Equine Influenza

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

Online CPD course

Module 1. General Introduction: Orthomyxoviridae (read text)

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

Equine influenza is an acute contagious disease of horses, mules, donkeys and zebras caused by infection with type A influenza viruses. The antigenic character of the haemagglutinin and neuraminidase define subtypes within a virus type. Antigenic drift occurs when mutations in the gene sequence result in amino acid substitutions, particularly in the haemagglutinin. Major or subtype changes in the surface glycoproteins occur as a result of recombination with other influenza viruses and are called antigenic shifts. Antigenic shift gives rise to new viruses that may result in outbreaks in susceptible populations.

Equine influenza has been reported in many parts of the world: New Zealand and Iceland are the only countries that are known to have remained free from the infection. The disease is considered endemic in the USA, UK and other European countries.

There are many different factors that influence the occurrence of equine influenza including intrinsic properties of the virus, the pathogenesis of the disease, the immune system of the animal and the equine industry structure and workings. Increased transportation of horses over long distances by air is important in the spread of the disease. Horses incubating the disease, or those that are clinically or subclinically infected, can introduce the infection into a susceptible population if they are not quarantined adequately.  In addition, inadequate vaccination may lead to horses with partial immunity and result in the suppression of clinical signs.  Such horses probably play an important role in the maintenance and spread of equine influenza.

Equine influenza is transmitted almost exclusively by direct contact through aerosols between horses. It is a highly contagious disease characterized by a short incubation period, rapid spread in susceptible populations and high morbidity rates. A harsh dry cough and fever are the most common clinical signs of the disease. Long-term carriers of the virus do not occur, and immunity is short-lived, lasting little more than a year.

Guidelines for control of equine influenza are discussed.

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

After completion of the course the learner will have a sound knowledge of equine influenza 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 equine influenza.
• understand the role of equine influenza virus and other epidemiological and management factors in outbreaks of equine influenza.
• explain the collection of specimens for diagnostic purposes and will have a basic understanding of the different diagnostic tests that are applicable to confirm equine influenza.
• understand the pros and cons of the different available vaccines and other measures that can be taken in the prevention/ control of equine influenza.

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

South African Veterinary Council (SAVC)

2 CPD Points

AC/0077/20

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