Mycoplasmoses in Poultry

Mycoplasmoses

Two of the established pathogens for domestic fowl out of the 17 named species are

g   Mycoplasma gallisepticum.

g   Mycoplasma synoviae

Mycoplasma Gallisepticum Infection

Causative agent – Mycoplasma gallisepticum.

Transmission

g   Direct contact of susceptible birds with carriers.

g   Also spread by air borne dust or droplets.

g   It is vertically transmitted.

Signs

g   Tracheal rales.

g   Nasal discharges and coughing.

g   Reduced feed consumption.

g   Birds lose weight.

g   Decreased egg production.

g   Disease is more severe in cold season.

g   Broilers-suffer mostly between 4 to 7 week of age.

g   In broilers the respiratory signs are more marked than layer flocks.

g   Sinusitis, conjunctivitis, with inflammation of one or both the eyes.

Gross Lesions

g   Catarrhal exudates in the nasal and paranasal passage, trachea, bronchi and airsacs.

g   Oedema of airsacs. 

g Caseous material may appear in airac or attached to their walls 

Cheesy mass in airsacs

g   Some degree of pneumonia may be observed.

Serofibrinous Pneumonia

g In severe and complicated cases with. E.coli there is fibrinous Perihepatitis and pericarditis along with massive airsacculitis. 

Histopathology

g   Thickening of tracheal mucosa due to hyperplasia. 

g All the alveoli and bronchioles are filled with purulent exudates comprising chiefly of polymorphs and mononuclear cells with extensive congestion and haemorrhages. 

g Alveoli and bronchioles are filled with purulent exudates with infiltration of heterophils and presence of caseation. 

g   Thickening and hyperplasia of the tracheal mucosa with oedema and infiltration of few mononuclear cells. 

g Lung parenchyma is filled completely with heterophils and mononuclear cells with presence of haemorrhages. 

g    Lymphofollicular reaction in the lung parenchyma with haemorrhages. 

Diagnosis

g   Isolation and identification of causative organism.

g   Serology by ElISA.

g   Mycoplasmoses must be differentiated from other respiratory infections like Newcastle disease. Infectious bronchitis, Fowl cholera and Coryza.

Paratyphoid Infection in Poultry

Paratyphoid Infection

g   Causative agent – Salmonella typhimurium

Transmission

g   Humans, rhodents, wild birds, insects, pigeons, water and feed are the sources of infection.

Signs

g   Affected birds are depressed, reluctant to move, have ruffled feathers and drooped wings.

g   Diarrhoea with pasting of vent.

chickens are drowsy, with eyes closed, ruffled feathers and grouped near the sources of heat.

Gross Lesions

g   Visible lesions  are not a must but one can see septicemic carcass with swollen liver, spleen, lungs and kidneys.

In the liver, hyperaemia, subcapsular haemorrhages and dystrophy

 

g   Inflamed unabsorbed yolk sac is a common feature. 

g   The most characteristic feature is typhilltis.

g   Caeca distended with hard white necrotic cores.

caeca are filled with gelatinous, fibrinous, cheese-like exudate. This is a finding, characteristic for salmonellosis,

 

g   Septicaemia, pericarditis and perihepatitis.

Histopathology

g  Congestion, haemorrhages, infiltration of mononuclear cells with degenerative changes and focal areas of necrosis in liver. 

g   Catarrhal enteritts with inflammatory cells and necrosis. 

g   Degenerative changes and focal areas of necrosis with hyperemia and presence of a few inflammatory cells in heart. 

Diagnosis

g   Confirmation by isolation and identification of causative agent

g   Liver, gall bladder, yolksac, intestines, caecal contents are the best sites for isolation of the organism.

Fowl Typhoid

Fowl Typhoid

Causative agent – Salmonella gallinarum.

Incidence and distribution – distributed all over the world in chicken, also reported in ducks, pheasants, guined fowl, goose and quails.

