title: Lack of correlation between antibody titers to fibrinogen-binding protein of Streptococcus equi and persistent carriers of strangles.
abstract: Previously published studies have neither used nor reported the results of an indirect enzyme-linked immunosorbent assay (iELISA) to measure serologic responses in natural outbreaks of strangles. The concept of using serologic responses to identify persistent carriers of Streptococcus equi has been proposed but not scientifically evaluated. The specific aims of the current study were to determine the duration and level of truncated fibrinogen-binding protein-specific (SeM allele 1) antibody production in ponies involved in a natural outbreak of strangles and to determine if test results from this serologic iELISA could predict persistent carrier status. Serologic samples were obtained before and after an outbreak of naturally occurring strangles infection. Persistent carriers of S. equi were identified via culture and polymerase chain reaction (PCR) testing of lavage fluid collected from the guttural pouches and nasopharynx or swabs of the nasopharynx after recovery from acute disease and at postmortem examination. Logistic regression analysis was used to determine if an association existed between serologic response and persistent carrier state. The ELISA reported in the current study definitively confirmed a recent exposure to S. equi. However, the measured serologic response did not predict carrier status in this strangles outbreak. Therefore, a guttural-pouch endoscopy with subsequent culture or PCR testing to detect S. equi remains the most accurate method available for the identification of persistent carriers.
authors.affiliation: Department of Clinical Sciences, Colorado State University, Fort Collins, CO 80521, USA. adavid@colostate.edu
authors.forename: Ann
authors.initials: A
authors.lastname: Davidson
authors.forename: Josie L
authors.initials: JL
authors.lastname: Traub-Dargatz
authors.forename: Roberta
authors.initials: R
authors.lastname: Magnuson
authors.forename: Ashley
authors.initials: A
authors.lastname: Hill
authors.forename: Vivienne
authors.initials: V
authors.lastname: Irwin
authors.forename: Richard
authors.initials: R
authors.lastname: Newton
authors.forename: Andrew
authors.initials: A
authors.lastname: Waller
authors.forename: Kenneth
authors.initials: K
authors.lastname: Smith
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Callan
authors.forename: Mary
authors.initials: M
authors.lastname: Meehan
authors.forename: Peter
authors.initials: P
authors.lastname: Owen
authors.forename: Mo
authors.initials: M
authors.lastname: Salman
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D001426:Bacterial Proteins / Q000276:immunology*; D002352:Carrier Proteins / Q000276:immunology*; D002353:Carrier State / Q000662:veterinary*; D004196:Disease Outbreaks; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D006734:Horse Diseases / Q000453:epidemiology* / Q000276:immunology*; D006736:Horses; D015203:Reproducibility of Results; D013290:Streptococcal Infections / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D018502:Streptococcus equi
chemical_list: D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D002352:Carrier Proteins; C112406:fibrinogen-binding protein, Streptococcus equi