COVID-19: The Avian Vector Loophole

Credit ECDC 

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Coronaviruses are divided into 4 distinct genera; Alphacoronaviruses, Betacoronaviruses, Gammacoronaviruses, and Deltacoronaviruses - and while both birds and mammals are susceptible to coronavirus infection - they each (at least, for the most part) stay in their own lane. 

Birds are primarily infected by gammacoronaviruses, such as infectious bronchitis virus (AIBV) and occasionally by deltacoronaviruses, while mammals are primarily affected by alphacoronaviruses and betacoronaviruses. 

But there are a few crossovers - particularly with Deltacoronaviruses - which have been detected mostly in birds and but occasionally in mammals (see Discovery of seven novel Mammalian and avian coronaviruses in the genus deltacoronavirus . . . . ).  

Porcine deltacoronavirus (PDCoV), first identified in 2012, is one of those DCoV outliers we keep an eye on (see PNAS: Broad Receptor Engagement of PDCoV May Potentiate Its Cross-Species Transmissibility) due to its feared zoonotic potential (see also ​New pig virus found to be a potential threat to humans). 

Which is why, when dealing with viruses, one never likes to say `never'.  

Luckily SARS, MERS-CoV, and SARS-CoV-2 (COVID-19) are all Betacoronaviruses, and have shown no signs of infecting avian species, which would likely complicate this pandemic enormously. 

But, according to the The Danish Veterinary and Food Administration - which has been investigating the rapid spread of COVID-19 between mink farms -  there is a plausible way birds could still be carrying and transmitting the virus between farms. 

The DVFA FAQ on Infection Routes For Mink first examines a number of possible ways the virus could have been spread, including :

• Machine stations / veterinarians / temp agencies : The Danish Veterinary and Food Administration investigates several routes of infection, and is in contact with feed suppliers, machine stations, temp agencies and veterinarians who have their way on the farms. These data are compared with data from SSI on knowledge of infection with COVID-19 in groups of people associated with mink productions.
• SSI and the University of Copenhagen have come to the conclusion that herd size and distance to the nearest infected mink farm are the two factors that are decisive for whether there is an increased risk of a mink farm becoming infected.
• Relocation : Trade in mink has not been a contagion in the suspected or infected herds. Live mink are not usually traded in the middle of the season, and in the few places that have happened, it has been a long time before the infection in the herd.
• Fences : The fences are generally intact on the Danish mink farms. Only very few farms have defective fences where mink can escape. The Danish Veterinary and Food Administration considers it too unlikely that escaped mink from infected farms play a role in the spread of COVID-19. To follow up on the risk that potential escaped mink from infected mink farms may have an impact on the spread of infection, the killing of wild mink has been intensified. Abandoned (and dead) mink are collected and sent regularly to the Danish Veterinary and Food Administration, which ensures that they are tested for COVID-19. So far, no COVID-19 has been found in mink killed / found outside mink farms.
• Feed : The Danish Veterinary and Food Administration has tested feed samples for the entire period, without finding COVID-19. We do not immediately assess that feed is a source of infection for COVID-19 in mink. Read more about feed further down the page.
• Pets : The Danish Veterinary and Food Administration has tested pets and other domestic animals. Some dogs have been infected, but only for a short period of time. The dogs have been isolated on the property. In addition, cats infected with COVID-19 have also been found. No spread to other domestic animals has been seen. ( Read more in the FAQ about pets and coronavirus )

In a separate section, the FAQ looks at Can birds transmit infection?

Yes, it is estimated that birds may play a role in the spread of COVID-19 between mink farms, both over short and long distances. This can be done by transporting the virus passively, either on the feet, beak or feathers or in the digestive tract.

Aarhus University has conducted a study for the Danish Veterinary and Food Administration on the potential role of birds in the spread of COVID-19 between mink farms. According to the study, it is considered likely that birds visiting a mink farm infected with COVID-19 will come into contact with viruses, for example via contact with feed residues or mink hair that has been in contact with infected mink.

Birds can transmit infection to mink by, for example, eating their food before the mink get it or while it is lying on top of the cage. In at least one case, it has been observed that rainwater dripping from a leaky roof over an enclosed hall has contained viruses. This virus could originate from the feet of birds that have been sitting on the roof.

Updated November 25th

Those with very long memories will recall this type of `mechanical transmission' (via the common house fly) was considered seriously during the rapid spread of H5N1 in Indonesia and East Asia during the last half of the first decade of the 21st century (see Cats and Dogs and Flies, Oh My!).

While scientists were able to successfully isolate the HPAI H5 virus either on/or in blowflies (see study below), actually proving they had spread the virus is another matter altogether.  But it did suggest it was possible. 

Detection and isolation of highly pathogenic H5N1 avian influenza A viruses from blow flies collected in the vicinity of an infected poultry farm in Kyoto, Japan, 2004.

We've seen other studies (which may be applicable) linking infected `dust' (dried feces, feathers, etc.) from poultry farms - often propelled by large exhaust fans - being carried several kilometres by the wind and infecting other nearby farms. 

The science of all of this even has a name; aerobiology – the study of how bacteria, fungal spores, pollen and even viruses can be passively transported in the air.

• In 2010 (see Viruses Blowin’ In The Wind?) we saw a report in the journal Environmental Health Perspectives, that suggested that it was possible for H5N1 (or any Influenza A virus) to be transported across long (hundreds of kilometers) distances in the air, although viability was unknown.
• In 2012's Barnstorming Avian Flu Viruses? we looked at a study in the Journal of Infectious Diseases called Genetic data provide evidence for wind-mediated transmission of highly pathogenic avian influenza that found patterns that suggested farm-to-farm spread of the 2003 H7N7 in the Netherlands due to the prevailing wind.
• Another study of the same outbreak, Modelling the Wind-Borne Spread of Highly Pathogenic Avian Influenza Virus between Farms (PloS One 2012), found that wind borne transmission could have accounted for up to 24% of the transmission over distances up to 25 km.

In the spring of 2015 during the North American H5Nx epizootic, the idea of farm-to-farm spread via infected dust was openly discussed by the USDA (see Bird Flu’s Airborne `Division’).

While not directly addressing this possibility of wind-borne spread of COVID-19, the ECDC's Rapid Risk Assessment on COVID-19 in mink (LINK) does note:

Mink are housed in adjoining cages made of wire netting, allowing free airflow and contact between animals in adjacent cages, which explains the rapid animal-to-animal transmission. Furthermore, the presence of viral RNA in inhalable dust collected from inside the farms indicates the possibility of workers having been exposed to the virus in mink excretions. 

