Infectious Bronchitis: Evolving Strategies for an Evolving Virus

POULTRY HIGHLIGHTS OF A ROUNDTABLE DISCUSSION HEALTH T O D A Y ®

INFECTIOUS BRONCHITIS:

EVOLVING STRATEGIES

FOR AN EVOLVING VIRUS

AUGUST 2019 • WASHINGTON, DC INFECTIOUS BRONCHITIS: EVOLVING STRATEGIES FOR AN EVOLVING VIRUS

WELCOME

T he evolution of infectious bronchitis virus (IBV) is a continuing challenge for poultry producers and veterinarians. In broilers, this highly infectious coronavirus can present in its traditional form as respiratory disease, predisposing birds to secondary bacterial infections. Relatively newer on the scene are potentially deadly nephropathogenic IBV strains. In any form, IBV impairs animal welfare and is an important source of economic loss for poultry producers.

Vaccination is key to IBV control. Although homologous vaccines are considered to be the

JON SCHAEFFER, DVM, PHD most effective, development of a new vaccine for every new IBV strain that emerges is difficult Director, Poultry Technical Services, Zoetis to impossible. Finding an effective existing vaccine or combination of vaccines that will [email protected] zoetisus.com/foodsafety cross-protect is a worthwhile venture, but there’s no guarantee of success.

Zoetis recently hosted a roundtable featuring renowned IBV experts as well as practitioners who shared their knowledge about IBV. These proceedings are highlights from the conversation and are provided with the hope they will help the industry achieve better control of IBV, improve animal welfare and minimize IBV’s ﬁnancial burden.

Sponsored by POULTRY HIGHLIGHTS OF A ROUNDTABLE DISCUSSION HEALTH T O D A Y ®

TABLE OF CONTENTS

1 IBV TRENDS...... 4

2 IBV DETECTION...... 5

3 IBV IN BROILER BREEDERS...... 6

4 IBV AND IMMUNITY...... 6

5 IMPACT OF NO ANTIBIOTICS EVER...... 7

6 IBV EVOLUTION AND SPREAD...... 8

7 ROLE OF IBV VACCINATION...... 9

8 VACCINATION STRATEGIES...... 11

9 IBV CROSSPROTECTION...... 12

10 VACCINATION OF BROILER BREEDERS...... 14

11 IBV AND NEWCASTLE DISEASE PROTECTION...... 16

12 HOW MANY IBV VACCINE SEROTYPES?...... 18

13 VACCINE APPLICATION PITFALLS...... 19

14 MINIMIZING VACCINE REACTIONS...... 22

15 IBV ARKANSAS CONUNDRUM...... 24

16 REFLECTIONS...... 25

IBV KEY: In conversation, poultry health specialists often use abbreviated terms when describing long, numeric names of IBV serotypes. Here’s a key to the ones used in this discussion:

DMV/1639 = IBV Delmarva 1639 • GA08 = IBV Georgia 08 • GA13 = IBV Georgia 13 • GA98 = IBV Georgia 98 • PA/1220 = IBV Pennsylvania 1220 INFECTIOUS BRONCHITIS: EVOLVING STRATEGIES FOR AN EVOLVING VIRUS

PANELISTS

MARK JACKWOOD, P h D UNIVERSITY OF GEORGIA

MARK BURLESON, DVM WAYNE FARMS

KALEN COOKSON, DVM ZOETIS

DAVID FRENCH, DVM SANDERSON FARMS

MEAGAN SLATER, DVM MOUNTAIRE FARMS POULTRY HIGHLIGHTS OF A ROUNDTABLE DISCUSSION HEALTH T O D A Y ®

SARAH TILLEY, DVM FIELDALE FARMS

MODERATOR: JEAN SANDER, DVM ZOETIS

BRIAN LADMAN, P h D UNIVERSITY OF DELAWARE

GUILLERMO ZAVALA, DVM, Ph D AVIAN HEALTH INTERNATIONAL INFECTIOUS BRONCHITIS: EVOLVING STRATEGIES FOR AN EVOLVING VIRUS 1 IBV TRENDS ...if signiﬁcant respiratory diseases pop up, it’s typically due to a new variant IBV. “ MARK BURLESON, DVM ”

? SANDER ? SANDER ? SANDER Would practitioners on the panel What geographic regions do your What I’m hearing is that the IBV briefly give us an idea about the operations cover, and do the IBV serotypes seen vary regionally. impact of infectious bronchitis in serotypes you see differ from one But given that, are you seeing an their respective operations? region to another? overall increase in problems with bronchitis, or is it really more of BURLESON FRENCH a shifting landscape? I’d say it’s our biggest respiratory issue. At Sanderson Farms, we see regional Bronchitis seems to be a year-long challenges that are a little different from TILLEY struggle — tracking variants as they arise one area to the next. We cover the We routinely take serum from processed and staying ahead of them. Southeast from Texas all the way over to flocks. In summertime, IBV calms down a North Carolina. I would say in Texas, our bit, whereas in winter titers will increase. FRENCH biggest challenge has been Newcastle But generally, I’d say our titers stay IBV Arkansas tends to be a nagging disease (ND). For IBV, our biggest relatively stable. problem for us. This year, we thought we challenge was with DMV/1639, which was had everything under control, particularly primarily in south Georgia, although we FRENCH with our vaccination program, but then found a little of it in Mississippi as well. In I’d say it’s a shifting landscape. A lot of we had our first experience with the Mississippi, we mostly find GA08. So, our problems with bronchitis before this IBV variant DMV/1639. It caught me there’s a bit of a different challenge in past year were self-induced with vaccine completely by surprise. We didn’t even different regions. application. This past year, it’s been a little know we had a respiratory disease. bit of a different scenario with DMV/1639 We were trying to explain some lost BURLESON and IBV evolving and then spreading. It’s feed conversion and stumbled upon We cover a lot of the Southeast from been a greater concern for us this year. DMV/1639. So, we have it in our operation, Arkansas to North Carolina and all the Maybe a little bit more of a bronchitis and it’s been a new challenge to figure out states in between. It’s very geographical challenge. I expect to see a new IBV how to keep it under control. That’s been — there are different IBV serotypes in variant emerge about every 5 years. our biggest issue. different places. For instance, we’ve isolated DMV/1639 isolates only in south BURLESON SLATER Alabama and in Arkansas. I agree. There is a seasonal aspect to Poultry flocks on the Delmarva shore have bronchitis. Generally based on my experienced quite a bit of bronchitis and SLATER experience, summer is always better, and continue to struggle with control of Mountaire has isolated GA13 in North winter and spring tend to be the worst. DMV/1639 — probably for the last 3, if not Carolina flocks. We’re going to try to do However, if significant respiratory diseases more, years. Prior to my position with more surveillance and see what’s going on pop up, it’s typically due to a new Mountaire Farms, I worked as a consulting in that area. On the Delmarva shore, variant IBV. veterinarian in Pennsylvania where I got there’s been quite a bit of DMV/1639 as quite a bit of experience with DMV/1639 well as some GA08. It was the same in Problems can also arise if someone in broilers. We saw the impact on feed Pennsylvania when I was there. misapplies vaccine, or maybe you decide conversion and a little bit of airsacculitis. to go to a different vaccine manufacturer The challenge was finding a vaccination and the new vaccine just doesn’t play well program that didn’t cause more with your current program. But I’d say airsacculitis than DMV/1639. primarily the ebb and flow of variant bronchitis viruses is what we struggle with from year to year.