Transmission

g   Through water, feed, wild birds, animals, files, unsterllised fish and meat meals.

g   It can be transmitted vertically.

Signs

g   Increased mortality

g   Reduced feed consumption.

g   Drop in egg production.

g   Watery mucoid yellowish diarrhea.

g   Pale combs. 

Gross Lesions

g   The most consistent finding is swollen fragile liver with dark red or almost black colour and the surface has distinctive coppery bronze sheen. 

g   In subacute or chronic stage-greenish brown or bronze colour swollen liver.

Enlarged bronzed liver - in right

g   Occasionally Milliary type grayish white foci are seen in the liver and myocardium 

Milliary nodules in liver

g   Misshapen and discoloured ova.

g   Enlarged spleen.

g   Catarrhal inflammation of intestine.

g   Dark brown bone marrow is the characteristic feature of this disease.

Diagnosis

The organism can be isolated from affected visceral organs

Salmonellosis in Poultry Birds - Killing profits

Salmonellosis

The gram negative rod shaped bacteria common in poultry are

g   Salmonella pullorum

g   Salmonella gallinarum

g   Salmonella typhimurium

Pullorum Disease

Causative agent – Salmonella pullorum.

Incidence and distribution- Chickens all over the world.

Transmission

g   Vertically through hatching eggs.

g   Horizontal through litter, feed and water.

Signs

g   High mortality in chicks below 3 weeks of age.

g   Excessive numbers of embryos dead in shell.

g   Chick death shortly after hatching.

g   Tendency to huddle.

g   Respiratory distress.

g   Loss of appetite

g   Soiled vent with white viscous droppings.

g   Occasionally swollen joints.

g   Dropped egg production in layers.

Gross Lesions

Chicks

g   Sudden mortality

g   Peritonitis with inflamed, unabsorbed yolk sac. 

Fibrinous peritonitis of poultry bird in salmonellosis

  g   Liver enlarged and congested . 

Enlarged liver of layer bird with rounded edges

                             

          g   Congested or anemic kidneys with distended ureters with urates as shown

Urates present in uraters of layer birds

g   Enlarged spleen.

Spleenomegaly in Pullorum Disease

g   Lungs may be congested.

g   Caeca are enlarged and distended with casts of hard, dry necrotic material. 

Layers

g   Ovaries irregular, misshapen, cystic, discoloured and pedunculated with prominent thickness and stalks.

Chronic fowl typhoid - pedunculated (mishappened)
ovary follicles

Pericarditis - Heart showing white nodulor lesions

g   Abdominal peritonitis, arthritis and pericarditis.

Odema of tibio tarsal in Salmonellosis (arthritis)

g   Discrete small white necrotic focl are often found in liver.

Liver showing copper sheen in salmonellosis 

 

Histopathology

g   Degenerative changes and necrosis of liver parenchyma with infiltration of mononuclear cells.

Mononuclear infiltration

g   Degenerative changes and focal necrotic areas of liver parenchyma with congestion and haemorrhages. 

Diagnosis

g   Confirmative diagnosis by isolation and identification of S. pullorum.

Salmonella growth on XLD agar for cultural diagnosis

g   Serology by rapid plate agglutination test.

Salmonella pullorum Antigen

LAH Pullorum Stained Antigen for Plate Agglutination Test (Material No. 10100762). This antigen is a suspension of five (5) killed, stained strains (4, 11, 77, 79 and 296) of Salmonella pullorum for serum plate agglutination (SPA) testing of chicken and turkey flocks.

Treatment of Salmonellosis:

There are several products available in the market to treat salmonella infection.

COLIDOX: Prevention of Salmonellosis

Composition :

Each kg contains:

• Colistin Sulphate : 1000 mg

• Doxycycline : 10,000 mg

• Excipient : Q.S.

Broilers & Layers: 500 g per ton of feed

Breeders: 1 kg per ton of feed

COLIGRO: For therapeutic use

Colistin Sulphate  for oral suspension USP (10%)

Usage: 1g/5lit for 7days