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Game Birds Diseases
You can find a brief descipton of diseases that can affect gamebirds. For more information log in to our clients page.
Aspergillosis
The disease is caused by a fungus Aspergillus fumigatus.
It is transmitted by inhalation of fungus spores from contaminated litter (e.g. wood shavings) or contaminated feed. Hatcheries may also contribute to infection of chicks. Partridges seem to be affected more often that pheasants.
Infected chicks are depressed and thirsty. Gasping and rapid breathing can be observed. Mortality is variable, from 5 to 50 %.
Ataxia
Pheasant ataxia is a neurological condition of pheasants. It is an important differential diagnose of Newcastle Disease (ND), which is notifiable. The nature of the lesions made one suspect the cause of the disease is a virus although a specific virus has not been found yet. Usually presents in poults 8 weeks or older. Affected birds show imbalance, walk backwards. These symptoms could progress to circling, leg paralysis and eventually lateral recumbency.
Avian encephalomyelitis (Epidemic Tremors)
Avian encephalomyelitis (AE) is caused by an enterovirus belonging to the picornavirus group. It is most often seen in very young birds. Presenting signs are a characteristic trembling (or tremor). Mortality may be as high as 50%. In laying and breeding flocks, AE virus infection causes a marked drop in egg production.
Egg transmission is the major route of transmission of AE virus. Infected chicks can transmite to other chicks in the incubator or in the farm.
Avian Influenza
Avian influenza occurs worldwide and can affect all poultry species. It is a notifiable disease and can involve the respiratory, digestive and/or nervous system. In layers, there is a drop in egg production and shell quality. Mortality is high rapid with virulent strains.
For more information visit DEFRA website: http://www.defra.gov.uk/foodfarm/farmanimal/diseases/atoz/ai/key-points.htm
Avian Tuberculosis
Avian Tuberculosis (Avian TB) is a chronic, slow spreading bacterial infection, characterized by the formation of tumor like lesions, called granulomas or tubercles, in the organs.
There are 20 different types Mycobacterium avium, only two of which are known to cause disease in birds. Most birds, including poultry, game birds, songbirds, crows etc can be affected. Pheasants for some reason are extremely susceptible.
Most commonly, a progressive weight loss is seen despite a good appetite, with a persistent diarrhoea and soiling of tail feathers. Eventually the birds will become emaciated and die.
Capillaria (Hair worms)
The worms are 7-18 mm long, about 0.05 mm wide and hair-like in appearance. Infection is by the oral route.
More commonly seen once birds have been released, but if the rearing site is contaminated with eggs, may be seen with devastating effects, usually from August onwards. Worm eggs in the environment are resistant.
Signs: Poor growth and feathering. Mortality can be very high in young birds with heavy infestation in the crop. They burrow in the gut wall causing weakness, weight loss, difficulty swallowing, diarrhoea and death.
Candidiasis
Candidiasis, also known as "thrush" or "sour crop", is caused by Candida albicans, a yeast-like fungus. It can be present in the digestive tract of healthy birds without causing any trouble.
However when birds are weakened due to other conditions such as disease, stress or poor nutrition, Candida may cause lesions in the digestive tract.
Birds of all ages are susceptible, although problems usually occur in young birds.
There are no specific clinical signs.
Colibacillosis/colisepticaemia
It is caused by the bacterium Escherichia coli and is seen worldwide in game birds, chickens, turkeys, etc. There are many strains of E. coli normally living in the intestinal contents without causing any trouble. Birds may be affected at any age, but it is mainly seen in (very) young or immuno-suppressed birds.
Poor navel healing, mucosal damage due to viral infections and immunosuppression are predisposing factors. Infection is by the oral or inhalation routes, and via shell membranes/yolk/navel, water, fomites, with an incubation period of 3-5 days.
Good hygiene in handling of hatching eggs, hatchery hygiene, good sanitation of house, feed and water.
Coccidiosis
It is caused by an intra-cellular parasite of the intestinal tract of the genus Eimeria.
The disease is characterised by enteritis and diarrhoea, and is of great importance in the game bird and poultry industry. Even subclinical disease will still cause economic losses. Coccidia are host specific, meaning they only infect one species of bird and are site specific, meaning every species of coccidiosis colonises only a certain part of the intestinal tract. Thus Pheasant cocci does not affect Partridge and vice-versa.
Oocysts, tough hard shelled bodies containing infective stages of cocci, are passed out in the droppings and ingested by other birds via contaminated drinking water and feed. Once ingested the coccidia go through a complex life cycle of several stages in the intestinal cells causing damage and disease. The life cycle can be as low as 7 days.
