Poultry Industry & Chicken Virus Flashcards
What are the light (egg type) breeds
Single comb white leghorn
What are the heavy (meat type) breeds
Cornish male and white rock female
What are the dual purpose backyard breeds?
Rhode Island Red, Barred Plymouth Rock, White Plymouth Rock, New Hampshire
How would you sex chickens by the feathers?
Long primary feather = female
Short primary feather = male
Pullets raised in pullet houses until ____ weeks of age, and they begin laying at ___ weeks of age
16 weeks old, moved to layer house, 17-18 weeks begin laying
White leghorns produce _____ eggs/hen/year ingesting ___ feed/dozen eggs
220-240 eggs/hen/year
2.9 lb of feed/dozen eggs
Brown egg layers produce ____ eggs/hen/year ingesting ___ feed/dozen eggs
187 eggs/year
3.3 lb of feed/dozen
What is the humane way to put your chicken flock through a molt?
Decrease the day length and give high fiber feed
Goal is a 4lb male broiler chicken. How long does it take to achieve this?
6 weeks old with a feed efficiency of 1.7:1
What are the top two reasons for a chicken to be condemned at slaughter?
Sep/Tox and Airsacculitis
What are the two biggest disease concerns in the duck industry?
Riemerella (Pasteurella) anatipestifer
E. coli septicemia
What are your top two differentials for splenomegaly in chickens?
#1 – Erysipelas #2 – Adenovirus II (HE of turkeys)
Name the 4 diseases associated with Aviadenovirus (group I adenovirus)
Quail bronchitis
Inclusion Body Hepatitis (chickens)
CELO Chicken Embryo Lethal Orphan
Serogroup I Adenovirus of Turkeys
You are given a dead quail to necropsy. The bird is less than 8 weeks of age. It has intranuclear inclusion bodies within the tracheal epithelium, as well as karyomegaly. What is your top differential?
Quail Bronchitis
Aviadenovirus
<8 weeks old
What is very important to remember about Inclusion Body Hepatitis for the exam?
“Egg Transmission” or Vertical Transmission
You are presented with 7 week old chickens that are suffering respiratory problems followed by death. Some are showing a hemorrhagic syndrome with aplastic anemia. There is a 10% drop in egg production. What disease are you most suspicious of?
Inclusion body hepatitis! Aviadenovirus
3-15 wk old chickens
Secondary to immunosuppression
Describe the Avian Encephalomyelitis virus
Aka AE aka Epidemic Tremor
Picornavirus,
Non-enveloped, ssRNA
You are presented with young chickens under 3 weeks of age showing muscle tremors of the head and neck, ataxia, and paralysis. On necropsy, you notice the birds have cataracts, as well as white areas in the muscular layers of the proventriculus, ventriculus, heart and pancreas. What is your top differential?
AE! Avian Encephalomyelitis! Epidemic Tremor!
Tremors + cataracts = AE
Also diagnostic: brown central chromatolysis in brain (remember Newcastle has peripheral chromatolysis)
On a slide from a brain sample from a chicken, you notice brown central chromatolysis. What is your diagnosis?
AE
Avian Encephalomyelitis
Epidemic Tremor
Describe the prevention/ vaccination process for AE
All breeders & laying hens
Prime with MLV and then wing web injection with pox at 8-10 weeks
Water vaccination probably best
Vaccinate layer pullets 4+ weeks prior to moving to layer house
What is the Flu D ELISA?
It’s like a pregnancy test for AI
Acute infection only
Remember IgG’s more efficient with ELISA
IgM more efficient with hemagglutination inhibition / AGID
Describe the AI virus
Orthomyxovirus, Type A
Enveloped, ssRNA
Name the two types of genetic mutation changes
Genetic Drift- gradual shift driven by vaccine pressure
Genetic Shift- overnight change in antigenic structure
A flock has a mass die-out overnight. On necropsy there were cyanotic combs, facial edema, comb blisters, blood in the trachea, esophagus, proventriculous and cecal tonsils. There were hemorrhages on the heart and small intestines. There was a fibrinous airsacculitis present. What is your top differential?
High Path AI
You are presented with a bird that has an irregular iris. What is your first differential?
Marek’s Disease (herpesvirus)
Lymphocytic plasmocytic iridiocyclitis
You are presented with a chicken with cataracts. What is your top differential?
Avian Encephalomyelitis
You are presented with a chicken with a cloudy cornea. What do you suspect is going on?
High concentration of ammonia in the barn.
If you are presented with an emaciated chicken, there are a number of possible causes, but what are your most common?
Marek’s disease and TB (mycobacterium avium)
Describe the Marek’s Disease virus
Aka Range paralysis aka neural lymphomatosis aka skin leucosis
Cell-associated herpes virus (subfam Alphaherpesvirnae, genus mardivirus)
Enveloped dsDNA
Name the three forms of Marek’s disease seen in poultry and their associated signs.