4 POULTRY HIGHLIGHTS OF A ROUNDTABLE DISCUSSION HEALTH T O D A Y ® 2 IBV DETECTION With GA13, we didn’t have a huge increase in mortality, but the processing plant complained about airsacculitis. “ SARAH TILLEY, DVM ”

? SANDER have other confounding factors. I think ? SANDER Are problems due to IBV usually it’s more of an issue at the plant than What about secondary infections? detected during live production or in the field. Someone in our organization at processing? once called it a silent airsacculitis where BURLESON you really don’t know you have any issues Those are primarily issues with FRENCH until the plant calls you and says, “Hey, Escherichia coli. When we found DMV/1639 in Georgia, it we’re basically shut down or our line was an interesting experience. We were speeds are down...with airsacculitis.” FRENCH off about 3 to 6 points in feed conversion It was mentioned earlier that there’s a and were trying to figure out why. We put TILLEY seasonality to it, and I think that has to do together a posting session. We looked at I agree that most of the impact is in the with the extra stress factors on the birds in 10 flocks of various ages. Those flocks plant. With GA13, we didn’t have a huge wintertime. In general, if you’ve got a appeared to be normal, healthy birds. increase in mortality, but the processing problem in the summertime and going There had been no mortality on the farm plant complained about airsacculitis. into fall, you can expect to have a and no flushing, but almost every bird we miserable winter. There are definitely opened up had a 3+ airsacculitis score. some outside circumstances that affect ? SANDER respiratory challenge. And I do think At first, I didn’t believe what I was seeing Dr. Burleson, what are the E. coli’s probably the biggest secondary and questioned whether the birds at “confounding factors” you bacterial infection. It can be either a posting were, in fact, normal, healthy referred to earlier? secondary problem or a primary birds. So, I went to the farm and picked pathogen, depending upon the type of out birds myself, only to find that it was BURLESON E. coli creating the difficulty. real. At first, I thought it couldn’t be I was thinking about the use or mis- DMV/1639 since there was no flushing, application of aggressive respiratory but the virus had changed to more of a vaccines, like IBV Arkansas or the respiratory challenge. I think we just Newcastle B1 strain. You’ve got a variant caught it early because mortality did IBV that’s relatively mild in itself. But if start to pick up and got worse after you throw in other factors like aggressive about 35 to 40 days of age. We adjusted respiratory vaccines, poor ventilation and our vaccination program to correct farm management issues, that’s when the situation. you start seeing more clinical disease, in my experience.

? SANDER Has anyone else had a similar experience?

BURLESON Based on my experience with GA08, GA13 and recently DMV/1639, I’d say IBV is a relatively mild virus — assuming you don’t

5 INFECTIOUS BRONCHITIS: EVOLVING STRATEGIES FOR AN EVOLVING VIRUS 3 IBV IN BROILER BREEDERS 4 IBV AND IMMUNITY We don’t have an autogenous DMV/1639 vaccine, so we used a commercial GA08 vaccine at day of age in our pullets. “ DAVID FRENCH, DVM ”

? SANDER BURLESON ? SANDER How about IBV in broiler breeders? I can’t say we’ve had many issues with Dr. Zavala, what’s the role of What are you ﬁnding? broiler breeders, at least with DMV/1639. immunity regarding infectious I can’t say that we’ve looked extremely bronchitis and secondary FRENCH hard either, but we have not really seen infections? Are broiler ﬂocks I was concerned when we found many issues. immunosuppressed? DMV/1639 was predominant in our south Georgia complex, and we didn’t have TILLEY ZAVALA protection for that particular strain in Whenever we see any kind of decrease in That’s a compound question. Can they our breeders. We heard stories about egg production, we try to correlate it with be immunosuppressed? Yes. However, false-layer syndrome and cystic ovaries in something, which is often a bit higher I don’t believe that, at least in North breeders in other locations, so we’ve since incidence of ND. America, immunosuppression is the included some protection in our breeder reason we see bronchitis in broilers, program to try and take care of that. But breeders or layers. But it can happen I was very concerned about it when I saw in pockets or in particular situations. how widespread the challenge was in our If it does happen, we surveil for operation in south Georgia. Those pullets infectious bursal disease (IBD) as are very similar in many ways to broilers well as chicken anemia virus and and they are in the same area, so they Marek’s disease. Those would be your should be exposed to the same diseases. primary infectious pathogens causing immune suppression.

? SANDER As far as immunity to infectious What changes did you implement? bronchitis, the only practical way we can actually measure that is with FRENCH serology. We know that a very important We don’t have an autogenous DMV/1639 component of the immune system and vaccine, so we used a commercial GA08 how it responds to bronchitis vaccines vaccine at day of age in our pullets. We’re and ﬁeld viruses is going to be cellular administering a day-of-age Salmonella immunity. Unfortunately, we don’t have vaccine anyway, so we mix it with our a way to measure that, so we have to Salmonella vaccine and give it to them go with what we can see, which are before we put them in the house. antibodies on ELISA, primarily.

As far as immunity to infectious bronchitis, “ the only practical way we can actually measure that is with serology. GUILLERMO ZAVALA, DVM, PhD ”

6 POULTRY HIGHLIGHTS OF A ROUNDTABLE DISCUSSION HEALTH T O D A Y ® 5 IMPACT OF NO ANTIBIOTICS EVER Our company has almost 50-50 conventional versus raised without antibiotics. I can’t say that withdrawing antibiotics is really playing a role. “ MARK BURLESON, DVM ”

? SANDER ? SANDER This question is for the practitioners Dr. French, you’re in a little bit of a on the panel: Have you noticed more unique situation because you are just infectious bronchitis problems in changing to removal of gentamicin flocks raised in “no antibiotics ever” from the hatchery. Are you seeing an (NAE) versus conventional increase in secondary infections? production systems? FRENCH BURLESON The only difference that I can see, really, Our company has almost 50-50 between NAE production and a traditional conventional versus raised without program is the fact that once they do antibiotics. I can’t say that withdrawing break with a secondary bacterial infection, antibiotics is really playing a role. I think we have options with conventional it’s more the densely populated areas production. And I’m sure that companies where you start getting some of these with NAE production have veterinarians viruses that start jumping around from who are allowed to treat those birds and company to company. We share remove them from the NAE market. But our problems. that’s the only difference.

TILLEY I agree with the other speakers about I agree with Dr. Burleson. We have only infectious bronchitis. I don’t think using NAE production and no conventional an antibiotic or not has any impact. I think production, but I think one of the beneﬁts NAE and conventional ﬂocks are all of NAE production is decreased bird equally susceptible. density. We would argue that the birds are not as stressed, so potentially you could have less of a problem with IBV. But I think it does go back to who your neighbors are, how close they are and what they’re vaccinating with.

7 INFECTIOUS BRONCHITIS: EVOLVING STRATEGIES FOR AN EVOLVING VIRUS 6 IBV EVOLUTION AND SPREAD One thing we do know is that these variants tend to hang around in long-lived birds... “ BRIAN LADMAN, PhD ”

? SANDER burned itself out. Unknown is whether ? SANDER Dr. Jackwood, would you please DMV/1639 is the current iteration of Is DMV/1639 genetically similar explain to us why IBV, which is a previous viruses. to the other circulating strains coronavirus, changes so easily? of bronchitis? One thing we do know is that these JACKWOOD variants tend to hang around in JACKWOOD Infectious bronchitis is an RNA virus, and long-lived birds, and there are quite a Dr. Ladman already indicated it’s rooted the length of its genome is huge. When few in Lancaster County (Pennsylvania), in a Pennsylvania virus that’s probably the virus replicates, it’s not very good at not too far from Delmarva. And so, there the progenitor of DMV/1639. So, it does copying the genome so it has a pretty are viruses like PA/1220 which, for have that history there, but as far as the high mutation rate, and when it replicates, whatever reason, have really stayed in vaccines we have available to us, none it’s going to make mistakes. If those the layer population. We continue to are anywhere close genetically to mistakes translate to a gene that gives the follow that, even to this day. DMV/1639. Now there is a vaccine that virus a selective advantage, it means the Dr. French indicated they use in their birds. virus may replicate quicker and may DMV/1639 then is most likely rooted It does show some cross-protection, but become more pathogenic. The key in layers. It didn’t cause too many the degree of cross-protection we get in with controlling this is to stop IBV problems initially. In 2011, we saw a the field is sometimes very different from from replicating. couple of isolated cases on Delmarva, what we see in a laboratory. I’ll leave it when it presented as a nephropathogenic at that. IBV variant. Then it kind of went away, ? SANDER for whatever reason, then came back Dr. Ladman, DMV/1639 has been hard in 2014. It popped up in Georgia, one of the bigger IBV problems in the although how these viruses travel is Delmarva region (eastern shore of unknown. They’re likely moving via Delaware, Maryland and Virgina). Can people and birds. We know they hang you tell us how the variant first became out in cecal tonsils. apparent and how it affected flocks? We’ve continued to see iterations of the LADMAN DMV/1639 type viruses since 2011. The Our lab shouldn’t have named it Delmarva vaccine that’s being used in Delmarva 1639 because it started in Pennsylvania I believe is the 2014 version, if you will, at the end of November 2010. I always of DMV/1639. There are some changes feel that fact gets lost, and everybody that we observed in 2017, and it continues who grows chicken on Delmarva is now to evolve today. Whether or not that’ll saddled with that black eye. burn out, I don’t know. But I certainly hope at some point it will. We see a regular invasion, if you will, of bronchitis variants from Pennsylvania into the Delmarva region. It’s been going on for quite a number of years. I think we first noted it in early 2000 or the late 1990s with IBV PA/171/99, which thankfully

