Expert Talks: Prof Sjaak de Wit on Avian Influenza
In June 2023 Vaxxinova colleagues from Africa, Asia, Europe, Latin America and Middle East gathered online with Prof Dr Sjaak de Wit in an inspiring MS Teams session on a very current global topic; highly pathogenic avian influenza (HPAI).
Prof de Wit is connected to the Royal GD in the Netherlands as senior researcher. Next to that he is Professor in integrated poultry healthcare at the University of Utrecht, President of the WVPA and internationally known expert in the field of avian influenza.
The status and the threat of HPAI for the global poultry industry, as well as possible (vaccine) solutions were on the agenda. But we also discussed regional LPAI issues and ways of dealing with the challenges in the field. We invite you to watch the videos and gain additional knowledge on this topic.
The content of the videos is under copyright of Royal GD.
Thank you to the Expert, Prof Sjaak de Wit. And thank you to all the Vaxxinova experts. Vaxxiknowledge at its best – true knowledge exchange.
Vaccines, diagnostics and sequencing are there in the first place to help the chicken. That this is not always the case, follows from the discussion in this video. Prof Sjaak de Wit explains.
Vaccination is one of the tools that can help to prevent the birds from getting sick. However, a vaccine by itself is not the magic bullet, there are more factors playing a role in health management.
These 3 videos have Prof Sjaak de Wit and Vaxxinova colleague Dr Ludio Gomes in disucssion on several topics. But all related to H5 and H9 AI viruses.
Prof Sjaak de Wit explains how specific viruses like H9N2 in Asia and H3N1 in Europe can affect the oviduct. And therewith causing huge losses in egg production. The damage to the oviduct can even cause mortality in the layer chickens.
The H9 virus is not known to spread vertically, but certain way of handling of disposed eggs in the haychery might cause transmission of the virus.
There are for sure differences in virus needed to infect a bird. And in immunogenicity between H5 and H9. But nbot always an exact answer to a question can be given. As follows from the discussion between Prof Sjaak de Wit and Vaxxinova colleague Ludio Gomes.
In the next 5 videos, Vaxxinova colleague Dr Zahid Hossain from Bangladesh has some questions for expert Prof Sjaak de Wit. They are all related to H5 and H9 specifications, differences and similarities.
The series kicks of with “what are the underlying causes of the current H5 and H9 infections?”
The current AI strains are extremely well adapted to wild birds. This is new compared to before and a real gamechanger!
How long can the AI virus survive in poultry farms?
This will only be a relatively short period of time. Prof Sjaak de Wit answers to questions from Vaxxinova’s colleague in Bangladesh, Dr Zahid Hossain.
A clear explanation from Prof De Wit on why a low pathogenic AI virus as H9 is more difficult to control than a high pathogenic AI virus as H9.
A co-infection is really bad news. Low pathogenic AI such as H9 is causing big problems when a co-infection appears.
What will be the best vaccination strategy to prevent a H9N2 infection?
What you need, to achieve a good level of protection, are strong vaccination programs, good and broad vaccines and fanatic monitoring and follow up after vaccination.
Definitively the AI virus has adapted over time – and this leads to a whole new chapter in the book of Avian Influenza. And has consequences….
Waterfowl seems to be less susceptible to the Avian Influenza virus, compared to commercial poultry. Here is why…..
Here’s a conversation on co-infection, interference and possible mixture of appearances of H5-H7-H8. Listen to the Expert Prof Sjaak de Wit and Vaxxinova colleague Ludio Gomes.
Expert Talks on AI – back to Asia. Ludio Gomes in conversation with expert Prof. Sjaak de Wit on the topic of serology.
Diagnosis by serology; the preferred method is depending on the circumstances and the circulating subtypes. But, on average in Asia, the HI test will be the most helpful. Prof. Sjaak de Wit explains why.
After vaccination with an inactivated AI vaccine, a high titre in an HI test does not necessarily mean a high protection level. The results do not guarantee a black & white conclusion.