Clinical signs include depression, reduced appetite, ruffled feathers, vent pecking, diarrhoea, dehydration, weight loss and death. Red Leg Partridges are very susceptible and sudden deaths (in large numbers) are not uncommon.
Corona-nephrosis
The disease mainly affects adult birds, both male and females, in the breeding pens, but it has also been seen in released poults. Birds are often found dead in good condition or severely depressed. Mortality can get up to 50%.
Post mortem reveals pale swollen kidneys and often the ureters are packed with urates showing as a pronounced white stripe. Urates can also be found on the pericardium (around the heart) and the liver, called "visceral gout".Female birds may be found dead in good condition and may also have egg peritonitis. Egg production and quality are reduced.
Gapeworm
Syngamus trachea, more commonly known as gapeworm, is the most important worm in game birds. More likely to be a problem with birds after release.
The adult worms live in the trachea (windpipe) of game birds, poultry and several other birds such as rooks, crows and starlings. The produced eggs are coughed up, swallowed and pass out in the droppings. An infective larva develops inside the egg. Birds may be infected by eating the eggs or larvae, or by eating earthworms that have themselves eaten eggs or larvaeThe worms suck blood and can cause weight loss, anaemia, weakness and reduced egg production.
Respiratory signs, such as coughing and “snicking”, are caused by irritation of the trachea by the worms. Death occurs by suffocation when worms block the airways. Partridges seem to be especially susceptible and mortality can be rapid and high.
Heterakis
Also called "caecal worms" because they live in the caecum. They are 7-14mm long. There are 2 types H. gallinarum and H. isolonche.
H. gallinarum is most common and causes few problems, although heavy burdens may affect breeding performance of adult birds and cause a reduction in bodyweight. Its main significance is that it is responsible for transmitting Blackhead (Histomonas meleagridis) where it acts as an intermediate host for this fatal disease.
H. isolonche is less common but burrows in the gut wall therefore causing more damage such as weight loss, diarrhoea and death.
Hexamita/Spironucleus
Hexamita, also called Spironucleus, is a single cell organism, a protozoon, only slightly bigger than bacteria. It causes acute disease characterised by enteritis with frothy/ watery diarrhoea.
The organism can spread between pheasants and partridges. It is often found together with other parasites such as Trichomonas and Coccidiosis.
Transmission occurs via direct bird-to-bird contact and ingestion of droppings, contaminated feed or water.
Symptoms include chilling, huddling, ruffled feathers, severe weight loss and watery or foamy diarrhoea. Mortality may be as high as 75-90% in young birds.
Other intestinal diseases also produce the same sort of droppings. Diagnose is based in lesions and findings in scrapings from fresh material.
Histomoniasis/ Blackhead
Histomoniasis, also known as Blackhead, is caused by a single cell organism called Histomonas meleagridis.
Turkeys, peafowl and partridges are most susceptible, then guinea fowl, domestic fowl and pheasants. Both adult and young birds can be affected.
Young birds are often found dead in good condition with little or no specific signs.In older birds the disease process is more chronic. Affected birds are lethargic, rapidly loose weight and become unable to fly.Some birds will have yellow diarrhoea. Mortality may reach 100% if left untreated.
Histomonas can live inside the eggs of the caecal worm, Heterakis, for many years. They are also able to live in the muscle of earthworms that have eaten Heterakis eggs. Ingesting either these eggs or earthworms may infect birds.
Marble Spleen Disease
First diagnosed in pheasants in the UK in 1972, but described in Italy in 1966. It is caused by a Type 2 Adenovirus that is very closely related to Turkey Haemorrhagic Enteritis.
It usually presents as a flurry of sudden deaths in the breeding pens, but it is also seen in poults shortly after release. It has only been seen in domestically reared pheasants. It has not been diagnosed in partridges.
Several birds are found dead in good body condition, often with food in the crop.
Mortality is usually between 5-10% but can get up to 50%. The episode usually stops spontaneously after spreading through a few pens. The incubation period is thought to be 6 to 10 days. Losses may be seen for several weeks. Recovered birds are immune for life.
Mycoplasma gallisepticum (Bulgy Eye)
Mycoplasmosis has been recognised in pheasants and partridges since the 1950`s. The commonest organism found in our pheasant and partridges is Mycoplasma gallisepticum. Clinical disease is most often seen in adult birds although all ages may be affected. Mortality in chicks 7 to 14 days old can be devastating.
