6 virus HA and NA genes are most similar to those previously detected in a wild bird in Hong Kong, but its internal genes have evolved - likely through reassortment. 

The AI committee also makes note of the high mortality observed in both ducks and chickens, characterized by `rapid clinical symptoms including sudden death and neurological symptoms'.

While ducks haven't been totally immune to H5N6 in the past, we have seen multiple reports of asymptomatic carriage of the virus, including:
Many of Korea's recent detections have been in dead, or dying, waterfowl, including multiple varieties of ducks.  Whether this signifies a change in the pathogenicity of the virus, or simply varied susceptibility between different types of aquatic birds, is uncertain. 

The committee also warns of the `possibility of continuous propagation among wild birds' of the virus, and the high risk of spreading the virus via the movement of people, poultry, or vehicles between farms.  

"The outbreak of this highly pathogenic AI (H5N6 type), estimation of influx from migratory birds, and prompt response to strong initial action"

 Date 2016-11-30 10:00:00

On November 29th, the AI ​​Subcommittee of the Epidemiological Investigation Committee (Chairman Kim Jae-Hong, Vice President of the College of Veterinary Medicine, Seoul National University) was held on the 29th of November in connection with the highly pathogenic avian influenza (HPAI H5N6 strain) .

* Epidemiological Investigation Committee (AI Committee): A total of 32 persons, including professors from veterinary schools and medical schools, related ministries such as the Ministry of Environment,
The Epidemiologic Investigation Committee has been investigating the occurrence, epidemiology, viral genetic analysis results, etc. of the situation that occurred since Nov. 16 on Nov. 16 in Chonnam Hainan (laying hens) and Chungbuk Voice (duck duck) There was intensive discussion of
The Epidemiologic Investigation Committee estimated that this highly virulent AI (H5N6 type) occurred for the first time in Korea, and that viruses originating from overseas countries such as China were introduced through migratory birds and recombinant in the process of domestic influx.

Genetic analysis of H5N6 virus (6 cases *) isolated from domestic wild birds and poultry showed similar to H5N6 virus which was popular in Guangdong province, Hong Kong, China

  • * Cheonan wild algae feces (2), Iksan Mangyeong river white cheek duck duck, voice duck duck, Haenam laying hen,
  • ** Genetic analysis of six highly pathogenic AI (H5N6) viruses showed that H5 and N6 genes had the highest homology with the virus isolated from Hong Kong wild bird
  • *** The Chinese H5N6 virus and the wild-type AI virus have been reassembled into a genetically engineered virus
  • **** So far, some internal genes (PA, NS) are different from each other in isolate viral genome comparison. In theory, up to 6 different viruses can be detected, and 11.29. (5), and (5)

In addition, it is estimated that the first occurrence of the farms occurred in the vicinity of the farms due to the migration of migratory birds and farmland around the farms, and the influx of wild birds such as wild birds, .

* A number of migratory birds were observed around the first farms such as Chonnam Hainan, Chungbuk Province, Muan, Jeonbuk Gimje, and the farmers cultivated in farmland around farms.

It was judged that there was a possibility of nearby radio propagation and mechanical propagation when the occurrence situation of the farms occurred in the concentrated farming area and some areas.

- However, it was suggested that the occurrence of some areas in the context of mechanical propagation needs to be confirmed through future gene analysis.

* Voice Vigorous duck farm near the first report farm densely populated farmers nearby, it is estimated to be easily propagated to neighboring farms by nearby radio (within the 500m to No. 8, 500m to 3km within the 25th duck farmhouse location)
The Epidemiologic Investigation Committee noted that the incidence of this highly pathogenic AI is occurring at the same time in various regions, and most of the chicken and ducks are showing rapid clinical symptoms including sudden death and neurological symptoms, and the occurrence of the disease is continuing.
* (Duck) Rapid increase of mortality, nervous symptoms such as turning and quadriceps, abrupt decrease of egg production rate, (chicken)
In addition, the Epidemiologic Investigation Committee emphasized the possibility of continuous propagation among wild birds and the risk of mechanical propagation such as people and facilities related to livestock.
① There is a possibility of sustainable occurrence due to wild birds. In order to prevent the blocking of wild birds, autonomous disinfection of farmers,

② Because the risk of horizontal propagation by contaminated person and vehicle is very high, it is necessary to promptly control disruption and early discovery of emergent farms and epidemiological farms for strong interception response measures. Dispossession

③ Preventive measures such as more thorough monitoring and management of poultry such as live chickens and ducks in the garden type, small farm and traditional market in the area where they occur

In addition, the quarantine headquarters held the Epidemiological Investigation Committee meeting from time to time in consideration of the occurrence situation, and consulted and consulted about the matters necessary for the promotion of epidemiological investigation and analysis.

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