What are the chances on having a live avian influenza vaccine available in the future?
With the current status of science a live AI vaccine would not considered to be safe – and therefor unlikely to be available. Unfortunately.
Hear the expert Prof Sjaak de Wit and Vaxxinova’s Sainos Manzira, regional manager for Sub-Saharan Africa, on the topic of vaccine protection against different lineages of the same haemagglutinin subtype. And what determines the quality of a vaccine, as such?
What is the importance of neuramidase subtype in a vaccine?
Homologous neuramidase certainly can help in providing protection. But haemagglutinin are the most important.
Prof Sjaak de Wit explains the difference between shedding of virus and transmission of virus.
And which vaccine types that are currently available perform well in these fields.
A feature of HPAI virus is its ability to mutate easily. Especially when there is little vaccine protection against the virus. A repeatedly mutated virus hat spreads to other flocks, will no longer respond to the vaccine. The importance of vaccination explained clearly once more.
It is clear that there is still a lot of (research) work to do when it comes to Avian Influenza. The effect of an early infection on the oviduct is a perfect example. In this video expert Prof Sjaak de Wit and Vaxxinova colleague Dr Husam Bakri exchange experiences from science and from the field on this specific topic. Basis for an interesting discussion!
Confirmation of H5 challenge by PCR, does not necessarily mean all the flocks in a farm are infected. There are cases where one house is infected, while the others are fine. Whether the flocks have been vaccinated or not plays a role, of course. But what if the flocks have not been vaccinated? Prof. Sjaak de Wit explains some scenarios.
The current available vector vaccines, both H5 and H9, can be very helpful. But it will take some time after vaccination to start protection. When there is an infection at early age, these vaccines will not be effective.
Can an inactivated H9 vaccine seroconvert for, and therewith protect aginst, H5? A short answer: No! But it depends on the HI test that is used. In this video Prof Sjaak de Wit explains how to interprete the results of the test and what conclusions to link to it. Message: if you are in an area with H9N2, do not use an H5N2 antigen!
In the Middle East region H9N2 low pathogenic avian influenza is widely present in the field. But, also several inactivated vaccines are available. It appears that vaccinated broilers do not always show seroconversion. Although they look okay. How come? It is important not to underestimate the role of maternally derived antibodies (MDA’s) in broiler chicks from vaccinated breeders. And this also affects the immunity after vaccination. Prof Sjaak de Wit in conversation with Dr Husam Bakri.
The next 4 videos focus on the HPAI situation in Brazil and Latin America. Cross regions, migratory birds are very often the source for spreading the avian influenza virus. But also local waterfowl plays a role. And even human beings can be a cause for the spread of the virus. Prof De Wit and colleagues from Brazil discuss this topic.
To keep Avian Influenza virus out of the farm, a good biosecurity is key. But if the farm still gets infected it is very important to act quickly and decisively! Also to avoid spreading to other poultry farms. Hear the concerns from Gustavo Schaefer from Vaxxinova and the response from expert Prof De Wit.
Reflecting on the Latin American situation – we see a lot of infected wild birds, but less so in commercial flocks. How come? And maybe, it is just pure luck or unluck whether or not your farm gets infected? Hear the expert talk.
Whether or not to vacinate against HPAI is not an easy decision to make. Given if a vaccine is available, there are many considerations: export considerations, cost considerations, risk evaluations….and more. Prof Sjaak de Wit discusses with Vaxxinova colleague Thiago Vinholi.
As we speak, the first vaccinations in ducks in France and the first vaccination field trials in layers in the Netherlands have started. How was the situation in the past, how is it now and what can we expect of vaccination in the future? Which factors play a role; trade regulations, politics, economics, health issues….. As being part of this process, prof De Wit knows all the ins and outs. Listen to his explanation.
recording date: June 20, 2023
Free range and organic birds live outdoors – and are therefor exposed to nature and wild birds. These type of chickens have a 6 to 7 times higher chance to get infected by HPAI then the chickens living inside the barn. Prof de Wit explains.
