Lack of correlation between antibody titers to fibrinogen-binding protein of Streptococcus equi and persistent carriers of strangles.
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.
Davidson
Ann
A
Department of Clinical Sciences, Colorado State University, Fort Collins, CO 80521, USA. adavid@colostate.edu
Traub-Dargatz
Josie L
JL
Magnuson
Roberta
R
Hill
Ashley
A
Irwin
Vivienne
V
Newton
Richard
R
Waller
Andrew
A
Smith
Kenneth
K
Callan
Robert J
RJ
Meehan
Mary
M
Owen
Peter
P
Salman
Mo
M
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
D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D002352:Carrier Proteins; C112406:fibrinogen-binding protein, Streptococcus equi