#17,316
Although it can be a bit misleading, the above map shows the reported incidence of zoonotic HPAI around the globe since October 1st of 2022. While the heaviest concentrations are depicted in Europe, North America, Japan, and along the Pacific coast of South America, vast swaths of the globe show little or no activity.
The reality is, many countries - either due to a lack of surveillance and testing ability, or for economic or political reasons - don't report outbreaks.
- Countries like Egypt, and Indonesia, declared HPAI H5 endemic years ago, and are now only required to file reports every 6 months (see Revisiting Egypt’s Murky H5N1 Battle).
- China, which has always held avian flu outbreak information close to the vest, last reported an HPAI H5 outbreak on their MOA page in 2021.
- In many countries, farmers have been known to hide outbreaks from their governments, for fear of losing their entire flock to culling (see Vietnam: Dozens Of Sacks Of H5N6 Infected Chickens Dumped on Nghe An Beach).
- And in remote regions, such as the interior of Africa, Asia, or South America (see The Challenge Of Avian Flu Surveillance In Sub-Saharan Africa), there is little or no infrastructure for testing and reporting.
Countries are essentially on the `honor' system to report outbreaks in poultry, wild birds, mammals, and even humans. There is currently little that international organizations like the FAO, WOAH, and WHO can do to ensure compliance.
Complicating matters further, only HPAI H5 and H7 viruses are considered `reportable', even though other subtypes can pose a risk to human health. As a result, outbreaks of LPAI H9N2, LPAI H3N8, or LPAI H10N3 often go unreported.
Over the weekend the FAO posted their monthly summary of global avian flu (with zoonotic potential) activity. Due to its length I've only posted some excerpts, so follow the link to read it in its entirety. I'll have a brief postscript after the break.
Global Avian Influenza Viruses with Zoonotic Potential
23 February 2023, 17:00 hours; Rome
Overview
This update covers avian influenza viruses with zoonotic potential occurring worldwide, i.e. H5Nx, H7Nx high pathogenicity avian influenza (HPAI) viruses and H3N8, H5Nx, H6N1, H7Nx, H9N2, H10N3, H10N7, H10N8 and H11 low pathogenicity avian influenza (LPAI).
Specific information is available for Avian Influenza A(H7N9) virus viruses and Sub-Saharan Africa HPAI in related FAO Avian Influenza situation updates.
HPAI outbreaks in animals officially reported since last update (26 January 2023): in total, 1098 outbreaks have been reported in four geographic regions caused by HPAI (19), H5 HPAI (33), H5N1 HPAI (1073), H5N2 HPAI (5), H5N5 (1) (see Table 1 for details).
LPAI events in animals officially reported since last update (26 January 2023): 4 new events were reported (see Table 2 for details).
Number of human cases officially reported since last update (26 January 2023): 1 new event.(SNIP)
Table 3. Epidemiological overview for avian influenza viruses with zoonotic potential
Subtype
Epidemiological Situation Overview
H3N8 LPAI
- In April 2022, the first human infected with avian influenza A H3N8 virus was reported in Henan Province, China. In May 2022, a 5-year-old boy was diagnosed with influenza A(H3N8) infection in Changsha City, Hunan Province, China. To date, only two confirmed human cases with influenza A(H3N8) virus have been reported to WHO [reference1; reference2]. Genetically similar H3N8 viruses were detected in chickens at live poultry markets and chicken farms in Hong Kong, China [reference].
- H3 LPAI viruses are commonly found in waterfowl populations in many regions of the world.
H5N1 HPAI (1997)
- The ‘classic bird flu’, a high pathogenicity AI virus that can occasionally infect humans
- Endemic in several countries in Africa, Americas, Europe, and Asia
- Different clade reassortments including 2.3.2.1 and 2.3.4.4 clades
- October 2020: one influenza A(H5N1) case in Lao People's Democratic Republic in a one-year old female that was exposed to backyard poultry. Since 2003, a total of 868 cases of influenza A(H5N1) human infection have been reported worldwide.
H5N1 HPAI (2020-onwards)
- These H5N1 viruses were first detected in Europe in October 2020 after reassortment of H5N8 viruses with wild bird lineage N1 viruses.
- Since Autumn 2021 there has been domination of the H5N1 clade 2.3.4.4b viruses with a relatively stable genotype
- These viruses have spread globally with the movement of wild migratory birds and have reassorted with local low pathogenic viruses in many places.
- In Africa these viruses were first detected in early 2021.
- In late 2021 they were introduced into Asia
- In late 2021 introduction into the Americas.
- In 2022 Extensive infection in coastal seabirds and mass die offs of numerous ecologically important species of wild bird.
- In mid 2022 the virus was first detected in Central America and late 2022 in South America in wild birds and poultry with the southwards migration of wild birds.