A short explanation on why the use of a DIVA (differentiating infected animals from vaccinated animals) vaccine is recommended, when vaccinating poultry with a live AI vaccine.
Listen to Prof Sjaak de Wit on this topic. Spreading to mammals, including humans, can happen. But the risk of an influenza pandemic is low. However, we have to make sure to notice spreading in time.
see also video below on this topic
Some examples from the field in Southeast Asia by Vaxxinova colleague Ludio Gomes, explained and commented by the expert.
The participants in this Expert Talks session introduce themselves. Off course, the Expert Prof Sjaak de Wit. But also the Vaxxinova colleagues from around the globe taking part in this session. Please click the link to access this video.
These 3 videos have Prof Sjaak de Wit and Vaxxinova colleague Dr Ludio Gomes in disucssion on several topics. But all related to H5 and H9 AI viruses.
Prof Sjaak de Wit explains how specific viruses like H9N2 in Asia and H3N1 in Europe can affect the oviduct. And therewith causing huge losses in egg production. The damage to the oviduct can even cause mortality in the layer chickens.
The H9 virus is not known to spread vertically, but certain way of handling of disposed eggs in the haychery might cause transmission of the virus.
There are for sure differences in virus needed to infect a bird. And in immunogenicity between H5 and H9. But nbot always an exact answer to a question can be given. As follows from the discussion between Prof Sjaak de Wit and Vaxxinova colleague Ludio Gomes.
In the next 5 videos, Vaxxinova colleague Dr Zahid Hossain from Bangladesh has some questions for expert Prof Sjaak de Wit. They are all related to H5 and H9 specifications, differences and similarities.
The series kicks of with “what are the underlying causes of the current H5 and H9 infections?”
The current AI strains are extremely well adapted to wild birds. This is new compared to before and a real gamechanger!
How long can the AI virus survive in poultry farms?
This will only be a relatively short period of time. Prof Sjaak de Wit answers to questions from Vaxxinova’s colleague in Bangladesh, Dr Zahid Hossain.
A clear explanation from Prof De Wit on why a low pathogenic AI virus as H9 is more difficult to control than a high pathogenic AI virus as H9.
A co-infection is really bad news. Low pathogenic AI such as H9 is causing big problems when a co-infection appears.
What will be the best vaccination strategy to prevent a H9N2 infection?
What you need, to achieve a good level of protection, are strong vaccination programs, good and broad vaccines and fanatic monitoring and follow up after vaccination.
Definitively the AI virus has adapted over time – and this leads to a whole new chapter in the book of Avian Influenza. And has consequences….
Waterfowl seems to be less susceptible to the Avian Influenza virus, compared to commercial poultry. Here is why…..
Here’s a conversation on co-infection, interference and possible mixture of appearances of H5-H7-H8. Listen to the Expert Prof Sjaak de Wit and Vaxxinova colleague Ludio Gomes.
Expert Talks on AI – back to Asia. Ludio Gomes in conversation with expert Prof. Sjaak de Wit on the topic of serology.
Diagnosis by serology; the preferred method is depending on the circumstances and the circulating subtypes. But, on average in Asia, the HI test will be the most helpful. Prof. Sjaak de Wit explains why.
After vaccination with an inactivated AI vaccine, a high titre in an HI test does not necessarily mean a high protection level. The results do not guarantee a black & white conclusion.
What are the chances on having a live avian influenza vaccine available in the future?
With the current status of science a live AI vaccine would not considered to be safe – and therefor unlikely to be available. Unfortunately.
Hear the expert Prof Sjaak de Wit and Vaxxinova’s Sainos Manzira, regional manager for Sub-Saharan Africa, on the topic of vaccine protection against different lineages of the same haemagglutinin subtype. And what determines the quality of a vaccine, as such?
What is the importance of neuramidase subtype in a vaccine?
Homologous neuramidase certainly can help in providing protection. But haemagglutinin are the most important.
Prof Sjaak de Wit explains the difference between shedding of virus and transmission of virus.