8 POULTRY HIGHLIGHTS OF A ROUNDTABLE DISCUSSION HEALTH T O D A Y ® 7 ROLE OF IBV VACCINATION The bottom line is that anytime this virus replicates, it’s changing. “ MARK JACKWOOD, PhD ”

? SANDER ? SANDER virus from replicating as much, and maybe Dr. Jackwood, you’ve been widely And the bottom line? instead of 5 years we can prolong it to quoted as stressing the importance of 8 years or 10 years. The virus mutates; vaccination to stop cycling infectious JACKWOOD that’s what this virus does and we can’t bronchitis. You’ve also said improper The bottom line is that anytime this virus change that. vaccination — particularly using the replicates, it’s changing. Period. Whether wrong vaccine — can lead to the those changes result in a virus that can ZAVALA emergence of new IBVs. Would you have a selective advantage and start to be I’d just like to muddy the water a bit. please explain how vaccination can a problem in our birds seems to occur We’re thinking in a single dimension here either dampen or hasten the about every 5 years. That’s what we’ve regarding the question as to whether evolution of bronchitis? determined. I think that if we have a immune pressure drives the virus to homologous vaccine and do a good job change. We know that from many JACKWOOD of vaccinating, we get sterile immunity. viruses. But you can easily complicate the There have been quite a few studies I mean, we can’t even get that with flu, situation when you are dealing with an published that show vaccines can right? But we can with bronchitis. area heavily populated with birds from accelerate the mutation rate of these multiple companies and where eight viruses. The theory behind that is that In my opinion, from a scientific point or nine different vaccine strains are they’re trying their best to survive in a of view, homologous vaccine applied circulating simultaneously all the time. bird that’s trying to get rid of it, so they’re properly is the best of all worlds. It accumulating those mutations at a quicker absolutely is. The problem we run into Take northeast Georgia, for example. rate, trying to stay ahead of the bird’s is like the one we have with DMV/1639. There are no fewer than eight different immune response to the virus. Other If we start trying to make a vaccine vaccine strains used every single day. studies have shown if the virus is able to today, it’s going to be probably 3 or 4 Some companies spray with one serotype replicate in the field without any vaccine years until we have it on the market. at the hatchery, some with two and some pressure, it will change quite rapidly and with three. Some even boost in the field move in the field. So, we vaccinate with one or more with yet another virus. So what does that strains of bronchitis virus to get as much actually do to virus evolution? I don’t One of the problems we have with some cross-protection as we can. We probably know; I don’t have the answer. I’m just of these studies — and why it can be get a lessening of the clinical signs muddying the water, as I said. somewhat confusing — is because we’re associated with that, and everybody constantly putting attenuated live congratulates each other and says we did vaccines into the field. If you’re isolating a great job. But meanwhile, the virus is ? SANDER an IBV Arkansas, is that an Arkansas replicating under the radar until it finally How then do we monitor for vaccine that was just put there a month gets to a point where it surfaces again. bronchitis virus? How are we going ago, a week ago or 5 days ago? Or has it to identify all the strains that are been circulating for over a year in those However, it’s probably not fair to make a circulating? Serology? Virus isolation? birds and had time to change? blanket statement that vaccine pressure Sequencing? Direct polymerase chain will push the virus to evolve and mutate reaction (PCR)? or emerge as a strain that will cause problems. I think that if we do a good job of vaccinating like we’re supposed to, continued I think it actually helps with keeping the

9 INFECTIOUS BRONCHITIS: EVOLVING STRATEGIES FOR AN EVOLVING VIRUS

7 ROLE OF IBV VACCINATION

The choices we have might not include a homologous vaccine but a vaccine that might give us some protection and relief from the clinical signs we’re seeing. “ DAVID FRENCH, DVM ”

LADMAN FRENCH From a laboratory standpoint, it I think we’d all agree that in a production depends on what clients are looking for, scenario, we just want the problem to and everyone seems to be interested in go away. We’ve got an issue, we’ve got something diﬀerent. Right now most mortality and we’re under pressure to ﬁx clients are spoiled by the rapid nature of the immediate problem. The choices we tests. They just want answers. Sometimes have might not include a homologous it’s pressure from above that’s forcing vaccine but a vaccine that might give them to seek that answer versus maybe us some protection and relief from the a long-term solution. And so it depends. clinical signs we’re seeing.

The development of real-time PCR has That’s the pressure we get. We’ve got been fantastic. Those assays that have to provide an answer to our senior been developed have been great tools to management or our stockholders. We help producers understand what’s going need to ﬁx that situation as quickly as on, and the beneﬁt is that we can detect we can. everything in a single swab. But as we start to work that up, those samples may not be ideal for additional testing such as sequencing. We sometimes tend to pull out more vaccine strains for samples if they’re in there.

Obviously, they’re highly embryo-adapted, so that’s what’s going to grow in an egg.

Next-generation sequencing seems to be fantastic, but that’s not rapid and it’s not cheap. Would you spend $700 only to ﬁnd out you have an Arkansas vaccine circulating?

10 POULTRY HIGHLIGHTS OF A ROUNDTABLE DISCUSSION HEALTH T O D A Y ® 8 VACCINATION STRATEGIES Antibodies that bind to the spike protein will block infection. That’s the strong immunity we’re after here. “ MARK JACKWOOD, PhD ”

? SANDER However, there are conserved regions on It’s been a very, very difficult chore, and And that’s a perfect segue to our spikes, so you will get antibodies to some nobody’s really come up with a good main topic: strategies for this evolving of these more conserved regions. way of doing that yet. So, it’s that virus. Vaccination is key, but selecting conformational epitope problem that the vaccines for bronchitis control in Think of it as a building. The scaffolding we have, getting these neutralizing broilers can be problematic. There of the building is all the same, but the antibodies that really causes us issues may not be vaccines available that surface or the top of it looks different. with trying to get this cross-protection. match the circulating strain, or Some of these antibodies will bind to cross-protection might be too limiting. these conserved areas and can help Dr. Jackwood, can you explain why block some of the infection that we ? SANDER cross-protection is difficult with see — block attachment of the virus to Are the conserved regions infectious bronchitis vaccines, and the host cell. When we give more than the same? does it involve genetics of the one type of IBV vaccine to birds, we’re bronchitis virus circulating? trying to induce those antibodies, those JACKWOOD cross-reactive antibodies, if you will. They’re not. JACKWOOD That’s a big one. Antibodies that bind to The other difficult part with cross- the spike protein will block infection. reactivity is the antibodies that neutralize That’s the strong immunity we’re after are against what we call conformationally here. In addition to that, cell-mediated dependent epitopes, which means that if immunity is involved in recovery from you take that spike out of the virus and the disease, which is also very important. express it in the laboratory, it doesn’t form So, when we have spike proteins that can those epitopes anymore. induce those neutralizing antibodies and also induce a good cellular immune That’s why we don’t have herpesvirus of response, we’ll get complete protection. turkey-vectored vaccines for IBV. That spike has to be folded properly to be able Different types of IBVs have different to induce neutralizing antibodies. It is spikes. Antibodies against one spike — always folded properly when it’s with say, a Massachusetts-type spike — a virus, and that’s why we try to use won’t bind to another spike like an attenuated live vaccines when the Arkansas-type spike. Therefore, they molecular ones won’t work. We take the won’t cross-neutralize each other. protein and cut it down into small pieces and try to figure out what it is that actually induces neutralizing antibodies.

