[Source: ProMedMail.org, full page: (LINK). Edited.]
Published Date: 2014-05-09 10:02:31 / Subject: PRO/AH/EDR> Avian influenza (61): Laos, HPAI H5N6, poultry, OIE, RFI / Archive Number: 20140509.2461275
AVIAN INFLUENZA (61): LAOS, HPAI H5N6, POULTRY, OIE, REQUEST FOR INFORMATION
A ProMED-mail post http://www.promedmail.org / ProMED-mail is a program of the International Society for Infectious Diseases http://www.isid.org
Date: Thu 8 May 2014 / Source: OIE, WAHID (World Animal Health Information Database), weekly disease information 2014; 27(19) http://www.oie.int/wahis_2/public/wahid.php/Reviewreport/Review?page_refer=MapFullEventReport&reportid=1521 7
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Communicated by: ProMED-mail promed@promedmail.org
[According to the immediate notification from Laos dated 31 Mar 2014, the outbreak statistics were the following:
Species / Susceptible / Cases / Deaths / Destroyed / Slaughtered
Birds / 5142 / 457 / 457 / 543 / 0
The affected population was described as, "affected birds, newly introduced into the village one week before the outbreak."
The "start" of the outbreak was given as 13 Apr 2014, "pre-confirmation" on 18 Apr 2014, when the Laos Laboratory performed the real-time PCR test, preliminarily concluding that the virus was HPAI H5N1.
Out of the 5142 susceptible birds on the farm, reportedly 457 died, 543 were destroyed, none reported as slaughtered. This means that 4152 contact birds on the farms have been kept alive.
Two questions arise:
- What were the considerations to declare the event as "resolved"? Has surveillance been applied, regionally?
- What was the origin of the introduced affected birds, reportedly causing the outbreak? Were they introduced from another location within Laos or was their introduction inter-boundary? In case the latter is the case, where from? Authorised or otherwise?
The designation of the isolate, by the Australian reference laboratory, as a highly pathogenic H5N6 strain is rather unique.
LPAI H5N6 strains have been recorded in wild birds (particularly mallards) in several continents in the past; H5N6 virus has been used as a poultry vaccine strain to produce DIVA ("differentiating infected from vaccinated animals") vaccines against HPAI H5N1.
Recently, an LPAI H5N6 virus was reported to cause (subclinical) infection in poultry and a fatal human case in Sichuan, central China (see ProMED-mail post 20140505.2451125 and OIE report at http://tinyurl.com/m6zfvoe ).
It would be interesting to check if the Chinese isolate was laboratory confirmed for its pathogenicity for chickens, and to investigate the genetic relationship between the H5N6 strains from China and Laos.
It would also be interesting to note if a poultry vaccine, including AI H5N6 vaccine strain, has been applied in Laos.
Re Laos' OIE reporting history, please refer to Mod.CRD commentary in ProMED-mail post 20140401.2371131. - Mod.AS A HealthMap/ProMED-mail map can be accessed at: http://healthmap.org/promed/p/146.]
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