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.