Discussion created on 08/28/2012

vaccines against infectious laryngotracheitis virus

Forum: Attenuated vs. vector vaccines against infectious laryngotracheitis virus (ILTV)

Infectious laryngotracheitis virus ILTV represents an important problem in production of chickens. The disease causes respiratory symptoms but also affects production of eggs, chicken body weight and finally mortality. As in case of other herpesviruses including Marek’s disease virus one of the most important aspect remains biosecurity. The most popular vaccination is based on attenuated ILTV strains (SA2 and A20, Pfizer) and (Serva, Intervet). However in some circumstances after serial passaging of the attenuated CEO (chicken embryo origin) strains on chickens the viruses may recover their virulence causing massive death of chickens. Moreover in 2008 the reports from Australia described the recombination event between virulent and attenuated ILTV strains that resulted mortality close to 18% of the flock. The solution for tomorrow are the new vector vaccines based of herpesvirus of turkey (HVT) or (FPV) fowl pox virus carring genes encoding viral glycoproteins gD, gI or gB. The main advantage of such vaccines application is the lack of viral transmission that overcomes the problem with the recombination between strains in chickens. Since these vaccines have been accessible in US I am curious about their efficacy in comparison to the live attenuated vaccines. Also the last results have shown that these vaccines are the most effective when in ovo route is applied vs. (ED) eye-drop or DW (drinking water) ways of application.

What is your experience using both live attenuated and vector vaccines based on HVT or FPV? All comments regarding your personal opinion of vaccination against ILT are highly appreciated.

Best regards,

Greg

Grzegorz Wozniakowski
Doctor of Veterinary Medicine
remove_red_eye 2822 forum 15 bar_chart Statistics share print
Share :
close
Eric Gingerich Eric Gingerich
Veterinary Doctor
August 28, 2012

The following are my experiences with egg layer chickens in the US: Good results have been seen with the rHVT-ILT vaccine to prevent early problems due to early exposure. In combination with either the CEO vaccine by eyedrop or the rPox-ILT vaccines, very good protection is seen over the long term. The rHVT-ILT by itself at day one by subQ will hold in moderate risk situations while the rPox-ILT vaccine by itself will only hold in very low risk conditions.

Reply
Manolo Fernandez Diaz Manolo Fernandez Diaz
Veterinary Doctor
August 29, 2012

Interesting forum about Infectious laryngotracheitis virus. In Peru, the LT problem began in 2007, a comprehensive work of the health authority (SENASA), Poultry Farmers Association (APA) and private laboratories and state agreed to not using live vaccines for the control of LT.
We have had a remarkable success with a harmonic work between biosafety,using recombinant vaccines (HVT-IBD-LT, HVT-LT and FOWL POX- LT) and inactivated vaccines with adjuvants that stimulate the immune response at mucosal level.

Today in our lab we are working on the development of multi epitope vaccines

Reply
March 27, 2013

Dear Dr. Greg,

I already use this vaccine in many layer & broiler breeders farms as I was working in CEVA SANTE ANIMALE as a key account manager in KSA. This enabling me to study & notice the advantages of vector vaccine FP LT or FP LT AE vaccine. Yes, I agree with you that with this vector vaccine there is no way to virus recovering to return back to its virulence while on the other hand i saw how is attenuated traditional vaccine can cause virus recovering to be virulent & infect other birds which have lower immune level against ILT specially in multi-age layer farms as the virus transmitted from newly transmitted poults in production houses to older birds at neughbour houses (lower immunilty due to decline in AB after 20 weeks from vaccination with attenuated ILT vaccines) which give a chronic or mild form of ILT with moderate increase in mortality & slight decrease in production. Also i saw how much traditional attenuated vaccine has a role to transmite disease to broiler in winter season in EGYPT. This is one advantage enough to change mind towards ILT prevention while there are other advantages which are valuable like:

1- No post vaccinal reaction which in attenauted types cause respiratory manifestation which adversely affect growth & cause mortality and it needs antibiotic cost to overcome PVR .
2- with this vaccine you vaccinate against 2 or 3 diseases within one shot.
3- by using this vector vaccine specially in hot countries with strict hygeinic measures you can eradicate disease at local areas where there is no way for virus shedding beside character of ILT virus itself which are:

a- ILT virus are easily distructed by heat over 32 C
b- ILT strains have only one serotype (no variants)
c- ILT virus has only one host which is chicken so there is no carriers for ILT except chicken
while at the level of effectiveness it gave excellent results

Yasser HUSSEIN

Reply
Manolo Fernandez Diaz Manolo Fernandez Diaz
Veterinary Doctor
May 20, 2013
Indeed the use of recombinant vaccines is the only alternative to eradication and control of avian laryngotracheitis.
We are in the era of biotechnology, inactivated vaccines currently have enhanced with new adjuvants and recombinant proteins and obtained
a very good protection against LT

Manolo Fernandez
Reply
Gary Butcher Gary Butcher
Doctor of Veterinary Medicine
September 23, 2013

Dear Dr. Greg,

I had worked with recombinant vaccines in my laboratory for over 10 years against a number of agents-- ILT, Gumboro, Newcastle, Marek's. These worked very well in the laboratory, giving complete protection against contolled challenge. However, in the field they were a disappointment in that small disease breaks consistently occurred. Recently in the state of Florida (USA), the recombinant ILT was used and these flocks broke with the disease. Since these vaccines worked very well in the laboratory and poorly in the field, it is clear that this is due to sanitary and vaccine application errors. I feel that if the poultry house is completely decontaminated of agents that would interfere with the replication of the vector virus, then these products will be successful.

My main problem at this time is that for a vaccine to be accepted it has to be at least as good in protecting as the currently available vaccines on the market and it has to be economical. I do not feel the ILT recombinant meets these critera at this time.

Gary Butcher

Reply
Manolo Fernandez Diaz Manolo Fernandez Diaz
Veterinary Doctor
September 23, 2013

The PERU is one of the few country in the world where LT control have Not been used live vaccines. The use of recombinant vaccines (HVT-LT, HVT-IBD-LT and FP-L) associated with LT inactivated vaccine have remarkable success in controlling LT.
The marketing system in PERU of broilers is 75% live (standing), and laying hens at the end of its production is sold for consumption 100% live in standing.
That shows if possible the LT control with recombinant vaccines and oil vaccines.
In Australia in July 2012 has been reported recombination of two commercial live vaccines in cell culture leading to a new highly pathogenic virus with mortalities more than 20%, this would not be possible in the control program of PERU

Reply
Eric Gingerich Eric Gingerich
Veterinary Doctor
October 2, 2013
In answer to Dr. Butcher's statement, please state which vaccine failed and what type of birds were involved. We have seen the pox vectored ILT vaccine fail badly in egg-type pullets in high challenge situations. The HVT vectored product has held up much better in egg-type pullets if the vaccine was properly applied at the hatchery and a second application of live vaccine or pox vectored ILT vaccine is given at 8 weeks. In broilers, none of the vectored ILT products applied inovo or day old has totally prevented outbreaks.
Reply
Alvin C. Besagsa Alvin C. Besagsa
Doctor of Veterinary Medicine
October 3, 2013
In our country, Ive been conducting serology among layer farm in northern Mindanao, farmers does not have ILT vaccination, but it turn outs positive in the ELISA test
what does it mean, do i need to recommend vaccination against ILT, what is the best recombinant vaccine that is safe to use? and what is the normal titer level that we can say that, this titer level come from vaccination or from the field challenge?