Nervous form: paralysis, dropped leg or wing, twisted neck
Skin form: enlarged feather follicles “skin leucosis”. Shed in dander!
Tumors: white masses on any internal organ
What would you see on histopathology of Marek’s Disease
Lymphocytic cuffing of blood vessels in brain
What two diseases cause caseous cecal plugs
Salmonella and Eimeria tenella
Compare Avian Leukosis to Marek’s Disease
Marek’s invades the Bursa and is a T cell lymphoma
AL is a B cell lymphoma
If you see a chicken with osteopetrosis or looks like Pop-Eye with swollen legs, what is your top differential?
Avian Leukosis
Infected periosteum
This is a disease of chickens over 14 weeks of age
What are the common presentations of Avian Leukosis
Lymphoid Leukosis “LL” most common
Also, erythroblastosis, myeloblastosis, myelocytomatosis (pale cells in liver), osteopetrosis
Describe the Avian Leukosis / Sarcoma Complex
Alpharetrovirus, 6 serotypes (ABCDE & J)
Enveloped, ssRNA
What is the most common finding in birds with Avian Leukosis
Tumors, often associated with bursal tumors and liver. Adult birds shouldn’t have bursas
Describe the Chicken Infectious Anemia virus
CIA aka Blue Wing
Gyrovirus of Circoviridae
Non-enveloped, ss circular DNA
You necropsy chickens from a flock experiencing increased mortality. The live birds are quite pale. On necropsy, there is fatty yellow bone marrow and hemorrhages under the skin and muscle. What is your top differential?
CIA
Chicken Infectious Anemia
Circoviridae
What cells does Chicken Infectious Anemia attack?
CIA kills T cells
Describe the Fowl Pox virus
Avipoxvirus of Poxviridae
Enveloped, dsDNA
What is the difference between the wet and dry form of Fowl Pox
Dry (cutaneous) form in crusts and scabs on skin (NOT feathers). Less problematic, decreased production parameter
Wet (diphtheritic) form in the mucous membranes of mouth and eye. There is increased mortality and difficulty breathing with this form
You find white to yellow masses and plaques on the eyelid, mouth and trachea. They are polypoid blocking masses. What is your top differential?
Fowl Pox!
+/- Infectious laryngotracheitis (ILT
ILT needs break in skin. Pox makes the break, ILT enters
Describe the Infectious Bronchitis virus
IB (NOT IBD)
Coronavirus (different from turkey corona)
Enveloped, ssRNA
Only causes disease in chickens
You are presented with a young flock of chickens who present with snick, cough and respiratory rales. On necropsy, hyperemia and mucus were found in the caudal 1/3 of the trachea, as well as enlarged pale kidneys with uroliths. What is your top differential?
Infectious bronchitis “IB”
Coronavirus
Enveloped ssRNA
You are presented with adult layer hens who have decreased egg production with misshapen, wrinkled eggs that have runny, thin albumen. What is your top differential
Infectious bronchitis IB
Coronavirus
Enveloped ssRNA
Describe the Infectious Bursal Disease (IBD) virus
IBD aka Gumboro aka Delaware disease
Avibirnavirus of Birnaviridae
Non-enveloped dsRNA
2 serotypes, only Type 1 is pathogenic
Describe what you see in a chicken <3 weeks old with IBD
Subclinical (no signs)
Immunosuppression with poor response to vaccination
May develop gangrenous dermatitis, inclusion body hepatitis and E. coli
Describe what you see in a chicken >3 weeks old with IBD
Clinically sick birds, diarrhea, vent picking. High morbidity, lower mortality.
You necropsy a bird with an enlarged Bursa of Fabricius. Other birds in the flock have Bursas that are gelatinous, hemorrhagic or shrunken. There is hemorrhage in muscles and the bird has swollen pale kidneys. What is your top differential?
IBD! Infectious Bursal Disease
aka Gumboro aka Delaware disease.
Describe the Infectious Laryngotracheitis virus
ILT aka LT
Gallid herpesvirus 1
Enveloped, dsDNA
Usually affected birds >4wks
A farmer contacts you because his flock of layer hens has an increased mortality rate and has stopped producing eggs. The live birds are showing conjunctivitis, cough, head shaking, blood on external nares, pump handle breathing and abnormal screaming vocalization. What is your top differential?
ILT
Infectious Laryngotracheitis
You necropsy a chicken from a flock with increased mortality and ceased egg production. You find conjunctivitis, blood on the nares, mouth, feathers and the cranial 1/2 of the trachea. There is some blood, mucus and fibrin in the larynx and trachea. There are intranuclear inclusion bodies on microscopy. What will you tell the farmer?
