Types of disease

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There are four main types of disease affecting poultry: metabolic and nutritional diseases; infectious diseases; parasitic diseases; and behavioural diseases.

Metabolic and nutritional diseases

These are conditions caused by a disturbance of normal metabolic functions either through a genetic defect, inadequate or inappropriate nutrition or impaired nutrient utilisation. These include Fatty Liver Syndrome, Perosis (or slipped tendon), Rickets and Cage Layer Fatigue.

Infectious diseases

An infectious disease is any disease caused by invasion by a pathogen which subsequently grows and multiplies in the body. Infectious diseases are often contagious, which means they can be spread directly or indirectly from one living thing to another. These include Avian Encephalomyelitis, Avian Influenza, Avian Tuberculosis, Chicken Anaemia Virus Infection (or CAV), Chlamydiosis, Egg Drop Syndrome (or EDS), Fowl Cholera (or Pasteurellosis), Fowl Pox, Infectious Bronchitis, Infectious Bursal Disease (or Gumboro), Infectious Coryza, Infectious Laryngotracheitis, Lymphoid Leukosis, Marek’s Disease, Mycoplasmosis, Necrotic Enteritis, Newcastle Disease, Salmonellosis

Parasitic diseases

Parasitic diseases are infections or infestations with parasitic organisms. They are often contracted through contact with an intermediate vector, but may occur as the result of direct exposure. A parasite is an organism that lives in or on and takes its nourishment from another organism. A parasite cannot live independently. These include Coccidiosis, Cryptosporidiosis, Histomoniasis, Lice and Mites, Parasitic Worms (or Helminths), Toxoplasmosis, Trichomoniasis.

Behavioural diseases

Abnormal behavioural patterns can lead to injury or ill health of either or both of the abnormally behaving bird and its companions. These include Cannibalism (or aggressive pecking).

List of avian diseases

Poultry can be affected by many types of disease, and a wide variety of pests (and behavioural problems) including those in the list below. Diseases caused by Viruses Avian Influenza Avian Encephalomyelitis Big... read more

Ascites

Under construction Ascites is considered a metabolic disorder and is common in commercially grown chicken and ducks. It is thought that in fast growing breeds, organs are unable to supply the... read more

Avian encephalomyelitis

Avian encephalomyelitis (AE) is a viral infection of the central nervous system of poultry, primarily chickens, turkeys, Japanese (coturnix) quail, and pheasants. It is found worldwide and is characterised by ataxia (loss of muscle coordination)... read more

Avian influenza

Avian influenza (AI) is a highly contagious viral infection which may cause up to 100% mortality in domestic chickens or turkeys. The disease is caused by a virus belonging to the family Orthomyxoviridae.... read more

Avian Intestinal Spirochaetosis

Avian Intestinal Spirochaetosis (AIS) is a disease affecting commercial laying and meat breeding hens resulting from the colonisation of the caeca and rectum by one or more species of anaerobic spirochaetal... read more

Avian tuberculosis

Avian tuberculosis is a slowly spreading, chronic bacterial infection. All bird species appear to be susceptible, although to variable degrees; pheasants seem to be highly susceptible, while the disease is uncommon in... read more

Cannibalism (or aggressive pecking)

While pecking is the natural means by which poultry investigate their surroundings and establish a stable social order, this behaviour can escalate to the stage where birds will literally peck... read more

Chicken anaemia virus infection (or CAV)

Chicken anaemia virus infection (known generally in the industry as CAV) is an acute viral infection of chickens that is found worldwide. The disease is not known to affect any other bird species,... read more

Chlamydophilosis

Chlamydophilosis is a bacterial infection that can range from subclinical through to acute or chronic disease states. It is characterised by respiratory, digestive or systemic infection. Chlamydiosis can infect a wide variety of... read more

Coccidiosis

Coccidiosis is one of the most common and economically important diseases of chickens worldwide. It is caused by a parasitic organism that damages the host’s intestinal system, causing loss of production, morbidity and... read more

Colibacillosis

Colibacillosis is an infectious disease caused by the bacterium Escherichia coli, or E. coli as it is commonly known, and is seen in poultry flocks worldwide. E. coli can cause an infection under the skin, known as cellulitis,... read more

Cryptosporidiosis

Cryptosporidiosis is a parasitic disease that affects quail, pheasants, peafowl, waterfowl, chickens, turkeys, finches and psittacines (such as parrots). Cryptosporidia are poorly host-specific and can affect other animal species including humans, other mammals,... read more

Candidiasis (or crop mycosis)

Under construction Candidiasis (or crop mycosis) is…

Egg drop syndrome (or EDS)

Egg drop syndrome (EDS) is caused by a viral infection in laying hens. It is characterised by production of soft-shelled and shell-less eggs in apparently healthy birds, leading to a sudden drop in... read more

