Unit 1 - Avian Part 1 (Leukosis to IBV) Flashcards
What are broiler chickens?
Chickens that are harvested at 5-6 weeks of age
What are broiler turkeys?
Turkeys that are harvested 14-18 weeks of age
When do breeders and egg layers begin laying eggs?
At about 18 weeks of age
What problems are unique to avian species?
There are drug residues in the eggs and the broiler chickens have short lifespans so immunization is in-ovo or not at all
What breeds are brown egg layers?
Plymouth Rock, Orpington, and RI Red
What breed is the meat breed of chickens?
Cornish Cross
What are the subgroups of the Avian leukosis viruses and what are they grouped based on?
Subgroups - A, B, C, D, E, and J grouped based on their envelope glycoproteins
What species is lymphoid leukosis/sarcoma clinically significant in?
chickens
Currently, what population of chickens is lymphoid leukosis a problem in?
Broiler chickens
Tumor mortality is ___ in chickens with lymphoid leukosis.
<4%
How do infected hens shed leukosis viruses?
It is shed into the albumen or yolk
True or False: Chickens that become congenitally infected with lymphoid leukosis usually remain viremic for life.
True
Most lymphoid leukosis virus spread is ______(direction) early in life.
horizontal
It is relatively easy to maintain lymphoid leukosis virus-free flocks if you do what?
eliminate the virus from the breeder hens
What is most economic loss caused by lymphoid leukosis due to?
Decreased egg production
What do most leukosis tumors result from?
Induction of bursal cells
What is the most common leukosis tumor type?
lymphoid
What are non-lymphoid leukosis tumors dependent on?
strain of virus, breed of chicken, age of exposure, dose, and route of infection
True or False: Demonstration of a leukosis virus is helpful in diagnosing lymphoid leukosis.
False
What tumors are pathognomonic for lymphoid leukosis?
bursal tumors
Where else can tumors form in lymphoid leukosis cases?
Liver, spleen, and other organs
How do you differentiate between Marek’s disease and Lymphoid Leukosis?
Lymphoid leukosis does not develop any peripheral nerve lesions, Marek’s does
Marek’s also doesn’t commonly effect the bursa
How is lymphoid leukosis controlled/eradicated?
Test eggs from breeder flocks for viral antigen
Discard eggs from positive hens
Rear breeder hens in small groups to limit the possibility of having an infected hen
Grow genetic resistant strains of hens
Is immunization successful for lymphoid leukosis?
No
What causes Marek’s disease (general)?
Alphaherpesvirus with lymphotrophic properties of gamma herpesvirus
What does Marek’s disease infect?
feather follicles
True or False: Marek’s disease is not contagious
False - it is highly contagious
Is Marek’s disease problematic in turkeys?
No
What are the three Marek’s disease viruses?
Gallid Herpesvirus 2
Gallid Herpesvirus 3
Meleagrid Herpesvirus 1
________ Herpesvirus ___ is also known as MDV2 and is avirulent for chickens.
Gallid, 3
________ Herpesvirus ___ is also known as MDV1 and is virulent for chickens.
Gallid, 2
________ Herpesvirus ___ is also known as MDV3 and is avirulent for turkeys.
Meleagrid 1
What are the four subdivisions for Gallid Herpesvirus 2 (MDV1)
M - mild
V - virulent
VV - very virulent
VV+ - very virulent plus
What are the most common Gallid Herpesvirus 2 viruses? Why?
Very virulent plus - it is thought to be a result of routine immunization
What can subclinical Marek’s disease cause?
It causes decreased growth rate and egg production
What main pathology does Marek’s disease cause?
lymphoid neoplasms
What ‘other’ lesions does Marek’s cause?
Transient paralysis, early mortality syndrome, cytolytic infection, atherosclerosis, and persistent neurologic disease
How is Marek’s diagnosed?
Enlarged nerves, enlarged feather follicles, and lymphoid tumors in the viscera
What is the most consistent gross lesion caused by Marek’s disease?
enlarged nerves
What clinical sign is associated with enlarged nerves caused by Marek’s disease?
Paralysis or paresis
What Marek’s disease diagnostic lesion is the cause for condemnation of broilers?
