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THE A-Z POULTRY DISEASE INDEX

 

 

ACUTE DEATH SYNDROME (HEART ATTACK)

The term 'flip over' syndrome accurately describes this condition of acute heart failure. The cause is unknown but is often seen along with fatty liver and kidney syndrome in flocks growing well, about three weeks before slaughter. Mortality may be in the region of 0.5 per cent.

Interference with potassium, sodium and chloride levels suspected. Recent evidence suggests that that it could be due to ventricular fibrillation.

 

ADENOVIRUS

EDS '76 - the Egg Drop Syndrome 1976 is due to one particular adenovirus which has been designated 127 or BC14. This causes depressed production either at peak or during the laying period together with loss in shell quality and colour, the production of soft shelled and shell-less eggs and substantial floor laying.

There may be poor appetite and/or diarrhoea. Diagnosis is by serology. There is no cure but an effective vaccine is available. Clinical disease is now uncommon, because most flocks are vaccinated.

Several other adenoviruses also cause disease (see inclusion body hepatitis and marble spleen disease). There are many non-pathogenic strains.

 

AFLATOXICOSIS

Poisoning due to a mycotoxin usually originating in feed raw materials. The toxin is produced by a fungus Aspergillus flavus. It causes lethargy and loss of appetite followed by death -- the poults lying with their legs fully stretched to the rear, often with ascites. Turkeys and ducks are especially susceptible. See Mycotoxicosis.

 

AMYLOIDOSIS

Common among adult ducks. Cause is unknown, but the condition gives rise to gross lesions of the internal organs.

 

ANATIPESTIFER INFECTION

Disease of young ducklings caused by the bacterium Riemerella (formerly Pasteurella) anatipestifer. Severely affected birds continually shake their heads or sit with their heads close to their body. They may have watery eyes, ruffled feathers and pass green diarrhoea. Mortality rate is usually 25-75 per cent. Streptomycin and sulphonamides may be effective treatments.

 

AORTIC RUPTURE

Rupture of the major blood vessels causing rapid death due to internal haemorrhage. Found especially in heavy turkeys, broiler breeders but also occasionally in capons, younger turkeys and commercial layers. Affected birds are frequently the best in the flocks. No effective treatment or prevention.

 

ARIZONA INFECTION

Egg transmitted salmonella infection of turkeys which causes general ill-health -- huddling, diarrhoea, pasted vents, listlessness and mortality of up to 50 per cent in newly hatched poults. In older turkeys, twisted necks and blindness also occurs. Treatment with nitrofurans (now banned in the EU) was successful. Control necessitates the elimination of infected breeder flocks. Now rare.

 

ASCITES

Most commonly occurs in broiler flocks. Occurs from several days of age to slaughter, death due to fluid in the body cavity with abnormal heart, liver and kidneys. Increasing in frequency. Caused by lung damage at early age. No specific treatment but can be alleyiated by attention to temperature, lighting, ventilation and feed control. Can be the cause of significant mortality and condemnations.

 

ASPERGILOSIS

Due to the inhalation of spores of various fungi. This causes lesions in the respiratory tract with obvious respiratory distress. Occasionally there is infection of the brain. It can occur in day-old chicks and poults due to hatchery infection, and in other birds from the spores in mouldy hay, straw and grain. No treatment. Ducks, turkeys and game birds are more susceptible than chickens.

 

AVIAN CLOSTRIDIAL INFECTIONS

Several species of clostridia cause poultry disease. These include botulism, necrotic enteritis, avian malignant oedema and gangrenous dermatitis, yolk sac infection and omphalitis. Botulism { Clostridium botulinum) is characterised by paralysis of the neck muscles, causing the bird to rest its head on the ground. Toxins are absorbed from contaminated feed and possibly from the bacteria multiplying in the gut.

Decomposing broiler carcasses in a broiler house are a source of infection. Cl perfringens causes necrotic enteritis. Damage to the wall of the small intestine may be direct or in association with coccidia. Penicillin in drinking water is effective treatment. Avian malignant oedema. See Gangrenous dermatitis.

 

AVIAN COLIFORM INFECTIONS (COLIBACILLOSIS)

E.coli is a frequent secondary invader of poultry of all ages, especially young broilers and turkeys, after respiratory infections or any other disease. There is poor growth, increased FCR and the damage to the respiratory tract and body cavity can result in high processing rejects. Mortality can be considerable. Antibiotics may provide reasonable treatment.