Following outbreaks of SARS-CoV-2 infection at mink farms in the Netherlands during 2020, the points below should be borne in mind.

• Mink-to-mink transmission is very efficient
• No link has been identified between infected farms.
• A proportion of farm animals had clinical symptoms suggestive of acute respiratory illness for about four weeks, but some animals were still RT-PCR–positive for SARS-CoV-2 in throat swabs after clinical symptoms had disappeared. This may vary, as seen recently in Danish outbreaks, where clinical symptoms were observed for shorter periods.
• The high diversity in the sequences from some mink farms can probably be explained by the existence of many generations of infected animals before an increase in mortality was observed.The current estimates are that the substitution rate of SARS-CoV-2 is one mutation per two weeks.
• There was also a relatively high sequence diversity observed in farms, which still tested negative one week prior to the outbreak, implying that the virus evolves more quickly in the mink population. This can indicate that the virus might replicate more efficiently in mink or that it may have acquired mutations which make it more virulent in mink [5].

Whether carried by the movement of humans or machinery between farms, by the wind, or on the feet, feathers, or GI tract of of wild birds, COVID-19 has repeatedly demonstrated its ability to quickly spread among mink farms in numerous countries. 

While COVID-19 has not proved to be a huge agricultural issue (outside of mink farming), the next pandemic threat may not be so constrained. 

Which means that agricultural interests must get much better at shutting the barn door before the next virus gets in - or out again. 

UK: North Yorkshire Turkey Farm Hit By H5N8 - DEFRA

 

North Yorkshire - Credit Wikipedia

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Although not as hard hit as many other northern and central European nations, the UK today announced their 6th bird flu outbreak (5 HPAI, 1 LPAI) in poultry or other captive birds since the start of November, this time involving more than 10,500 turkeys as a farm in North Yorkshire. 

This announcement from DEFRA:

H5N8 strain avian influenza confirmed on farm in North Yorkshire

The risk to public health from the virus is very low and this strain of avian influenza does not pose a food safety risk

Published 29 November 2020

From:Department for Environment, Food & Rural Affairs, Animal and Plant Health Agency, Victoria Prentis MP, and Lord Gardiner of Kimble

Avian influenza of the H5N8 strain was confirmed at a turkey fattening premises near Northallerton on Saturday 28 November.

All 10,500 birds at the farm will be humanely culled to limit the spread of the disease. A 3km and 10km Temporary Control Zone has been put in place around the infected site to limit the risk of the disease spreading.

Public Health England (PHE) advises that the risk to public health from the virus is very low and the Food Standards Agency advises that avian influenzas pose a very low food safety risk for UK consumers. Properly cooked poultry and poultry products, including eggs, are safe to eat.

Chief Veterinary Officer, Christine Middlemiss, said:

• Avian flu has been confirmed at a commercial turkey fattening farm near Northallerton, North Yorkshire. Immediate steps have been taken to limit the risk of the disease spreading and all the remaining turkeys at the farm will be culled.

• Public Health England has confirmed that the risk to public health is very low and the Food Standards Agency advises that bird flu poses a very low food safety risk for UK consumers.

• Bird keepers should remain alert for any signs of disease, report suspected disease immediately and ensure they are maintaining good biosecurity on their premises.

• We are urgently looking for any evidence of disease spread associated with this farm to control and eliminate it.

Dr Gavin Dabrera, Consultant in Acute Respiratory Infections at PHE said:

• To date the World Health Organisation has never confirmed any cases of H5N8 in humans and the risk to the public is considered very low. 

• As a precaution the local Health Protection Team will offer routine health advice to those working on the farm. We will work with DEFRA to monitor the situation closely.

A Food Standards Agency spokesperson said:

• We advise that, on the basis of the current scientific evidence, avian influenzas pose a very low food safety risk for UK consumers.

• Properly cooked poultry and poultry products, including eggs, remain safe to eat.

• A detailed investigation is in progress to determine the most likely source of this outbreak.

• There is not anticipated to be any impact on the supplies of turkeys or other birds over Christmas.

Wild birds migrating from mainland Europe during the winter period can spread the disease to poultry and other captive birds. There are some simple measures that all poultry keepers, whether they are running a large commercial farm, keeping a few hens in their back garden, or rearing game birds, should take to protect their birds against the threat of avian flu.

These include:

• All bird keepers in England (whether they have pet birds, commercial flocks or just a few birds in a backyard flock) are required by law to take a range of biosecurity precautions.
• If you keep poultry or other captive birds, you must take action to reduce the risk of disease in your flock by following government advice on biosecurity. Further details of the measures that apply in the AIPZ can be found in the AIPZ declaration and our biosecurity guidance.
• Keeping the area where birds live clean and tidy, controlling rats and mice and regularly cleansing and disinfecting any hard surfaces
• Cleaning footwear before and after visits
• Placing birds’ feed and water in fully enclosed areas that are protected from wild birds, and removing any spilled feed regularly
• Putting fencing around outdoor areas where birds are allowed and limiting their access to ponds or areas visited by wild waterfowl
• Where possible, avoid keeping ducks and geese with other poultry species.

The UK produces a weekly report (see below) of HPAI detections in wild and migratory birds, and for the first 44 weeks of 2020, no infected birds were reported.  Over the past 3 reporting weeks - starting with Epi week 45 - more than 40 reports have come in. 

    Avian influenza in wild birds: 2020
      Updated 27 November 2020
      Download CSV 2.91KB

With more migratory birds expected to flood into the UK and Europe in the days and weeks ahead, this year's outbreak appears to have plenty of fuel to continue for weeks or months to come.  

Denmark's COVID-19 Cat Cull Controversy

 

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In addition to having to cull and dispose of millions of mink, Danish media are reporting that authorities have culled more than a dozen COVID infected cats found on at least two mink farms. 

While I haven't seen any official confirmation from Denmark's DVFA or Serum Statens Institute (SSI) website, several local media outlets (see below) are claiming they have a witness and additional confirmation of infected cats from the SSI. 

Authorities are killing cats on mink farms - TV 2

 

On a mink farm in Holstebro, coronavirus was found in 12 cats that were killed

Cats killed after finding corona

Reportedly, 3 asymptomatic dogs have been found as well.  Genetic testing on the strain of COVID-19 in these animals is reportedly underway. 

All of this has caused a bit of a flap among pet owners in Denmark, as has a recently faked Facebook announcement claiming the Danish Prime Minister was warning citizens to be prepared for the fact that their pets may have to be killed to stop coronavirus. 

