ANS 150: Comprehensive Study on Poultry Diseases and Their Treatments

2 Avian Primary Immune Organs

Thymus

Bursa of Fabricius

What happens to both the Thymus and Bursa after puberty in the chicken?

It regresses in the chicken.

Thymus produces...

T lymphocytes

Thymus structure in chicken

lobes on both sides of neck

Bursa of Fabricius produces...

B lymphocytes

Bursa of Fabricius structure in chicken

little pouch dorsal to the cloaca

5 Examples of Avian Secondary Immune Organs

cecal tonsils

Peyer patches

Harderian gland

Spleen

Lymphoid follicles

Chicken Infectious Anemia (CIA) is also known as what 3 other names?

Chicken Anemia Virus (CAV)

Chicken Anemia Agent

Blue Wing Disease

Chicken Infectious Anemia (CIA) is characterized by what 4 things?

aplastic anemia

lymphoid atrophy

hemorrhages

immunosuppression

How common is Chicken Infectious Anemia (CIA)?

It is ubiquitous/everywhere

What type of virus causes Chicken Infectious Anemia (CIA)?

DNA virus

5 Characteristics of Chicken Anemia Virus (CAV)

Smallest DNA virus to exist

Circular

Not enveloped

Lives for a long time

Less susceptible to heat/chemicals

How does the capsid of Chicken Anemia Virus (CAV) make it more resistant?

It is very tight and secure so it is harder for soap to go in and destroy the genome

Infectious Bursal Disease (IBD) is caused by what type of virus?

double stranded non-enveloped RNA virus

Infectious Bursal Disease (IBD) characterized by what 3 things?

Inflammation and subsequent atrophy of the bursa of fabricius plus immunosuppression

How long does the inflammation infection of Infectious Bursal Disease (IBD) last?

3-5 days

What age does Infectious Bursal Disease (IBD) usually affect in chickens?

3-6 weeks old

How do you control Infectious Bursal Disease (IBD) and Chicken Infectious Anemia (CIA)?

Vaccination in breeders

What is an example of a disease that causes Avian Viral Tumors?

Marek's Disease Virus (MDV)

What type of virus is Marek's Disease Virus (MDV)?

alpha-herpesvirus

DNA enveloped virus

Marek's Disease Virus (MDV) is a tumoral disease of what 3 species?

chickens, turkeys and quails

What age of chickens does Marek's Disease Virus (MDV) usually affect?

2-7 months old

What does it mean when we say that Marek's Disease Virus (MDV) is cell associated?

It needs cells to survive

How many serotypes does Marek's Disease Virus (MDV) have and what are they?

Three serotypes.

1. mild, v (virulent), vv(very virulent), vv+

2. non-oncogenic

3. HVT

Why is it important to know the different serotypes of Marek's Disease Virus (MDV)?

So that we know which vaccines to use to protect against which strains.

If we want to protect against all strains of Marek's Disease Virus (MDV), what serotype should we vaccinate against?

serotype 1 [mild, v (virulent), vv(very virulent), vv+]

How common is Marek's Disease Virus (MDV) in the environment?

It is ubiquitous and hard to get rid of.

ALV

Avian leukosis virus

Avian leukosis virus (ALV) and Marek's Disease Virus (MDV) are important because...

they are the most diagnosed diseases in backyard flocks

(3) Transmission for Marek's Disease Virus (MDV)

Feather dander (most important)

Sporadic shedding through lifetime, latency (sheds when chicken is stressed as it goes out of the nerve - herpesvirus)

Very contagious

3 signs of Marek's Disease Virus (MDV)

Depression, poor body condition

Asymmetric partial paralysis/dilation of crop (vagal nerve paralysis)

Blindness

4 Lesions of Marek's Disease Virus (MDV)

Nerve enlargement

Discoloration of the iris

Enlargement of feather follicles

lymphomas in nerves and viscera

What 3 things are you looking for when diagnosing Marek's Disease Virus (MDV)?

History

Age

Location of Tumor

Marek's Disease Virus (MDV) is most common in what age?

most common in immature chickens (2-5 months old)

What is it called when Marek's Disease Virus (MDV) is found in older chickens?

