Iceland, Horses, and Hendra: Greg thinks about infectious disease when he’s supposed to be on vacation

By Greg Mercer

I recently visited Iceland, which in addition to being naturally beautiful and having weird day/night cycles thanks to its latitude, is something of an ecological paradise with an excellent renewable energy record. I was surprised to learn about their horses and the restrictions placed upon them, partially for the prevention of disease.

The Icelandic horse is notable for being fairly small (pony-sized, but don’t call it a pony), adaptable, hardy, and having 5 types of gaits, a detail which is basically meaningless to me but is apparently of great significance to horse dressage enthusiasts. My companions and I stopped at a stable, where one of the breeders told us about the breed, its history, and its unique international commerce status. I haven’t met too many horses but these ones seemed pretty nice.

Icelandic horses are popular around the world, and are frequently exported to foreign buyers for work or show. Imports of horses to Iceland, however, are banned. Once they leave, they can’t go back home, and horses born outside the country aren’t allowed in. Allegedly, this has been the case for about a thousand years. It’s hard to pin down a start date for that, but the policy is in effect today. There are two reasons for this: Icelandic horses are prized for being purebred and having a heritage that dates back to Viking settlers. They’re the only breed of horse in Iceland, so maintaining these traits is easy. Presumably the 80,000 horses in the country are enough to avoid a population bottleneck (I must reiterate that I am no horse expert).

But the import ban also guards against disease. Iceland has few natural horse diseases, and the breeder I spoke to said that Icelandic horses are frequently unvaccinated, which would be very unusual in the rest of the world. When they’re exported, they have to be treated as if they don’t have any immune protection. The import ban prevents foreign diseases from entering the country (via other horses, anyway).

Horse vaccines are big business. Throughout the rest of the world, horse owners can vaccinate their horses against West Nile Virus, Influenza, Potomac Horse Fever, Rabies, and other diseases. It makes a lot of sense: horses represent a major investment. For a horse owner, the cost of vaccination could be a fraction of the financial loss from a fatal horse disease. Plus, people tend to like their horses, and want to keep them from getting sick.

Even if you aren’t a horse dressage enthusiast or otherwise equine-inclined, horse diseases are no joke. Consider Hendra virus: Named for the suburb of Brisbane, Australia, where it was first isolated, Hendra is a Henipavirus, in the same family as Nipah virus. It’s found in Australia, Southeast Asia, India, and Madagascar. It can be transmitted from horses to humans via exposure to a horse’s bodily fluids, tissues, or excretions, and can prove fatal in both humans and horses. It’s likely that horses are exposed to the virus from the urine of flying foxes, a type of large bat. The details of the fatal Brisbane outbreak are detailed in David Quammen’s excellent book, Spillover.

This is all to say that Icelandic horses have a unique situation. As long as no new equine diseases enter the country, it’s more or less a closed system. The Icelandic Food and Veterinary Authority takes this equilibrium very seriously, offering warnings about foreign disease and guidelines for preventing infection.