Manipulated cat postings from the Prime Minister are circulating on the net

While I don't have official confirmation of the culling of cats, given the near panic Danish authorities expressed 4 weeks ago at the discovery of 5 mutated strains of the virus circulating in mink, and even jumping to humans,  I find the report plausible. 

And given they were dealing with a potentially dangerous mutated strain - not the COVID strain already prevalent in humans - I can understand their desire to operate swiftly and with an abundance of caution. 

I'm not sure why a small number of infected cats couldn't have been placed in isolation until they cleared the virus, but we are working with minimal information here, and they may have had good reasons. 

It's no surprise that cats and dogs on mink farms were exposed to and infected by COVID-19.  We've seen evidence for months that both species are susceptible (cats, supposedly more than dogs) to the virus, and that cats may be better able to transmit the virus. 

Seroprevalence of SARS-CoV-2 in Dogs & Cats - Italy

CDC: Pets & Other Animals and COVID-19

NEJM: Transmission of SARS-CoV-2 in Domestic Cats 

The following excerpt comes from the CDC's Nov 18th Update COVID-19 and Animals:

What you need to know

• We do not know the exact source of the current outbreak of coronavirus disease 2019 (COVID-19), but we know that it originally came from an animal, likely a bat.
• At this time, there is no evidence that animals play a significant role in spreading SARS-CoV-2, the virus that causes COVID-19, to people.
• Based on the limited information available to date, the risk of animals spreading COVID-19 to people is considered to be low.
• More studies are needed to understand if and how different animals could be affected by COVID-19.
• We are still learning about this virus, but it appears that it can spread from people to animals in some situations.

Research on animals and COVID-19

Many studies have been done to learn more about how this virus can affect different animals.

• Recent experimental research shows that cats, dogs, ferrets, fruit bats, hamsters, and tree shrews can become infected with the virus. Cats, ferrets, fruit bats, and hamsters can also spread the infection to other animals of the same species in laboratory settings.
• Data from studies suggest that dogs can get infected but might not spread the virus to other dogs as easily as cats and ferrets can spread the virus to other animals of the same species.
• A number of studies have investigated non-human primates as models for human infection. Rhesus macaques, cynomolgus macaques, Grivets, and common marmosets can become infected SARS-CoV-2 and become sick in a laboratory setting. 
• Laboratory mice, pigs, chickens, and ducks do not seem to become infected or spread the infection based on results from studies.

These findings were based on a small number of animals, and do not show whether animals can spread infection to people. More studies are needed to understand if and how different animals could be affected by COVID-19.

CDC, USDA, state public health and animal health officials, and academic partners are working in some states to conduct active surveillance of SARS-CoV-2 in pets, including cats, dogs, and other small mammals, that had contact with a person with COVID-19. These animals are being tested for SARS-CoV-2 infection and also tested to see whether the pet develops antibodies to this virus. This work is being done to help us better understand how common SARS-CoV-2 infection might be in pets as well as the possible role of pets in the spread of this virus.

 While it is possible that a small number of human COVID cases have been caused by exposure to an infected dog or cat - as long as they are carrying the same strain that is circulating in millions of humans - their impact is likely negligible. 

Of greater concern would be a mutated strain emerging in companion animals - such as we saw in Danish mink - but so far we've not seen any evidence of that happening. 

For now, your pets are at greater risk of being infected by you, than you are by them. 

Denmark's Mink Disposal Problem

 

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Whether we are talking about tens of millions of HPAI infected poultry in America's heartland, millions of FMD infected livestock in South Korea, or millions of COVID infected mink in Denmark, the problem is the same; how do you humanely cull and then dispose of tons of infected carcasses? 

In the summer of 2015, in Debating The Humane Methods Of Depopulating Infected Chickens, we looked at a disturbing – yet potentially necessary – option for quickly depopulating hundreds of thousands (even millions) of poultry who are infected with highly infectious HPAI viruses.

But even after that job is done, the disposal of millions of infected carcasses must be accomplished in a way that avoids reintroduction of the virus into the environment.  Unfortunately, in too many places around the world, culled livestock are simply dumped into rivers and lakes, and the diseases continue to spread. 

Incineration is considered the safesr way to dispose of infected carcasses, and many countries have mobile incineration units, but isn't really practical on a large scale.

Earlier this month Denmark announced they had the capacity to incinerate 100,000 mink a day - but with 17,000,000 ordered destroyed, it would take 170 days to accomplish the task. 

Onsite burial (or transported to a landfill) is often an acceptable alternative, although it must be done properly to avoid environmental contamination. 

During South Korea's 2010-2011 FMD outbreak roughly 3.5 million animals were destroyed (151,425 cattle, 3,318,299 pigs, 8,071 goats, and 2,728 deer) and buried at more than four thousand locations around the country (see EID Journal Control of Foot-and-Mouth Disease during 2010–2011 Epidemic, South Korea).

But in 2018's Frontiers: Two Studies On The Epidemiology of Avian Influenza Viruses, we looked at the challenges of doing it safely (see Garbage Management: An Important Risk Factor for HPAI-Virus Infection in Commercial Poultry Flocks).

After the lessons from North America's Epizootic, the USDA's APHIS issued updated Landfill Disposal Guidance—Recommended Waste Acceptance Practices for Landfills.

Because of the perceived urgency over their mink mutations, Danish officials pivoted from incineration  to onsite burial of COVID infected mink earlier this month.  But things have not gone smoothly.

• The Presidential order to cull 17 million mink was later determined illegal, and modified to a `recommendation' pending legislative action.

• Agriculture Minister Mogens Jensen resigned following the furor over the illegal cull.

• Several million mink that were culled under the original order were hastily buried, including (reportedly) one site near a recreational lake and another close to a drinking water source. 

• In recent days there have been reports of improperly buried carcasses popping to the surface as they decomposed, presenting an environmental (and possibly infectious) hazard, and inciting a plethora of `zombie mink rising from the grave' stories in the popular press. 

All of which has led to calls from opposition MPs to dig up and incinerate up to 11 million mink that have been buried improperly, and some reportedly in environmentally sensitive areas. You'll find the details in the following BBC report. 

Coronavirus: Calls in Denmark to dig up millions of dead mink

While the number of `zombie' mink resurfacing has reportedly been small (a few hundred) - and it seems unlikely all of the mink will be exhumed and incinerated - Denmark's DVFA (Danish Veterinary and Food Administration) does accept that at least one burial site was inappropriate. 

Problem with mink buried too close to lake must be solved as soon as possible

Some of the mink buried in an area by Holstebro are too close to the nearby Boutrup Lake. The Danish Veterinary and Food Administration is working on solutions. (press release issued by the Ministry of the Environment and Food)News , Published: November 26, 2020

Gutters for killed mink have been dug too close to Boutrup lake in a military training ground in Holstebro in West Jutland.

