We typically don’t worry over testing a show chicken for diseases as we prepare for a fair or poultry exhibition. Our thoughts turn to the condition of the show cages at the event, on the availability of fresh water, on the parking situation, on kinds of competition amongst the other birds. Testing a chicken prior to entering the exhibition hall? Just a formality we all have to deal with.
Until it’s no longer a formality and becomes a shocking reality.
Why Does My Bird Need Testing?
Because Pullorum disease (caused by the bacteria Salmonella pullorum) and Fowl typhoid (caused by the bacteria Salmonella gallinarum) are such devastating afflictions, with 100-percent mortality, poultry shows require that all birds being brought onto the premises must test negative for these illnesses, collectively called Pullorum-Typhoid (PT).
Even if a chicken looks perfectly healthy, it still requires testing for diseases. Why? Because it may carry PT. That means you chicken can spread these diseases.
Testing occurs on site by testers certified by the National Poultry Improvement Plan (NPIP). This nationwide program was established in 1935 in response to Pullorum’s calamitous effects on the U.S. poultry industry.
How Is Testing Conducted?
When it your bird’s turn arrives, the tester will conduct a rapid whole-blood plate test. This involves carefully drawing blood from the brachial vein located on the underside of your chicken’s wing.
The tester will hold the chicken firmly to ensure it does not injure itself by flapping during the blood draw. For larger birds, an assistant may need to hold the bird steady while the tester draws the blood sample.
A special tool called a bleeding needle draws the sample. This device has an end loop that gathers the blood.
The blood sample then gets mixed together on a special testing plate with a drop of a liquid antigen containing killed strains of the bacteria. Your tester then tilts and rotates the testing plate for approximately two minutes, watching for any reaction.
After two minutes, the tester places the testing plate on an illuminated box for easy result readability.
Reading the Testing Results
When illuminated, the testing plate will clearly show either a positive or a negative result. If the result reads as negative, the blood/antigen sample will simply look like a translucent red or blue smear (dye added to the antigen makes the results easier to read).
If the result comes back positive, however, clumps will form, caused by antibodies in the chicken’s blood combining with the dead bacteria in the antigen. This clumping, called agglutination, will draw the dye in, leaving the remaining sample more transparent in color.
Required Steps for Reactors
Birds whose rapid whole-blood plate tests yield positive results are called reactors. Should your bird test positive as a reactor, the tester will band its leg and place it in a special quarantine pen, safely away from the testing area and from all other birds.
After approximately 15 minutes, the rapid whole-blood plate test happen again, using blood from the other wing. If this result is negative, then your chicken will be marked as having tested negative. You can then proceed into the fair or exhibition.
Should the second rapid plate test return a positive result, however, your chicken—and all of the birds you brought to the event—will be returned to you. You will need to leave, and your state’s Department of Agriculture (or poultry association, depending on your state) will receive notification.
Your flock will receive a “hold order,” requiring quarantine of all of your poultry. During this time, you should not have any interaction with anyone else’s flock. This will ensure that you do not inadvertently carry the bacteria to other people’s birds.
Your state’s animal diagnostic lab will contact you to arrange a time to draw a blood sample from your reactor. This blood sample will undergo either a tube agglutination test or a microagglutination test at the diagnostic lab.
If this test comes back negative, your flock is free and clear.
Should the test come back positive, however, you will get a choice. You can continue your quarantine for an additional 30 days, then retest the reactor. Or you can voluntarily release your reactor chicken to the state for euthanasia and further testing for the PT diseases.
Should you choose to extend your quarantine, your reactor will receive another blood sample draw after 30 days for testing. Positive results will require the release of the reactor to the state for euthanizing and culturing.
The Final Steps
When you release your reactor to your state for euthanasia and study, your state’s veterinary diagnostic laboratory will carefully culture its internal organs, watching for the growth of Salmonella pullorum and Salmonella gallinarum bacteria. If the cultures remain bacteria free, then your flock is considered PT free and the quarantine is lifted.
Should the cultures indeed grow either bacteria, then a positive diagnosis of PT is indicated.
This requires the veterinary diagnostic lab to notify both your state veterinarian’s office and the United States Department of Agriculture (USDA). Together, these agencies will make the difficult decision of either requiring the euthanasia of your entire flock or extending the quarantine and retesting until your entire flock tests negative.