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Diseases in Poultry

Viral Diseases

New Castle Disease

It is one of the most dreaded diseases of poultry as it can cause very heavy mortality at a very high speed. The disease is caused by a virus of paramyxo group and classified into many serotypes based on the virulence. Chicken is the natural host but vast majority of birds are susceptible to infection including ducks and turkey .

Signs

• Depression, prostration, loss of appetite

• Greenish/yellowish diarrhea

• Nervous signs like in coordination, twitching of neck

• Mortality heavy in acute outbreak

Post Mortem Lesions

• Pin pointed hemorrhages at the tip of proventricular glands

• Hemorrhagic/ diphtheritic ulcers on the intestine and caecal tonsils

 

 

 

 

 

 

Greenish diarrhea                                                                                                                                         proventricular hemorrhagic

Diagnosis

Typical lesions are diagnostic. Laboratory diagnosis with hemagglutination and Inhibition tests can be employed.

 

Treatment and Prevention

Effective vaccines are available for prevention. F vaccine given at the day old stage followed by RDK vaccine at 2 months can protect the bird.

Infectious Bursal Disease (Gumboro Disease)

Infectious Bursal Disease(IBD) is a highly contagiousviral disease of young chicken causing serious economic losses. The virus targets the Bursa of Fabricius, an important part of immune system making the bird susceptible to other infections. Vaccination failures may happen due to the associated immunosupression.

 

Signs

• Dullness, depression and death

• Whitish diarrhea

• Mortality heavy in the initial out breaks in a farm

Post Mortem Lesions

• Hemorrhages in the thigh and pectoral muscles

• Bursa enlarged, edematous and hyperemic with bloody or mucoid contents inside.

• Bursa firm and atrophic in chronic form

• Kidney may show nephrosis and mottling

 

Prevention

Vaccines are available for prevention.

Infectious Bronchitis

It is a highly infectious viral disease of poultry of worldwide distribution. It can affect any age, breed or type. Chicken is the only bird that is naturally infected by this virus. There are different serotypes of IB virus and many strains continue to evolve.

Signs

• Respiratory signs like coughing, sneezing and rales in chicks

• Drop in egg productionand hatchability

• Production of deformed, thin shelled, rough eggs with low internal egg quality

• Mortality low in uncomplicated cases

Post Mortem Lesions

• Catarrhal exudates in nasal cavity, caseous plugs in bronchi in chicks

• Enlargement of kidney with urates deposition and distention of ureters with pasty uric acid in uraemic form

• Egg peritonitis in layers

Diagnosis

Lesions are suggestive and can help in diagnosis.

ELISA can also give a reliable diagnosis.

Prevention

Vaccines are available for prevention

Avian Influenza

Highly Pathogenic Avian Influenza(HPAI) is a highly lethal systemic disease affecting vast majority of birds caused by the Influenza Type A virus. Because of the zoonotic as well as pandemic potential, the disease gained much public health importance. Water birds and migratory birds act as carriers and spread the infection.

Signs

• Sudden, heavy and unusual mortality reaching almost 100% without any clinical signs

• Edema of face, cyanosis of comb and wattles in less fulminating cases

• Nervous disorders like tremors, torticollis and opisthotonus

Post mortem lesions

• Extremely variable depending on the severity

• Hemorrhagic lesions (petechial to ecchymotic) on all the visceral organs, serous membranes, skin and muscles in acute cases

• Lungs pneumonic

• Enteritis, air saculitis, spleenomegali

Diagnosis

Sudden, heavy, unusual mortality arise the suspicion.

The disease is to be differentiated from the other fulminating diseases of chicken like Newcaslte Disease,

IBD, Fowl cholera etc.

 

 

Reoviral Arthritis

Reoviruses have been associated with many diseases in chicken like arthritis, enteritis, nephrosis and runting syndrome.

Reoviral arthritis affects mainly broilers of 6 to 7 weeks age. Turkeys are also susceptible.

Signs

• Lameness

• Synovial sheaths of the tendons of foot pads or hock joints are inflamed and swollen

Post mortem lesions

• Foot pads and hock joints are swollen with purulent fluid

 

Diagnosis

ELISA, AGPT

Adinoviral diseases

Egg Drop Syndrome

• Sudden and variable drop in egg production (30- 40%) in laying hens

• Production of depigmented, cracked or shell less eggs

• Disease runs for a few weeks and egg production returns to normal.

Inclusion Body Hepatitis (IBH)

• Broilers of 4 to 8 weeks are affected mainly

• Anaemia, depression and sudden mortality

• Hepatitis

• Pale muscles and bone marrow

• Hemorrhages in the muscles

 

 

Bacterial Diseases

Fowl cholera

Fowl cholera (avian pasteurellosis) is an acute contagious septicaemic disease with high morbidity and mortality. But chronic form often occurs. Pasteurella multocida is the causative agent. Chicken, turkey and ducks are commonly affected. However the disease affects other type of birds also.

Signs

• Fever, anorexia, mucous discharge from the mouth

• Diarrhoea, dehydration

• Cynosis of combs and increased respiratory rates

• Odema of comb, wattles, sinusitis and arthritis in chronic form

Post mortem lesions

• Petechial hemorrhages on heart, serosa of intestine, abdominal fat

• Generalized visceral congestion

• Enteritis

• Pneumonia and catarrhal inflammation

• Fibrinous peritonitis, congested and ruptured ova in layers

Diagnosis

Sudden onset, high mortality, septicaemic lesions on post mortem and presence of large number of bipolar organisms in blood smears and tissue smears help in field diagnosis.

 

 

Colibacillosis (E. coli infections)

Avian pathogenic Escherichia coli are associated with many disease conditions in poultry mainly colisepticaemia, air sac disease, coligranuloma, omphalitis in chicks, peritonitis in layers, synovitis and sinusitis. E.coli are important pathogens in bad management and stress and is the most common complicating organisms in other viral and respiratory infections.

Signs and Post mortem lesions

Colisepticemia

• Diarrhoea, loss of appetite,dyspnoea

• Fibrinous pericarditis, perihepatitis and air saculitis

• Dark liver

• Mortality may be heavy in chicks

• Mortality may be heavy when flock is affected