Measures of tracheal lesions are more discriminatory and reproducible indications of chronic respiratory disease caused by <i>Mycoplasma gallisepticum</i> in poultry
Creators: name: Arachchige, Sathya N. Kulappu
name: Underwood, Gregory J.
name: Andrews, Daniel M.
name: Abeykoon, A. M. Hasanthi
name: Wawegama, Nadeeka K.
name: Browning, Glenn F.
Publisher: name: Taylor & Francis
Year: 2022
Subjects: subject: Space Science
subject: Medicine
subject: Biotechnology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: Sociology
subject: FOS: Sociology
subject: 69999 Biological Sciences not elsewhere classified
subject: FOS: Biological sciences
subject: Cancer
subject: Science Policy
subject: 110309 Infectious Diseases
subject: FOS: Health sciences

description: <i>Mycoplasma gallisepticum</i> is the primary causative agent of chronic respiratory disease in poultry, and vaccination is the measure most commonly used for its control. Pathological changes caused by <i>M. gallisepticum</i> are mainly observed in the trachea and air sacs, but assessment of air sac lesions is subjective. Standardized parameters for evaluation of pathological changes, and their reproducibility and discrimination in uninfected and infected groups, are critical when assessing the efficacy of <i>M. gallisepticum</i> vaccination. This study reviewed and critically appraised the published literature on evaluation of vaccine efficacy against pathological changes caused by <i>M. gallisepticum</i> in poultry in the trachea and air sacs. A search of four electronic databases, with subsequent manual filtering, identified 23 eligible papers published since 1962 describing the assessment of histopathological changes in the trachea using tracheal lesion scores and/or measurement of tracheal mucosal thicknesses and assessment of gross air sac lesions using lesion scores. Measurement of tracheal lesions proved a more reliable and robust method of assessing disease induced by <i>M. gallisepticum</i> when compared to assessment of air sac lesions, highlighting the importance of including assessment of tracheal lesions as the primary outcome variable in vaccine efficacy studies. In addition, this study also identified the necessity for use of a standardized model for evaluation and reporting on <i>M. gallisepticum</i> vaccines to minimize variations between vaccine efficacy studies and to allow direct comparisons between them. <b>RESEARCH HIGHLIGHTS</b>Tracheal and air sac lesions have been used to assess <i>M. gallisepticum</i> vaccine efficacy.The specific parameters and statistical tests used to compare tracheal and air sac lesions vary greatly.Measures of tracheal lesions are more discriminatory than measures of air sac lesions.A standardized model is needed to evaluate vaccines against infection with <i>M. gallisepticum</i>. Tracheal and air sac lesions have been used to assess <i>M. gallisepticum</i> vaccine efficacy. The specific parameters and statistical tests used to compare tracheal and air sac lesions vary greatly. Measures of tracheal lesions are more discriminatory than measures of air sac lesions. A standardized model is needed to evaluate vaccines against infection with <i>M. gallisepticum</i>.