Skin leukosis (enlarged feather follicles)
How is Marek’s controlled?
With strict sanitation
Once in a poultry barn, how does Marek’s transmit?
via feather dust
How long can Marek’s survive in the poultry house litter and dust?
months
How can Marek’s viruses be inactivated and how long may it take?
You can inactivate the virus in 2 weeks with high humidity and 37.5 C
What is the recommendation for the initial vaccine type (strain) for Marek’s disease?
Initially, chickens should be immunized with turkey virus or a combination of one or more other ‘avirulent’ strains
When should in-ovo immunization for Marek’s occur?
At 18 days of incubation
What type of vaccine should the Marek’s booster be?
A more virulent vaccine virus to protect against the most common (VV+) virus in the industry
What causes infectious laryngotracheitis?
Gallid herpesvirus 1
True or False: Infectious laryngotracheitis is a life-long infection
True
What causes the recrudescence of infectious laryngotracheitis?
stress
Infectious laryngotracheitis is a (acute/chronic), (not/highly) contagious virus that affects mostly _____ and ________.
Acute, highly contagious
Chickens and pheasants
What is the age of onset of infectious laryngotracheitis?
Usually 14 weeks of age or older
What clinical signs are associated with infectious laryngotracheitis?
Dyspnea, coughing with bloody discharge, and reduced egg production
What forms of infectious laryngotracheitis are there?
Acute, subacute, and subclinical
What lesions are associated with acute infectious laryngotracheitis?
Necrotizing tracheitis
Blood, mucus, caseous exudates or hollow caseous casts in the trachea
Swelling of infraorbital sinuses
What lesions are associated with subacute infectious laryngotracheitis?
Punctiform hemorrhages in the trachea and larynx
Low virulence vaccine strains can spread to non-immune birds
How is infectious laryngotracheitis diagnosed?
Intranuclear inclusions in tracheal epithelium early in the disease
PCR
Virus isolation
How is infectious laryngotracheitis controlled and prevented?
Good biosecurity and immunization in endemic areas
How long is infectious laryngotracheitis virus viable in droppings?
8-10 days
How long does infectious laryngotracheitis virus remain viable in a carcass?
For up to 80 days
What areas is immunization for infectious laryngotracheitis virus recommended?
It is recommended in endemic areas
What type of vaccines are available for infectious laryngotracheitis virus?
Live attenuated - eye drop, water, or spray
Recombinant vector - in-ovo, subq, and wing web
What is one of the most important disease worldwide?
Newcastle Disease
What is the etiologic agent of Newcastle disease?
Avian paramyxovirus 1
_______ and ________ viruses are highly pathogenic and are now referred to as vNDV.
Velogenic and mesogenic viruses
What are the lentogenic newcastle viruses?
They are low virulence viruses that can be used as vaccines
Also known as loNDV
What clinical signs are associated with Newcastle disease?
It starts with respiratory signs and then muscle tremors, CNS signs, paralysis, watery diarrhea, swelling of head and tissues
What clinical signs are associated with the milder disease cases of Newcastle?
Coughing, sneezing, nasal discharge, and depression
What may occur in Newcastle vaccinated hens or hens with LoNDV?
There will be a sudden decrease in egg production or production of thin shelled eggs
What is severity of Newcastle disease dependent on?
Age at infection, immune status, and susceptibility of host species
What avian species are most susceptible to Newcastle disease?
chickens
What strain are significant Newcastle lesions associated with?
VVND
What significant lesion does Newcastle disease cause and where?
Hemorrhages in the serosa, intestinal mucosa, cecal tonsils, and spleen
What clinical signs are associated with lentogenic strains of Newcastle disease?
Milder respiratory signs such as congestion in respiratory tract, mucoid exudate, and opacity in thickening of air sacs
How do you diagnose Newcastle disease?
With PCR or inoculation of embryonated check eggs (can be used to detect an increase in titer)
True or False: There are no vaccines for Newcastle virus.
False - Their vaccines available for chickens, turkeys, and pigeons
How are Newcastle vaccines administered?
As an aerosol spray or via drinking water
How long can maternal antibody interfere with Newcastle vaccination?