11 INFECTIOUS BRONCHITIS: EVOLVING STRATEGIES FOR AN EVOLVING VIRUS 9 IBV CROSS-PROTECTION We produced three serials at three diﬀerent times of a GA13 vaccine, and we had really good responses. “ SARAH TILLEY, DVM ”

? SANDER ? SANDER was already some experience with My next question is about cross- We’re dealing with novel, new cross-protection from GA08 for control protection. When do multiple IBVs like DMV/1639 or GA13, for of DMV/1639. serotypes help with cross-protection? which there are no commercial How does that work in the field when vaccines. Dr. Tilley, did you not Since we didn’t have an autogenous to you’re vaccinating? produce a GA13 vaccine, and what draw on, we went with the quickest way was your experience with that? we could find to solve the problem. And JACKWOOD I have to say, it’s been a very effective It’s biology, I guess. We’re putting a TILLEY response. The control we’ve gotten using foreign protein into the animal. They’re Yes, we did. We produced three serials at that vaccine has been very good. The responding by making antibodies against three different times of a GA13 vaccine, short-term benefits are great. I’m a little it. We should have a vaccine virus that’s and we had really good responses. We concerned about the long-term effects, going to induce an antibody that’s going used them during times of the year but the short-term benefits are great. to bind to a circulating field virus in a place when the challenge was higher, which where it could potentially block that virus generally began around November/ from infecting a cell. It’s like a lock and December (depending on how cold ? SANDER key. It might also not fit well. A conserved the winter was) and would continue Dr. Burleson, you’ve had some region between an Arkansas and a Q1 IBV through April/May. We continued to run experiences trying to control have nothing in common. But we do have surveillance to see if the virus was still DMV/1639. What vaccine approach some conserved regions between, say, a circulating and vaccinated with GA13 did you take? GA08 and a DMV/1639, and we can see vaccines for about 3 to 4 years on and some cross-reaction between them. But off. When we finally stopped seeing the BURLESON we can’t predict it. challenge, we stopped vaccinating. We Very similar to Dr. French’s. My experience did not want to continue to vaccinate if it has been very limited at this point. We We now have three-dimensional was not necessary. So during that period have had about five or six isolations structures of the spike, but we still don’t for our birds, it worked wonderfully. It across two complexes. We’re now trying know what the amino acids are that worked beautifully. It was like turning to decide what to do for next winter, if it make up that conformationally dependent on a light switch. becomes an issue. I expect we’ll probably epitope that induces the neutralizing use what’s available — the same approach antibodies and then which conserved as Dr. French. epitopes also around that area can SANDER potentially induce antibodies that ? Dr. French, you’ve had some SLATER would be stereotypically protective. experience trying to control or When I was in Pennsylvania last You can’t predict it at this point either prevent the disease from DMV/1639. winter [working as a technical service with a computer or by just looking at the How did you manage that? representative for a vaccine distributor], differences between the two different I had five different companies that had viruses. The bird is the only way. The bird FRENCH DMV/1639 in multiple PCR sequences. tells us whether it will be protective or First, we had to determine whether it A couple of them had really bad issues not. And that’s why we have to do vaccine was in fact bronchitis; then we had to at the plant because of it. We tried challenge studies. figure out what type of bronchitis it was. multiple vaccine approaches because of I have to say we got very quick response company preferences. Some opted for with PCR, which is a great tool, and there a generic multiple-boost protection approach. Others tried both GA08

12 POULTRY HIGHLIGHTS OF A ROUNDTABLE DISCUSSION HEALTH T O D A Y ® 9

vaccines. It was kind of a wash across the Vaccination is going to decrease your clinical signs, but if the board. There were breakthroughs on pressures in the environment are too high — decreased ventilation every program, although I think generally “ and other factors that come along with winter — people were happy because it was less of a problem. it’s just not going to hold. MEAGAN SLATER, DVM After talking a lot with the vaccine ” manufacturers, it sounded like the experience was generally the same elsewhere. Vaccination is going to decrease your clinical signs, but if the pressures in the environment are too high — decreased ventilation and other COOKSON Some companies have done quite factors that come along with winter — well with it and others have not. it’s just not going to hold. I don’t think there’s anyone in the industry Management is a factor. At the start, it giving only the GA08 vaccine, right? It’s ZAVALA always in combination. No one gives seemed to work very well. It was new and more attention was likely paid to ensure This roundtable is essentially about just one vaccine unless they have no proper application. Once the novelty broilers. But it would be interesting to challenge, although they might give wears off, I think people fall into a routine; mention a few words about what the layer just IBV Massachusetts. So, it’s GA08 perhaps there are personnel changes, industry is doing and continues to do to plus IBV Massachusetts — up to three results change, who knows. Although at fight this particular virus in different areas IBV serotypes. other companies, the vaccine continues to where there is no specific vaccine. be used with good results. I think, because

SANDER somebody needs to find a problem, GA08 seems to have helped a lot. As a ? bronchitis is detected and it becomes the matter of fact, in northeast Georgia, there Dr. Ladman, weren’t you scapegoat simply because it seems like it are some relatively large layer complexes involved with development is always there. Is it a problem to detect that are very, very open, unfortunately — of a DMV/1639 vaccine? the vaccine in the absence of disease? and by that I mean they don’t start LADMAN vaccinating with live bronchitis vaccines It’s been an interesting road, and I don’t until the birds are 2 to 3 weeks of age. Yes, we were approached by a company know if we started down that road again on the shore. We started working on it today that we would be lucky enough We’re seeing the very first cases that are even though it wasn’t something we to end up with something that was possibly DMV/1639. They already have a were looking to do. It took 3 years to beneficial, as I think to this point that number of flocks with cystic oviducts and go through testing to the point where vaccine has been. false layers. Birds are peaking at 70%, we felt we had something that could where they normally peak at 96%. be beneficial.

So, this is one of the approaches we are copying from what’s been done up on the shore and other regions.

13 INFECTIOUS BRONCHITIS: EVOLVING STRATEGIES FOR AN EVOLVING VIRUS 10 VACCINATION OF BROILER BREEDERS I think it’s very important to think about broiler breeders, and yes, economics is absolutely important. I think it’s very important to vaccinate. “ GUILLERMO ZAVALA, DVM, PhD ”

