Poultry Diagnostic Tests and Drug Selection Flashcards
What is critical to remember when trying to treat backyard birds?
Considered food animal species
In diagnostics, what are the two overarching ways to identify a pathogen?
ID the Antigen or Antibody
As antibody detection decreases, antigen detection…
Increases
What is an antigen test detecting?
Infectious particles
- direct or indirect
Viral or bacterial material (viable or not)
RNA or DNA
What do antibodies detect?
Immune repsone or exposure
-antibody and antigen interaction with indicator
- need signs, vaccination repsonse and retrospective exposure
Acute and convalescent samples helpful
When looking at serology why do we need acute and convalescent titers?
Acute - at infection
Convalescent - see if antibodies increase
2-3 weeks apart
What is acquired immunity?
Development of antibodies to disease
IgY in birds
What are some methods that can be used to detect antigen?
-PCR
-Whole Genome Sequencing
-Isolation and culture (must be viable) (Aerobic and anerobic)
-ID stained tissue (Histo)
How does PCR work?
Primers used to ID target
Amplified and quantified
DNA polymerase vs reverse transcriptase
How does whole genome sequencing work?
New
entire genome looked at
What must you remember is you are using cell culture or egg culture?
Antigen must be viable or alive to detect it
Place in right location in egg for growth
What is decteded on EMB agar?
E. Coli
What is the Maldi-tof?
Gold standard isolation machine for virus and bacteria
5 second ID
What are you looking for in a stained tissue sample?
Inclusion body - intranucler or cytoplasmic
-pox
What are some tests you can run for antibody detection?
Virus neutralization, hemagglutination inhibition, ELISA, plate agglutination, Agar Gel
IFA
Complement Fixation
Latex Agglutination
How does virus neutralization work?
Serum is incubated with target virus cell culture
Cytopathic effect - antibodies present then virus cant destroy cell culture, not present can
Get titer
How does hemagglutination inhibition work?
Hemagglutinin protien on surface virus interact with RBC
Antibody present then bind to virus (cant destroy RBC)
How does an Elisa work?
Common
Cheap and easy
many samples
antibodies, antigen and protein
How does plate agglutination work?
Serum + known fixed/stained AG leads to agglutination
What is an agar gel precipitin/immunodiffusion?
Diffusion of antigen and antibody through agar gel
Antibody present then complex with antigen
Complex make a noticeable line (positive)
How do you test and confirm AI?
Elisa for screening
AGID for conformation
When performing PCR what is the positive control or threshold?
27 cycles
40 pretty sure positive since only 45 cycles
Lower number of cycles the higher the pathogen and sooner it was amplified
When switching from passive to active immunity how long does it take to shift?
3 week passive goes down and titer up to normal in 2 weeks
If you vaccinate a flock and check the titers and they are all over the map what does that mean?
Unsuccessful vaccination