For 3-4 weeks
What Newcastle vaccines can be used in-ovo?
Recombinant fowlpox and Turkey herpesvirus vectored NDV vaccines for chickens
What Newcastle vaccines can be used to booster live vaccines? And what population is this used in?
Oil-adjuvanted inactivated virus vaccines
For breeder and laying hens
True or False: Vaccination for Newcastle in the presence of other disease agents can lead to disease.
True
Newcastle is zoonotic. What lesions/clinical signs can it cause in humans?
It can cause conjunctivitis
What pathotypes of avian influenza are a concern for high pathogenicity?
H5 and H7
Most infections of Avian Influenza are _______or produce _______disease or ______egg production.
Subclinical, respiratory, lowered
What respiratory signs does avian influenza cause?
Sneezing, coughing, swollen sinuses, ocular and nasal discharges
True or False: Highly pathogenic avian influenza (HPAI) is a mild disease with low mortality.
False - it is a severe systemic disease with high mortality
What clinical signs are associated with acute HPAI?
Cyanosis and edema of the head, wattles, comb, etc.
Red discoloration of the shanks and feet due to ecchymotic hemorrhages
Hemorrhages in viscera
Blood tinged oral and nasal discharges
Greenish diarrhea
CNS signs
How is avian influenza diagnosed?
Virus isolation from tracheal and cloacal swabs
ID the virus with AGID or PCR
Is avian influenza reportable?
Yes
Can you vaccinate for avian influenza?
Yes, but you need to get permission from the state veterinarian and the USDA to vaccinate
Is vaccination for avian influenza typically done?
It isn’t done with highly pathogenic outbreaks and it is not routinely done with low pathogenicity because of lack of efficacy and masking of clinical signs
What causes avian infectious bronchitis? And what species is affected?
Coronavirus affecting only chickens
True or False: Avian infectious bronchitis is a highly contagious disease with a morbidity near 100%
True
How does avian infectious bronchitis spread?
It spreads via respiratory secretions and the fecal-oral route
What anatomical location does avian infectious bronchitis primarily affect?
The respiratory tract but the oviducts are often damaged as well
___________ strains of avian infectious bronchitis can cause severe kidney damage.
Nephropathogenic
What secondary bacterial infections can occur with avian infectious bronchitis and cause a more serious disease with higher mortality?
Mycoplasmas, E.coli, or Avibacterium paragallinarum
What clinical signs are associated with avian infections bronchitis?
Coughing, sneezing, gasping, nasal discharge
In what age of chickens is infectious bronchitis most severe in? How does it manifest?
It is the most severe in young chicks. Sinusitis can occur with secondary bacterial infections.
How does avian infectious bronchitis manifest in layering chicken?
Respiratory distress, decreased egg production, loss of egg quality
What lesions are associated with infectious bronchitis?
Cirrus, catarrhal respiratory discharges Caseous exudates in the upper respiratory tract Clouding and thickening of the air sacs Defective egg formation Smaller or cystic oviducts
How is the egg defective as a result of infectious bronchitis?
there is yolk material or a fully formed egg within the abdominal cavity of the layer hens
What lesions do nephrotropic strains of avian infectious bronchitis cause?
Necrosis of nephrons, interstitial nephritis, urate retention, and urolithiasis
How is avian infectious bronchitis diagnosed?
Seroconversion or an increase in tighter is indicative but you must differentiate from vaccine virus which can initiate respiratory signs
What diagnostic method can detect viral RNA and has been developed to the point where it can identify infectious bronchitis serotype differences?
PCR
How is infectious bronchitis prevented?
Vaccination
What type of vaccines can be used for infectious bronchitis prevention?
Attenuated vaccines and killed vaccines
What infections bronchitis vaccines may produce mild clinical signs?
Attenuated vaccines
When are attenuated vaccines for infectious bronchitis given?
At 1 to 14 days of age and either a spray, drinking water, or and eye drop
What is it suggested to booster attenuated vaccines for infectious bronchitis with?
A different serotype as it may give broader protection
When are killed infections bronchitis vaccines used?
To boost immunity in laying hens - it avoids egg defects
