Avian Diseases: Infectious and Non-Infectious

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Questions and Answers

What is the main characteristic of non-infectious diseases in birds?

They require a common experience among flock members to contract (correct)

They can be passed from bird to bird

They are caused by microorganisms

They can only be transmitted vertically

What is the term for diseases that can be passed from one bird to another?

Vertical diseases

Infectious diseases (correct)

Contagious diseases (correct)

Non-infectious diseases

What is an example of direct transmission of a disease?

From parent to offspring via the egg or sperm (correct)

Via an intermediate host such as insects

Through contaminated feed or water

Through respiratory droplets

What is an example of indirect transmission of a disease?

Via an intermediate host such as insects Signup and view all the answers

What is the smallest pathogen that can cause harm to birds?

Viruses Signup and view all the answers

What is required for viruses to multiply and cause harm?

To be inside the animal cell Signup and view all the answers

What is the term for organisms and microorganisms that have the potential to cause harm to birds?

Pathogens Signup and view all the answers

How do viruses invade and damage animal cells?

By injecting their genetic material into the cell Signup and view all the answers

What is the main difference between Mycoplasmas and Fungi?

Ability to form spores Signup and view all the answers

Which of the following is NOT a characteristic of Mycoplasmas?

Can survive long outside of the host Signup and view all the answers

What is the primary way Fungi harm birds?

By destroying tissue Signup and view all the answers

What is the primary way Protozoa harm birds?

By destroying tissue Signup and view all the answers

What is the term for chemicals that interfere with the Protozoan life cycle?

Coccidiastats Signup and view all the answers

Where do Internal parasites typically live in poultry?

Inside the bird, usually in specific organs Signup and view all the answers

What is the primary difference between Internal and External parasites?

Their location in the bird Signup and view all the answers

How many Internal parasites in poultry are likely to cause harm?

Three Signup and view all the answers

What is a common consequence of having a large quantity of bloodsuckers on a bird?

Anaemia Signup and view all the answers

What is the primary goal of maintaining good hygiene practices on a poultry farm?

To kill microorganisms that cause disease Signup and view all the answers

What is a major factor that can contribute to disease outbreaks in a poultry flock?

Stress in the flock Signup and view all the answers

What is the term for the period of isolation or separation of a bird or flock to prevent the spread of disease?

Quarantine Signup and view all the answers

What is a common route of entry for disease-causing organisms into a poultry flock?

Through several routes Signup and view all the answers

What is the term for the microorganisms that are injected into a bird by bloodsuckers while feeding?

Spirochaetes Signup and view all the answers

What is a consequence of a primary infection on a bird's ability to fight subsequent invaders?

Reduced ability to fight Signup and view all the answers

What is a factor that can predispose a bird to disease?

Stress Signup and view all the answers

What is the benefit of being able to differentiate between healthy and sick birds in a poultry flock?

To take early action to prevent the spread of disease Signup and view all the answers

What is a normal level of mortality for meat chickens?

4% to 40 days Signup and view all the answers

What is the purpose of monitoring the current disease situation in a poultry flock?

To monitor the success of cleaning and vaccinating procedures Signup and view all the answers

What is a characteristic of a healthy bird?

Having a normal appetite and behavior Signup and view all the answers

What action may be taken if a disease is detected in a poultry flock?

All of the above Signup and view all the answers

Why is it important to recognize sick birds in a poultry flock?

To take early action to prevent the spread of disease Signup and view all the answers

What is the normal level of mortality for layer and breeder replacements?

Less than 5% to point of lay Signup and view all the answers

What is the benefit of reducing mortality in a poultry flock?

To reduce the economic impact of disease Signup and view all the answers

Study Notes

Non-Infectious Diseases

Non-infectious diseases cannot be passed from bird to bird and require a common experience for individuals to contract.
These diseases are not caused by microorganisms.

Infectious Diseases

Infectious diseases are caused by microorganisms such as parasites, fungi, protozoa, bacteria, mycoplasmas, chlamydia, and viruses.
These diseases can be passed from one bird to another either directly or indirectly.
Direct transmission occurs when a diseased bird passes the cause of the disease to a susceptible healthy bird via direct contact.
Indirect transmission occurs when the causal organism is passed from one bird to another via an intermediate host or object.

Causes of Infectious Diseases

Pathogens or disease vectors are organisms and microorganisms that have the potential to cause harm.
There are many different types of pathogens that can be transferred from one bird to another or from one flock to another by various means.

Viruses

Viruses are the smallest pathogens and can only be seen through an electron microscope.
They consist of an outer layer surrounding special protein material similar to the genetic material of the cells they invade.
Viruses can multiply and do harm only when inside the animal cell.

Mycoplasmas

Mycoplasmas are single-cell organisms slightly larger than chlamydia.
They have a cell wall and nucleus.
The most commonly known disease caused by Mycoplasma is Mycoplasmosis or Chronic Respiratory Disease (CRD).
Mycoplasma organisms respond to some antibiotics.

Fungi

Fungi are organisms larger than bacteria and are considered to be members of the plant kingdom.
They multiply by forming spores that are released and enter the local environment.
Fungi harm birds in two ways: by direct invasion and by producing toxins.

Protozoa

Protozoa are single-cell organisms larger than bacteria.
They have a complex reproduction system that allows them to multiply quickly.
Protozoa generally harm birds by destroying tissue.
Chemicals can be used to treat birds infected by protozoa.

Internal Parasites

Internal parasites are multi-celled organisms that live inside the bird.
They are usually located in specific organs.
Most internal parasites are visible to the naked eye.
Only three internal parasites are likely to cause harm in poultry.

External Parasites

External parasites live outside the bird.
They can cause harm by irritating the bird or by being bloodsuckers that can cause anemia.
Some external parasites can carry organisms that they inject into the bird while feeding.

Prevention of Disease

Good hygiene practices are essential to prevent disease.
Quarantine is necessary to maintain control over the means of entry by disease-causing organisms.
Vaccination can be used to combat infectious diseases.
Preventive medication may be necessary to combat infection by some organisms.

Resisting Disease

Many disease outbreaks occur because of predisposing circumstances that ensure the success of the invasion by the causal organisms.
Stress in the flock can reduce the bird's ability to fight disease.
A primary infection can reduce the ability of the bird to fight invasion by secondary invaders.

Disease Severity

Disease in poultry can be one of two levels of severity: catastrophic or chronic.
In each case, affected birds and recovered birds are carriers that can transfer the causal organism to other stock.

Vaccination

Vaccination triggers the bird's immune system to produce antibodies to fight infection.
Not all diseases can be vaccinated against.
A suitable vaccination program should be developed to combat identified disease threats.

Preventative Medication

Preventative medication may be necessary to combat infection by some organisms.
Veterinary advice may be necessary to determine an appropriate preventive medication program.

Monitoring Program

A monitoring program is necessary to detect disease early.
Techniques used in monitoring programs include laboratory tests, observation, and examination of bird behavior.

Recognising Healthy and Sick Birds

A healthy bird will have a good appetite, be alert, and have a smooth, shiny plumage.
A sick bird will show signs such as lethargy, loss of appetite, and changes in droppings.
Early recognition of disease is essential to take appropriate action to prevent the spread of disease.

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Description

Learn about the differences between infectious and non-infectious diseases in birds, including their causes and modes of transmission.