ISSN 2398-2942      

Streptococcus equi

icanis

Synonym(s): S. equi


Introduction

Classification

Taxonomy

  • PhylumFirmicutes
  • ClassBacilli
  • Order: Lactobacillales
  • FamilyStreptococcaceae
  • GenusStreptococcus
  • Speciesequi
  • Subspeciesequi (Synonym: S. equizooepidemicus (Synonyms: S. zooepidemicus)

Etymology

  • L. gen. N. equi, of a horse.
  • Gr. n. zoon, an animal; Gr. adj epidemios, among the people, epidemic; L. masc. suff. icus, suffix used with various meanings; N.L. masc. adj. zooepidemicus, prevalent among animals.

Active Forms

This article is available in full to registered subscribers

Sign up now to obtain ten tokens to view any ten Vetlexicon articles, images, sounds or videos, or Login

Clinical Effects

Epidemiology

Habitat

  • S. equi subsp. equi found on upper respiratory mucosa and associated lymphatics of infected horses.
  • S. equi subsp. zooepidemicus common commensal on mucous membranes of the upper respiratory tract and lower genital tract of horses.
  • S. equi subsp. zooepidemicus is found with varying frequencies as a commensal or opportunistic pathogen in many other animal hosts, including ruminants, pigs, poultry, guinea pigs and, rarely, dogs and people.

Lifecycle

  • Cells divide by binary fission to produce pairs or chains.

Transmission

  • Both S. equi subspecies may be transmitted by inhalation or ingestion.
  • Indirect transmission by contaminated fomites also occurs.
  • S. equi subsp.zooepidemicus may also be transmitted by sexual contact or congenitally during passage through the birth canal.
  • Most individual infections arise from endogenous, pre-existing clones; however, outbreaks may result from the horizontal spread of a single clone.
  • Transmission of S. equi subsp. zooepidemicusf rom dog to man reported.

Pathological effects

Immunological

  • Host defense depends on phagocytosis.
  • Hyaluronic acid capsules antiphagocytic.
  • Antibodies raised against M protein, an antiphagocytic surface protein.
  • Recovered animals have short-term resistance to infection.
  • Immunity is serotype-specific.

Pathological

  • Pyogenic bacteria produce suppurative host response.
  • Adhesins mediate attachment.
  • Extracellular products include streptolysin O and S, hyaluronidase, protease, streptokinase, streptococcal pyrogenic exotoxins.
  • Virulence mechanisms of highly pathogenic infections are unresolved.

Other Host Effects

Clinical

  • S. equi subs .equi - associated with submandibular swelling and lymphadenitis.
  • S. equi subsp. zooepidemicus - rare commensal in upper respiratory and lower genital tracts.
  • S. equi subsp .zooepidemicus - associated with neonatal septicemia and severe forms of respiratory disease with hemorrhagic pneumonia Lung: bacterial pneumonia.

Other

  • Co-pathogens found in some (but not all) outbreaks of severe respiratory disease.

Control

Control via animal

  • Isolate and treat clinically affected animals.
  • Isolate and treat exposed animals (to control outbreak).
  • Quarantine until 2 weeks after resolution of signs.

Control via chemotherapies

  • Usually susceptible to penicillins, cephalosporins, potentiated sulfas, macrolides, chloramphenicol Chloramphenicol.
  • Often resistant to aminoglycosides and tetracyclines Tetracycline.
  • Treatment only effective if started early following onset of clinical signs.

Control via environment

  • Clean, disinfect and dry all environmental surfaces that were exposed to infected dogs.
  • Most disinfectants, at recommended use dilutions and contact times, effectively kill pathogenic streptococci.
  • Control via other means.
  • Use of separate protective clothing (glove, mask, footwear, etc) when examining infected animals.

Vaccination

  • No streptococcal vaccines available for use in dogs.

Other countermeasures

  • Isolate newly admitted dogs from clinically affected and exposed dogs.
  • Prophylactic treatment of newly admitted dogs may be indicated in some circumstances.

Diagnosis

This article is available in full to registered subscribers

Sign up now to obtain ten tokens to view any ten Vetlexicon articles, images, sounds or videos, or Login

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Abbott Y, Acke E, Khan S et al (2010) Zoonotic transmission of Streptococcus equi subsp. Zooepidemicus from a dog to a handler. J Med Microbiol 59 (Pt 1), 120-123 PubMed.
  • Pesavento P A, Hurley K F, Bannasch M J et al (2008) A clonal outbreak of acute fatal hemorrhagic pneumonia in intensively housed (shelter) dogs caused by Streptococcus equi subsp. zooepidemicus. Vet Pathol 45 (1), 51-53 PubMed.
  • Kim M K, Jee H, Shin S W et al (2007) Outbreak and control of haemorrhagic pneumonia due to Streptococcus equi subspecies zooepidemicus in dogs. Vet Rec 161 (15), 528-530 PubMed.
  • Ladlow J, Scase T & Waller A (2006) Canine strangles case reveals a new host susceptible to infection with Streptococcus equi. J Clin Microbiol 44 (7) 2664-2665 PubMed.
  • Chalker V J, Brooks H W & Brownlie J (2003) The association of Streptococcus equi subsp. zooepidemicus with canine infectious respiratory disease. Vet Microbiol 95 (1-2), 149-156 PubMed.
  • Sundberg J P, Hill D, Wyand D S et al (1981) Streptococcus zooepidemicus as the cause of septicemia in racing Greyhounds. Vet Med Small Anim Clin 76 (6), 839-842 PubMed.

Other sources of information

  • Hirsh D C & Biberstein E L (2004) Streptococcus and Enterococcus. In: Hirsh D C, MacLachlan N J & Walker R L (eds).Veterinary Microbiology. 2nd ed. Blackwell Publishing, Ames, IA,USA pp. 159-167.

Can’t find what you’re looking for?

We have an ever growing content library on Vetlexicon so if you ever find we haven't covered something that you need please fill in the form below and let us know!

 
 
 
 

To show you are not a Bot please can you enter the number showing adjacent to this field

 Security code