With advice from the Danish Environmental Protection Agency, the Danish Veterinary and Food Administration is taking care of the problem so that the lake does not risk being polluted with e.g. phosphorus and nitrogen from the dead mink.

- This must be resolved as soon as possible, and therefore action must be taken immediately. It is a very unfortunate situation, and it is important that the best possible solution is found quickly, so that the citizens of the area can safely count on the water in the lake being clean. In addition, we must discuss the situation with the local authorities to ensure the best possible coordination and to get as many brains as possible to think with, says Minister of Food, Agriculture and Fisheries Rasmus Prehn.

Precautionary considerations of 300 meters

In connection with the burial in the area, the Danish Environmental Protection Agency, for precautionary reasons, set a distance requirement for the lake of 300 meters.

However, parts of the burials are less than 200 meters from the lake.

The Danish Veterinary and Food Administration is now clarifying with the Danish Environmental Protection Agency how the situation is handled in the best possible way. Among other things, it is being considered whether drainage pipes should be established that ensure that the polluting liquid is collected and cleaned so that it does not come close to the lake.

- It is important to emphasize that this does not spread corona infection. What we must ensure is that the lake is not polluted with i.a. nitrogen and phosphorus, and there are a number of different solutions to this. In this connection, we have asked the Danish Environmental Protection Agency to contribute to the assessment of any risks to the water quality in the lake, says the Danish Veterinary and Food Administration's director, Nikolaj Veje.

The Danish Veterinary and Food Administration will also carry out an EIA assessment to review the professional assessments already made, qualify any remedial measures and ensure openness in relation to the public.

As a supervisory authority, the Danish Environmental Protection Agency has already decided to initiate environmental monitoring of the lake and a study of the groundwater in particular.

More soil in the gutters

There are also problems in the same area with dead mink being pressed up against the soil surface after they have been dug down.

As recommended, the gutters are dug approx. two and a half meters down with one and a half to two meters of soil on top of the buried mink. This is considered to be a temporary problem related to the animals' putrefaction process. To avoid any problems for animals and humans, the area will be staffed 24 hours a day until fences are set up around the area.

The National Operating Staff, which has coordinated the mink burials, is aware of the challenges and the dead mink are being covered on an ongoing basis.

Over the past 10 years we've seen major animal cull and disposal problems due to Avian Flu, FMD, African Swine Fever, and now COVID-19. Events such as these are only likely to increase in frequency and scope in the years ahead, and we need to be a lot better prepared to deal with them. 

HPAI Roundup: Norway's 1st HPAI Detection - South Korean Outbreak In Poultry

Credit Wikipedia

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Somewhat surprisingly - even during Europe's 2016-2017 record setting avian epizootic - Norway has never reported HPAI in migratory birds or poultry before. Neighboring Scandinavian countries, like Sweden, Denmark, and Finland - while not as hard hit as many central European nations - have reported multiple outbreaks over the past 15 years.

Norway's lucky streak has ended with the announcement yesterday by the The Norwegian Food Safety Authority, of the first detection of HPAI in a migratory bird (wild goose) in Rogaland, located on the Southwestern coast. 

It is too soon to know if this detection is a one-off event due to a lone wayward migratory bird, or if it heralds a bigger threat to the region.  But due to the risks poultry interests in the region are ordered to boost their biosecurity. 

This report from Norway's FSA. 

Bird flu in Norway and Europe in autumn 2020

Published 19.11.2020 Last changed 27.11.2020

Highly pathogenic bird flu has been detected in Norway, Sweden, Denmark and several countries in Europe this autumn. The bird flu that is now being detected is first and foremost a risk to birds and not humans. The risk of infection to humans is considered by the Norwegian Institute of Public Health to be very low.

The Norwegian Food Safety Authority introduces a curfew to prevent infection of domestic birds

Bird flu has been found on a wild goose in Rogaland. To prevent infection from wild to domestic birds, the Norwegian Food Safety Authority is now introducing a curfew for poultry in all coastal municipalities from and including Rogaland and the entire coastal strip up to Oslo and even former Østfold.

A curfew means that all domestic birds must be indoors or possibly under a roof.

The infection situation is assessed on an ongoing basis

The infection situation can change quickly and the Norwegian Food Safety Authority therefore makes continuous assessments of the situation.

The infection is thought to come from migratory birds, and based on previous years' experience, it is unlikely that Norway will be affected by the main migration of birds in the autumn, along the south-western migratory route from eastern nesting areas. 

The Norwegian Food Safety Authority is not aware that there is knowledge of changed migration routes that will change the risk of introducing HPAI to Norway in the autumn of 2020. While both Sweden, Finland and Denmark have detected HPAI in poultry and wild birds before, HPAI has never been detected in Norway.

Major consequences for poultry - preventive measures can be implemented at short notice

The consequences of any infection from wild birds to poultry can be very serious for the poultry herd.

If the Norwegian Food Safety Authority considers that the risk of infection to Norway increases, we will consider initiating preventive measures to prevent infection from wild to domestic birds. Such preventive measures can be implemented at short notice.

This year's variant of bird flu is dominated by the H5N8 virus. The virus is highly pathogenic, which means that it is highly pathogenic to poultry.

Low risk of infection for humans

There are no previously known cases of infection from birds to humans with this virus, and the risk of infection to humans is considered very low.

Remember to avoid direct physical contact with sick and / or dead birds, as these e.g. may be infected with Salmonella .

Europe has seen three previous major introductions of HPAI H5, with the first occurring in 2005-2006 (with H5N1), again in 2014-15 (with H5N8's first appearance), and lastly with the 2016-2017 HPAI H5N8 epizootic (see map below).  

From  EID Journal: Comparison of 2016–17 and Previous Epizootics of HPAI H5 In Europe).

Figure 5. Geographic and temporal spread of the 2016–17 HPAI H5N8 epizootic. A) Location of each incident reported. Blue shading indicates countries where cases were reported.

While scattered outbreaks  (particularly in Eastern Europe) of HPAI have occurred outside of the 3 above mentioned epizootics, these three events (along with this year's uptick) have all been associated with a reassortment event that altered the virus's virulence or behavior. 

Not all reassortments are bad, however. The reassorted HPAI H5N6 virus that briefly appeared in Europe during the winter of 2017-2018 was considerably less robust and widespread than the HPAI H5N8 virus it supplanted. 

