Hi Marina. Thank you for sharing this interesting case. I

t would be useful to carry out PCR and/or immunohistochemistry of the affected bursas in order to detect infectious bursal disease virus (IBDV). I also think that Marek disease virus (MDV) can´t rule out because of the chicken´s age and the bursal atrophy you highlighted.

Do you have information about the characteristics of the production area of studied chickens (e.g. densely populated)? Do you have information if any health issue previously happened?

Thank you

Daniel

Hi, Daniel.

Thank you very much for your advices.

I am still waiting for the decision of our virologist (because the titer of maternal antibodies was more than satisfactory). I also submitted the samples of bursa for PCR (IBDV), but I think that, unfortunately, IHC is excluded so far.

From the owner of the farm we were able to just find out that they were not vaccinated against IBDV in ovo. Namely, the chickens are imported from abroad and the producer only confirmed the vaccination against MDV in hatchery/ for the parent flock he did not say anything! /). The owner vaccinated them against coccidiosis (Paracox/1st day), and then against salmonella (8th day). Talking about Paracox, I know that it can be used only in birds if they are not under the stress. Perhaps something like: inadequate transportation, and other confirmed diseases - could induce IBD (only hypothesis!). The same chickens were dissected again at the age of 4 days and then at the age of 15 days. At the age of 4 days again I found hemorrhagic bursitis, but at the age of 15 days the bursae were completely ok. Since the beginning the macroscopic and microscopic findings have been typical for infectious stunting. However, the results of histopathology examination in chickens aged 15 days showed a picture suspicious to AE, and some of them to the infection with MDV / macroscopically it was still stunting followed by sporadic cases of coli septicaemia /E. coli was isolated in all three cases/!). According to my knowledge, the MDV should not cause hemorrhagic bursitis (atrophy – yes, but not hemorrhagic bursitis). So, I am not quite sure that it will be of some help, but this is the only what I know till now.

Oh, yes, I can send you a photo of PH findings in one of this hemorrhagic bursa (if you want, of course?!?)

Best regards and thank you again

Marina 

Hi Marina,

Many thanks again for sharing your case and the full description you provided.

I agree that the stressor factors you mentioned could triger immunesupression.  The bursal lesions you mentioned could indicate IBD as you said but Marek disease could appear as a concurrent condition. Do you have samples of the peripheral nerves to check the presence/absence of lymphomas caused by Marek disease?

It could be a good idea to recommend a full serologic study including  IBD, chicken anemia virus and adenovirus group 1 of the studied broiler chicken flock and the broiler breeder flock from which they came.

Because mycotoxins are known to cause of immunosupression in poultry, it could be useful to make a mycotoxin analysis of the provided food.

Please send me the photos of the tissues you think are relevant

Best regards

Daniel

Hi Daniel,

Unfortunately I did not take sciatic nerves for HP because the necropsy finding was completely negative on MD. I agree with you regarding CAAV, MDV and adenogroupvirus group 1, but these analyses do not depend on me, so, I have to wait....oh, yes, a small correction: the chickens are light hybrids - commercial layers (TETRA SL). 

Do you think that the presence of mycotoxins in food of their parents could induce such lesions in bursa of newly-hatched chickens? Hm, I do not know for this...

I will send you a photo tomorrow, because I forgot to take my disc with me.

Thank you again for your advices!

Best regards

Marina

Hi Marina,

Many thanks for this additional information.

I understand that you didn´t find any gross lesions possible associated with MD. However, I studied some cases in which the microscopic lesions of MD can be noted without gross lesions at necropsy. The peripheral nerves (e. g. vagus, sciatic) are always the key to confirm or discard MD.

Regarding the analysis of the mycotoxins, I think that it could be a good a idea if you could suggest the study of the mycotoxin profile in food. It could be possible that the broiler breeders received enough mycotoxin levels capable of producing immusupression which in association with concurrent stressors factors could lead to low antibody levels transmit to their progeny. 

I will wait for your photos.

Thnks again

Best regards

Daniel

Hi Daniel,

here are the photos of hemorrhagic bursa in newly-hatched commercial layers chicken (they are not broiler chickens). I think that mycotoxins can hardly be the cause of these hemorrhages, because they were newly-hatched (they did not reach the food). Talking about the maternal titer: it was satisfactory.

BR

Marina

Hi Marina,

Thank you for the photos you sent.

There is a severe lymphoid depletion together with extensive hemorrhages in the bursa you showed. I saw some cases of bursal hemorrhages associated with IBD in broiler chickens but the bursal hemorrhages of your case are massive.