 

AVIAN ENCEPHALOMYELITIS (EPIDEMIC TREMORS)

A picornavirus disease Of chicken which can cause high mortality with nervous symptoms in chicks up to 5 weeks of age. Can cause egg drops in laying stock. The infection is spread vertically and laterally. All breeders and replacement pullets should be vaccinated between 9 and 14 weeks of age. The vaccine can cause mortality in young chicks.

 

AVIAN INFLUENZA (FOWL PLAGUE)

This virus infection causes a wide range of disease symptoms with depression, decreased production, respiratory symptoms and varying mortality rate. Severity of the disease depends on the strain of the virus. The highly virulent form causes very high mortality and is a notifiable disease. No vaccine and no treatment (in the EU).

 

AVIAN MALARIA

Protozoal infection of the blood in tropical areas spread by mosquitoes. Causes reduced production and mortality. No effective treatment. Not a problem in the UK.

 

AVIAN MYCOPLASMOSIS

Mycoplasma gallispecticum, M. iowae and M. meleagridis - all egg transmitted. Transmission by lateral spread and fomites can occur. M. synoviae spreads in a similar way to M. gall.isepticum. Clinically they may be involved in respiratory infection together with reduced egg output, increased feed conversion, depressed hatch-ability, lameness and more severe colibacillosis. M.meleagridis is confined to turkeys.

Stress and other infections such as IB, ART can activate subclinical infections and results in increased severity of the disease process.

Infection can be controlled but not eliminated by a variety of antibiotics. Diagnosis can be confirmed by blood tests. Most breeding stock are now free from Mg, Ms and Mm.

 

AVIAN RHINOTRACHEITIS (ART)

Also known as TRT and Swollen Head Syndrome (SHS). A pneu-movirus infection in turkeys and chickens affecting birds from about 10 days of age to end of laying life. Clinical signs include bubbles in the corner of the eye, swollen sinuses and tracheitis. In breeders interference with egg production and reduced hatchability. Secondary infection causing severe airsaculitis and colibacillosis is common especially in older birds for slaughter.

Disease now widespread and causes disease in chicken. In Broiler Breeder flocks torticollis is a common finding and must be differentiated from Newcastle Disease as the cause. Treatment unreliable and difficult. Live and inactivated vaccines are now available.

 

AVIAN SALMONELLOSIS

The two main species in poultry S pullorum and S gallinarurn cause pullorum disease and fowl typhoid respectively. These infections are spread by vertical and lateral transmission and are controlled in breeding flocks by blood testing and slaughter of reactors. These two salmonellae are now eradicated from UK commercial poultry. There are many other serotypes, of which S typhimurium and S enteritidis are the most frequent, causing septicaemia and mortality with lesions closely similar to colibacillosis usually in young birds. Laboratory diagnosis is essential for accurate identification of salmonellae. Salmonellae such as typhimurium and enteritidis can cause illness and death in man. Very important zoonosis.

Septicaemic birds may be a risk to handlers. Antibiotics followed by competitive exclusion products can be used for treatment. An inactivated enteritidis vaccine is available. The BEIC Lion Code requires that all flocks are fully vaccinated against S. enteritidis.

Regular statutory testing of UK breeders and hatcheries. Note due to improvements in the taxonomy of the salmonellae S enteritidis and S typbimurium are now more correctly known as S enterica subsp enterica serovar Enteritidis and S enterica subsp enterica serovar Typhimurium. There are now only two species of salmonellae -- S enterica and S bongori.

 

AVIAN STAPHYLOCOCCUS INFECTIONS

 Frequent in adult poultry, especially breeders. Can cause conditions ranging from septicaemia to arthritis and bumblefoot, may also be involved in gangrenous dermatitis. Antibiotics may help but treatment is difficult.

 

AVIAN TUBERCULOSIS

Rarely seen in modern poultry units but frequent in backyard flocks. Causes un-thriftiness with subsequent mortality. There is no treatment and control is by careful sanitation. Disease of older birds on fowl sick land.

 

AVITAMINOSIS

Loss of performance and subsequent ill health, due to inadequate intake or utilisation of vitamins. Symptoms vary widely. Infrequent with modern feeds and stabilised vitamins.

 

BACTERIAL SYNOVITIS

Weight loss and reluctance to walk following swollen hock joints and foot pads, caused by bacteria invading the bones and joints. Usual causal bacteria are Staphylococcus aureus and Escb-erichia coli but sometimes Salmonellae, Pasteurella and Eysipclas. Treatment often disappointing.

