A Comparison of Methods of Inducing Lachrymation and Tear Collection in Chickens for Detection of Virus-specific Immuoglobulins After Infection with Infectious Bronchitis Virus

Four-week-old specific-pathogen-free chickens were infected with virulent infectious bronchitis virus Massachusetts strain M41 via the ocular-nasal route. At weekly intervals up to 3 weeks post-infection, excess lachrymation was induced either by placing sodium chloride (salt) crystals on the eyes or by intramuscular injection of carbachol. Tears were collected using micropipettes or on filter paper. Levels of virus-specific immunoglobulin (Ig)A and IgG were similar, irrespective of the method of tear induction. When tears were collected using filter papers, IgG was detected in eluted samples but at significantly lower levels than in those collected by pipette. Collection of IgA in this way was even less productive, and only trace amounts were detected. Possible reasons for these discrepancies have been discussed.