The disease is mainly characterised by respiratory symptoms and sinusitis ("bulgy eye") however joint infections may be seen as well.Transmission occurs through bird to bird close contact, via air droplets, infected litter and equipment (horizontal transmission), and from hen to chick via the egg (vertical transmission). Recovered birds will remain carriers and shedders, therefore, once your flock is infected it will remain infected.
Necrotic enteritis and Ulcerative enteritis
Necrotic enteritis was first described in poultry in the 1960’s and has subsequently been reported pretty much all over the world. It is defined as being related to infection with Clostridium perfringens.
Clostridia are natural inhabitants of soil. They persist as spores. It is only when there is a trigger factor or factors, such as moving, hard weather, exposure to other intestinal injury (e.g. coccidiosis) that problems arise.
Ulcerative Enteritis is caused by the bacterium Clostridium colinum and has been described for over 100 years, and was initially seen in quail (hence its nickname Quail disease). It has also been seen in grouse, pigeons, chicken, and pheasants. We have seen several episodes of ulcerative enteritis in Red Legged Partridge in the last few years.
Newcastle disease
Newcastle disease is a notifiable disease caused by a Paramyxovirus Type 1.
The disease was first reported in pheasants in the UK in 1963. The severity of the disease depends on the virus strain, the species affected, the immune status, condition and age of the bird and whether the birds are suffering from concurrent diseases.
Newcastle Disease is notifiable but statutory action only needs to be taken for virulent strains. The last virulent outbreak in England was in 2005 (in pheasants imported from France).
Symptoms include respiratory disease, diarrhoea, nervous signs, swelling of the neck and face and sudden death. Hens may stop laying or produce misshapen eggs. In severe outbreaks mortality can reach 90%. In young birds, nervous signs with sudden high mortality are most likely to be seen.
Newcastle disease virus is highly contagious through infected droppings and respiratory discharge between birds. Spread between farms is by infected equipment, trucks, personnel, wild birds or air. The incubation period is variable but usually about 3 to 6 days.
Rickets
Vitamin D deficiency or phosphorus/calcium imbalance. Generally seen in birds slightly older than 10 days, but in severe cases may be younger.
Birds usually presented with lameness or go off legs. Hock swelling and soft bones and beak are other signs.
Rotavirus
Rotavirus infection is seen in pheasants and partridges, affecting birds from a few days old right up to 7 or 8 weeks of age. The route of infection is oral and maximum viral excretion occurs 2-5 days post infectionSigns vary with the age of the bird affected. In the first week of life moist droppings, lethargy may be seen. Mortality is variable, but can be as high as 80%.
2 to 3 week old birds suffer lower mortality, but fail to thrive. They are often wet around the vent, huddling and eating less. Once again large numbers can be affected. Virus may be found in asymptomatic birds.
Roundworms - Ascarid worms
Ascaridia sp. are roundworms up to 12 cms in length, seen worldwide. The route of infection is oral usually by direct ingestion of the embryonated egg Large numbers will cause wasting, mainly in young birds, and may cause obstruction of the intestines resulting in death.
Trichomonas
Trichomonas are single cell organisms that have become more and more important in causing disease in both pheasants and partridges. They are often found together with other parasites such as Hexamita (Spironucleus) and coccidiosis.
Presenting signs are similar to those caused by Hexamita, with weight loss, frothy yellow diarrhoea, weakness, dehydration and death. Trichomonas can be detected under the microscope when moving. Therefore it is very important to bring in fresh samples as the organism starts to die soon after the bird has died and thus stop moving. Finding Trichomonas will not necessarily mean it is the cause of disease, as the organism can be found in the gut of perfectly healthy animals.
TRT – Turkey Rhino-tracheitis
TRT is a highly contagious respiratory disease first found in turkeys (hence the name).
In the late 1980`s a respiratory infection in chickens appeared to be associated with the same virus. The virus has subsequently been found to infect a wide range of birds world wide, including pheasants, guinea fowl and ducks. The name has been changed to Avian Pneumovirus (APV) although TRT is still commonly used.
The virus primarily affects the upper respiratory tract. The severity of the disease depends on age and species of birds, as well as the involvement of other pathogens.
Uncomplicated cases will last from 7 to 14 days. Mortality is low.
Yolk sac infection / Omphalitis
Bacterial infection of the navel and yolk sac of chicks due to contamination before healing of the navel. Various bacteria may be involved, especially E .coli, Staphylococci, Proteus, Pseudomonas and Clostridia. Large numbers can be affected and mortality is high.
Birds can present swollen abdomen, vent pasting, diarrhoea.
It is seen where there is poor breeder farm nest hygiene, use of floor eggs, inadequate hatchery hygiene or poor incubation conditions.