- In many areas these viruses have been maintained in poultry populations and there have been re introductions with wild bird movement.
- There have been a number of mammalian infections reported particularly in scavenging species
- For the updated list of bird species affected by H5Nx HPAI see HERE.
- For an updated list of mammalian species infected with H5Nx (all clades) see HERE at bottom of the page.
- For an updated list of confirmed human cases with A(H5N1) see HERE.
H5N8 HPAI (2014)
- New strain spread from Far East to Central Asia, Middle East, Western Europe and Africa in June 2016 – September 2018: 52 countries affected.
- Since December 2019: upsurge in Europe, Central and East Asia, and Middle East. H5N1 and H5N5 HPAI viruses have emerged from reassortments between clade 2.3.4.4b H5N8 HPAI viruses and other LPAI viruses found in wild bird reservoirs.
- Since October 2020, new H5Nx reassortants emerged in Europe originating from the H5N8 HPAI clade 2.3.4.4b and Eurasian LPAI viruses. Several subtypes were detected including H5N1, H5N2, H5N3, H5N4, and H5N5 subtypes. H5N1 HPAI virus clade 2.3.4.4b was also detected in Africa, Asia, and was introduced in North America during end 2021.
- Algeria, Senegal, Lesotho, Mauritania, and Mali reported H5 HPAI for the first time ever in January-February 2021.
- Seven human detections caused by influenza A(H5N8) were reported in the Russian Federation, all cases were asymptomatic and no sustained human-to-human transmission was observed.
H5N6 HPAI (2014)
- To date, 83 human cases of influenza A(H5N6) have been reported, 82 occurring in China and one in Lao People's Democratic Republic.
- H5N6 (2017, Netherlands) was not zoonotic and genetically different.
- Detection of a H5N6 HPAI virus in June 2019 in Nigeria marked the first ever report of this subtype on the African continent.
- Outbreaks in wild birds in Western China, in domestic poultry in Viet Nam, and a new introduction reported by the Philippines in the first quarter of 2020
- Reassortants of these viruses with clade 2.3.4.4b H5 viruses has lead to the emergence of a different H5N6 which has largely replaced the clade 2.3.4.4h H5N6 viruses.
H5N2 HPAI
- A sub-type widespread in its LPAI form, can cause local epizootics in its HPAI form.
- Major epizootics occurred in the United States of America and France in 2015.
- Enzootic in Taiwan Province, China.
- Occasional sporadic reassortments detected in Europe.
H5N5 HPAI
- Enzootic in Taiwan, Province of China first detected in September 2019.
H7N9 LPAI (2013) and HPAI (2017)
- Reported only in China; recent HPAI mutation (observed end 2016)
- Most human cases exposed in live bird markets
- Period 5 (Oct 2016 to Sep 2017): significant increase in case numbers and geographic expansion
- Nation-wide vaccination campaign since Sep 2017: drop in number of animal outbreaks and human cases as well as detections
- See monthly FAO H7N9 situation update.
H7N3 HPAI (2020)
- The United States of America reported an outbreak of H7N3 HPAI in a turkey farm in South Carolina. It was noted this new HPAI virus emerged from spontaneous mutation of an H7N3 LPAI virus that has been circulating in the country since March 2020 and was reported on the same premise. [reference1, reference2]
- H7 HPAI outbreaks have occurred yearly in Mexico since introduction in 2012.
H7N4 LPAI (December 2017)
- Found only in China and Cambodia (through live bird market surveillance)
- One human case in China with reported exposure to poultry
H9N2 LPAI
- First human case reported in 1998
- To date, around 89 influenza A(H9N2) human cases diagnosed worldwide, with at least 82 cases occurring in China since December 2015.
- Cause of significant production losses and mortalities in poultry production systems
- Endemic in several countries in Africa and Asia
H10N3 LPAI
On 31 May 2021, the National Health Commission, China reported the first influenza A(H10N3) human infection. This was the first human case reported globally. [reference]
- In September 2022, a second laboratory-confirmed human case of influenza A(H10N3) was reported in Henan Province, China. To date, two human cases of avian influenza A(H10N3) virus has been reported globally. [reference]
Nearly 3 months ago ago, in Flying Blind In The Viral Storm, we looked (and not for the first time) at the lack of infectious surveillance and reporting coming out of China - and from many other countries around the globe - and the very real risk of being blindsided by another pandemic virus.
If anything, the situation has become more dire since then.
Even as global pandemic threats increase, our visibility of what is happening around the globe continues to dim. We often hear about human infections with avian flu, or MERS-CoV, weeks or even months after the fact.
Assuming we hear about them at all.
While `no news' is generally thought of as `good news', history has shown us repeatedly that isn't necessarily true.
