Immunofluorescence scores for the presence of Cp. psittaci antigen in tissues of vaccinated and placebo-vaccinated budgerigars. The scores were compared with the Mann–Whitney test. The level of significance is indicated with asterisks as * p < 0.05; ** p < 0.01; *** p < 0.001 and ns stands for non significant. Bars are indicating 25 and 75 percentiles around each median. The groups were significantly different for all tissues, except for the conchae.