A dot-immunobinding assay for the serodiagnosis of Pasteurella multocida infection in laboratory rabbits

A dot-immunobinding assay was developed to detect serum IgG specific for lipopolysaccharide of rabbit isolates of P. multocida. The assay detected serum IgG as early as 1 week after experimental subclinical nasal infection, whereas 8 weeks were required to detect antibody by a gel diffusion precipitin test. The assay was more reliable than nasal cultures, in that up to 46% of 16 weekly nasal washings of some infected rabbits failed to yield P. multocida. The bacterial antigen (proteinase k digested cell lysate) used in the assay reacted with IgG that did not cross-react with lipopolysaccharide antigens of B. bronchiseptica, P. pneumotropica or P. hemolytica. The assay is sensitive and specific, easily performed, cost effective, requires no special laboratory instruments and provides a permanent easily stored record.