Meanwhile, in South Korea, where they have announced numerous environmental detections of HPAI H5N8 from migratory birds this fall, they are reporting their first outbreak in a poultry (duck meat) farm in Jeongeup, North Jeolla. 

This (translated) statement from MAFRA, South Korea's Ministry of Agriculture, which has imposed a 48-hour nationwide stop movement order for poultry farms, Livestock (feed factories, slaughterhouses, etc. ) and livestock vehicles.

Highly pathogenic avian influenza confirmed at a meat duck farm in Jeongeup, Jeollabuk-do

2020.11.28 15:41:33 Bureau of Defense Policy

□ Agriculture, Forestry, Animal Husbandry and Food ( Secretary : Kim Hyun - soo , under ' agri-food unit ") is 11 Mon. 28 days ( Sat ) , Chonbuk Jeongeup material broiler duck farm in the Highly Pathogenic Avian Influenza (H5N8 type ) has confirmed today announced that .

* agri-food section 11 Mon. 27 days in their farm H5 type AI antigen was detected immediately Farm access control and that poultry breeding farm for the prophylactic live disposal - including an emergency preventative measures are carried out ,

* 11 Mon 28 am occurred farm about 19 shoaling buy complete disposal , during subsequent processing, such as rendering

O the country temporarily move to stop (Standstill) commands a "11 Mon 28 days ( Sat ) 00 hour from 11 Mon 29 days ( days ) 24 hour " to " national poultry farms , Livestock ( feed factories , slaughterhouses, etc. ), livestock vehicles to Was issued .

□ agri-food portion in accordance with this occurs the Agri-Food Minister Headquarters as " highly pathogenic avian influenza central accident probation office " and local governments by Defense Headquarters ( General Manager : City , Province , market , military , mayor ) to install and follows the same top level It was decided to implement quarantine measures of .

① Avian Influenza (AI) crisis, warning the " Note " from " severe " to upgrade to the step

② Preventive killing of poultry raised within a 3km radius of the originating farm and restrictions on movement to poultry farms within 10km for 30 days

③ Restriction of movement for 7 days to all poultry farms in Jeongeup , Jeollabuk-do

④ occurred farm belonging integration business is operating slaughterhouses to test enhanced ( chicken 10% → 20%, Ducks 30 → 60% ), belonging to the farm inspection in Japan

⑤ nationwide traditional markets live from chickens , ducks distribution ban , Japan closed on Wednesdays , disinfection carried out

⑥ wide bangjegi , water spray , military (軍) Admiral vehicles , the available resource control helicopters by mobilizing migratory doraeji , highways , farms around Japan disinfection

□ agri-food sub-official " national poultry farms nearby Small Stream In - soryuji , farmland visits restraint , farm driveway , around the quicklime Belt building , farmyard , barn inside the daily disinfection , stalls out when rain boots to wear to wear, such as a farm unit is either the preventative measures than thoroughly implement when you need to " emphasize that .

Meanwhile, in Japan, no new farm outbreaks have been reported since Thursday (see Japan Reports 8th, 9th & 10th Poultry Farm Outbreak With HPAI), but another environmental sample has tested positive in Izumi City, Kagoshima Prefecture which is the primary overwintering site for thousands of rare Hooded, and White-naped cranes.

Highly pathogenic avian influenza virus test positive in water collected in Kagoshima prefecture (6th case in wild birds)

November 27, 2nd year of Reiwa

Highly pathogenic avian influenza virus (H5N8 subtype) was detected (positive) in an environmental sample (water) collected in Izumi City, Kagoshima Prefecture on Monday, November 23, 2nd year of Reiwa by a test conducted by Kagoshima University. There was a report that it was done. The collection point will be the same as the collection point where the highly pathogenic avian influenza virus was detected on November 13th and 20th.

China MOA: HPAI H5N8 Outbreak In Wild swans - Pinglu County, Shanxi Province

 

Shanxi Province - Credit Wikipedia 

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Given the amount of avian flu activity being reported in South Korea, Japan, Russia, and Europe over the past few months it is not surprising that today - for the first time since February of 2020 - China is reporting an outbreak of HPAI H5N8 in landlocked Pinglu County, Shanxi Province near the border with Henan Province.

China has a history of holding outbreak information close to the vest - arguably even more so since the COVID crisis began last winter - as we seem to be getting less information than usual (see Flying Blind In the Age Of Pandemics & Emerging Infectious Disease. 

Those with good memories, however,  will recall that in January of 2015 this same region reported another outbreak of HPAI (H5N1) at Henan's Swan Lake Wetland Park. The Pinglu Wetland, - which forms part of the Sanmenxia Reservoir Area - is a major winter habitat for more than 10,000 swans that migrate from Siberia in Russia.   

Seven months later we learned that die off was due to a new reassortment of H5N1 (see Novel H5N1 Reassortment Detected In Migratory Birds - China), one that possessed a Clade 2.3.2.1c HA gene and a H9N2-derived PB2 gene.

Over the years, die offs in wild birds have occasionally heralded the introduction of new reassortments or clades of HPAI H5, and have often preceded regional epizootics or international expansion of bird flu. A few notable examples include:

• A huge outbreak at Qinghai Lake in 2005 was clade 2.2 (aka QH05) of the H5N1 virus. And over the next 18 months, this new clade vastly expanded its geographic range across Asia, and into Europe and Africa (see H5N1 Influenza Continues To Circulate and Change 2006 by Webster et. al.).

• Four years later researchers found evidence of another clade (2.3.2) (see 2011 EID Journal New Avian Influenza Virus (H5N1) in Wild Birds, Qinghai, China), at another bird die off in the same region. In short order the 2.3.2 clade began to show up in migratory birds, and poultry, from Japan to India, supplanting the old 2.2 clade in many regions.

• Over the summer of 2016, a new reassortant HPAI H5N8 appeared in Siberia, killing wild birds. Four months later it appeared in Europe and sparking their worst avian epizootic on record (see EID Journal: Reassorted HPAI H5N8 Clade 2.3.4.4. - Germany 2016).

• And just three weeks ago, in a pre-print article from researchers at Wageningen Bioveterinary Research (WBVR) in the Netherlands, we saw evidence that Europe's recent uptick in HPAI H5N8 is due to a `genetically distinct' strain of HPAI H5N8.

It isn't clear whether the HPAI H5N8 virus currently affecting Europe is genetically similar to what is being reported in East Asia, or if we are dealing with more than one variant.  Either would a significant development. 

For now the only details we have come from the following (translated) announcement from China's MOA.

