Worries are far from over even when all-clear is given
Infected horses must rest and will take weeks to recover full fitness, writes Jamie O’gorman
Alarm bells have been ringing after equine influenza outbreaks in Ireland, France, Germany, Belgium and Holland, as well as cases in the non-racing population here, which have been occurring in vaccinated horses.
The challenge for vaccine manufacturers, who are constantly having to play catch-up, is that, like human flu, equine influenza changes fairly regularly as a result of mutations. While an immunised horse will be protected against some versions, the goalposts are constantly shifting.
The various strains of flu are generally named after the place they were discovered and the one currently causing most of the problems in Europe is known as Florida Clade 1.
Like humans with flu, horses will feel awful, they look dull, lose their appetite, run a temperature, have a snotty nose, normally cough and can have swelling of the glands between the jaws. Definitive diagnosis is usually by swabbing the nasal passages and isolating the virus directly or by finding rising levels of antibodies to the virus in the blood.
Like its human counterpart, it is usually self-limiting and normally resolves within a couple of weeks without complication, but it can be very serious, and occasionally fatal, in young foals and horses with other problems that mean their immune system is severely compromised.
It is highly contagious, which is the nub of the problem. The incubation period is generally one to five days, with horses shedding the virus into the environment for up to approximately 10 days post-infection. It is spread from horse to horse via an aerosol of tiny droplets when a horse snorts or coughs. The virus can also last for a relatively short period in the environment and can be transmitted by humans who have been in contact with the horse or by grooming and feeding equipment or anything else carrying the products of the horse’s nose.
The problem for racing yards is not that the virus is life-threatening, but that it can cause massive disruption to training. Horses usually need resting for a couple of weeks and then can take many weeks to recover lost fitness, losing a substantial portion of the season.
The spread of the virus around a yard can be unpredictable, meaning new cases can occur for several weeks, dragging out a complete resolution, and secondary infections can significantly delay recovery. It certainly would not be ideal for a trainer’s big Cheltenham hope to succumb now, given average recovery periods.
The focus for the racing authorities has to be on knowing where the infected cases that are contaminating the environment are, isolating them wherever possible and restricting movement of those horses and the horses, humans and equipment in contact with them.