? SANDER well. You want to ask “How do I protect the through IgG (immunoglobulin G), which What about IBV vaccination for breeder? How do I broaden the spectrum is really what you’re stimulating more broiler breeders? Dr. Zavala, is of protection?” and “How do I indirectly than anything. that important? minimize my potential problems in the progeny?” It’s very important. We know very well that when it comes to ZAVALA humoral immunity against IBV in broilers, If you look at birds on an individual-flock it’s going to depend very much on IgA basis, it’s important. If you look at it on ? SANDER (immunoglobulin A), which is the one an industry-wide basis, the better you What about vaccination and that’s going to essentially neutralize the can control bronchitis in one or two or false-layer syndrome? You mentioned virus in the respiratory tract. multiple companies, the more benefit that maternal antibody isn’t very you’re going to find for everybody else. protective. We know that some poultry But if you think about long-lived birds, it’s companies wait until 2 weeks of age not just IgA. You’re trying to protect the I find it interesting that if you look at the to vaccinate, yet that early infectious bird against infection of the reproductive composite of companies in Georgia, for period is critical for the development tract or even the urinary tract, for which example, there’s a significant proportion of false-layer syndrome. you do need other types of antibodies of companies that do not use killed and cellular immunity — IgG and cellular vaccines for bronchitis. Most of them rely Is there anything we could be doing — immunity. I wish it were very simple, but only on live vaccines. Many other areas of whether it’s for broiler breeders or you have to use a multi-pronged approach the world would never think about doing layers — that’s going to help prevent and think in multiple dimensions. “What that, particularly in layers. But that applies that early exposure that results in do I do with breeders?” “What do I do with to broiler breeders as well. false-layer syndrome? the broilers?” And then “What do I do with the other 50% of the problem?” — So, I think it’s very important to think ZAVALA which is ventilation, litter quality, drinker about broiler breeders, and yes, I would speculate that maternal management and so on. economics is absolutely important. immunity probably contributes partially I think it’s very important to vaccinate. to protecting that young bird, but it’s I thinkit’s very important to complement going to be how soon can you get it ? SANDER vaccination with killed vaccines and, of protected through active immunity Will the practitioners here share your course, to use an array of strains that versus passive immunity. approach to vaccinating breeders will help you increase broad protection, against IBV to help control the disease if you can. in both breeders and broilers? ? SANDER We know that maternal-antibody transfer So, would using killed vaccines TILLEY is not very protective for progeny. But if in breeders expand protection Our pullets and breeders are vaccinated you look at the years when IBV Arkansas to broilers? with IBV strains that our breeders and was introduced in the Southeast, it wasn’t broilers will encounter, as well as what our until we introduced the Arkansas vaccine ZAVALA broilers will be vaccinated with later on. in the breeder population that things were Maybe not so much expand the spectrum During the pullet-rearing stage, the birds buffered in broilers a little bit. And I think of protection, but you can certainly raise are vaccinated at 3, 7 and 16 weeks of age that’s an important thing to think about as your antibody levels. You can also extend with multiple live IBV strains — different the longevity of that immune response, combinations of Arkansas, GA98 and specifically in the case of the breeders Massachusetts — so that they have ”seen”

multiple strains before going into lay. We Normally, there’s plenty of bronchitis circulating on a do split the live IBV and ND vaccinations in commercial layer operation. You have multiple ages the pullet phase by 5 to 7 days to prevent “ and it’s always floating around. replication-site interactions. KALEN COOKSON, DVM Once moved into the hen house, the ” breeders are boosted with a live IBV/NDV program every 10 weeks since we use a live program. We run routine serology at two points in the hen’s life — at over to a killed vaccination program COOKSON 26 weeks of age and 58 weeks of age in breeders to maintain good I think if you can have a good, diverse live to monitor incoming immunity to eggshell quality. program in your long-lived birds, whether IBV/NDV/IBDV/reovirus and toward the they’re broiler breeders or layers, followed end of life to see what the hens have BURLESON by a killed IBV vaccine, it works very well, been exposed to. We have the ability to We vaccinate breeders for IBV at 2, 6, 10 in my experience. We’ve done some work monitor serology both in-house and at and 16 weeks of age. They get nothing with that. external labs when production drops or else for the life of the bird. We collect there are shell changes. serology at 26 and 50 weeks and we do Normally, there’s plenty of bronchitis see some increasing titers from time to circulating on a commercial layer FRENCH time, but we haven’t pinpointed bronchitis operation. You have multiple ages and I think Dr. Zavala did a great job as being a major cause of any kind of it’s always floating around. From what explaining that there are really two eggshell or production issues. We try to we’ve seen, if you have good primers up reasons to consider IBV vaccination of present the hen with everything she front and a good killed response, you have breeders. From my point of view, it takes might see during lay in that geographic good immunity on board when birds are the edge off the vaccine that we’re going area. That’s our goal. placed on the farm. The circulating IBV to administer to broilers. I saw first-hand on the layer farm acts almost like a good what happens when you vaccinate SLATER autogenous booster vaccination. broilers with Arkansas and you don’t Most of the broiler breeders in have Arkansas in your breeder vaccination Pennsylvania when I was there were We conducted one layer study and program. It was years and years ago, vaccinated with live primer vaccines and saw good cross-protection well into but not a mistake I would want to then at least one killed vaccine. In fact, production against an IBV serotype that repeat again. most layers there actually received two wasn’t present in the killed vaccine the killed vaccines before they were moved. birds received.1 And I think the live/killed The other reason to vaccinate breeders A large percentage of companies do not vaccination strategy also can be beneficial is to protect those birds while they’re in boost throughout the life of the flocks, to the breeder side of things where you’ve production. We use a killed vaccine in so they try to get the antibodies up got these novel variants circulating. IBV is breeders. Years ago, when I came on front. So, for good or bad, that’s what more of an insidious disease in long-lived board and they were not getting a killed they’re doing. It seems to be working birds, just because they’re not under the IBV vaccine, I began to see some eggshell and helping to protect against some intense stress that broilers are. It’s not problems. I was uncomfortable boosting shell-quality issues. always as obvious if you do have a novel with a live bronchitis virus, thinking it bronchitis exposure, but it might be there might contribute to more eggshell so you’re at least hedging your bets and problems. So, we converted everything protecting yourself a little bit.

15 INFECTIOUS BRONCHITIS: EVOLVING STRATEGIES FOR AN EVOLVING VIRUS 11 IBV AND NEWCASTLE DISEASE PROTECTION Whether it’s an IBV or ND challenge, the more that you can reduce the respiratory stress on birds, the better oﬀ you are. “ DAVID FRENCH, DVM ”

? SANDER BURLESON ? SANDER There are areas where broilers We have relatively little to no Newcastle Dr. Zavala, you do the most also need protection against ND. challenge in our geographic areas, at least international travel of folks on the Dr. French, you mentioned that ND right now, fortunately, but we employ a panel and are probably in more areas was a challenge in your Texas recombinant Newcastle to try to minimize that have the more virulent Newcastle. complexes. How do you balance that impact of Newcastle and bronchitis Have you seen any strategies that your bronchitis and Newcastle reaction. And we’ve been very successful you could share that might be vaccination programs for broilers? with that. helpful to those who will be using this information? FRENCH Whether it’s an IBV or ND challenge, ? SANDER ZAVALA the more that you can reduce the Does anyone have birds anywhere Yes, I’ve seen way too many strategies. respiratory stress on birds, the better near the virulent Newcastle outbreak I can’t say all of them are good. If you off you are. We utilize recombinant in California? And if so, what would be look between the Tropics of Cancer and Newcastle vaccines as much as we can your approach to vaccinating against Capricorn — the number of countries in areas where ND is a concern, and Newcastle and bronchitis? affected by Newcastle genotypes 5, 7, 13, we supplement with a very mild live 13A, 13B and 12 — that involves, really, Newcastle vaccine at day of age. I feel FRENCH a lot of countries. it takes a little while for the recombinant I don’t know if anyone in the room has vaccines to generate enough protection, birds that close to California, but I think Basically, the strategy in general is going and the live vaccination at day of age we would all employ the international to be hyperimmunization of breeders. It’s helps to carry them through, regardless strategy of using a more aggressive the first thing you have to do to protect of maternal-antibody protection, until Newcastle vaccination program relative breeders and egg production. But it poses the recombinant protection is adequate. to whatever challenge is in the area. It a real problem with progeny. It makes it The birds can concentrate on responding depends on how close you are and how very difficult to successfully immunize to the bronchitis vaccine with the big a threat it is. broilers when they’re very young. minimized stress of a much milder ND maternal immunity is neutralizing, Newcastle vaccination program. COOKSON and it really makes it difficult for you to I think Dr. Zavala would back me up on succeed with a live vaccination program. this — why we see the killed Newcastle ? SANDER and bronchitis and more use of four-way What about protection against vaccines when they’re giving a killed ND and IBV in broiler breeders? IBD/reovirus in high Newcastle challenge areas. Progeny benefit from the Newcastle TILLEY maternal antibodies because velogenic When we use a live vaccination program Newcastle is often waiting as soon as in broiler breeders, we’ll split up Newcastle they hit the floor in those operations. and bronchitis vaccines 5 to 7 days apart. In addition, you’d probably use a We don’t give them together. recombinant and a live Newcastle at day of age.

? SANDER And the most successful programs?