 

BLACK TONGUE

 Inflammation and necrosis of the mouth and upper throat, due to a deficiency of the vitamin nicotinic acid. Now rare.

 

BREAST BLISTER

Found on well grown meat birds. It can be due to M synoviae or squatting on hard litter. The blister may become infected and result in downgrading or rejection of carcasses.

 

BUMBLEFOOT

A localised infection of the feet of chickens and turkeys. It is characterised by swelling, in one or both feet. The infection is usually caused by staphylococci entering the foot through a bruise or injury. No effective treatment.

 

CAGE LAYER FATIGUE

Paralysis associated with thin brittle bones which frequently fracture. Occurs in high producing commercial layers in cages. May be associated with deficiency of calcium and/or phosphorus in the diet but frequently occurs in birds receiving normal feed. Treatment with Vitamin D3 and extra phosphorus may help.

 

CANDIDIASIS

Yeast infection -- Candida albicans -- which affects the mouth and crop. Also known as thrush, the disease is highly infectious usually affecting poults but also game and chicks. No precise symptoms, post-mortem reveals a 'turkish toweling' appearance to the crop lining. Treatment with copper sulphate may help.

 

CARDIO-HEPATITIS

Affects 1-4weeks old turkeys; usually the faster growing and larger male poults, which are found dead on their backs. Cause is unknown. Ascites in body cavity and enlarged heart.

 

CHICKEN ANAEMIA

Disease synonyms - blue wing disease, infectious anaemia, haemorrhagic syndrome and anaemia dermatitis syndrome. Caused by a vertically transmitted circovirus from an infected parent flock.

The clinical signs reflect both the anaemia and the immunosuppression resulting from infection. Broilers -- increases in mortality seen from 7 days, most commonly gangrenous dermatitis like disease at 14 days. Treat for the secondry bacterial infection. Layers and parents subclinical infection that may intefere with vaccination responces. Control by vaccination of the parent stock.

 

CHLAMYDIOSIS (ORNITHOSIS)

Caused by Chlamydia psittaci; there are many strains with differing degrees of pathogenicity. Frequent in parrots and occasionally endemic in ducks and turkeys. In turkeys can cause considerable disease and mortality. Treatment with tetracycline usually effective, but prolonged dosage is required. May affect man (a Zoonosis) causing pneumonia and mortality and abortion in women.

 

CHONDRODYSTROPHY (PEROSIS)

 Pathological term describing the short, thickened, misshapen long bones with swollen joints. This can result in a slipped tendon. It is often seen in association with skeletal deformities such as "Twisted leg". In young chicks the condition has been caused by manganese deficiency but this is rare and confined to chicks. In turkeys, it is associated with mycoplasma infections and excessively high brooding temperatures.

 

CHORIORETINITIS

Blindness in turkeys and layers. The affected eyes have a frosted glass appearance and the birds have difficulty in finding nest boxes, feeders etc. Uncommon, cause unknown, no treatment.

 

COCCIDIOSIS

There are seven different species of Eimeria causing disease in chicken and five in turkeys and one in ducks. Other species cause disease in geese and game birds. All parts of the intestinal tract can be affected.

This disease is widespread throughout the world and effective control is necessary wherever poultry are reared. Modern anticoccidials in the feed give a high level of control but outbreaks continue to occur due to incorrect .levels of the drug in the feed, in association with wheat feeding and reduced appetite as a result of the disease.

When feed is restricted the level should be raised. There are many proprietary drus which provide a good treatment. The oocyst is resistant to most disinfectants. Careful diagnosis is required. An attenuated coccidiosis vaccine (Paracox) is available for chickens.

 

COLIBACILLOSIS/ COLISEPTICAEMIA

See avian coliform infections

 

CROOKED TOES

Common in meat type birds and may be seen in male egg breeders. Usually associated with other leg disorders in the flock. Cause not known but there may be a generic factor and it has also been associated with brooding under infrared lamps.

 

CURLED TOE PARALYSIS

A shortage of Vitamin B2 (riboflavin) gives rise to this condition in chicks and poults. It is usually seen in 'birds up to three weeks of age and is normally caused by deficient starter diets. Now rare

 

DERMATITIS

Inflammation of the skin. Usually associated with a deficiency of the vitamin pantothenic acid, but can be associated with bacterial infection especially after skin injuries.

