With more than 20 farms confirmed as having avian flu (apparently a hodgepodge of H5N2, H5N8, and a new H5N2), and with more than 40 farms under investigation (see Taiwan’s Avian Flu Outbreak Spreads To More Farms) this OIE notification of 5 outbreaks of HPAI H5N2 among geese and ducks across two counties will likely expand over the next few days.
We do get a description, via the Epidemiological notes, that this `new’ H5N2 virus is apparently a mixture of the Korean H5N8 and a strain of H5N2 previously seen in China.
Being a new reassortant of H5N2, we’ll have to watch it carefully to see if it presents any greater threat to poultry, or humans, than have the other HPAI H5N2 subtypes that have been encountered.
Source of the outbreak(s) or origin of infection
- Unknown or inconclusive
Epidemiological commentsAbnormal mortalities in 4 goose farms in Yun-Lin County and an acute egg drop syndrome in a layer duck farm in Ping-Tung County were noticed early January 2015. Local disease control center staff went to these farms to conduct movement restrictions and clinical inspection and then sent dead geese and layer ducks samples to the National Laboratory for diagnosis.
Specific RNA product of avian influenza virus was detected and subtyped as H5N2 by RT-PCR. Highly pathogenic avian influenza strain was confirmed by the National Laboratory based on sequencing analysis of HA0 cleavage site. It is worth noting that H and N genes of these isolates are different from the H5N2 strains previously isolated in Taiwan.
The homology of H5 between the isolates from these infected farms and the South Korea 2014 H5N8 strain is near 99%. The homology of N2 between the isolates from these infected farms and the China 2011 H5N2 strain is 96%. This H5N2 strain is obviously novel to Taiwan.
All the geese and ducks on the infected farm will be culled. The actual number of culled geese and ducks will be available when stamping out will finish and be reported in the next follow-up report. Thorough cleaning and disinfection will be conducted after stamping out operation. Surrounding poultry farms within a 3 km radius of the infected farm are under intensified surveillance for 3 months.
- Stamping out
- Movement control inside the country
- Disinfection of infected premises/establishment(s)
- Vaccination prohibited
- No treatment of affected animals
Measures to be applied
- No other measures