ZAVALA I would say the most successful programs involve use of a recombinant Newcastle vaccination at the hatchery, whether it’s in ovo or subcutaneously at hatch, coupled with a mild live strain of ND virus at hatch as well. In many of these countries, they also tend to grow a pretty heavy bird. You have to boost those birds in the ﬁeld, I would say the most successful programs involve use of a recombinant usually between 12 and 14 days of age, Newcastle vaccination at the hatchery, whether it’s in ovo with live vaccines that are quite a bit “ or subcutaneously... stronger — the LaSota strain, for example. GUILLERMO ZAVALA, DVM, PhD ” If you’re in certain countries of the world, you might have to give them a killed vaccine. You’d be surprised at the vaccination devices that have been put in place for broilers and the speed at which you can vaccinate broilers with killed vaccines in the ﬁeld — where you have the labor, of course. But those are the main strategies that I would say.

I get to visit companies in no less than 40 countries, and I always tell them that in the absence of catastrophic disease, the most important respiratory problem they’ll face is bronchitis. You need to focus on bronchitis and put Newcastle on the back burner, but you cannot leave yourself completely unprotected.

If you are in an area where Newcastle is constantly waiting for you to just look the other way, then you have to sustain the economic cost of vaccinating aggressively. It’s the only way you can continue to operate economically.

17 INFECTIOUS BRONCHITIS: EVOLVING STRATEGIES FOR AN EVOLVING VIRUS 12 HOW MANY IBV VACCINE SEROTYPES? In one study we did, I was very surprised when we moved from two to three serotypes. “ KALEN COOKSON, DVM ”

? SANDER trying to determine whether we were We’ve done quantitative PCR, and Dr. Cookson, is there a limit on going to get cross-protection or not. We Massachusetts replicated to the the bronchitis serotypes that can were asking whether all three or four highest titer. Arkansas was the lowest. be administered? of these vaccines actually infect and We expected that, actually. The GA98 replicate in the chick and if they was second lowest, and then GA08. So COOKSON would be protected against in progression, the lowest was Arkansas, Let me first say that, in my opinion, our homologous challenge. the next was GA98, then GA08; IBV best opportunity in the US for bronchitis Massachusetts was the highest. control is in the hatchery. From what I’ve Using new molecular techniques, we seen, focusing on hatchery vaccination can now see more than one bronchitis LADMAN has, in general, been successful. virus type in a single swab from a bird. We conducted similar studies a few years Five days post-vaccination, we saw all back looking at three serotypes, which The rule of thumb most people have three vaccines in every single bird, were IBV Massachusetts, Arkansas and adopted is no more than three IBV meaning they all got infected and the Delaware. It appears that Massachusetts serotypes per dose. However, there’s vaccines were replicating. When we didn’t play too well with Arkansas. We some recent evidence that using up gave four different serotypes, we saw observed a difference between the to four serotypes may have some all four vaccines in every single bird, and replication of vaccine when given by itself advantages, but as an industry, we they all were replicating. We gave those versus when given with other vaccine still need to figure out when that should vaccines by eye drop, and we gave a full viruses. At the end of the day, birds were be considered. dose of every single one of them. protected from the challenge strains represented in the vaccines. Regardless, it In one study we did, I was very surprised When we challenged the birds that got was very interesting to track progression when we moved from two to three three vaccines, they were protected of the IBV vaccine strains in the bird. It serotypes. We had over 90% protection against all three viruses they were comes back to the fact that we know that in broilers against DMV/1639.2 I rarely see vaccinated with. In birds that got four IBV has a negative impact on ND virus that kind of protection unless you have viruses, they were protected against replication, but we haven’t paid much an autologous challenge vaccination all four different viruses. That was at attention to IBV-IBV interactions. In program. I think even 80% protection is 35 days of age. accordance with the 9CFR regulations, the stellar. It will be interesting if that can be vaccines work, but a small body of work repeated, which we plan to do. Now that said, not all vaccines play suggests that immunity is perhaps not well together. We gave Massachusetts, induced at the same rate. Can anyone share their experience with Arkansas, GA98 and GA08. If we would using four serotypes? have given a Connecticut instead of one JACKWOOD of those four, or we would have given a The other thing we have to consider JACKWOOD Delaware instead of one of those four, with all of this is vaccine application. It’s We recently did a study where we we might have seen some different really tough to do well. It really is. Even vaccinated birds at 1 day of age with results. I only say that because those spray vaccinations in the hatchery, which three bronchitis virus types, and we vaccines tend to not be as aggressive as you would think would be fairly straight- vaccinated another group with four some of the others. And in our study, forward, can often get messed up. different types. We weren’t necessarily not all the vaccines replicated to the same titer.

18 POULTRY HIGHLIGHTS OF A ROUNDTABLE DISCUSSION HEALTH T O D A Y ® 13 VACCINE APPLICATION PITFALLS ... the mechanical shearing forces we have with syringe-based spray cabinets can damage a lot of the virus if they’re not maintained well... “ MARK JACKWOOD, PhD ”

? SANDER the water you can mix it with, the better. COOKSON Dr. Cookson, you have some tips on It should be 60° F or lower, at least when One other thing I want to mention is how to get uniform distribution of you’re mixing, and even at application about preparation with frozen bronchitis bronchitis vaccine administered by would be great. When you get up above products. It’s a little bit diﬀerent compared spray at the hatchery. Could you 70° F to 80° F, the titer can really start to a Marek’s vaccine, and the people who share those with us? coming down quickly. are preparing the bronchitis vaccine may be the same people preparing the Marek’s COOKSON JACKWOOD vaccine. Yes. It’s not rocket science, but there are a We did some studies with spray lot of potential pitfalls when vaccinating. vaccination using a bronchitis vaccine When you thaw your bronchitis vaccine, You’re in a broiler hatchery with a lot as a model. Dr. Cookson is absolutely you don’t want it to get all the way thawed of moving parts, so you need to pay right — mixing the vaccine with cold out because it’s sitting in water that’s attention to details. diluent or cold distilled water is really 78° F (25.5° C), right? If you let it thaw important. If we mixed the vaccine with completely, the temperature of the There are essentially two components in water that was 4° C (39° F) and we kept vaccine will increase to 78° F or 80° F the hatchery: There’s the preparation of it at that temperature, we maintained (25.5° C or 26.7° C). That’s really important the vaccine and the application of the the titer for well over 120 minutes. If you to emphasize to hatchery employees. vaccine. As far as preparation of the mix it with room-temperature water and vaccine, we’re dealing with a pretty fragile let it sit at room temperature, you lose FRENCH virus. It’s not like an IBD virus or a reovirus almost a log immediately. There’s literally The other thing I see in the hatchery is where there’s some forgiveness and the no vaccine there after about 120 minutes. that the person mixing the vaccine can be virus holds its titer well. You’re not giving a full dose at that point, very busy and not pay close attention to obviously. Dr. Brian Jordan did those all the details required for what they’re That’s really the major thing we have to studies at the Poultry Diagnostic and doing. If you don’t watch carefully, some be concerned about — and that’s keeping Research Center, University of Georgia.3 may prepare the new vaccine too early, that titer as high as we can, especially resulting in mixing too much of the old when we’re spray-applying. How much The other thing that we found is that the vaccine with the new vaccine, which is of that vaccine is actually getting to mechanical shearing forces we have with going to dilute the vaccine that you’re the mucosal surfaces and infecting the syringe-based spray cabinets can damage administering to the chicks. bird? Probably less than a tenth. This is a lot of the virus if they’re not maintained why using full doses is important — well and kept in perfect working order. BURLESON to preserve as much of the titer as we We have to make sure those syringes are Let’s not forget about storage. We don’t can before the bird actually sees it working properly. They are disposable want to put thousands of dollars’ worth and responds. syringes. And that means you’re supposed of vaccine into a $200 refrigerator we got to dispose of them, right? But some on clearance at a home store because The University of Georgia has done a lot people use them for days on end. We need it’s dented. of the work showing the importance of to be careful with that. We also need to handling the temperature of the water watch for air in the lines. If you’re not you’re mixing with the vaccine. The cooler ﬁlling that syringe completely full, you’re continued not giving a full dose.

