Exacerbation of Streptococcus Equi (Strangles) by Overly Nutritious Diets in Horses: A Model for Infectious Bacterial Diseases of Horses and Other Livestock
Strangles is a highly pathogenic and contagious infection of horses and other equids caused by Streptococcus equi. Reports in the literature summarize the severe complications of strangles, but provide little information on the factors enhancing the pathogenicity and complications that result in high mortalities. However, there are reports suggesting exceptionally nutritious diets will exacerbate strangles infections and promote complications, including bacteremia and metastases to lymph nodes throughout the body and sequalae like purpura hemorrhagic and myositis. Dietary ingredients may enhance S. equi capsular polysaccharide (CPS) which protects bacteria from the immune system and phagocytosis. Low-virulent bacteria may become highly virulent pathogenic bacteria. Overly nutritious diets enhance the pathogenicity of S. equi and efficiency of bacterins, vaccines and antibiotics intended for controlling and treating strangles in horses. The effect of diet on the pathogenesis of S. equi in horses may be an ideal model for other bacterial diseases of horses as well as bacterial diseases like Pasturella multocida respiratory infections in cattle and other livestock.
Thomas Walter Swerczek,
Exacerbation of Streptococcus Equi (Strangles) by Overly Nutritious Diets in Horses: A Model for Infectious Bacterial Diseases of Horses and Other Livestock, Animal and Veterinary Sciences.
Vol. 7, No. 1,
2019, pp. 18-23.
Bryans, J. T., Doll, E. R, Shephard, B. P. (1964) The etiology of strangles. Cornell Vet. 54, 198-205.
Sweeney, C. R., Whitlock, R. H., Meirs, D. A., Whitehead, S. C, Barningham, S. O. (1998) Complications associated with Streptococcus equi in a horse farm. JAVMA. 191, 1446-1448.
Boyle, A. G. (2017) Strangles and its complications. Equine Vet. Educ. 29(3), 149-157. doi: 10.1111/eve.12568
Spoormakers, T. J., Ensink, J. M., Goehring, L. S., Koeman, J. P., Ter Braake, F., van der Vlugt-Meijer, R. H., van den Belt, A. J. (2003) Brain abscesses as a metastatic manifestation of strangles: symptomatology and the use of magnetic resonance imaging as a diagnostic aid. Equine Vet J. 35(2), 146-151.
Newton J. R., Wood J. L. N., Dunn K. A., DeBrauwere M. N., Chanter N. (1997) Naturally occurring persistent and symptomatic infection of the guttural pouches of horses with Streptococcus equi. Vet. Rec. 140, 84-90.
Knight A. P., Voss J. L., McChesney A. E., Bigbee H. G. (1975) Experimentally-induced Streptococcus equi infection in horses with resultant guttural pouch empyema. Vet Med Small Anim Clin. 70(10), 1194-1199.
Swerczek, TW. Pathogenesis, Treatment and Control of Streptococcus equi Infection (strangles) in Horses. Proceeding of the First Annual Eastern States Veterinary Conference, Orlando. Fl. January 18, 1984.
Ford, J., Lokai M. D. (1980) Complications of Streptococcus equi infections. Equine Pract. 2, 41-44.
Bin Xu, Xiaomeng Pei, Yiqi Su, Zhe Ma, Hongjie Fan. (2016) Capsule of Streptococcus equi subsp. zooepidemicus hampers the adherence and invasion of epithelial and endothelial cells and is attenuated during internalization. FEMS Microbiology Letters, 363 (16) https: doi.org/10.1093/femsle/fnw164.
Woolcock, J. B. (1974) The capsule of Streptococcus equi. J. of General Microbiology. 85, 372-375.
Petruzzi, B., Briggs, R. E., Tatum, F. M., Swords, W. E., De Castro, C., Molinaro, A., Inzana, T. J. (2017) “Capsular Polysaccharide Interferes with Biofilm Formation by Pasteurella multocida Serogroup A” J American Society of microbiology. Volume 8, no. 6. doi:org/10.1128/mBio.01843-17
Swerczek, T. W. The Interrelationship between Nutrition and Infectious Diseases of Livestock. East Central Nebraska Cattlemen Association Meeting. November 20, 1998. Boone County, Nebraska.
Duffee, L. R., Stefanovski, D., Boston, R. C., Boyle, A., G. (2015) Predictor variables for and complications associated with Streptococcus equi subsp equi infection in horses. JAVMA. 247:1161–1168. Doi:10.2460/javma.247.10.1161.
Timoney, J. F. (1993) Strangles. Vet. Clin. N. Am. Equine Pract. 9, 365-374.
Bazeley, P. L. (1942) Studies with Equine Streptococci, 3. Vaccination against strangles. Austral. Vet. J. 18, 141-155.
Woolcock J. B. (1975) Immunity to Stretococcus equi. Aust Vet J. 51, 554-559.
Waller A. S., Jolley K. A. (2007) Getting a grip on strangles: recent progress towards improved diagnostics and vaccines. Vet J. 173, 492-501.
Timoney, J. F. (2007) Strangles vaccines in trouble again. Equine Vet. J. 39, 196. doi.org/10.2746/042516407X196744
Fairley, J. K. (1991) Strangles in horse studs: incidence, risk factors and effect of vaccination. Aust Vet J. 68(8), 282-283.
Swerczek, T. W. (2013) Tyzzer’s Disease in Foals: Retrospective studies from 1969 to 2010. Canadian Veterinary Journal, 54, 876-880.
Swerczek, T. W. (1980) Toxicoinfectious Botulism in Foals and Adult Horses. JAVMA 176, 217-220.
Swerczek, T. W., Dorton, A. R. (2019) Effects of Nitrate and Pathogenic Nanoparticles on Reproductive Losses, Congenital Hypothyroidism and Musculoskeletal Abnormalities in Foals: New Hypotheses. Animal and Veterinary Sciences. 7 (1), 1-11 doi: 10.11648/ j.avs.20190701.11
Swerczek, T. W. (1978) Inhibition of the CEM organism by the normal flora of the reproductive tract. The Veterinary Record. 133 (6), 125.
Swerczek, T. W. (1979) Aggravation of Strangles, Equine Clostridial Typhlocolitis (Colitis X) and Bacterial Venereal Diseases in the Horse by Antibacterial Drugs. Proc AAEP, Miami Fl. pp 305-310.
Richmond, R. (2015) Practical management of strangles outbreaks in horses. Aust Vet J. 93(8), N20.
Mallicote, M. (2015) Update on Streptococcus equi sub sp equi infections. Vet Clin North Am Equine Pract. 31(1), 27-41.
Waller, A. S. (2013) Strangles: taking steps towards eradication. Vet Microbiol. 167, 50-60. doi: 10.1016/j.vetmic.2013.03.033.
Holland R. E., Harris, D. G., Monge, A. (2006) How to control strangles infections on the endemic farm. Proc 52nd Annu Meet AAEP. 78-80.
Sweeney, C. R., Timoney, J. F., Newton, R., Hines, M. (2005) Control, and Prevention of Strangles Infections in Horses: Guidelines for Treatment. J Vet Intern Med. 19, 123–134.