Fatty liver syndrome

Fatty liver syndrome is a condition that affects only hens, primarily caged layers. It is a metabolic or nutritional disease and is characterised by general obesity with an enlarged, fatty liver that becomes... read more

Fowl cholera (or pasteurellosis)

Fowl cholera is a contagious bacterial infection. The disease can range from acute septicaemia (blood poisoning) to chronic and localised infections. Domestic fowl, game birds and small feral birds are susceptible. Turkeys... read more

Fowl pox

Fowl pox is a relatively slow-spreading viral infection that affects most bird species, including all commercial forms of poultry. It occurs in both a wet and dry form. The wet form is characterised... read more

Histomoniasis

Histomoniasis is a parasitic protozoan infection of turkeys, chickens peafowl and several game bird species. In turkeys, most infections are fatal while in other birds, mortality is less common. Although chickens are relatively... read more

Inclusion body hepatitis (or Fowl adenovirus type 8)

Under construction Inclusion body hepatitis or Fowl adenovirus type 8) is…..

Infectious bronchitis

Infectious bronchitis is a highly contagious viral respiratory infection of chickens, however the virus will also infect the urogenital and gastrointestinal tracts. Symptoms include coughing, sneezing and gasping in young birds, loss of... read more

Infectious bursal disease (or Gumboro)

Infectious bursal disease (IBD), also known as Gumboro, is a highly contagious viral infection of chickens that is seen worldwide. The severity of the disease will depend on the age and breed of... read more

Infectious coryza

Infectious coryza is a contagious bacterial respiratory infection of chickens. While there are reports of a similar disease in other birds such as pheasants and guinea fowl, there is considerable doubt if these... read more

Infectious laryngotracheitis

Infectious laryngotracheitis (ILT) is a highly contagious viral respiratory infection of chickens and pheasants and the disease is notifiable in most states in Australia. A number of other bird species such as turkeys,... read more

Leg and skeletal problems

Leg and skeletal problems are a very important area especially from welfare points of view and are common in some breeds of broilers. Issues include rickets, TD, spondylolisthesis, slipped tendons, tibial rotation and... read more

Lice and mites

Lice and mites are common external parasites of poultry. Lice are insects, while mites belong to the same family as spiders. There are a large number of lice and mite species that can... read more

Lymphoid leukosis

Lymphoid leukosis is a neoplastic (tumour causing) viral infection of chickens. The infection is found worldwide and is known to exist in virtually all chicken flocks except for some SPF (specific pathogen free)... read more

Lympoid Tumour Disease

Reticuloendotheliosis or Lympoid Tumour Disease is a retrovirus infection common in chickens, turkeys, ducks, geese and quail with morbidity rates reaching up to 25%. A gradual increase in death-rate and poor... read more

Marek’s disease virus or MDV

Marek’s disease virus (MDV) is a highly contagious viral infection that predominantly affects chickens but can also affect pheasants, quail, gamefowl and turkeys. The disease is one of the most common diseases affecting... read more

Mycoplasmosis

Mycoplasmosis is a collective term for infectious diseases caused by the micro-organisms called mycoplasmas. There are a number of mycoplasmas that can infect poultry, with the main ones being: Mycoplasma gallisepticum (MG), which affects a... read more

Necrotic enteritis

Necrotic enteritis (NE) is the most common and financially devastating bacterial disease in modern broiler flocks. It is an infectious disease caused by Clostridium perfringens, which is a gram-positive, anaerobic bacterium that can be... read more

Newcastle disease

Newcastle disease is a highly contagious viral infection that affects many species of domestic and wild birds. Most susceptible are domestic fowls, turkeys, pigeons and parrots. Milder disease is seen in a number... read more

Parasitic worms (or Helminths)

All birds are naturally subject to infection by parasitic worms, or Helminths. The majority of Helminths infect the digestive tract but some are also found in other organs, such as the brain, trachea and eye. Not all Helminth... read more

Rickets and cage layer fatigue

Rickets and cage layer fatigue are nutritional diseases seen in chickens, turkeys and ducks that results in soft bones, with the leg bones often becoming bowed and hampering the bird’s ability to stand and... read more

Toxoplasmosis

Toxoplasmosis is a zoonotic (can be transmitted from animals to humans) parasitic protozoan disease and is rare in poultry, more common in aviaries and backyard poultry than commercial producers. It is characterised by... read more

Trichomoniasis

Trichomoniasis is a parasitic protozoan disease that affects domestic fowl, pigeons, doves, and hawks. It occurs in the digestive tract in two forms. The lower form is characterised by depression, weight loss and watery yellow... read more

Viral arthritis (tenosynovitis)

Viral arthritis also known as tenosynovitis is a classic manifestation of reovirus infection of chickens wit at least 5 sero-types of the virus occur. Morbidity is high but mortality is usually... read more