 

DUCK VIRUS ENTERFIIS

Duck plague, caused by a herpesvirus, spreads rapidly through the flock and can cause heavy mortality. Ducks from 2 to 7 weeks of age are affected and appear reluctant to walk. A live vaccine is available, although it is normally used to control outbreaks spreading rather than as a preventative measure.

 

DUCK VIRUS HEPATITIS

Acute disease affecting ducks, particularly duckling up to three weeks of age. Types l and 3 are caused by a picornavirus whilst Type 2 is caused by an astrovirus.. Death occurs soon after the onset 'of the infection. The ducks may fall onto their sides, paddle with their feet and die. Opisthotonus is a typical finding. Mortality ranges from 500 per cent. A live vaccine is available.

 

EGG PERITONITIS

Non-specific disorder due to whole or broken eggs inside the body cavity. Incidence and mortality can be substantial especially in early lay and free range. Causes not understood.

 

ENCEPHALOMAEACIA

"CRAZY CHICK DISEASE"  Damage to the brain associated with Vitamin E deficiency in the feed and/or failure to absorb and utilise the vitamin. Usually seen in young chicks and poults. A variety of nervous symptoms are obvious. Reduced selenium levels and rancid fat may be involved.

 

ERYSIPELAS

Can occur in any type of poultry usually over about 3 to 4 months of age. Can cause acute septicaemia with mortality or a more chronic arthritis. Antibiotic treatment and vaccination are usually highly effective. Possible risk to handlers - Zoonosis.

 

EXUDATIVE DIATHESIS

Occurs in younger chickens and turkeys. Accumulations of gelatinous yellow fluid beneath the skin and within the muscles, usually associated with deficiency or imbalance of vitamin E and selenium.

 

FATTY LIVER AND KIDNEY SYNDROME

Occurs in chicks 1 to 4 weeks. Associated with deficiency of or failure to absorb and utilise biotin. Causes sudden death usually in birds in good condition. Treatment by biotin feed supplements. Associated with wheat diets.

 

FATTY LIVER IN LAYERS

Sudden death associated with haemorrhage from ruptured livers. Usually occurs in overweight birds in high producing flocks and especially in those with excess fat in hot weather. Treatment difficult. Vitamin supplementation may help.

 

FAVUS (Ringworm)

Fungal infection caused by Trichophyton megninii, which affects the comb and wattles producing a grayish scab-like appearance. The disease is also known as white comb.

 

FEMORAL HEAD NECROSIS

An osteomyelitis affecting the head and neck of the femur of one or both legs in rapidly growing birds. Clinically the lameness looks similar to Kinky Back in broilers. Growth rates are reduced. Bacteria cause microabscesses in the bone. Viruses may also be involved. Affected birds should be culled on welfare grounds. Tylan may help prevent infection.

 

FLEAS

Brownish-black jumping insects which thrive in dirty conditions.

 

FLOPPY BROILER SYNDROME

Suspect acute Mareks disease infection in broilers 24 days and older. Affected broilers can be mistaken for Gumboro Disease. Broilers are limp and unable to stand or feed themselves. If spotted quickly enough and put in a nursing pen then they may recover. Day old vaccination with Mareks vaccine may be of benefit. Terminal hygiene is important.

 

FOWL CHOLERA

See Pasteurellosis

 

FOWL PLAGUE

Peracute infection with avian influenza virus. Mortality often 100 per cent. Notifiable disease (see Avian influenza).

 

FOWL POX

Spread by biting flies. Occurs in two forms (a) a skin type with wart-like growths on the comb and wattles and (b) a diphtheritic form with lesions inside the mouth and the trachea. This latter form carries a high mortality. Vaccination of growing stock is common on the continent but not in the UK.

 

GANGRENOUS DERMATITIS

Necrosis and gangrene of the skin anywhere on the body. Can cause considerable mortality in chicks usually 3 to 6 weeks. Cause not understood but clostridia and staphylococci may be involved. Treatment with antibiotics has variable results. Vaccination for infectious bursal disease (Gumboro) often helps.

 

GAPES

See Helminth parasites

 

HAEMORRHAGIC SYNDROME

Cause unknown, but believed to be associated with a Vitamin K deficiency. Can occur in growers following the use of sulphonamides which increase the birds vitamin K needs. Symptoms are ruffled appearance and general morbidity, although deaths may occur without obvious signs of ill health

HEXAMITIASIS

Intestinal protozoal parasite affecting turkeys and game birds causing watery droppings, listlessness, emaciation and mortality. Occasionally occurs in chicken. Prevention and treatment as for histomoniasis.