Late Marek's vv+

What is usually involved in Marek's Disease Virus (MDV) that indicates the disease?

Nerve involvement

What two diagnostic tests are not very useful for diagnosing Marek's Disease Virus (MDV)?

virology and serum not very useful

What diagnostic tool is used to help diagnose Marek's Disease Virus (MDV)?

qRT-PCR

3 Ways to Control Marek's Disease Virus (MDV)

Vaccination

Minimize exposure during the first days of chicks hatching

Buy vaccinated chickens from National Poultry Improvement Plan (certified) Hatchery

When is vaccination done for Marek's Disease Virus (MDV) in commercial industries?

in ovo

When is vaccination done for Marek's Disease Virus (MDV) in smaller farms?

hatch one day of age

How long does it take for immunity to develop in chicks?

Immunity is not fully developed for 7-10 days

What are the 3 vaccines available for Marek's Disease Virus (MDV)?

HVT

HVT + serotype 2

Attenuated serotype 1

3 Symptoms of Marek's Disease that you can see visually

Ballet Dancer Position (legs splayed in opposite directions)

Walking on hock

Depressed chicken

What are the two places that Marek's Disease Virus (MDV) causes lesions in chickens?

Neoplastic nerve lesions

Eye lesions

What 2 nerves are enlarged due to Marek's Disease Virus (MDV) tumors?

Sciatic Nerve

Vagus Nerve

What happens to the eye when there is lymphoid infiltration of Marek's Disease Virus (MDV) into the iris?

The pupil becomes polygon/squared shape

What happens to carcasses of meat chickens that have Marek's Disease Virus (MDV)?

They have skin tumors all over their body. Carcass is condemned and cannot be consumed.

Why can't Marek's Disease Virus (MDV) chicken carcasses be used for human consumption?

It doesn't look good with all the tumors. But it won't spread disease.

5 Organs Marek's Disease Virus (MDV) can create tumors

Heart

Spleen

Liver

Ovary

Lung

2 Types of Respiratory Diseases in Chickens

Infectious Bronchitis (IB)

Newcastle Disease (ND)

What type of virus causes Infectious Bronchitis (IB)?

RNA enveloped virus

Infectious Bronchitis (IB)

acute and highly contagious respiratory disease of chickens

Infectious Bronchitis Virus (IBV) targets what two things in chickens?

Upper respiratory

Urogenital tracts

How does Infectious Bronchitis Virus (IBV) affecting urogenital tracts affect egg production?

Egg production and quality goes down

Describe the drop in egg production for chickens that have Infectious Bronchitis (IB) in percentages and time

20% Drop in egg production for 1-3 weeks

Does the egg production of chickens that were infected with Infectious Bronchitis Virus (IBV) ever go back to normal?

No, it will never go back to what it normally was before they were infected.

4 Symptoms of Infectious Bronchitis (IB)

Tracheal Rales (gasping, crackles in breathing)

Sneezing

Nasal discharge

Coughing

How contagious is Infectious Bronchitis (IB)?

Highly contagious

How long is Infectious Bronchitis (IB) incubation period?

short incubation period of 24-48 hours

What type of transmission is most important in Infectious Bronchitis (IB)?

Horizontal transmission through aerosols

5 Economic Losses due to Infectious Bronchitis (IB)

Reduced feed conversion

Reduced weight gain

Increased mortality in young chickens

Increased condemnations at processing plants

Reduced egg production & quality

Where does Infectious Bronchitis (IB) first infect and replicate in?

the upper respiratory tract

replicates in eyes, nostrils, etc.

When Infectious Bronchitis Virus (IBV) goes into the blood (primary viremia), what two places does can it go to?

Intestinal tract

Reproductive tract

2 Ways to prevent Infectious Bronchitis (IB)

Vaccination with live vaccine (does not protect against all strains because of variability of the virus)

Cleaning/Disinfection (it's a very sensitive virus)

What are the 3 types of Influenza Virus and who does it affect?

Type A (a-m) affects mammal and avian

Type B (h-s) affects human and seals

Type C (h-p) affects human and pig

Avian Influenza is in the family....

