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This article was published in 1957
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INSTITUTE OF INSPECTORS OF STOCK OF N.S.W. YEAR BOOK.
I.L.T. and Mucoid Tracheitis
PRACTICAL SUGGESTIONS IN DIFFERENTIAL DIAGNOSIS
M. LINDTNER, D.V.M., Veterinary Research Station, Glenfield.
Although laboratory examination is essential for a definite differential diagnosis between I.L.T. and Mucoid Tracheitis, some differentiating features in symptomatology, history and response to treatment have been observed in the majority of outbreaks, and these may be of some significance to the field diagnostician.
Both diseases are respiratory conditions in which gasping and gurgling are the dominant symptoms, but gurgling alone is prevalent in mucoid tracheitis.
Examination of the trachea through the oral cavity in live birds will show in I.L.T. cases rather bright red congestion of the tracheal mucosa, which is covered with thin, clear exudate usually accompanied by a few haemorrhages. There is no obvious abnormal odour.
In dead birds, haemorrhagic tracheitis with various amounts of coagulated blood in the lumen is usually observed. Blood-stained mucus coughed up and found lying on the bird or in the vicinity emphasises I.L.T.
In mucoid tracheitis the trachea is covered with thick, greyish, opaque exudate; masking the reddening of the mucosa below. No blood is present in the cavity, although on some occasions a few small haemorrhages can be found. A foul smell from the trachea will be noted. In many severe and advanced cases of 7-10 days duration, the tip of the trachea is covered with whitish, cheesy material obstructing the respiration. Its removal with a thin wire hook will save the bird.
Data regarding the spread, mortality and egg production are of considerable differential importance. I.L.T. spreads very rapidly through the flock, accompanied by increasing mortality; out of which certainly a few cases of haemorrhagic tracheitis will be found on post-mortem. Egg production usually is not changed in affected birds.
In mucoid tracheitis the spread is slow and completed after a few weeks. Mortality is low and occasional. Fall of egg production is evident from the beginning.
Streptomycin injection of birds with respiratory symptoms of no longer than 4-5 days duration proved to be of very useful differential value. One gramme of Streptomycin powder dissolved in five ml. of sterile water and 1-1.5 ml. of this solution injected into the breast muscle, one dose only. will make all respiratory symptoms disappear completely in 2-5 days in the case of mucoid tracheitis. No response will be observed in I.L.T.
Chronic cases of mucoid tracheitis do not respond to Streptomycin Injection and, therefore, data from the history gains in importance.
I.L.T. is a deadly disease with rapid resolution; while mucoid tracheitis is a wasting disease with gurgling continuing for 1-3 months.
For laboratory diagnosis live, sick birds should be sent; possibly accompanied by some dead specimens.