 

HELMINTH PARASITES

Group name for the many roundworms which can be found in poultry. A few of the more important species are:-- caecal worm (Heterakis gallinarum) generally harmless except in very large numbers or when they harbour the parasites which cause Black head in turkeys: Gape worms (Syngamus trachea) give rise to gasping, coughing and signs of partial suffocation among chicks and poults and game birds. Hair worms (Capillaria spp) parasites of the intestines which may produce severe and rapid emaciation in growers and, in layers, a steady fall in egg production. Large roundworms (Ascaridia). Gapes and Capiiiaria can cause considerable mortality.

The large roundworm can rarely be found in eggs. A licenced in-feed treatment for hens laying eggs for human consumption is now available.

 

HISTOMONIASIS

Blackhead. A major protozoal disease in turkeys but which occurs in game birds and chicken. Signs include lethargy, yellowish diarrhoea, weakness and occasionally a high mortality. Dimetridazole is available for prevention. Consult your veterinary surgeon with respect to it's availability for treatment.

 

HOCK BURNS

Found on broilers and meat turkeys. Associated with poor litter containing high levels of ammonia. The real cause is not clear. Causes downgrading. No treatment. Prevention is by careful attention to all aspects of management. Severe cases are an important welfare concern.

 

IMPACTION OF THE OVIDUCT

Also known as egg bound whereby the layer's oviduct is blocked by a mass of egg material. Can reach high levels in some flocks. Treatment usually fails.

 

INCLUSION BODY HEPATITIS

Due to an adenovirus. Causes increased mortality between 3 and 6 weeks in broilers, pullets and game birds. In broilers results in poor growth rates and increased FCR. No effective treatment and no vaccine.

 

INFECTIOUS BRONCHITIS

A coronavirus infection causing respiratory disease and kidney damage in young birds with reduced growth rate and increased FCR in broilers. In layers causes depressed egg production and poor shell quality. Infection in young birds often followed by colibacillosis. Many strains of IB exist. Currently, mortality and drops in egg production without gross respiratory signs can occur following infection with an IB variant, 4/91 (793B, or CR88). These strains are more pathogenic than the other Dutch strains (D278). Diagnosis can be complicated serology, PCR and virus isolation are used. Elimination of the involvement of other respiratory viruses is essential. The standard vaccines have not given good control. The correct use of both the inactivated and live vaccines properly administered is essential. A live 4/91 vaccine is now available.

 

INFECTOUS BURSAL DISEASE (GUMBORO)

A birnaviral infection which can cause high mortality and reduced growth rate in chicks from 2 to 6 weeks of age and occasionally up to point-of-lay. Prevalent wherever poultry are kept. The disease is of particular importance because it' is immunosuppressive. Response to subsequent vaccinations may be less effective and other diseases are more severe. Live and dead vaccines are available. These can induce high levels of maternal antibodies. Diagnosis by PM and serology. Effective control can now be obtained by using the appropriate vaccine combined with good terminal hygiene.

 

INFECTIOUS LARYNGOTRACHEITIS

A highly infectious herpesvirus disease in broilers, pullets and layers. The acute form is characterised by high mortality and the coughing of blood but sub acute and chronic forms are more usual. Spread by mechanical carriage and possibly by windborne dissemination. Vaccination is effective but needs to be continued and care is needed. Continues on same site from flock to flock. Chronic infections will exacerbate the severity of other respiratory infections.

 

INFECTIOUS STUNTING

Cause not known but various viruses affecting intestines and causing pancreas degeneration are suspected. Clinical signs in broilers occur between 10 to 14 days of age. Signs include poor growth, bad feathering, increased mortality and fat in the faeces. Stunted chicks are about half normal size. No known treatment or prevention. High early mortality can occur. Occurs in broilers and replacement pullets, turkeys and Guinea fowl.

 

KERATOCONJUNCTIVITIS

Ulceration of cornea caused by high ammonia levels in houses. Affected birds appear dejected with ruffled feathers and closed eyes. Treatment is by reducing environmental ammonia. Antibiotic medication systemically and topically will help prevent secondary bacterial infections. Recovery is prolonged. Continually working in an ammonia laden environment will reduce your ability to smell it.

