Skip to main content
ARS Home » Southeast Area » Gainesville, Florida » Center for Medical, Agricultural and Veterinary Entomology » Mosquito and Fly Research » Research » Publications at this Location » Publication #308152

Title: Experimental transmission of Corynebacterium pseudotuberculosis in horses by house flies

item BARBA, MARTA - Auburn University
item STEWART, ALLISON - Auburn University
item PASSLER, THOMAS - Auburn University
item HU, XING PING - Auburn University
item CHAMORRO, MANUEL - Auburn University
item CATTLEY, RUSSEL - Auburn University
item HATHCOCK, TERRI - Auburn University
item Hogsette, Jerome - Jerry
item WOOLDRIDGE, ANNE - Auburn University

Submitted to: Journal of Veterinary Internal Medicine
Publication Type: Abstract Only
Publication Acceptance Date: 8/4/2014
Publication Date: 8/4/2014
Citation: Barba, M., Stewart, A.J., Passler, T., Hu, X., Chamorro, M.F., Cattley, R., Hathcock, T., Hogsette, Jr, J.A., Wooldridge, A.A. 2014. Experimental transmission of Corynebacterium pseudotuberculosis in horses by house flies. Journal of Veterinary Internal Medicine. 28:1106.

Interpretive Summary:

Technical Abstract: The route of infection of pigeon fever remains undetermined. The purpose of this study was to investigate house flies (Musca domestica L.) as vectors of Corynebacterium pseudotuberculosis in horses. Eight ponies were used in a randomized, controlled, blinded experimental study. Ten wounds were created in the pectoral region where cages for flies were attached. Three ponies were directly inoculated with C. pseudotuberculosis. Four ponies were exposed for 24 hours to 20 C. pseudotuberculosis-inoculated flies. One negative control pony was exposed to non-inoculated flies. Ponies were examined daily for swelling, heat, pain and drainage from the inoculation site. Blood was collected weekly for complete blood cell count and fibrinogen analysis. Serum was collected twice weekly for synergistic hemolysis inhibition titers. Data were analyzed using linear regression or repeated measures ANOVA analysis. Significance was assumed at P < 0.05. Clinical signs of local infection and positive cultures were observed in 7/7 ponies exposed to C. pseudotuberculosis and were absent in negative control. In exposed ponies, peak serologic titers (1:512 to 1:2048) were obtained between days 17 and 21. There was no difference in the linear increase in titers between the exposed groups. The titer increase was greater in both exposed groups compared to the negative control group (P = 0.0002). Fibrinogen concentrations were significantly greater on day 7 and 21, and neutrophil counts were significantly greater on day 3 in both exposed groups compared to the negative control. House flies are confirmed as mechanical vectors of C. pseudotuberculosis and can transmit the bacteria to naïve ponies.