Evaluation of Current Equine Influenza Vaccination Protocols Prior to Shipment, Guided by OIE Standards.

María Barrandeguy,Charlene Judith Fernandez,Monica Venner,Jacinta Gahan,Johanna Entenfellner,Ann Cullinane,Cathal Walsh,Cecilia Olguin-Perglione,Manabu Nemoto,Tao Qi Huang Fu,Marie Garvey,Takashi Yamanaka

doi:10.3390/vaccines8010107

Abstract

To facilitate the temporary importation of horses for competition and racing purposes, with a minimum risk of transmitting equine influenza, the World Organisation for Animal Health (Office International des Epizooties, or OIE), formally engaged in a public–private partnership with the Federation Equestre Internationale (FEI) and the International Federation for Horseracing Authorities (IFHA) to establish, within the context of existing OIE standards, a science-based rationale to identify the ideal time period for equine influenza vaccination prior to shipment. Field trials using vaccines based on different technologies were carried out on three continents. The antibody response post-booster vaccination at intervals aligned with the different rules/recommendations of the OIE, FEI, and IFHA, was monitored by single radial haemolysis. It was determined that 14 days was the optimum period necessary to allow horses adequate time to respond to booster vaccination and for horses that have previously received four or more doses of vaccine and are older than four years, it is adequate to allow vaccination within 180 days of shipment. In contrast, the results indicate that there is a potential benefit to younger (four years old or younger) horses in requiring booster vaccination within 90 days of shipment, consistent with the current OIE standard.

Highlights

Equine influenza (H3N8) viruses are highly contagious, in immunologically naïve populations [1]
The single radial haemolysis (SRH) antibody titre of all horses was measured at the time of booster vaccination and 7, 14, and 21 days post-vaccination
Ninety-four horses seroconverted between the day of booster vaccination and day 7 post-vaccination, and 49 seroconverted between day 7 and day 14 post-vaccination, but 25 of those had already seroconverted by day 7

Summary

Introduction

Equine influenza (H3N8) viruses are highly contagious, in immunologically naïve populations [1]. The first incursion in Australia resulted in the infection of approximately 75,000 horses on 9,400 premises in New South Wales and Queensland, and at the very early stage of the epidemic up to 98 premises became infected through the movement of horses from two equestrian competition events [2,3]. Similar equine influenza virus incursions in Hong Kong [5], Japan [6], South Africa [7,8], Turkey [9], Malaysia [10] and other countries have resulted in economic loss, due to movement restrictions and cancellation of equestrian events. In 2019, many European countries experienced an increase in equine influenza activity [13], and in the United Kingdom horse racing was cancelled for six days, with media reports of revenue loss in excess of £100 million

Methods

Results

Conclusion