 

LEUCOCYTOZOONOSIS

Protazoan parasites which are transferred to poultry by blood sucking arthropods. The problem causes loss of appetite and anaemia in severe cases. Not reported in the UK but it is present in cage and aviary birds.

 

LEUKOSIS

Group name for several tumour diseases caused by RNA tumour viruses, largely affecting chicken over about 20 weeks of age. Tumours occur in liver, kidney, bursa, spleen, bone and ovaries. Disease of the leucosis complex include Erythroid Leucosis, Myeloid Leukosis. Lymphoid Leukosis and Osteopetrosis. Now virtually eliminated from major breeding hnits. A new strain, the "J" strain, has been found in broiler parents and broilers worldwide. Confirmation of the diagnosis requires histopahology. No treatment or vaccine.

 

LICE

Parasites of the skin, especially around the vent and under the wings. Heavy infestation can affect birds performance. Species of lice include the chicken or yellow body louse (Menocantbus stramineus), the headlouse (Cuclotogaster heterograpbus) and the wing feather louse (Lipeurus caponis). Other species affect turkeys, geese, etc. Treatment may prove difficult.

 

MARBLE SPLEEN DISEASE

Adenovirus infection characterised by sudden mortality in pheasants. Losses can be high. The birds die from suffocation due to sudden oedema of the lungs. There is a two to three times enlargement of the spleen which has a distinct marbled appearance. No treatment or vaccine available. Also occurs in chickens and turkeys but less severe. (see haemorrhagic enteritis virus)

 

MAREK'S DISEASE

Caused by a lymphotropic herpesvirus which varies widely in it's ability to cause disease. Tumours can be seen after 6 weeks in unvaccinated birds and from 14 weeks in vaccinated flocks. It affects the nervous system and also produces turnouts in  many of the internal organs, muscles and enlargement of nerves. Mortality in unvaccinated birds can rise to 30 per cent or more. The tumours and skin lesions can also cause down-grading in broilers. The vaccine given to day-old chicks at the hatchery has been outstandingly successful although occasional breaks continue to occur -- mostly associated with poor chick house disinfection. The virus is classified into three serotypes. Serotypc 1 -- all tumour causing and derived attenuated strains; Serotype 2 -- naturally occurring non pathogenic strains and Serotype 3 -- non pathogenic related viruses from turkeys.

 

MITES

Blood sucking parasites which irritate the bird and can cause anaemia and depressed performance or even mortality. The red mite (Dermanyssus gallinae) is often encountered. It feeds off the fowl during the night and rests in crevices during the day, In contrast, the northern fowl mite (Liponyssus [formerly Ornitho-nyssus] sylviarum) lives continuously on the fowl.

There is also a scaly leg mite (Cnemidocoptes mutans) which burrows in the leg scales, and an air sac mite (Cytodites nudus) which infests the lungs and air sacs. Mites are generally associated with dirty conditions and free range. Treatment with acaricides may require several applications

 

MYCOTOXICOSIS

Alflatoxin and many other mycotoxins are produced by fungi growing in raw materials or finished feed. The toxins are very stable and remain in the feed indefinitely. Major effects vary from slight ill-health to substantial mortality. Symptoms include reduced appetite which may be due to unpalatability of the feed, lethargy, diarrhoea, thirst, prostration, poor growth, reduced egg production and immunosuppression. There is frequently severe damage to liver, kidneys and other organs. Diagnosis of disease in the birds may be difficult or impossible. Products are available to prevent mould growth in the stored feed. No effective treatment but vitamin supplements may be helpful.

 

NEWCASTLE DISEASE

A highly infectious p.aramyxovirus disease which can affect all commercial poultry and cause heavy mortality. Causes various symptoms including respiratory and nervous disorders, diarrhoea, severe lethargy and depression and on occasions very high mortality. Outbreaks vary from very mild to per acute. In young birds causes severe reduction in growth and long term secondary disease such as colibacillosis and airsaculitis. Severe egg drops and reduced shell quality in layers. Control requires an appropriate vaccination schedule and careful vaccine administration. Notifiable disease.

 

NUTRITIONAL MUSCULAR DYSTROPHY

Degeneration and necrosis of the muscles (known as white muscle disease). More prevalent among poults but also seen in chickens and ducklings associated with diets containing low levels of vitamin E and the amino acids methionine and cystine. Prevented by increasing the vitamin E level in the ration. Often occurs in conjunction with exudative diathesis -- also a vitamin E deficiency problem.