Orthomyxoviridae

Avian Influenza is usually what type of influenza?

Influenzavirus A

Genetic material/structure of Influenza Virus

Negative double stranded RNA with 8 segments

Why is the Influenza Virus such high variability?

it is prone to mutations and recombination events

Antigenic drift

point mutations due to selective pressure

Antigenic shift

genetic reassortment of gene segments

What two animals are mixing vessels for the Influenza virus, creating antigenic shift?

Ducks and pigs

What are the 2 most important proteins for the Influenza Virus and why?

Hemagglutinin (HA) (18) allows virus to enter cell

Neuraminidase (NA) (11) allows virus to exit cell

Avian-type receptor for Influenza Virus

alpha-2,3 = sialic acid links

Human-type receptor for Influenza Virus

alpha-2,6 = sialic acid links

Nomenclature and example for Influenza Virus

Type/Affected Species/Country or Location/Year

A/Chicken/California/15

Nomenclature short version for Influenza Virus

Hemagglutinin type + Neuraminidase type

H1N1

How do they determine whether Avian Influenza in chickens is highly pathogenic or low pathogenic?

Determination in laboratory

What are the 2 ways to determine pathogenicity of Avian Influenza in the laboratory?

Intravenous Pathogenicity Index (IVPI > 1.2) in chicks (inoculate chicks and see how they react)

Molecular sequencing (sequence portion of gene that gets divided when virus successfully replicates aka the cleavage portion)

What do you call the portion of gene that gets divided when a virus successfully replicates?

Cleavage portion

When a gene cleaves easily, what does it mean it has a lot of?

Basic amino acids

How does OIE (World Organization for Animal Health) categorize Avian Influenza?

Highly Pathogenic Notifiable Avian Influenza (HPNAI)

Low Pathogenic Notifiable Avian Influenza (LPNAI)

Highly Pathogenic Notifiable Avian Influenza (HPNAI)

severe clinical signs and high mortality in birds

Low Pathogenic Notifiable Avian Influenza (LPNAI)

Strains H5-H7

Little or no clinical signs in birds

When was a HPAI outbreak?

2022-2024

In the HPAI outbreak, what type of birds were affected a lot?

wild birds that were majority resident non-migratory had a lot of clinical cases

5 examples of wild birds affected by the HPAI outbreak

waterfowl, raptors, pelicans, terns, cranes

What 5 continents did HPAI outbreak affect?

Europe

North, South & Central America

Africa

Asia

Where was the first case of the HPAI outbreak detected in the US?

First detected in the Atlantic flyway (east coast)

How did the HPAI outbreak move in the US and through what birds?

It moved westward throughout the continent from east coast to west coast through migratory birds like raptors, waterfowl and crows.

Describe the epidemic curve of the HPAI outbreak

Longer outbreak with a higher proportion of backyard birds affected and wider bird distribution

Describe the epi curve of the 2014-2015 Avian Influenza outbreak

2 peaks

Describe the epi curve of the 2022 H5N1 Avian Influenza outbreak

Multiple peaks that are extended in time

3 comparisons of the epi curves from the 2014-2015 AI outbreak VS. 2022 H5N1 AI outbreak

2022 commercial outbreak lasted longer

Higher proportion of backyard to commercial flocks in 2022 (60% in 2022 vs. 9% in 2014-15)

Greater number and diversity of wild bird species affected in 2022 and much wider geographic area affected.

What two wild birds were the most affected by the HPAI outbreak (highest percentage of testing positive out of the ones sampled)?

Vultures

Pelicans

By knowing what wild birds are most affected by HPAI, how can we use that information to protect our chicken flocks?

Prevent those wild birds from getting close to poultry farms by learning their migratory patterns and knowing which birds live in the area that are more likely to carry the virus (ex. Vultures in CA)

For the 2022 HPAI outbreak, how was the virus introduced in most cases?

point introduction

Due to biosecurity, what type of spread was limited in the HPAI outbreak?

lateral spread

How common was the virus in the environment during the HPAI outbreak?

a lot of virus in the environment