Wild swans H5N8 subtype highly pathogenic avian influenza outbreak in Pinglu County, Shanxi Province

Release time: 2020-11-26 

The Information Office of the Ministry of Agriculture and Rural Affairs announced on November 26 that a wild swan H5N8 subtype highly pathogenic avian influenza epidemic occurred in Pinglu County, Yuncheng City, Shanxi Province.

On November 26, the Ministry of Agriculture and Rural Affairs received a report from the China Animal Disease Prevention and Control Center, which was confirmed by the National Avian Influenza Reference Laboratory that a wild swan H5N8 subtype highly pathogenic avian influenza epidemic occurred in the Sanwan Whooper Swan Scenic Area, Pinglu County, Yuncheng .

There are more than 4,000 wild swans living in this area, with 2 sick and 2 dead. After the outbreak, the local area immediately activated an emergency response mechanism, carried out emergency response work, and disinfected the surrounding environment. All sick and dead swans were treated harmlessly. 

Nature: Evolution & Pathogenicity of H6 Avian Influenza Viruses, Southern China 2011-2017

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There are two broad categories of avian influenza; LPAI (Low Pathogenic Avian Influenza) and HPAI (Highly Pathogenic Avian Influenza).

• LPAI viruses are common in wild birds, cause little illness, and only rarely death.  They are not considered to be a serious health to public health (LPAI H7N9 being the exception). The concern is (particularly with H5 & H7 strains) that LPAI viruses have the potential to mutate into HPAI strains. 

• HPAI viruses are more dangerous, can produce high morbidity and mortality in wild birds and poultry, and can sometimes infect humans with serious result. Again, H5 and H7 viruses are of greatest concern, but other subtypes have also caused human illness and large poultry losses. 

Until the first decade of the 21st century, there was no uniform requirement to report or track LPAI infections. That changed in 2006 when the OIE made reporting of LPAI H5 & H7 viruses mandatory.

While other LPAI subtypes are not currently reportable to the OIE (see Terrestrial Animal Code Article 10.4.1.), that doesn't make them entirely benign.

The most obvious, and worrisome loophole is for LPAI H9N2, which is common in Asia and the Middle East, and has recently moved into Africa. While not a notifiable virus, H9N2 has demonstrated its ability to infect humans and to reassort with other viruses, and is on the CDC's short list of novel viruses with pandemic potential (see CDC IRAT Score).

But H9N2 is not alone. 

One of the other low-profile and little watched zoonotic contenders are H6 viruses, which are common in both wild birds globally and domesticated poultry in China, and have demonstrated the ability to jump species (to humans, to pigs, and to dogs) as well. 

• In 2013, LPAI H6N1 was identified as the cause of pneumonia in a human  in Taiwan. The patient, a 20-year-old female, was hospitalized with mild pneumonia on May 8th, treated with oseltamivir (Tamiflu ®), and released from the hospital on May 11th.

• The following year, we learned that H6N1 had jumped to Taiwanese dogs (see Taiwan: Debating The Importance Of H6N1 In Dogs).

• In 2015's EID Journal: Seropositivity For H6 Influenza Viruses In China, researchers found a a small, but significant number of people in their survey who tested positive for H6 influenza antibodies (indicating previous exposure).

• Also in 2015, in Study: Adaptation Of H6N1 From Avian To Human Receptor-Binding, we saw a report citing changes the authors suggest are slowly moving the H6N1 virus towards preferential binding to human receptor cells instead of avian receptor cells

• LPAI H6N6 emerged in Chinese swine more than a decade ago (see Pathogenicity and transmission of a swine influenza A(H6N6) virus),  and continues to show signs of adaptation to mammalian hosts (see Trans. Emerg, Dis: Continued Reassortment of Avian H6 viruses - Southern China, 2014-2016.)

• In 2018, in Infect. Gen. Evol.: Emergence Of Novel Reassortant H6N2 Avian Influenza Viruses In Ducks In India, researchers isolated from apparently healthy domestic ducks in Kerala and Assam, India during 2014 and 2015, respectively. 

• Last December, in BMC Vet. Rsrch.: Continuing Evolution of H6N2 Influenza A Virus in South Africa, we looked at evolution of H6N2 viruses in South Africa which, according to the authors, may have zoonotic potential. 

• Even Europe isn't exempt, as a year ago today in Netherlands: Multiple Farms Report LPAI H6, we looked at an unusual outbreak of LPAI H6 in poultry farms in the Netherlands. 

But since H6 viruses only rarely produce clinical illness in poultry, and are not legally reportable to the OIE, we are only rarely aware of their presence, or of the potential threat they may pose. 

All of which serves as prelude to a new study, published yesterday in Nature Scientific Reports, that looks at the evolution of H6 viruses in China, and their growing adaptation to mammalian physiology. 

It's a detailed and lengthy open-access report, so I've only reproduced the abstract. Follow the link to read it in its entirety.  I'll have a brief postscript when you return. 

Evolution and pathogenicity of H6 avian influenza viruses isolated from Southern China during 2011 to 2017 in mice and chickens

Weishan Lin, Hongrui Cui, Qiaoyang Teng, Luzhao Li, Ying Shi, Xuesong Li, Jianmei Yang, Qinfang Liu, Junliang Deng & Zejun Li

Scientific Reports volume 10, Article number: 20583 (2020) Cite this article

Abstract

H6 subtype avian influenza viruses spread widely in birds and pose potential threats to poultry and mammals, even to human beings. In this study, the evolution and pathogenicity of H6 AIVs isolated in live poultry markets from 2011 to 2017 were investigated. 

These H6 isolates were reassortant with other subtypes of influenza virus with increasing genomic diversity. However, no predominant genotype was found during this period. All of the H6N2 and most of the H6N6 isolates replicated efficiently in lungs of inoculated mice without prior adaptation.

 All of the H6N2 and two H6N6 isolates replicated efficiently in nasal turbinates of inoculated mice, which suggested the H6N2 viruses were more adaptive to the upper respiratory tract of mice than the H6N6 viruses. 

One of H6N2 virus caused systemic infection in one out of three inoculated mice, which indicated that H6 avian influenza virus, especially the H6N2 viruses posed a potential threat to mammals. Five H6 strains selected from different genotypes caused no clinical signs to inoculated chickens, and their replication were limited in chickens since the viruses have been detected only from a few tissues or swabs at low titers. 

Our study strongly suggests that the H6 avian influenza virus isolated from live poultry markets pose potential threat to mammals.

          (Continue . . . )

 
The conventional wisdom is that H6 viruses are unlikely to pose a serious zoonotic threat, but eight years ago LPAI H7 viruses were also thought to be a weak cousin of HPAI H5N1, and incapable of producing the same level of virulence or spread in humans.