 

OMPHALITIS

See Yolk Sac Infection.

 

OREGON MUSCLE DISEASE

Commonly seen in turkey breeders at slaughter but also occurs in heavy turkeys, broiler breeders and occasionally capons. Degeneration of deep pectoral muscle which becomes green. Difficult to detect at meat inspection but is an important cause of carcass down grading. Cause associated with poor blood supply to muscles together with excessive exercise. No treatment or prevention.

 

ORNITHOBACTERIUM RHINOTRACHEALE

A bacterial infection associated with respiratory disease in chickens and turkeys. It is a difficult organism to culture. Infection can cause mild to severe signs. In turkeys, it could be confused with ART and Bordetella avium infections. Treatment with amoxycillin, lincomycin, polymixin and erythromycin maybe beneficial.

 

PASTEURELLOSIS (FOWL CHOLERA)

The pasteurellosis group includes Yersinia pseudotuberculosis, P anatipestifer, P gallinarum and P haemolytica. The latter two are rarely pathogenic. Fowl cholera is caused by Pasteurella multocida is the most important. This can be either a mild infection or a severe septicaemia causing sudden heavy and long-lasting mortality in a flock. Signs vary widely but will include respiratory distress, lameness, lethargy and swollen wattles. The infection is particularly prevalent in turkeys. Antibiotics and sulphonamides are usually effective and vaccines give reasonable protection but there are wide variations in the response to both treatment and vaccination. Relapse after treatment is common. Carrier birds and rodents are sources of infection.

 

PENDULOUS CROP

Occurs in chicken and turkeys. Cause not understood but Marek's disease and yeast infections may be involved. Occurs as both sporadic and flock problems. No effective treatment.

 

PLANTAR PODODERMATITIS

Ulceration and necrosis of the foot pad infection by various bacteria including Necrobacillus fusiformis. Occurs in broilers and meat turkeys and may be associated with poor litter conditions. No effective treatment. An important welfare problem.

 

POISONING

Many compounds are toxic to poultry, including certain disinfectants, pesticides and excessive levels of certain nutrients and drugs. See aflatoxicosis and toxic fat syndrome.

 

PSEUDO-TUBERCULOSIS

Caused by Yersinia pseudomber culosis giving rise to a septicaemia and mortality. Treatment with tetracyclines but no vaccination. Often associated with poor hygiene. A potential zoonosis.

 

PULLET DISEASE

Normally affects growers and layers in late summer, creating digestive disorders and loss of production. The birds may develop a blue-purple comb and there is some mortality. Cause unknown -- was once linked with feeding newly harvested wheat, but now believed to be an infectious virus. Now uncommon. Differential diagnosis -- acute pasteurellosis and spotty liver syndrome.

 

RICKETS

Softening of the bones of young birds. The correct levels of calcium, phosphorus and vitamin D in the ration should prevent this disease which is now uncommon.

 

RINGWORM

see Favus.

 

ROUNDHEART DISEASE

Cause unknown, primarily affects turkeys from 2 weeks of age. No signs but death often follows sudden exertion. Post mortem reveals enlarged, distorted and discoloured heart. Predisposing causes include sodium and previously furazolidone. It can also be a problem in adult chicken.

 

RUPTURED GASTROCNEMIUS TENDON

"Green Leg" in roasters, capons and adult stock. The incidence can be reduced by feeding lower protein starter diets. The tendon ruptures just above the hock. Bruising and a green coloured swelling will be seen. May be associated with viral tenosynovitis.

 

SCABBY HIP

Non-specific dermatitis over hip region. Causes not known. Can result in serious down grading. No treatment.

 

SERPULINA

A bacterial infection of the caecae of layers with Serpulina spp. As serpulina may be a normal inhabitant in the caecum diagnosis is uncertain. Stated to cause inflammation and loss of production. Dimetridazole and tetracyclines may be an effective treatment.

 

SPONDYLOLITHIASIS

"Kinky back" in 3-6 weeks old broilers, particularly among very fast growing strains. The birds squat on their hocks, due to a "step" like deformity of the spinal column. Can be confused with femoral head necrosis.

 

SPOTTY LIVER SYNDROME

Can cause substantial mortality and drops in production in primarily free range but also barn, perchery and caged flocks of 24-30 weeks of age.

