Avian Influenza H9N2 in the Middle East Countries

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Summary

Avian influenza (AI) is a highly contagious disease caused by type A influenza viruses that are members of the family Orthomyxoviridae in the genus Influenza virus A. Middle East countries have an estimated poultry population of 3 billion broilers, 137 million commercial layers, 30 million breeders, 2x106 layer breeders and 500.000 GP broilers,180.000 GS layers. Since 1999 the region faces different health problems such as drop in egg production, close to peak production: up to 62 % during 2-3 weeks, thin – shelled, rough and misshapen eggs, moderate mortality and respiratory signs in commercial Layer and Breeder production; while in broiler it was noticed severe mortality (over 60% after 3 weeks of age), severe respiratory signs, high percentage of condemnation due to secondary bacterial infections. Different serum and tissues samples were taken from breeders, layers and broilers from different countries and analyzed by serology and virus isolation. The results showed the presence of AI H9N2 virus in the Middle East area combined with IB or ND.; different investigations were done using reduction in mortality and improvement in production as parameters. By using Nobilis Influenza H9N2, the farmers were able to control the economic impact of the infection.

 

Keywords: AIV; Middle East; Nobilis Influenza H9N2 vaccine. 

 

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 earth, circulating in wild bird and domestic poultry populations worldwide. Although AIV infections commonly result in low mortality in avian populations, in immunosuppressed chickens, recent isolates of H9N2 virus have been associated with high mortality in young chicken and a severe decline in egg production in laying chickens via secondary bacterial infections of the upper respiratory tract and other viruses resulted in significant economic losses of domestic poultry.

 

AI in the Middle East

Estimated poultry population in the Middle East consists of 3 billion broilers, 137 million commercial layers, 30 million breeders, 2 million layer breeders. Since 1999 the region faces different health problems such as drop in egg production, close to peak production: up to 62 % during 2-3 weeks, thin – shelled, rough and misshapen eggs, moderate mortality and respiratory signs in commercial Layer and Breeder production; while in broiler it was noticed severe mortality (over 60% after 3 weeks of age), severe respiratory signs, high percentage of condemnation due to secondary bacterial infections. Thus, it has been believed valuable to find out what is the reason behind above mentioned respiratory problems.

 

Materials and methods

Several field visits to flocks with these clinical signs were performed in Kingdom Saudi Arabia (KSA), Jordan, Syria, Lebanon, United Arab Emirates (UAE), Kuwait, and Yemen. A large number of samples (serum and tissues) have been collected for serological testing and virus isolation. ELISA tests performed for the major respiratory diseases such as IB, ND, AI, TRT, EDS and ILT. Test results showed the presence of AI. So HI test and virus isolation from tissues, kidney, trachea, lung and ceacal tonsils was done to detect and type the strain of AI.

 

Results and discussion

More than 60%, 1790 blood samples showed positive AI antibody response in AGP and Elisa tests. Same sera tested in HI showed positive titers against AI H9 strain, (Figure 1) and IB 4/91(data not shown).

From tissues frequently AI H9N2 virus was isolated, (Table 1), and IB serotype 4/91 (793B) also, (data not shown).

 

 

Figure 1: HI results of Broilers, Breeders and Layers

Table 1: Number of virus isolation samples.

 

Discussion and Conclusion 

Field trials have been conducted in UAE at a farm, where AI H9 was isolated the first time. In this commercial layer farm one house (45,000 birds, Lohmann) was vaccinated. A second house (45,000 birds, Lohmann) was not vaccinated as control. Birds were vaccinated twice with 0.5 ml of the vaccine Nobilis® Influenza H9N2 at 12 weeks and 16 weeks of age. Production and mortality were monitored. (See figure 2). The control flock which showed a severe drop in egg production just before the peak of lay: 62% at 21 weeks of age. No drop in egg production and mortality were observed in the vaccinated flock. Intervet was the first company to introduce Nobilis® Influenza H9N2 in the area after intensive field investigation. Field trials were performed in the most endemic area and showed good protection against clinical signs. Figure 3 showed Production and mortality curves of a breeder flock, infected with AI H9N2, while figure 4 showed the egg quality of during AI problems in a commercial layer farm.

 

 

Figure 2: Results of a field trial with commercial layers in UAE: Production curve of a non-vaccinated flock (Non Vac) and a flock vaccinated with Nobilis Influenza H9N2 at 12 and 16 weeks of age (Vac).

  Figure 3: Production and Mortality curves of a breeder flock, infected with AI H9N2.