19 INFECTIOUS BRONCHITIS: EVOLVING STRATEGIES FOR AN EVOLVING VIRUS

13 VACCINE APPLICATION PITFALLS

Are you making sure the birds’ uptake of vaccine occurs in the appropriate amount of time? There’s deﬁnitely a checklist you go through. “ MEAGAN SLATER, DVM ”

ZAVALA I don’t know where 7 ml came from, but preparation need to be considered such And it shouldn’t be stored on the we found if you increase that to a 14-ml as priming the water lines and making door shelves. volume, you get more vaccine into the sure they’re drained. Do you use a dye? chicks. If you increase it to 21 ml, you get Are you making sure the birds’ uptake of BURLESON a lot of vaccine to the chicks. vaccine occurs in the appropriate amount That’s right! We try to put a lot of emphasis of time? There’s definitely a checklist you on good storage, and we have alarms set Now, the combination of keeping the go through. on all of our refrigerators so the vaccine vaccine cold and getting 14 ml or 21 ml doesn’t freeze or get too warm. to the chicks in wintertime is something a lot of people don’t like to do. They ? SANDER ZAVALA think they’re going to have a chilled chick What else do the practitioners here Believe it or not, one of the most common and problems with chick quality. However, do regarding field vaccination to problems that I see is failure to check air our experience is that if the hatchery is make sure bronchitis vaccines are pressure. If the spray cabinet calls for a managed properly and it’s warm, the administered effectively? 50 psi and you’re using 78 psi, that along chicks will dry out in less than 30 seconds with the shear force applied with a and they’ll be just fine. FRENCH syringe system essentially destroys the We’re not field boosting now, but we virus you’re giving to those birds. have periodically in the past. It’s difficult ? SANDER to double-check and see how well JACKWOOD Dr. Slater, you’ve had some experience you’ve done. You can certainly look at Clogged nozzles are another big issue. with educating producers on proper routine serology to see what kind of I’ve seen where they’ve got two nozzles vaccine administration. What are some response you’ve got. and one of them is not spraying anything. of the common mistakes with field vaccination that can be remedied, that One common mistake is not having BURLESON can be fixed? enough people there to spray vaccinate It’s amazing. You can see these problems in the field. We monitor our spray-vaccine easily in a hatchery, and I’d say over SLATER procedure carefully. We watch how the 90% of hatcheries have a process and There are a lot of things that can go person mixes the vaccine and how long it are supposed to be checking for these wrong with field vaccination. Bronchitis takes to get it out there to the birds. The problems at least a couple times a day if vaccines should theoretically be sprayed best vaccinators we have know exactly not more. It’s very obvious when a nozzle since it’s a respiratory virus, but sometimes how many steps it is from one end of the is clogged if you’re looking. You’re passing water vaccination gets into birds better. house to the other. They know exactly a box underneath and you’re hardly It’s really what you think your crews can how much time it’s going to take them getting any coverage on the paper. do. When I was in Pennsylvania, we had to vaccinate, and they finish vaccination the luxury of a crew that did nothing but with no vaccine left over. They don’t run JACKWOOD vaccinate birds at multiple companies. out before they’re done. Those things all One more thing that we’ve found and They were good at doing their job. The have to happen in order to spray vaccine that’s regarding volume. Typically, disadvantage is that they did every properly. It’s when we take shortcuts that hatcheries were giving 7-ml volumes. company in Pennsylvania. we get in trouble.

That being said, if you are water vaccinating, water sanitation and

LADMAN JACKWOOD I‘m not a practitioner but hearing things We have real-time PCR that’s specific like using a quarter dose or an eighth of a for those vaccines. We can monitor 5 or dose is mind-boggling to me. You spend 10 days after vaccine application to see millions on vaccines and then cut them, in what percent of birds in that flock actually some cases, to some fraction of a dose. received vaccine and how much. It’s not May look good on paper, but how is that cheap. Maybe you’re not going to do it going to work? with every single house, but if you spot check your crews every once in a while, TILLEY you can be fairly sure you’re doing a We field boost our larger birds — birds good job. that will process at 46 to 53 days of age — between 16 to 18 days of age and up to 19 days of age. We have a crew of four that field boosts with backpack sprayers. To Dr. French’s point — we actually do base Let’s not forget about storage. We don’t want to put thousands the number of people vaccinating on the of dollars’ worth of vaccine into a $200 refrigerator size of the house. In a 40-foot-wide house “ we got on clearance... we’ll have two people with backpack sprayers, and for a 50-foot or wider house MARK BURLESON, DVM we’ll have three people vaccinating. One ” person will go through and cut the birds while the other two follow behind.

In the past, we turned oﬀ lights and fans, but then the crews would forget to turn the lights and fans back on. That’s one of those compromises and where human error can hurt you. And going back to Dr. Sander’s initial question of how to check for the eﬀectiveness of vaccine application? I’m not sure. Perhaps it’s looking for a mild reaction 5 to 7 days after vaccination and not lingering around, causing residual airsacculitis.

21 INFECTIOUS BRONCHITIS: EVOLVING STRATEGIES FOR AN EVOLVING VIRUS 14 MINIMIZING VACCINE REACTIONS If, say, 40% to 50% of the birds are head shaking, that’s probably an excessive or rolling reaction. “ KALEN COOKSON, DVM ”

? SANDER If you see too much reaction, start looking I thought there was a lot less tolerance for With respiratory vaccines, including at the application and all those things we vaccine reactions. bronchitis vaccines, you’re going talked about. Reconsider the vaccine to expect some clinical response. combinations you’re using. Much of the industry is vaccinating only What is a normal response to once now, at the hatchery. In the past, bronchitis vaccination? A true rolling reaction is more often the there was more field boosting between result of poor application. If a significant 12 and 14 days of age if you were COOKSON amount of birds on the farm never got producing a small bird or 14 to 18 days if It can vary by the combination of vaccines the vaccine, they’re getting it from the you were producing a heavy bird. It was you’re using, with your management ones that did respond. A big problem not considered acceptable to have any and the type of bird you’re growing. Every with vaccination occurs when those reactions from hatchery vaccination that location needs to develop a sense for vaccines have passed back into chickens lasted beyond 10 days. Today, it seems what is within the bell-shaped curve for and are shed back — it’s not the same there’s a bit more tolerance and that it’s their flocks. as vaccinating at day of age. The amount okay if birds are still snicking a little at 12 of exposure can be higher. The shedding days of age. I don’t think it’s okay. I don’t Generally speaking, a normal vaccine interval of those vaccines can be know what everybody else feels about reaction after hatchery vaccination for prolonged without uniform vaccination. that, but I think that’s an important point. bronchitis viruses will occur between 5 to The field challenge often comes on top 9 or 10 days of age. That’s probably when of a rolling reaction and that’s a your reactions peak, and it can be quite real complication. ? SANDER mild, especially if you’re not also giving a Would anyone like to comment? live Newcastle vaccine. Even when it’s ZAVALA subtle, you should hear something in the What is the duration of the head shaking COOKSON flock. You may need to go in and hang out and snicking that represent a normal With Massachusetts vaccines you get with the birds for a while and listen and reaction? You said it was about 9 days? more of a very noticeable reaction up observe. Some of them might shake their front. But it also clears out pretty heads a little. That’s normal. COOKSON religiously, too. I think most variants cause In my experience what you see and a milder reaction, actually, and tend to hear occurs 5 to 9 or 10 days after persist a bit more in their presentation. ? SANDER vaccination. But if you’re looking at air We also see it with PCR and when we And a rolling reaction? sacs — and that’s another very important look at Ct values. way of evaluating — that usually comes COOKSON on a little bit later. That usually occurs [Editor’s note: Using real-time PCR If, say, 40% to 50% of the birds are head about 9, 10 or up to even 14 or 15 days technology, the DNA of a virus is identified shaking, that’s probably an excessive after vaccination. with a fluorescent signal. It can take or rolling reaction. If you hear a lot of multiple cycles to identify a virus, and the snicking or what I call the “frog noise,” ZAVALA number of cycles it takes is the cycle which sounds like a wet cough or gurgle, The reason I ask is because I don’t know if threshold (Ct) value. When more virus is as soon as you walk into the house, it has anything to do with the composite present, it takes fewer cycles to be identified that’s excessive. of vaccines we’re using today and if it with the test. When less virus is present, it differs from what used to be used maybe takes more cycles.] 10, 12 or 14 years ago. In the past,

JACKWOOD I always like to say you need some vaccine reaction, I agree. I think it depends on the vaccine. because if you’re not getting any, you probably don’t A lot of people think bronchitis vaccines “ have birds that are immunized. are all created equally and they’re not. We have more aggressive vaccines and MARK JACKWOOD, PhD we have very mild vaccines. And those ” vaccines and the combinations of those vaccines can push the vaccine reaction out to 12 days. I always like to say you need some vaccine reaction, because if you’re not getting any, you probably don’t have birds that are immunized. On the other hand, you don’t want production losses or severe reactions or long-lasting reactions either.

