Backyard Poultry Forum • View topic - A blood test for Avian Leukosis ? Vet question

Backyard Poultry Forum

Chickens, waterfowl & all poultry - home of exhibition & backyard poultry in Australia & New Zealand
Login with a social network:
It is currently Thu Aug 16, 2018 3:47 am

All times are UTC + 10 hours [ DST ]




Post new topic Reply to topic  [ 10 posts ] 
Author Message
PostPosted: Thu Jan 18, 2018 11:50 am 
Offline
Prime Pekin
Prime Pekin
User avatar

Joined: Sat Oct 31, 2009 10:33 pm
Posts: 3318
Location: Melbourne CBD fringe
I've been searching online for information about Avian Leukosis and what to do if your bird might have it. So far it seems only a post-mortem will confirm it but wondering if there is a blood test that might hint at it while the bird is still alive?



thanks!


Top
 Profile  
 
PostPosted: Thu Jan 18, 2018 2:50 pm 
Offline
Showy Hen
Showy Hen

Joined: Fri Apr 28, 2017 6:04 pm
Posts: 166
Location: NSW Southern Highlands
hi TookTook,
I had a little search on the internet too on this. Yes, on the surface, vets seem to go for the post mortem thing.
However, it seems there ARE diagnostic tests for flocks - but this is testing egg albumen, not chicken's blood. Note what is says in the below under the "Control" heading: "Breeder flocks are evaluated for viral shedding by testing for viral antigens in the albumen of eggs with enzyme immunoassays or by biologic assays for infectious virus." So - there are tests available. Whether this assists you or not is another thing.... I guess you could find a vet that services breeders, or talk to a breeder. This is the link and copied text frm the link...

http://www.merckvetmanual.com/poultry/n ... in-poultry
Diagnosis:
Because avian leukosis virus is widespread among chickens, virus detection tests, including virus isolation and PCR and the demonstration of antigen or antibody, have limited or no value in diagnosing field cases of lymphomas. Gross characteristics of diagnostic significance include the tumorous involvement of the liver, spleen, or bursa in the absence of peripheral nerve lesions. The tumors are found in birds >14 wk old. Histologically, the lymphoid cells are uniform in character, large, and contain IgM and B-cell markers on their surface. Tumors can be differentiated from those of Marek’s disease by gross and microscopic pathology and by molecular techniques that demonstrate the characteristic clonal integration of proviral DNA into the tumor cell genome with the associated disruption of the c-myc oncogene. Lymphoid leukosis cannot easily be differentiated from B-cell lymphomas caused by reticuloendotheliosis virus except by virologic assays; however, such tumors probably are extremely rare. Several PCR primers specific for detection of the most commonly isolated avian leukosis viruses, particularly subgroups A and J, have been developed. Other primers specific for endogenous, subgroup E avian leukosis virus have also been used. PCR has been used to detect and characterize avian leukosis virus strains contaminating commercial live virus vaccines of poultry. ELISA kits for detection of antibodies to avian leukosis virus subgroups A, B, and J are available commercially.

Control:
Eradication of avian leukosis virus from primary breeding stocks is the most effective means to control avian leukosis virus infection and lymphoid leukosis in chickens. Breeder flocks are evaluated for viral shedding by testing for viral antigens in the albumen of eggs with enzyme immunoassays or by biologic assays for infectious virus. Eggs from shedder hens are discarded, so that progeny flocks typically have reduced levels of infection. If raised in small groups, infection-free flocks can be derived with relative ease. These control measures are applied only to primary breeder flocks. Voluntary programs to reduce viral infection have already reduced mortality from lymphoid leukosis and improved egg production in most layer strains; similar programs were equally successful in certain meat strains. Some breeders favor, and have virtually achieved, total eradication, while others favor a reduced level of viral infection. Some chickens have specific genetic resistance to infection with certain subgroups of virus. Although genetic cellular resistance is unlikely to replace the need for reduction or eradication of the virus, the cellular receptor gene has recently been cloned, and quick molecular assays for viral susceptibility could be developed. Thus far, vaccination for tumor prevention has not been promising.


Top
 Profile  
 
PostPosted: Thu Jan 18, 2018 9:35 pm 
Offline
Prime Pekin
Prime Pekin
User avatar

Joined: Sat Oct 31, 2009 10:33 pm
Posts: 3318
Location: Melbourne CBD fringe
Thanks for the reply Okaru :)

Still wondering if there are any vets out there who can comment?