All the results from isolation, Elisa and HI tests show that H9N2 is present in the Middle East countries. Most of the governments allowed the use of vaccines containing the antigen H9N2 in order to control the economical impact of the disease.

 

In conclusion: AI H9 virus has a high prevalence in the Middle East region. The vaccine Nobilis® Influenza H9N2 helps the farmers to control the economical impact of the infection.

 

Figure 4: Egg quality during AI problems in a commercial layer farm.

Acknowledgements

  • The author would like to extend his thanks to Animal Health Service Deventer – The Netherlands.
  • Institute of Animal Health, Compton – UK.
  • R&D service laboratory, MSD-International – The Netherlands for their technical help.

 

References

1. HOMME, J. and EASTERDAY, C. (1970) Avian influenza virus infections I Characteristics of influenza A-turkey-Wisconsin-1966 virus. Avian Disease, Vol.14, pp. 66-74.

2. KAWAOKA, Y., CHAMBERS, M., SLADEN, L., and WEBSTER, G. (1988) Is the gene pool of influenza viruses in shorebirds and gulls different from that in wild ducks? Virology, Vol. 163, pp. 247-250.

 
Author/s
 
April 16, 2017

Could you please advise the distribution of H9N2 in Middle East countries. Thanks

2
Reply
Mohamed Swelam Mohamed Swelam
diploma degree
April 16, 2017

Dr.Hossam; I send you questions related to your post but no answer.

0
Reply
Husam Bakri Husam Bakri
Veterinary Doctor
April 16, 2017
Dear Mohamed,
I am sorry the below is my email :
Husam_bakri@hotmail.com
Mobile : 00962795553703

All the best
1
Reply
Husam Bakri Husam Bakri
Veterinary Doctor
April 16, 2017

Dear Dr. Turki,
Hope you are doing well. AI H9N2 is present in most of the Middle East and North Africa countries and most of them using the vaccine to control the disease.

All the best

Bakri

1
Reply
Youssef Youssef
lecturer of avian disease (virology)
April 24, 2017
Dear Hussain what about gene sequence in all isolates and it's relationship to original clade I suspected that diverse changes are done so vaccination process not achieved full former protection
and what your think about dis tincture difference between titer log in the same virus between HA and HI titer
1
Reply
Husam Bakri Husam Bakri
Veterinary Doctor
April 25, 2017

Dear Dr. Yousef,
Thank you for your questions.
1- We hade 3 new isolation on 2013 from different countries and we found that they are 93% - 95% close to the vaccines strain. From my field experience, the vaccine did a great job to control the AI, specially in layer and breeder. Regarding using the vaccine and not getting good protection, specially in broiler, the following reasons are playing main roles:
1-Biosecurity is not good. 
2- If AI infection before 3 weeks in this case. vaccine will not help as the protection from the killed vaccine will be after 3 weeks. we have seen this cases in many areas.
3- Vaccine application. During my hatcheries vaccination audit, I have seen many cases with the % of the proper vaccination at day one is not more than 60%, in this case 40% are not protected.

We have farmers using the vaccine in high challenge with very good results, this showed that AI vaccines from most of the good international companies giving good protections.

Regarding titer question. Can you please give me more explanation.

All the best.

Bakri

1
Reply
Entang Bustanudin Entang Bustanudin
Animal Health Technologist
April 27, 2017

Dear Dr. Husam,
There are some questions I will ask you:
1. To obtain a high viral titer, how many virus particles of AI H9N2 should be inoculated into embryonated eggs?
2. Can H9N2 virus cause dwarf and curling in embryo?

0
Reply
Husam Bakri Husam Bakri
Veterinary Doctor
April 28, 2017

Dear Entang,

1-Thank you for your massage and hope you are doing well. Honestly, I do not have any data on this, but according to the potency test, every dose has 7.0 Log HI unite.
2- The only sure information I can reply is when you challenge SPF birds by spray method with AI H9, the virus showed clinical signs and mortality.

All the best.

0
Reply
jignesh barot jignesh barot
M. V. Sc. (Avian Diseases)
May 3, 2017
Dr. Bakri,

Thank you for being a continuous source of information on H9N2 vaccine/vaccination.

Can I get your Inactivated H9N2 vaccine in Anand, Gujarat (India)

Which age would be perfect for vaccination, Day-1 or Day-5?

Thanks
Dr Jignesh Barot
jgbivrig@gmail.com
0
Reply
May 3, 2017

Import of avian influenza vaccines into India is banned by government of India.

0
Reply
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