? SANDER What about reactions when combining a bronchitis and Newcastle vaccine? Is there one component that causes any kind of interference or concern?

FRENCH It can certainly complicate the issue. I think it makes it a bit worse. I appreciate your comments about checking air sacs, Dr. Cookson. To me, the level of airsacculitis you see in birds is critical. I expect to see it show up about 7 or 8 days after vaccination and to last for about 5 to 7 days. I don’t, however, want to see a 2+ score.

Whether you’re putting Newcastle or something else that’s really aggressive, like a laryngotracheitis vaccine, on top of a bronchitis vaccine, you start to really create problems, and birds can have a hard time getting over the response to vaccination. The more stuﬀ you add to the vaccination, the worse the reaction gets.

23 INFECTIOUS BRONCHITIS: EVOLVING STRATEGIES FOR AN EVOLVING VIRUS 15 IBV ARKANSAS CONUNDRUM I also wonder if some of the continued problems we have with IBV Arkansas is self-induced. “ SARAH TILLEY, DVM ”

? SANDER improved our performance. Bird health FRENCH I hear concern about IBV Arkansas got better, yaddah-yaddah.” I’m on the We’re looking at it right now. We’re bronchitis vaccines leading to rolling other end of the spectrum, where I’ve trying some new combinations and are reactions and condemnations, yet IBV been using Arkansas now for 11 or 12 wondering if we’ll get enough protection Arkansas is still prevalent in the US. years, and we have some of the best against Arkansas to be able to pull it out. Does anybody have any experience in livability and low condemnation rates — We’re as nervous as we can be about it, the field with managing vaccination we’re in the top 25% in both of those but that being said, I’ve never been a big against this serotype? categories. Maybe I could do a little fan of Arkansas vaccines anyway, so I’m better, but I really don’t want to touch kind of excited that we’re pulling it out. TILLEY it if it’s not broken. It’ll be interesting to see. I’ve not had personal experience, but when my predecessor removed the Now, with the addition of these new COOKSON Arkansas vaccine from the bronchitis variants, it does make you question if We did a study this year in broilers program, everything worked well for a IBV Arkansas plays well with GA08. involving combinations of IBV serotypes while, then condemnations went through Can I give them together? If not, then and an IBV Arkansas challenge. The the roof. He said, “No way am I ever going which one do I pull? It opens up a lot combination was Massachusetts plus to do this again.” of questions. GA98 or Massachusetts plus GA08. Both gave us about 50% protection, which isn’t There have been some studies, and I think LADMAN too bad in broilers. GA08 plus GA98 gave it’s fairly well known that IBV Arkansas is We’ve always found IBV Arkansas works about 30% protection. By itself, the just not very immunogenic. If you don’t great but that’s by eyedrop, and that’s not Arkansas IBV vaccine alone gave 86% use a proper dose and don’t properly the real world. It’s always interesting to protection.4 If you’re trying to eliminate an prepare and administer the vaccine hear the woes. I don’t know whether it’s IBV Arkansas vaccine from your program, correctly, your best bet is a very low management or something specific about it seems like IBV Massachusetts is a good vaccine take, and you don’t get a robust certain regions. It’s interesting to me place to start, then build from there. immune response. If you are giving because I see how it works in a lab. It’s a multiple bronchitis vaccine serotypes polarizing vaccine strain, for sure. The caveat is that if a bronchitis program along with IBV Arkansas, Arkansas doesn’t is successful without an IBV Arkansas compete enough and you don’t get a high COOKSON vaccine, it’s probably highly dependent enough immune response and it can I think that’s complicated to some degree, on how much IBV Arkansas virus you persist. I also wonder if some of the for the simple reason there are several actually have floating around. If the IBV continued problems we have with IBV different Arkansas vaccines out there, and Arkansas virus starts to build up, the Arkansas are self-induced. there’s quite a difference between them. program probably isn’t going to hold up without an IBV Arkansas vaccine. There’s BURLESON no protection like IBV Arkansas against It’s funny that when you talk to broiler ? SANDER IBV Arkansas, right? veterinarians about IBV Arkansas vaccines, Is anyone aware of experience you get both ends of the spectrum. Some involving trouble with an say, “Yeah, we pulled it out and we really IBV Arkansas who has pulled it from their program and found cross-protection against Arkansas with other bronchitis serotypes?

24 POULTRY HIGHLIGHTS OF A ROUNDTABLE DISCUSSION HEALTH T O D A Y ® 16 REFLECTIONS ...I think we have to be realistic and get away from the idea that we’re going to have one vaccine that’s going to cross-protect against everything. “ This virus just does not lend itself to a strategy like that. MARK JACKWOOD, PhD ”

? SANDER This virus just does not lend itself to a We’re almost out of time. But before strategy like that. There are, however, we wrap up, I’d like to give everybody some new technologies that exist today an opportunity to tell me where you where we can create a tailor-made vaccine think we might be with bronchitis in a matter of months against a new IBV control within the next 5 years. that we just isolated and all we have is Will we still be fighting it? Are we sequence data for it. Whether USDA — going to see enough advances in and this goes back to my 5-year prediction research or vaccine technology — will allow us to license such a vaccine, that’s going to allow us to see some which would be a recombinant, and use it significant improvement and cut in the field, remains to be seen. So it might our producer losses? be 10 years from now — we’ll see. But I think the future does look bright. It’s going BURLESON to change. I’m not so optimistic. In 5 years, I think we’ll still be in the same spot. I’d like to LADMAN think within 10 years, maybe. I hope I’m I’ve seen good, smart people that I and not having to deal with bronchitis until many others respect retire after making I retire. significant contributions to the IBV body of knowledge, yet the disease is still here. FRENCH I hate to say it, it chews people up and I think history has told us we can expect spits them out. I can’t say I’m as optimistic, another wave every 3 to 5 years. I’d like to unfortunately. We know the challenges, see vaccines that could be tailor-made to and we have a long way to go. Regulation our challenges and that can be developed is important and certainly a big challenge, quicker than 3 years. By the time a new probably the largest challenge of all. vaccine is developed, the virus is I think it comes down to learning how to spreading and creating more mutations. use the tools we have in front of us, using them well and staying on top of what I don’t know how tailored vaccines could 1 Data on file. Study No. 06-15-7ADMJ. Zoetis LLC. be made faster, but that would be the we’re doing. answer to our biggest concerns. 2 Cookson K, et al. Broiler challenge study evaluating SANDER different combinations of infectious bronchitis vaccines JACKWOOD I want to extend my thanks to each of on protection against a contemporary DMV/1639 IBV you. This has been an informative and challenge isolate. Am Assoc Avian Pathol. 2019. I’m with Dr. Burleson. I think in 5 years we’re going to be at about the same place educational panel that should be of 3 Jordan B. Infectious bronchitis vaccination: How can we we are now. But I think we have to be benefit to the industry. improve? XXIV Congreso. Centroamericano y del Caribe de realistic and get away from the idea that Avicultura. Antigua Guatemala. November 2016.

we’re going to have one vaccine that’s 4 Data on ﬁle. Study No. 032419-KL-70AQO-KC-5821. going to cross-protect against everything. Zoetis LLC.