Top
 Profile  
 
PostPosted: Wed Mar 21, 2018 10:43 pm 
Offline
Prime Pekin
Prime Pekin
User avatar

Joined: Sat Oct 31, 2009 10:33 pm
Posts: 3318
Location: Melbourne CBD fringe
Bump?


Top
 Profile  
 
PostPosted: Thu Mar 22, 2018 12:18 pm 
Offline
Old Mother Goose
Old Mother Goose
User avatar

Joined: Thu Apr 23, 2009 11:15 pm
Posts: 6731
Location: ACT area
Diagnosis:
Because avian leukosis virus is widespread among chickens, virus detection tests, including virus isolation and PCR and the demonstration of antigen or antibody, have limited or no value in diagnosing field cases of lymphomas. Gross characteristics of diagnostic significance include the tumorous involvement of the liver, spleen, or bursa in the absence of peripheral nerve lesions. The tumors are found in birds >14 wk old. Histologically, the lymphoid cells are uniform in character, large, and contain IgM and B-cell markers on their surface. Tumors can be differentiated from those of Marek’s disease by gross and microscopic pathology and by molecular techniques that demonstrate the characteristic clonal integration of proviral DNA into the tumor cell genome with the associated disruption of the c-myc oncogene. Lymphoid leukosis cannot easily be differentiated from B-cell lymphomas caused by reticuloendotheliosis virus except by virologic assays; however, such tumors probably are extremely rare. Several PCR primers specific for detection of the most commonly isolated avian leukosis viruses, particularly subgroups A and J, have been developed. Other primers specific for endogenous, subgroup E avian leukosis virus have also been used. PCR has been used to detect and characterize avian leukosis virus strains contaminating commercial live virus vaccines of poultry. ELISA kits for detection of antibodies to avian leukosis virus subgroups A, B, and J are available commercially.

https://www.msdvetmanual.com/poultry/ne ... in-poultry


Top
 Profile  
 
PostPosted: Wed Mar 28, 2018 10:34 pm 
Offline
Prime Pekin
Prime Pekin
User avatar

Joined: Sat Oct 31, 2009 10:33 pm
Posts: 3318
Location: Melbourne CBD fringe
Thanks but i cannot understand those quotes - I don't know if this tells me there is a blood test or there isn't??The language is completely foreign. What is a "PCR primer" for instance?

My gut feel is that there is NO blood test and the vet I saw was seriously on the verge of malpractice in suggesting there was.


Top
 Profile  
 
PostPosted: Thu Mar 29, 2018 8:24 am 
Offline
Dapper Duck
Dapper Duck

Joined: Wed Sep 24, 2014 5:56 pm
Posts: 51
PCR is polymerase chain reaction which is used in diagnostics, amongst other things. In order for diagnostics to be possible a primer for the specific section of DNA of interest is required.

It appears there are ways of identifying four strains of the virus, however it is stated in the opening sentence that it is considered to be of little or no value to conduct this identification, as the virus is so widespread.

Hope that helps rather than hinders, I am often good at confusing things when I try to explain.


Top
 Profile  
 
PostPosted: Thu Mar 29, 2018 8:35 pm 
Offline
Prime Pekin
Prime Pekin
User avatar

Joined: Sat Oct 31, 2009 10:33 pm
Posts: 3318
Location: Melbourne CBD fringe
Perhaps it is easier if I re-state my question: Are any of these things describing what the average person in the street would understand as a blood test?


Top
 Profile  
 
PostPosted: Thu Mar 29, 2018 10:36 pm 
Offline
Old Mother Goose
Old Mother Goose
User avatar

Joined: Thu Apr 23, 2009 11:15 pm
Posts: 6731
Location: ACT area
I think that what it is saying is that the virus is so widespread that it will show up in the blood of most birds (as antigens or antibodies). Blood tests may identify the virus but that does not necessarily mean that the bird will have symptoms of the disease.


Top
 Profile  
 
PostPosted: Fri Apr 06, 2018 10:52 pm 
Offline
Prime Pekin
Prime Pekin
User avatar

Joined: Sat Oct 31, 2009 10:33 pm
Posts: 3318
Location: Melbourne CBD fringe
thanks Sue55 -


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 10 posts ] 

All times are UTC + 10 hours [ DST ]


Who is online

Users browsing this forum: No registered users and 6 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
Powered by phpBB® Forum Software © phpBB Group
©2004-2014 Backyardpoultry.com. Content rights reserved
freestone