Following the photos you showed, my first differential diagnosis is IBD. I think the PCR targeting the viral RNA of IBDV could play a key role in the diagnostic work-up of this case. Do you have the possibility of sequencing the PCR products you may obtain?

Best regards

Daniel

Hi Daniel,

since the incubation period is usually 3 days, some experts, including our main virologist, think that it (IBDV infection) is impossible. For example, when I showed him the pictures (including the macro-pathology (cherry-like bursa)) he told me that it could be because of some other reasons (e.g. non-infectious causes). Ok, I can accept this explanation, but I did not see any hemorrhages in other tissues as well as the macroscopic findings typical for e.g. CAA. But, two days ago I heard from the owner that these chickens had two days (means they were not newly-hatched chickens) when they were delivered to my lab. She told us that it was some kind of misunderstanding (?!!?). I know very well the way of IBDV transmission, but if you have been working as avian pathologist an histopathologist all these years than you also have to have a very good eye for (at least) basic avian (and poultry ) diseases signs. What do you think? I only want to say that I agree with you! I sincerely hope that somebody will do PCR one day (even if I will not be able to find out the results:)))! 

Best regards and thank you once again for your advices!

(If I find out something new, I will write you a message!)

Marina

Hi Marina,

Thanks again for your new answer.

Firstly, I would like to say that I unserstand the point of view of your virologist. However, the cherry-like gross aspect of the affected bursas are commonly associated with IBDV which is supported by the histopathologic figures you showed. 

Despite the early age of the affected chicks, IBD is my first differential diagnosis. I think there is/are non-infectious cause/s associated with that bursal gross lesions. 

Can you send bursal samples (e.g. FTA cards, formalin-fixed, paraffin-embedded blocks) abroad for other molecular analysis different from those provided by your virology Lab?

Thanks again

Best regards

Daniel

HI Daniel,

thank you for your advice. I will see what can (may) I do regarding the molecular analysis other than those provided in virology lab. Have you any idea which non-infectious causes can be involved? For  example, the gastrointestinal tract of all chicken cadavers (necropsied in age of two days) was empty, and there was not any sign of uricosis (talking about the possible intoxication). However - this is only: "For example...

Best regards

Marina

Hi Marina,

Many thanks. I was thinking about possible non-infectious causes associated with the cherry-like bursas you found. However, it´s difficult to include other differential diagnosis only considering this gross lesion.

How was the thymus and yolk sacs of the affected chickens?

If we didn´t consider this cherry-like bursal gross lesion, several non-infectious management causes of mortality in 2-to-3-day-old chickens can be included.

Best regards

Daniel

Hi Daniel,

In almost all cases E. coli was isolated, but the pathogenicity was not determined. I did not found any data about hemorrhagic bursitis in chickens infected with E.coli. In all of them the changes typical for malabsorption syndrome were also confirmed. Thymus was atrophied (which is common change in malabsorption syndrome). The problem is not connected with the causes of high mortality (I think E. coli infection and malabsorption syndrome were quite enough for high mortality). I was surprised with the finding of hemorrhagic bursitis in so young chicks.

Best regards

Marina

Hi Marina,

I agree that malabsorption syndrome and Escherichia coli infection may be related to the mortality in the affected chickens.

I also agree that the hemorraghic bursal gross lesions are quite surpring at that age.

The atrophy of the thymus is a key finding for this case. Did you see an overgrowth of E, coli on the agar plates? 

Many thanks

Daniel

Hi Marina,

Will it be possible to demonstrate IBDV bey means of immunohistochemistry?

I think that the micro picture closely corresponds to Infectious Bursitis and as Daniel nicely mentioned that MD will be another nosology that should not be excluded.

If you're able to perform IHC will be of great help.

Best regards/ Sve nejbolje,

Ivan

Hi Daniel,

E. coli was isolated from all parenchymatous organs, yolk sacs and intestines of two-days and five-days old chickens (I think that several samples of lungs were also examined). The agar plates were covered all over with E. coli colonies.

Best regards

Marina

Hi Marina

Many thanks for the information. As you said, colibacilosis was one of the causes of death of the afftected chickens.

Best regards

Daniel

Hi Daniel,

thank you again for all your advices. If I will be able I will try to send you a paraffin block  with bursa.

Best regards

Marina

Hi Marina

Thank you for sharing this interesting case. I will be very happy to receive a bursa block to carry out further studies.

Best regards

Daniel

Dear Ivan,

I'm so sorry I missed your question and advice. Only now I see that you have been involved in the "case of hemorrhagic bursitis:))". Unfortunately, the case is still unresolved. Thank you very much for your advice (i.e. IHC). I also thought it would be the only possible solution in this situation.

Best regards

Marina