A BACTERIOLOGICAL STUDY OF INFECTIOUS LARYNGOTRACHEITIS OF CHICKENS.

Area of Science:

• Avian Pathology
• Veterinary Virology
• Poultry Diseases

Background:

• Infectious laryngotracheitis (ILT) is a significant respiratory disease affecting chickens.
• Understanding the distribution of the causative agent is crucial for disease control and prevention strategies.

Purpose of the Study:

• To determine the presence and distribution of the infectious laryngotracheitis virus (ILTV) in various tissues of infected chickens.
• To assess the infectivity of different tissues for disease transmission studies.

Main Methods:

• Bacteriological examination of tracheal exudate, spleens, and livers from chickens with active ILT.
• Inoculation of susceptible chickens with suspensions derived from these tissues to assess infectivity.
• Testing the susceptibility of various avian and mammalian species to ILT.

Main Results:

• The ILT virus was detected in bacteriologically sterile tracheal exudate, spleens, and livers of infected chickens.
• The virus was consistently found in tracheal exudate, present in approximately 60% of spleens and 30% of livers.
• Tracheal exudate suspensions were more effective in inducing ILT than spleen or liver suspensions, suggesting limited active involvement of these organs.

Conclusions:

• The ILT virus disseminates to the spleen and liver via the bloodstream, but these organs are not primary sites of replication.
• Tracheal exudate is the most effective source for transmitting infectious laryngotracheitis in chickens.
• Chickens are the primary susceptible host; ducks, various wild birds, rabbits, guinea pigs, rats, and pigs are refractory to the infection.