The emergence of LPAI H7N9 in China in 2013 - sporting a mortality rate (among those hospitalized) of 30% - has dispelled that notion. A severe human infection with LPAI H7N4 in China in 2018 showed this was not a fluke.

Admittedly, H6 sits pretty low on our novel flu worry list, but the more we know about these non-notifiable LPAI viruses, the less likely we are to be blindsided by a pandemic threat coming at us from out of left field.

Japan Reports 8th, 9th & 10th Poultry Farm Outbreak With HPAI

 

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Japan's avian flu outbreak worsened over the past 48 hours with 3 new poultry farms deemed affected, and two new prefectures (Fukuoka and Hyogo) added to the list. After going nearly 3 years without an incident, since November 1st Japan has reported 10 outbreaks, along with dead birds and environmental evidence of HPAI in migratory birds in Hokaido, Niigata and Kagoshima Prefecture. 

Three (translated) reports from Japan's Ministry of Environment:

Confirmation of pseudo-patients with highly pathogenic avian influenza in Kagawa Prefecture (8th case in domestic poultry)

November 24, 2nd year of Reiwa

On November 21, 2nd year of Reiwa, it was reported that a pseudo-patient with highly pathogenic avian influenza, which was the 8th case in domestic poultry, was confirmed at an egg-laying chicken farm in Mitoyo City, Kagawa Prefecture. In response to this report, we will strengthen the monitoring of wild birds by designating the area within a radius of 10 km around the outbreak farm as a priority area for wild bird monitoring.

(Continue . . . )

Confirmation of pseudo-patients with highly pathogenic avian influenza in Fukuoka Prefecture (9th domestic poultry case)

November 25, 2nd year of Reiwa

On November 25, 2nd year of Reiwa, it was reported that a pseudo-patient with highly pathogenic avian influenza, which was the ninth case in domestic poultry, was confirmed at a meat chicken farm in Munakata City, Fukuoka Prefecture. In response to this report, we will strengthen the monitoring of wild birds by designating the area within a radius of 10 km around the outbreak farm as a priority area for wild bird monitoring.

(Continue . . . ) 

Confirmation of pseudo-patients with highly pathogenic avian influenza in Hyogo Prefecture (10th domestic poultry case)

November 26, 2nd year of Reiwa

 On November 25, 2nd year of Reiwa, it was reported that a pseudo-patient with highly pathogenic avian influenza, which was the 10th case in domestic poultry, was confirmed at an egg-laying chicken farm in Awaji City, Hyogo Prefecture. In response to this report, we will strengthen the monitoring of wild birds by designating the area within a radius of 10 km around the outbreak farm as a priority area for wild bird monitoring.

          (Continue . . . )

 

HPAI H5 has been reported in numerous environmental samples (water and/or bird feces) this fall, and since many of the migratory birds carrying this virus continue to head towards warmer over-wintering spots, those countries along the East-Asian migratory flyway (see map below) are at particularly risk of seeing incursions of avian flu in the months ahead as well.

DEFRA: Updated European HPAI Outbreak Assessment #6 & African Union (AU) Notification

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The global uptick in HPAI (Highly Pathogenic Avian Influenza) - which began in August in Western Siberia after 3 years of relative quiescence,  continues to expand both in Asia (mostly Japan & South Korea), the UK, and much of Europe. 

In Europe, the UK, and Russia the primary culprit is the recent arrival of a new variant of HPAI H5N8 that has been described as being `genetically distinct' from recently circulating strains in the region (see Pre-Print: Novel Incursion of a HPAI H5N8 Virus in the Netherlands, October 2020).

We've also seen some other scattered HPAI subtypes (H5N5, H5N1) caused by reassortment of this H5N8 variant with local LPAI viruses.  As we've discussed often, Clade 2.3.4.4 H5 viruses have demonstrated a highly promiscuous nature, and occasionally spin off reassortments. 

DEFRA's last update on avian flu activity in Europe - published 6 days ago - listed only 5 European nations reporting outbreaks; (UK, Ireland, Denmark, Netherlands & Germany).

Today's update lists 10; (UK, Ireland, Denmark, Netherlands, Germany, France, Belgium, Croatia, Sweden, and Italy).  But overnight there are media reports from several other countries, including Slovenia and Poland, of outbreaks and/or detections of avian flu. 

I've posted some selected excerpts from today's DEFRA report below, but you'll want to follow the link to read it in its entirety. 

Updated Outbreak Assessment #6Highly pathogenic avian influenza (HPAI) in the UK,and Europe

24 November 2020

Ref: VITT/1200 HPAI in the UK and Europe Disease Report 

Since our last report on 17 November, in the United Kingdom there has been one new outbreak of HPAI H5N8 in poultry, three new reports of HPAI H5N8 in wild birds, and one new outbreak of HPAI H5N8 in captive birds. Elsewhere in Europe, H5N8 has been reported: in poultry in Croatia, Denmark, France (Corsica), Germany and Sweden; in wild birds in Belgium, Denmark, Germany, Ireland and the Netherlands; and in captive birds in the Netherlands. HPAI H5 has been reported in wild birds in Denmark and Italy; and HPAI H5N5 in captive birds in Germany, and wild birds in the Netherlands.

Situation Assessment

In the United Kingdom, since our last report on 17 November, there have been new reports of HPAI H5N8 in poultry, wild birds and captive birds.

Following confirmation of HPAI H5N8 in captive birds, on 20 November 2020 at a wetland centre near Stroud in Gloucestershire, a 3km Captive Bird (Monitoring) Controlled Zone has been put in place around the site.

There has been one new outbreak of HPAI H5N8 in poultry. HPAI H5N8 as confirmed on 23 November in poultry and captive birds at a premises near Melton Mowbray, Leicestershire: at a theme park containing multiple species, including domestic and exotic birds.

A 3km and 10km Temporary Control Zone has been put in place around the premises. In England, in Lincolnshire (near Boston), HPAI H5N8 was reported in a Eurasian Wigeon, three Brent geese, a Shelduck, a Canada goose and two Greylag geese.

In a nature park in Lancashire HPAI H5N8 was confirmed in an unspecified wild bird. In Northern Ireland, near Lough Beg (on the border between County Londonderry and Country Antrim), a Mute swan tested positive for HPAI H5N8. Lough Beg is a stopping point for migratory birds. 

HPAI H5N8 in Western Europe

In Belgium, on 20 November, there were three reports of HPAI H5N8 along the north coast in West Flanders; in a European herring gull, a Eurasian Curlew, and a number of captive birds described as mute swans.