i need your comments plz.
Reply
Eric Gingerich Eric Gingerich
Veterinary Doctor
October 3, 2013
In my opinion, serology is not an accurate method to diagnose ILT. Clinical signs along with histopathologic lesions, positive PCR, or positive FAT should be used to determine if vaccination is needed. As far as safety, any of the recombinants are safe to use and will not result in ILT disease issues.
Reply
Alvin C. Besagsa Alvin C. Besagsa
Doctor of Veterinary Medicine
October 3, 2013
Clinical signs are the following
1. tears in the eye with seems and reddish in color
2.swollen face.
3.Upon necropsy some birds has hemorrhagic tracheal ring
Blood stained trachea or even clotted blood was observed near the syrinx,this sign convince me conduct serology on ilt, and yet it turn out positive
to mention, farm has high ammonia level since it is situated in poorly ventilated areas,this flock also has high antibody titer of ibv, that reaches 20,000+++, peak production is only at 85%
please comment......
Reply
Eric Gingerich Eric Gingerich
Veterinary Doctor
October 3, 2013
IBV, Mg, ammonia, infectious coryza, Pasteurella, avian influenza, Newcastle can all produce the signs you describe. Antigen or pathogen detection tests need to be utilized to differentiate these diseases. For ILT diagnosis, one can also use histopathology. Finding intranuclear basophilic inclusion bodies in syncytia of the tracheal or brohchial epithelium is diagnostic for ILT.
Reply
Aoun Khan Aoun Khan
general manager production
October 21, 2013

I  think that a possible solution would be the use of tissue culture ILT Vaccination

Reply
Dr. Mahadi Hasan Dr. Mahadi Hasan
Consultant
April 5, 2014

Dear Mr. Manolo,

Nice to meet with you, I got your contact address from your colleague Mr. Avi. I am Dr. Mahadi Hasan working in vaccine field and more interested in recombinant vaccine. I saw you discussion and know that your company can produce recombinant vaccine, I would like to work on your vaccine and interested to import your vaccine in our country. In Bangladesh there is a huge business opportunity, there is no local manufacturer and we are fully depends on import from other MNC companies but they can't meet the full demand. So there is a gap and also there is huge demand of this new technology. I believe I will capture the full market and give you good business with your best cooperation. So if you are interested please contact me.

Waiting for your quick and positive feedback.

Best Regards,

Dr. Mahadi Hasan
Dhaka, Bangladesh

Reply
nosheen naheed nosheen naheed
Student
November 29, 2016

In my farm birds are producing voice like (garer) and sneezing. the age of broiler birds are10 days. killed vaccination was given at 5th day (ND and IB). I think this is ILT problem but I'm not sure about it. Mycoplasma galisepticum and synovi are negative. What can I do? Please, help me.

Reply
Mustafa Ezat Mustafa Ezat
Veterinary Doctor
July 17, 2018

I totally agree with you. Attenuated live ILT vaccine (CEO) can be transmitted to low immunity chicken or unvaccinated chicken lead to vaccinal laryngotracheitis infection, and also have severe vaccine reaction but you can use live vaccine tissue culture, which has a low vaccine reaction.
About usage vector ILT vaccine, I have some comment about it , immunity and protection against ILT mainly cellular immunity not humoral immunity vector vaccine induce cellular immunity or not some scientific article about vector ILT vaccine will provide 35 % protection in high challenge area but if you like to maximize protection should be give booster dose to achieve 80% protection.

Thanks,
Dr. Mustafa Ezat
Poultry Health Division Head.

Reply
1
print
(2822)
(15)
Would you like to discuss about this topic: Forum: Attenuated vs. vector vaccines against infectious laryngotracheitis virus (ILTV)?
Engormix reserves the right to delete and/or modify comments. See more details
Post a comment
Create new discussion :
If this discussion does not cover topics of interest or raises new questions, you can create another discussion.
Consult a professional in private:
If you have a specific problem you can perform a consultation privately to a professional in our community.
Frederic Hoerr
Frederic Hoerr
DVM, PhD, Diplomate ACVP, ACPV
  Strasburg, Virginia, Estados Unidos de América
 
   | 
Copyright © 1999-2019 Engormix - All Rights Reserved