This is ILT, a herpesvirus.
This is one disease that you can vaccinate for during an outbreak! But no treatment.
Inclusions are there 12hr - 5 days post infection only
Reportable disease!!!
What is important to remember about the ILT vaccine?
Due to vaccine virus recrudescence, it is only practiced on farms with a previous diagnosis. Depending on the state, it may not be allowed. This is administered via eye drop, water or spray
How is the Pox vectored vaccine administered?
In the wing web. It does not contain the entire virus
How is the Marek’s disease vectored ILT vaccine administered?
SQ.
Meat type chickens - day 1, 3 wks.
Egg type: 6-10wks with booster after 10 wks
What is an important difference between AI, Newcastle and ILT
ILT - fibrin, blood clots and frank blood in trachea
AI & Newcastle- will also have blood in esophagus and other organs
Describe Newcastle Disease virus
aka Avian pneumoencephalitis
Avulavirus of paramyxovirus type 1 (in chickens) (type 2,3,6 in turkeys)
Enveloped ssRNA
What are the three different pathogenic types of Newcastle Disease and how do they affect young chickens?
LMV
Lentogenic: mildly pathogenic (B-1, LaSota)
Mesogenic : marked respiratory disease, neck paralysis with >50% death
Velogenic: same as meso but faster and 50-100% death
What are the 3 different pathogenic types of Newcastle disease and how do they affect adult chickens?
LMV
Lentogenic: mild to no respiratory disease, drop in egg production or soft/deformed eggs
Mesogenic: depression, respiratory signs, some CNS signs, ceased egg production
What are the different gross lesions seen with each pathogenic type of Newcastle Disease
Lento & mesogenic: reddening of entire length of trachea, conjunctivitis, airsacculitis
Velogenic: Hemorrhages of trachea, esophagus, proventriculus, ventriculus, intestine & cecal tonsils
Describe the vaccination schedule for Newcastle Disease in broilers, egg-type and turkeys.
Broilers: 1d, booster every 2-3 wks
Egg-type: 3wks (combo with IBV), booster every 2-3 wks
Turkeys: 3 & 6 wks
Describe the Viral Arthritis virus
aka Tenosynovitis aka ruptured gastroc tendon aka reovirus infection
Reovirus (Resp Enteric Orphan virus)
Nonenveloped, dsRNA
Which birds are most affected by Viral arthritis?
Primarily broiler chickens, some egg-type and turkeys in Midwest
Chickens are resistant to infection >2wks old
Which diseases can be egg transmitted?
Reovirus
Aviadenovirus (inclusion body hepatitis)
Avian Encephalomyelitis
CIA
You are presented with chickens that are showing lameness and swollen hocks. Some are unable to bear weight. There is non-uniformity in the flock with many stunted birds. What is your top differential
Viral Arthritis (reovirus)
You are necropsying a chicken and find swelling, edema, hemorrhage and discoloration of the tendons and tendon sheath of the hock joint. There is some scarring present. What is your top differential?
Viral Arthritis (reovirus)
Rule out bacterial infection
Describe the duck viral enteritis virus
Herpesvirus (of alphaherpes)
Enveloped dsDNA
There is a massive die out of wild waterfowl in the area. There is evidence of bloody diarrhea and a prolapsed phallus. On necropsy, you find ulcers in the esophagus, hemorrhages on the heart and intestinal lymphoid structures, as well as bloody intestinal contents. What is your top differential?
Duck Viral Enteritis
Remember ducks don’t show disease from HPAI, are just carriers.
Look for eosinophilic inclusion bodies on histopath
Maple Leaf Farm makes its own vaccine for this
What are the 3 explosive hemorrhagic diseases?
AI
Velogenic Newcastle
Duck Viral Enteritis
Describe the Duck Viral Hepatitis virus
DHV 1 : picornavirus
DHV 2: astrovirus in England
DHV 3: picornavirus, in US, lower mortality than 1
DHepB Virus, hepadnavirus, wild & domestic ducks in US, no disease or lesions
You are presented with a duck for necropsy. It is 1 week old and is one of many ducklings that died. It is exhibiting opisthotonus. There is hemorrhage in the liver on necropsy. What is your top differential given the signalment and signs?
Duck Viral Hepatitis
You are presented with broiler chickens who have swollen faces, are depressed and disoriented with twisted necks. Birds who have died show enlarged pale kidneys. What are you suspicious of?
Swollen Head Syndrome
metapneumovirus (thought same as TVRT)
Transovarial transmission suspected
If you suspect an arboviral disease outbreak, what should the farmer do?
EEE, WEE, St. Louis EE
frequent removal and disposal of dead birds is very important to prevent spread within a flock