On 21 November, Croatia reported one outbreak of HPAI H5N8 in domestic poultry. Increased mortality had been observed on a large commercial premises with approximately 70,000 turkeys. The farm is in Delovi in the county of Koprivnica- Križevci.

Implementation of disease control measures according to the Directive 2005/94/EC have been put in place, and epidemiological investigations are ongoing.

Since our last report on 17 November, Denmark has reported one outbreak of HPAI H5N8 in poultry on a commercial poultry farm, containing approximately 25,000 birds. There have also been 20 reports of HPAI H5N8 in wild birds, and two reports of HPAI H5 in wild birds. While most reports continue to be from Jutland, there were a small number from Sjaelland (Zealand). Eleven of these reports related to dead barnacle geese. Other species included a brent goose, common buzzards, peregrine falcons, a curlew and a herring gull.

France has reported one outbreak of HPAI H5N8 (as reported to the OIE) in poultry. This was in the pet department of a garden centre. This was in the French department of Haute-Corse, in the northern part of the island of Corsica (in total, there were 575 specimens of various species (poultry and ornamental birds). The birds were culled on 15 November, and the garden centre's pet facility is now closed. Epidemiological investigations are ongoing.

Since our last report on 17 November, in Germany there have been 70 further reports of HPAI H5N8 in wild birds. While the majority of outbreaks continue to be in the north, and primarily in South Jutland, isolated cases have been identified further south, through Prignitz (in north-west Brandenburg – in a bean goose), Berlin (the federal state, southwest of the city – a greylag goose), and as far south as Nordsachsen (North Saxony – a mallard duck). There have also been three reports of HPAI H5N5 in wild birds.

Also in Germany, three outbreaks of HPAI H5N8 were reported in poultry. One was a premises of 1339 birds (fattening geese, hens and ducks). The second was a premises of 660 birds (laying hens and fattening geese). The third was a smaller, non-commercial premises of 43 birds (layer hens and turkeys). It is reported on ADNS that following a risk assessment (and in accordance with Council Directive 2005/94/EC) restriction zones for this premises have not been put in place. 

Ireland has reported two cases of HPAI H5N8 in wild birds. One was in a mute swan in the north-east (in County Monaghan), and the other a curlew in County Mayo, in Ireland’s north-west.

Italy reported two cases of HPAI H5 in wild birds on 21 November. One was in the province of Venice, where a common teal was shot in a hunting area. The other was in Rovigo province, again in hunted wild birds (wigeons and mallards). The same virus was detected: HPAI H5 viruses belonging to the 2.3.4.4 B clade. The HA sequence surrounding the cleavage site is highly related to that of HPAI currently circulating in Northern Europe. Identification of the NA subtype and characterization of the full genome is in process 

Since our last report on 17 November, there have been six further HPAI H5N8 cases reported in wild birds in the Netherlands. Species included mute swans, barnacle geese, and several buzzards. There were four reports of HPAI H5N8 in captive birds (with no details regarding species on ADNS). There was also one report of HPAI H5N5 in wild birds – in a reed (or bean) goose. 

Sweden has reported one outbreak of HPAI in poultry on 18 November. This was in a premises containing 5,100 turkeys. On the premises there were two populated sheds, and only the shed containing 1,800 birds displayed symptoms. All birds on the premises were culled.

(SNIP)

Conclusion

As a consequence of the H5N8 HPAI poultry outbreaks in the UK, and in Germany and the Netherlands; as well as the increasing HPAI H5N8 cases in wild birds in the UK, Belgium, Denmark, Germany, Ireland, Italy, the Netherlands and Sweden this week, and the known migration routes on to the UK from these countries: the risk of HPAI incursion in wild birds in the UK is HIGH. The overall risk of infection of poultry in the UK is MEDIUM; although it should be noted that the risk of introduction to individual premises, depends upon the level of biosecurity implemented on farm to prevent direct or indirect contact with wild birds 

          (Continue . . . )

While the Avian flu action so far has been limited mostly to Europe, the migratory flyways (see map below) that connect Siberia to Western Europe also extend into the Mediterranean, the Middle East, and even Africa.  During the 2016-2017 record-setting European avian epizootic, HPAI H5N8 also made its deepest inroads into Africa, and even crossed the Equator into South Africa. 

Yesterday the African Union (AU) issued an alert due to the increased bird flu activity in Europe, warning that a fresh round of HPAI could be winging its ways towards the African continent as well. 

Highly Pathogenic Avian Influenza (HPAI) H5N8 – Notification
  
Date/Time: 24 November 2020
Incident/Event title/Name: Highly Pathogenic Avian Influenza (HPAI) H5N8
Notification*: Alert Warning Activation Execution
From AUC Technical Offices: AU-IBAR, AU-PANVAC and Africa CDC
To: AU Member States

1. Situation

Summary: As of 22 November 2020, a highly pathogenic avian influenza (HPAI) H5N8 outbreak in wild birds and poultry has been reported in 12 countries, mainly in western Europe. The virus has been carried across from Southern Russia to Kazakhstan, and now Eastern Europe through migratory birds heading back to their winter feeding grounds primarily in Africa. As these are migratory birds, and even poultry flocks or products, coming into Africa from the affected regions could be carrying the virus, this poses a threat to poultry flock health, farmer livelihoods, and food security on the continent. And while this particular virus has not caused illness in humans to date, the likelihood of a spill-over event that could impact human health should not be ignored.

Background: The HPAI H5N8 virus of concern is of the H5 2.3.4.4.b. clade that has been circulating across Eurasia and into Africa since 2016. The first report regarding this current outbreak came from southern Russian in late July. To date, 12 countries have been impacted: Belgium, Croatia, Denmark, France, Germany, Ireland, Israel, Kazakhstan, Netherlands, Russia, Sweden, and the UK. The species most commonly affected have been wild and domestic fowl (e.g. domestic ducks, geese, chickens, swans).

While the original virus has reassorted with other wild bird influenza viruses to form new strains of H5N5 and H5N1 HPAI virus, no evidence of spillover of this clade into human populations has been detected. However, direct transmission from an infected bird or through another infected animal reservoir, while rare, is possible.

According to World Organisation for Animal Health (OIE) reports, several African countries have reported previous HPAI H5 or H7 outbreaks over the past 5 years. Specifically, all five AU regions and at least 15 AU Member States have been impacted (Table 1). Nigeria and South Africa are the only two countries reporting ongoing H5 outbreaks this year.

While this year's outbreak hasn't reached anywhere near the levels we saw in 2016-2017,  it is gaining momentum, and is well worth our attention.