#13,882
In the 18 months since China launched an aggressive nationwide H5+H7 poultry vaccination program, avian influenza reports (in poultry, and in humans) have been greatly suppressed across China.
Reported H7N9 activity has been almost nonexistent since last summer, but starting in August we did see a small uptick in H5N6 outbreaks in China's poultry, and 4 human infections in the last half of 2018.
Today China's MOA is reporting their first H5N6 outbreak since the end of November, once again in Yunnan Province, which reported two outbreaks three months ago.
A poultry H5N6 subtype of high-pathogenic avian influenza epidemic occurred in Huaping County, Yunnan Province
Date: 2019-02-22 16:58 Author: Source: Ministry of Agriculture and Rural Press Office
The Information Office of the Ministry of Agriculture and Rural Affairs released on February 22nd, a high-pathogenic avian influenza epidemic of poultry H5N6 subtype occurred in Huaping County, Lijiang City, Yunnan Province.
On February 22, the Ministry of Agriculture and Rural Affairs received a report from the China Animal Disease Prevention and Control Center and was diagnosed by the National Avian Influenza Reference Laboratory. The H5N6 subtype highly pathogenic avian influenza epidemic occurred in poultry raised by a farmer in Huaping County.
The farmer stocked 2,861 poultry, 463 pigeons and 463 deaths. After the outbreak, the local authorities in accordance with the relevant plans and technical requirements for prevention and control, do a good job in the handling of the epidemic situation, have culled 559,17 poultry, all the sick and culled poultry have been harmless treatment.
While the number of H5N6 breakthrough events since China's massive poultry vaccination remain small, they appear to have increased over the past 6 months, possibly a sign of some antigenic drift in the H5N6 virus.
Adding weight to that idea, yesterday the World Health Organization released their updated semi-annual candidate vaccines For pandemic preparedness report, where they recommend development of a vaccine for a recently emerged, antigenically distinct H5N6 virus.
Antigenic and genetic characteristics of zoonotic influenza viruses and development of candidate vaccine viruses for pandemic preparedness
February 2019
The development of influenza candidate vaccine viruses (CVVs), coordinated by WHO, remains an essential component of the overall global strategy for pandemic preparedness.
Selection and development of CVVs are the first steps towards timely vaccine production and do not imply a recommendation for initiating manufacture. National authorities may consider the use of one or more of these CVVs for pilot lot vaccine production, clinical trials and other pandemic preparedness purposes based on their assessment of public health risk and need.
Zoonotic influenza viruses continue to be identified and evolve both genetically and antigenically, leading to the need for additional CVVs for pandemic preparedness purposes. Changes in the genetic and antigenic characteristics of these viruses relative to existing CVVs, and their potential risks to public health justify the need to select and develop new CVVs.
This document summarizes the genetic and antigenic characteristics of recent zoonotic influenza viruses and related viruses circulating in animals 1 that are relevant to CVV updates. Institutions interested in
receiving these CVVs should contact WHO at gisrs-whohq@who.int or the institutions listed in announcements published on the WHO website 2 .
Influenza A(H5)
Since their emergence in 1997, highly pathogenic avian influenza (HPAI) A(H5) viruses of the A/goose/Guangdong/1/96 haemagglutinin (HA) lineage have become enzootic in some countries, have infected wild birds and continue to cause outbreaks in poultry and sporadic human infections. These viruses have diversified genetically and antigenically, including the emergence of viruses with replacement of the N1 gene segment by N2, N3, N5, N6, N8 or N9 gene segments, leading to the need for multiple CVVs.
This summary provides updates on the characterization of A/goose/Guangdong/1/96-lineage A(H5) viruses and the current status of the development of influenza A(H5) CVVs.
Influenza A(H5) activity from 25 September 2018 to 17 February 2019
Three A(H5N6) human infections were detected in China during this period; no A(H5N1) human infections were reported. Since 2003 there have been 860 and 23 confirmed human infections with A(H5N1) and
A(H5N6) viruses, respectively. A/goose/Guangdong/1/96-lineage A(H5) viruses were detected in poultryand wild birds in multiple countries (Table 1).
Antigenic and genetic characteristics of influenza A(H5) viruses
The nomenclature for phylogenetic relationships among the HA genes of A/goose/Guangdong/1/96-lineage A(H5) viruses is defined in consultation with representatives of WHO, the Food and Agriculture
Organization of the United Nations (FAO), the World Organisation for Animal Health (OIE) and academic institutions 3 .
A(H5) viruses circulating and characterized from 25 September 2018 to 17 February 2019 belong to the following clades:
Clade 2.3.2.1a viruses were detected in birds in Bangladesh and India. The majority of viruses tested reacted poorly with post-infection ferret antiserum raised against the CVV derived from A/duck/Bangladesh/19097/2013 and were genetically more similar to A/duck/Bangladesh/17D1012/2018, from which a CVV is in development.
Clade 2.3.4.4 viruses were detected in three humans, birds and environmental samples in China, as well as birds in at least nine other countries in Africa, Asia and Europe (Table 1). Two of the three human infections were fatal. The HAs of the clade 2.3.4.4 viruses belonged to several genetic subgroups.
Viruses from humans, an increasing number of poultry and environmental samples from China, some poultry in Viet Nam and a wild bird (common gull) in the Russian Federation belonged to an HA subgroup not currently represented by an existing CVV (Fig. 1).
Correspondingly, viruses from this group reacted poorly to post-infection ferret antisera raised against available CVVs (Table 2). The detection in the Saratov region, Russian Federation, represents the first report of this 2.3.4.4 HA subgroup outside of Asia.
(SNIP)
Influenza A(H5) candidate vaccine viruses
Based on the current antigenic, genetic and epidemiologic data, a new A/Guangdong/18SF020/2018-like A(H5N6) CVV is proposed. The available and pending A(H5) CVVs are listed in Table 3
(Continue . . . )
The need for a new H5N6 human vaccine - and a recent uptick in H5N6 activity - may indicate that China's H5+H7 poultry vaccine may need updating as well.
Despite the dearth of H7N9 activity out of China since the vaccination campaign, a little over a year ago a single human H7N4 infection was reported (see Jiangsu China Reports 1st Novel H7N4 Human Infection) and yesterday's report also recommended the creation of a suitable candidate vaccine.
Influenza A(H7) candidate vaccine virusesA reminder that while avian flu activity has dropped globally over the past year - viruses have survived for millions of eons based on their ability to evolve and evade acquired herd immunity - and that modern vaccines and antivirals used to combat them generally have a limited lifespan.
Based on the current antigenic, genetic and epidemiologic data, a new A/chicken/Jiangsu/1/2018 (H7N4)-like CVV is proposed. The available and pending A(H7) CVVs are listed in Table 6.
We should enjoy this current lull for as long as it lasts, but we should not be surprised when the tide turns again.