And which vaccine types that are currently available perform well in these fields.
A feature of HPAI virus is its ability to mutate easily. Especially when there is little vaccine protection against the virus. A repeatedly mutated virus hat spreads to other flocks, will no longer respond to the vaccine. The importance of vaccination explained clearly once more.
It is clear that there is still a lot of (research) work to do when it comes to Avian Influenza. The effect of an early infection on the oviduct is a perfect example. In this video expert Prof Sjaak de Wit and Vaxxinova colleague Dr Husam Bakri exchange experiences from science and from the field on this specific topic. Basis for an interesting discussion!
Confirmation of H5 challenge by PCR, does not necessarily mean all the flocks in a farm are infected. There are cases where one house is infected, while the others are fine. Whether the flocks have been vaccinated or not plays a role, of course. But what if the flocks have not been vaccinated? Prof. Sjaak de Wit explains some scenarios.
The current available vector vaccines, both H5 and H9, can be very helpful. But it will take some time after vaccination to start protection. When there is an infection at early age, these vaccines will not be effective.
Can an inactivated H9 vaccine seroconvert for, and therewith protect aginst, H5? A short answer: No! But it depends on the HI test that is used. In this video Prof Sjaak de Wit explains how to interprete the results of the test and what conclusions to link to it. Message: if you are in an area with H9N2, do not use an H5N2 antigen!
In the Middle East region H9N2 low pathogenic avian influenza is widely present in the field. But, also several inactivated vaccines are available. It appears that vaccinated broilers do not always show seroconversion. Although they look okay. How come? It is important not to underestimate the role of maternally derived antibodies (MDA’s) in broiler chicks from vaccinated breeders. And this also affects the immunity after vaccination. Prof Sjaak de Wit in conversation with Dr Husam Bakri.
The next 4 videos focus on the HPAI situation in Brazil and Latin America. Cross regions, migratory birds are very often the source for spreading the avian influenza virus. But also local waterfowl plays a role. And even human beings can be a cause for the spread of the virus. Prof De Wit and colleagues from Brazil discuss this topic.
To keep Avian Influenza virus out of the farm, a good biosecurity is key. But if the farm still gets infected it is very important to act quickly and decisively! Also to avoid spreading to other poultry farms. Hear the concerns from Gustavo Schaefer from Vaxxinova and the response from expert Prof De Wit.
Reflecting on the Latin American situation – we see a lot of infected wild birds, but less so in commercial flocks. How come? And maybe, it is just pure luck or unluck whether or not your farm gets infected? Hear the expert talk.
Whether or not to vacinate against HPAI is not an easy decision to make. Given if a vaccine is available, there are many considerations: export considerations, cost considerations, risk evaluations….and more. Prof Sjaak de Wit discusses with Vaxxinova colleague Thiago Vinholi.
As we speak, the first vaccinations in ducks in France and the first vaccination field trials in layers in the Netherlands have started. How was the situation in the past, how is it now and what can we expect of vaccination in the future? Which factors play a role; trade regulations, politics, economics, health issues….. As being part of this process, prof De Wit knows all the ins and outs. Listen to his explanation.
recording date: June 20, 2023
Free range and organic birds live outdoors – and are therefor exposed to nature and wild birds. These type of chickens have a 6 to 7 times higher chance to get infected by HPAI then the chickens living inside the barn. Prof de Wit explains.
A short explanation on why the use of a DIVA (differentiating infected animals from vaccinated animals) vaccine is recommended, when vaccinating poultry with a live AI vaccine.
Listen to Prof Sjaak de Wit on this topic. Spreading to mammals, including humans, can happen. But the risk of an influenza pandemic is low. However, we have to make sure to notice spreading in time.
see also video below on this topic
Some examples from the field in Southeast Asia by Vaxxinova colleague Ludio Gomes, explained and commented by the expert.
The participants in this Expert Talks session introduce themselves. Off course, the Expert Prof Sjaak de Wit. But also the Vaxxinova colleagues from around the globe taking part in this session. Please click the link to access this video.