This online CPD course has been designed to provide easy access to up-to-date scientific information on strangles. The course material was developed by Dr AS Waller, Head of Bacteriology, Animal Health Trust, Newmarket, Suffolk, United Kingdom.

In this course the differences in pathogenesis, clinical signs and pathology between typical, atypical (catarrhal) and bastard strangles are highlighted. The pros and cons of different diagnostic techniques and available vaccines, therapeutics and management practices in the control of strangles are pointed out.

Who Should Enrol

Veterinary, para-veterinary and allied animal and human health professionals and students.

Course Design

Online CPD course

Course Content

Module 1.  General Introduction: Gram-positive cocci: Streptococcus spp. (read text)

Module 2. Strangles: Introduction, Aetiology, Epidemiology, Pathogenesis, Clinical signs, Pathology, Diagnosis, Differential Diagnosis and Control (2 CPD points)

Course Highlights

Strangles is an acute contagious disease of horses, mules and donkeys, characterized by fever, acute mucopurulent inflammation of the upper respiratory tract, purulent lymphadenitis and abscessation of the submandibular and retropharyngeal lymph nodes. It is endemic throughout the world. Information from 20 countries, indicates that strangles ranks with equine influenza and herpesvirus abortion as one of the three most significant equine infectious diseases.

Strangles occurs in animals of all ages, but is more common in those less than two years old. The disease is highly contagious, transmission occurring via the oral and nasal routes. Contaminated feed, water, bedding, stables and stable utensils, are important in the spread of the infection.

A proportion of horses that recover from strangles remain persistently infected with S. equi, usually harbouring the bacteria within their guttural pouches or sinus providing a reservoir of infection. The identification and treatment of carriers to eliminate S. equi is critical if future outbreaks of strangles are to be prevented.

Stressful situations, particularly those caused by transportation, very cold or hot weather and overcrowding, enhance susceptibility of animals and transmission.

Three clinical forms are described — typical, atypical (catarrhal) and bastard strangles. Purpura haemorrhagica, an acute nonthrombocytopenic leukocytoclastic vasculitis, is another serious sequela of strangles.

Guidelines for control of strangles are given.

The learner will be able to study and complete the course material and online test at his/her own pace.

Learning Outcomes

After completion of the course the learner will have a sound knowledge of strangles and will be able to:

  • understand and discuss the most important features of the aetiology, epidemiology, pathogenesis, clinical signs, pathology, diagnosis, differential diagnosis and control/prevention of strangles.
  • point out the differences in the pathogenesis, clinical signs and pathology of the different forms of strangles.
  • understand the role of Streptococus equi and other environmental and management factors play in the development of strangles.
  • explain the collection of specimens for diagnostic purposes and will have a basic understanding of the different diagnostic tests that are applicable to confirm strangles in clinical settings.
  • understand the pros and cons of the different available vaccines and therapeutics and other measures that can be taken in the prevention/ control of strangles.


Some of the modules will have a multiple-choice test, while others are read for information.


South African Veterinary Council (SAVC)

2 CPD Points



In order to qualify for CPD points, the learner will be required to complete the course and pass the multiple-choice test with 80%.

Strangles is an acute contagious disease of horses, mules and donkeys.

2.0 CPD Points