Many small white pinpoint areas of liver necrosis can be seen on post mortem. Cause not known but probably bacterial. Antibiotic treatment is effective both therapeutically and prophylactically. Occurs less frequently now. Differentiate from acute pasteurellosis.

 

SPRIOCHEATOSIS

Caused by the bacterium Borrelia anserina. Occurs in various tropical areas causing septicaemia with lethargy, green diarrhoea, reduced production and mortality. Spread by mosquitoes and ticks and lateral spread in a flock. Treat with antibiotics.

 

STARVE-OUT

Mortality in day old chicks and poults. Birds die without feeding or drinking. Can be associated with poor chicks, inadequate hus\-bandry of the chicks, brooding facilities or prolonged journeys.

 

STUNTING AND RUNTING SYNDROME

(Also called Helicopter Disease and Malabsorption Syndrome)

See Infectious Stunting.

 

SUDDEN DEATH SYNDROME

A syndrome specifically associated with broiler breeders. Clinical signs - Mortality ranging from 0.5 to 8% per week with most of the birds dying at feeding time. No evidence of respiratory infection. Commences as flock reaches about 5% production and being worst about 20-30% production. It is believed that this is most likely to be due to a mineral imbalance associated with low potassium as the flock comes into lay. Treatment including 3.5Kg/tonne of potassium carbonate has reduced the incidence. (Not to be confused with Heart attacks or "Flip-overs" See Acute death syndrome.)

 

SWOLLEN HEAD SYNDROME

A clinical description of a disease of fowl with extensive swelling of the head, particularly noticeable around the eyes. Pathogenic E.coli, IB, ART and possibly other viruses may be involved. Can cause serious losses. No effective treatment. Control of the viral component by vaccination is possible.

 

SYNGAMUS TRACHEA

See Helminth parasites.

 

TIBIAL DYSCHONDROPLASIA

A skeletal deformity observed particularly in broilers, meat type turkeys and ducks. Can be associated with increased downgrading. Cause not known but associated with rapid growth and calcium/ phosphorus imbalance. No effective treatment.

 

TOXIC FAT SYNDROME

Toxins produced in incorrectly stored or processed animal fat. Causes ascites, cardiac abnormalities and death.

 

TRICHOMONIASIS

Parasite -- Trichomonas gallinae -- which causes yellowish mouth lesions. More common in pigeons than poultry. Causes caecal damage in Game birds. Prevention and treatment as for Histomoniasis.

 

TURKEY HAEMORRHAGIC ENTERITIS

A group 2 avian adenovirus infection. Virus isolation is difficult. Isolates have been made from turkeys, chickens and game birds. Occurs in many flocks which will seroconvert between 8 and 19 weeks. The infection can be subclinical or acute resulting in 50% mortality. The acute form is characterised by haemorrhagic enteritis.

 

TWISTED LEG

Skeletal deformity among a few birds in a broiler or turkey flock, causing downgrading and economic loss. Many causes.

 

VENT GLEET

Inflammation of the cloaca with a high offensive odour once common but rare nowadays. Probably a contagious venereal disease, but the cause is unknown. No effective treatment.

 

VICES

Cannibalism, egg eating, feather pecking and vent pecking -- arising from poor management, inadequate feeding or adverse environmental conditions. Control necessitates the rectifying of the fault, but it may be aided by reduced lighting intensities, anti-peck sprays/ointment, and possibly beak trimming.

 

VIRAL TENOSYNOVITIS

A reovirus infection causing damage and swelling of the tendons of the legs. Can cause leg weakness in broilers that have swollen shanks and hocks and frequently ruptured tendons. This results in poor growth and increased FCR. Disease frequently associated with other infections. Vaccines are available in some countries. No effective treatment. Adenoviruses have also been isolated from affected birds.

 

VISCERAL GOUT

Seen in chicken and layers of all ages. Associated with failure of the kidneys which are frequently swollen and full of urates. Urates are also deposited on and within internal organs, muscles and joints as chalky white deposits. Can occur as flock problems with high mortality.

Cause not understood, IB may be involved and also excess calcium (over 0.8%) in rearing rations.

 

YOLK SAC INFECTION

A major cause of mortality in the first week of life. It can be caused by several different bacteria including Bacillus cereus, Staphylococcus aureus, Escherichia coli, Clostridium perfringens and occasionally salmonella and pseudomonads.

High levels of contamination ar hatching time of one or more of these agents gives rise to toxaemia, causing death on the hatching tray and in the first few days of brooding. Losses cease after 6-8 days.