Introduction The avian influenza virus (AIV) H9N2 subtype was first characterized in 1966 as causing mild respiratory diseases in turkeys (Homme and Easterday, 1970) and, for the first decade after its isolation, was found only in shorebirds and mallards (Kawaoka, et al., 1988). However, after almost 50-years evolution and propagation, the H9N2 viruses have spread across most of the ea...
Dear Amen, First thank you for your question. Elisa test is group titer, you will not know which strain is giving the titer. That is why when the vaccine is used with strain H9 or H5 and you need to evaluate the vaccine HI is the accurate test for this.
Dr. Husan Bakri!
I read you write up with great enthusiasm. It's a good piece where it is applicable but in most cases like Nigeria for example, vaccination against the virus is being discouraged due to high mutation being witnessed. In some farms where some of this vaccines are secretly being used they still came down with the virus even in a more severe form.
Those even vaccinated could serve as reservoir and shedding the virus to other free areas. I think a more proactive measures should be researched into as this disease is causing too much ripples in the poultry agri-business sector.
Good job but could we have some work done on H5N8 that is ravaging many farms now? People are no longer reporting cases due to non government challant attitude to assist farmers.
Waiting to read more from you Dr Husan.
Stay Blessed
Dr. David G.O
Dear Dr HUSAM BAKRI,
Thank you for discussing this topic. I'd like asking you about the adjuvant used in the killed vaccines for H9 and the influence that make the nature of this, especially in the waiting time of setting-up protective immune status. I like to focus in if it has some adjuvant that recommended much more for the broilers as short lived in comparison to other long lived poultry such breeders or layers for example?
Thank you.
Abdelaadim EL HILOUFI.
Dear Dr. Abdelaadim, Yes, I agree with you. Type of adjuvants are playing a big role in immune response as you need antigens to be very well distributed in the adjuvants, otherwise you will not see the homogeneity in titers response and the stability for a long time.
Soon you will see in the market type of adjuvant give immunity before 2 weeks, this 100% will help to protect the birds with early AI H9 early infection, specially in broiler without maternal immunity.
I think avian flu H9N2 in middle east represent avery big problem in avian rearing and i think using of killed vaccine in layer is very important and from my field observation through my lab in egyptian market the vaccination in broiler is of no value as this virus can enter farm from one day as i see
Thank you
Dear Dr. Yes, I agree with you when there is early infection in broiler from AI, the vaccine will not help. That is why we strongly advice to know when you have AI challenge in broiler, this way you will know if the vaccine will help or not.
Live attenuated, cloned and variant strains are used to protect against ND, IBD, Marek's etc.
Unfortunately, we cannot handle this virus live in any form.
Killed vaccines are meant for sustained and slow release of the antigen so that the protection can be given for a longer time. Consequently, the action starts late.
If we can find an adjuvent which can release fast, it should help. This is a very natural thought. Should be explored by vaccine manufacturers who specialize in that subject.
Why only broilers? Even Breeders and Layers are under threat till the immunity is established.
I think that it will be very interesting to use adjuvants that make earlier and faster immune response, that will be of very interest especially in the first stage of poultry life, but we must turn attention to maternal antibody in order to avoid any interference. So if we carry out the follow components, i assume that it will come off :
1- to have chickens with protective maternal antibody as high as we can.
2- delay the administration of the vaccine, it will be late on the farm.
3- regarding how life span will take, in order to give booster dose if nessecary.
4- to combine each type of vaccines, the first with faster adjuvant working and the second later working and durable one for the same vaccine programm, this may be encouraged especially for long lived poultry.
5- having vaccine strain enough similar to circulating virus.
All the best,
Dr Abdelaadim EL HILOUFI.
Dear Talapaneni, Thank you for your comments. No, this vaccine with special adjuvant will not be just for broiler it will be for all birds, but I have mentioned broiler as they are the ones getting infection early.
Dr. Bakri,
Thank you very much for your quick reply.
Have you conducted challenge trials (under Isolation) ? -
I. e. Vaccinated birds challenged against different isolates/strains of H9N2 viruses - what were the results ?
Thanks & Regards,,,
Is there any difference between fast growing and slow growing birds in attaining protective level of immunity after injection with this inactivated (H9N2) vaccine?
03/04/2017 | Dr. Bakri,
Thank you very much for your quick reply.
Have you conducted challenge trials (under Isolation) ? -
I. e. Vaccinated birds challenged against different isolates/strains of H9N2 viruses - what were the results ?
Is there any difference between fast growing and slow growing birds in attaining protective level of immunity after injection with this inactivated (H9N2) vaccine?
Thanks & Regards,,,
Dear Barot ,
First thank you for your message and sorry for late reply as I was traveling.
- yes we did challenge under isolation condition and the group has been vaccinated was very well protected and the challenge method was as spray .
- yes with differant isloations of H9 to evaluate the pathogensity all of the gave same level except one of them gave more than , others but the area where the vaccines are used from different producers gave good results.
All the best
Bakri
le test H I il faut qu'il soit specifique du H9 ou H5 de la souche du pays pourquoi parceque le HA c'est la portion qui mute et pour cela qu' ont specifie le serotype du pays par sequencage