"Aspergillosos"

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"Aspergillosos"

 

 

 

Mycotic diseases are divided into two classifications:

 

 

 

Mycoses These are the results from fungal growth within the host tissues and is either superficial or deep. Superficial mycoses refers to fungal growth within the skin, while in deep Mycoses fungal elements invade deeper body tissues or are systemic.

 

 

 

Mycotoxicoses, which occur when toxic fungal metabolites gain entry into the host.

 

 

 

Aspergillosis is the most common form of deep mycoses and is caused by the spores of Aspergillus Fumagalus. It is primarily a disease of the lower respiratory tract and can occur as either an acute or chronic disease. In its acute form, it is a fatal respiratory disease. Its most common form is chronic. Although the lungs and air sacs are the primary affected organs, the trachea, syrinx and bronchi are frequently involved.

 

 

 

Aspergillus grow readily in decaying organic matter, damp feed, dusty or deteriorating feed, on utensils or wherever damp conditions and poor ventilation exist. In fact, our birds are constantly exposed to Aspergillus spores in their aviary environment and yet they do not usually present a disease problem.

 

 

 

However, under certain conditions, these fungal agents can become pathogenic. For example, in aviaries where there is low humidity, excessive dust interferes with normal mucociliary activity of ciliated epitheliums, which predisposes a bird to respiratory mycoses. In this case, inhalation of an overwhelming number of spores results in acute Aspergillosis.

 

 

 

Damp materials in the nest box create a medium for Aspergillus to grow, contaminating incubating eggs as well as causing mycoses in nestlings.

 

 

 

Immunosuppression due to stress or a pre-existing disease and malnutrition which causes primary Thiamine deficiency are all additional predisposing factors influencing fungal pathogenesis.

 

 

 

Diagnosis

 

 

 

Clinical signs of both chronic and acute Aspergillosis are not diagnostic because they resemble other chronic debilitating diseases. Tentative diagnosis is made through signs of Dyspnea, a history of environmental conditions conducive to fungal growth and exposure to stress. A stronger diagnosis is made if the respiratory condition has been unresponsive to antibiotics. A history of Dyspnea, Anorexia, Lethargy and weight loss, combined with x-rays, which reveal increased density or nodules involving air sacs and lungs and a positive crop culture confirm the diagnosis.

 

 

 

Clinical Symptoms

 

 

 

Acute Form:

 

 

 

Rapid onset.

 

 

 

May include Anorexia, Dyspnea or sudden death.

 

 

 

 

 

Chronic Form:

 

 

 

Insidious onset (slow) Often reaches extensive involvement of the respiratory system before detection.

 

 

 

Dyspnea.

 

 

 

Lethargy.

 

 

 

Depression.

 

 

 

Emaciation.

 

 

 

Lesions of the trachea, syrinx and primary bronchi.

 

 

 

Respiratory clicking.

 

 

 

Gurgling noise.

 

 

 

 

 

Treatment

 

 

 

In general, this disease has a poor to grave prognosis with or without treatment. The best way of dealing with Aspergillosis is prevention and this centres on elimination of fungal growth and reduction of stress in the aviary. There is some evidence that oral 5-Fluorocytosine given twice a day for 10-14 days prior to a bird entering a stressful situation is an effective precautionary measure against Aspergillosis.