Equine Influenza has not gone away and data strongly confirms it is gathering pace

Posted on 24th June 2019

As you all are aware, Britain had equine influenza (EI) circulating back in February and March, and you may have thought that everything was quiet now on that particular front after Cheltenham and Aintree went without a hitch and Royal Ascot approached its last day without apparent incident.

However, the news to you all is not good because EI appears to be rising again in certain parts of the country, and in fact we know that it never actually went away.

The number of confirmed outbreaks now exceeds 130 – in this context, ‘outbreaks’ refers to discrete foci of infection, usually separate premises. The not-yet-complete second quarter of 2019 has actually seen more outbreaks confirmed than the first quarter, during which EI made the national headlines because racing was stopped for six days whilst the BHA and its veterinary advisors took stock to assess the extent of EI in the racing network, all with the imminent Cheltenham Festival in mind.

As the graph below illustrates, we did indeed see month-on-month decreases in EI outbreaks confirmed in Britain in March and April following the peak in February. The picture in May and June, however, has seen a reversal of this trend such that May (n=28) saw the second highest monthly total of diagnoses after February (n=35) up to that point and only for June today to surpass the February total (n=37).

The week-on-week trend since the end of April has largely been of increasing numbers of diagnoses of EI outbreaks being made. This week (17–23 June) has seen the second highest total number of diagnoses after the peak in the week of February when racing resumed following the publicity around its stoppage.

It is important to note that the vast majority of outbreaks that occurred in June were diagnosed in horses who were not vaccinated against EI.

The EquiFluNet reports are regularly updated and accessible from the AHT website at; https://www.aht.org.uk/disease-surveillance/equiflunet

To summarise:

There have been several themes which have, based on supplied information, seemingly contributed to EI transmission in Britain at different points in the past 6 months. These have included links to attendance at hunt meetings during the winter/early spring, introduction of animals following importation from other EU countries, including but not exclusively Ireland, and most recently a rise in diagnoses following attendance at a well-known horse fair in the north-west of England.

EI has definitely NOT gone away and in contrast the data would strongly confirm that it is possibly gathering pace.

The recent resurgence in activity is undoubtedly related to the increased movement and mixing of animals at events that regularly occur at this time of year, with these animals returning back to home premises where there may be unvaccinated animals. Perhaps not all of these events had heard or heeded the advice that had been pushed out and promoted earlier in the year to seriously consider adopting requirements for vaccination of entrants and policing these requirements through applying passport checks.

We urge you all to maintain awareness of outbreaks through regular monitoring of the EquiFluNet updates and registering for TellTail text alerts from Boehringer Ingelheim;


and generally raising awareness among your colleagues & friends. The AHT still considers that vaccination of entire premises and quarantining of new or returning animals is strongly merited in limiting the spread of this disease.

Your veterinary surgeon will advise horse and yard owners on premises on which EI is confirmed to implement premises-wide voluntary movement restrictions and not sending animals to events, even if they are outwardly healthy.   Please see this link for BEF press release 23 6 19;


Richard Newton, Head of Epidemiology & Disease Surveillance at the Animal Health Trust in Newmarket.

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