The disease, nutrition, and management challenges island horses face

They’ve never had a case of strangles, equine influenza, or equine infectious anemia. Never any Lyme or piroplasmosis, either. And they’ve never had to deal with Rhodococcus equi in their newborn foals.

Isolated hundreds of miles from their nearest neighbors, Iceland and its residents benefit from inherent biosecurity. The vast expanse of ocean around the 40,000-square-mile island provides a natural barrier against most infectious diseases. By maintaining strict import rules in place well before the first air travel into Reykjavik, Icelandic veterinarians and horse owners have so successfully kept pathogens at bay, they don’t even vaccinate their horses—for anything.

But that kind of island paradise comes at a price. No horse, equine reproductive material, or blood product can enter Iceland. Horses that leave can never come back.

Island life can present other drawbacks, as well, such as increased risks of natural disasters and reduced access to resources such as food, water, and veterinary care.

While each island presents its own challenges and benefits for horse health and welfare, they all have one major point in common: isolation. Join us as we island-hop across the globe, exploring the unique world of island horse health.

Infectious-Disease-Free Havens

It’s near-impossible to eliminate or prevent all equine infectious diseases, but veterinarians and animal health officials indeed benefit from the geographic advantages island life offers. Iceland has arguably been the most successful, having sustained a disease-free status for all major equine infectious diseases, says Sigridur Björnsdóttir, DVM, PhD, veterinary officer for equine health and welfare in Iceland.

“We’re the only nation in the world that’s never had strangles,” she says. Also on their list of never-hads: equine influenza (EI), equine herpesvirus-1 (EHV-1), equine viral arteritis, equine infectious anemia, R. equi, Lyme disease, and piroplasmosis. In fact, its disease-free status has made Iceland the go-to place for international equine scientists looking for negative control groups and naive populations for infectious disease research. 

In the 19th century the government set up rigid official restrictions: zero animal imports or even returning animals into Iceland—a rule still in effect today (except for dogs and cats, which have recently been granted controlled access), Björnsdóttir says. That includes animal genetic material such as semen and embryos or blood products such as plasma. But it’s not just animals that are forbidden: Humans can’t bring in used equestrian equipment, and any clothing has to be machine-washed and fully dried first. 

They don’t always follow the rules, though, she adds. “That’s likely the source of the few outbreaks we have had,” she says. Iceland was hit with a novel strain of Streptococcus zooepidemicus in 2010, and the bacteria have been circulating in its 70,000-strong horse population ever since.

A less restrictive, but nonetheless conservative, import policy keeps Hawaiian horses mostly disease-free, says Jason D. Moniz, DVM, program manager of the Hawaii Department of Agriculture’s Animal Disease Control Branch. With rigid biosecurity requirements that mandate disease testing, inspection, and quarantine on the U.S. mainland before import to the state’s Pacific islands, they’re able to keep their roughly 7,000 horses essentially safe from pathogens.

“We don’t have (the right) ticks, so we don’t see tick-related diseases,” Moniz says. Although Hawaii has the rare equine epidemic—including a 2019 strangles outbreak in a group of polo horses that “spilled over to roping horses” in the same barn—it generally maintains a disease-free status for strangles, EI, Lyme, piroplasmosis, and all strains of EHV.

Hawaii officials also require generous use of insecticide on newly arrived horses, he says. “We’re not supposed to have competent vectors for many equine diseases, but we always worry about vectors that aren’t recognized as competent but end up being competent after all.”

Ongoing surveillance further safeguards equine health on islands, he says. It’s not only useful but also more practical in such a restricted area. “We’ve always got our eye out for strangles, but if a state like California were trying to monitor its path, that’s all they’d be doing,” Moniz explains.

While mainland goals might be to contain epidemics, island goals are to eliminate the pathogen from their borders completely, says Lucy Richardson, DVM, owner and senior veterinarian at CedarTree Vets Ltd. and national head veterinarian of Bermuda for the Fédération Equestre Internationale (FEI). “In the face of any outbreak, we lock down the entire stable and implement strict biosecurity guidelines,” she says of the British Isle 900 miles east of the South Carolina coastline.

Natural Disasters

Islands’ very nature often puts them at significantly higher risk of natural disasters compared to mainland continents. Many islands are volcanic, and some still have active volcanoes. Hawaii and Iceland, for example, both had eruptions in 2018 and 2010, respectively. Hot lava and burning ash present significant health risks to all life, including horses. “Individual barns usually have disaster plans in place, to know where to take horses if they need to get them away from lava flow,” says Moniz.

Lava and ash killed hundreds of horses used in the tourist industry when the Taal volcano erupted in the Philippines in January 2020, says Dan Arreola, DVM, a veterinarian based in Manila. The fact that volcanic activity occurs on an island is doubly treacherous, he says, because horses and animals get “trapped” on the island during the eruption.

“The horses that came under my care had symptoms of pneumonia from inhaling ash, with greenish yellowish discharge from nostrils, high fever, refusing to eat—essentially textbook pneumonia, which we treated aggressively with antibiotics,” he says. “Some had serious burns from falling ash, although fortunately their winter coats helped protect them.”

Earthquakes and tsunamis also cause extensive destruction, producing calamitous trembling and sending crashing waves onto inhabitants and the buildings in which they live. “We know that tsunamis aren’t a matter of if, but when,” Moniz says.

That’s why many islands have stables designed with such disasters in mind, says Jaime Masters McDowell, secretary general of the Bermuda Equestrian Federation. “Our barns have walls and roofs that are built to withstand ­hurricane-force winds,” she says. They also have their own generators for pumping water and have storage areas for stocks of feed, bedding, and hay, and barn teams and owners all pitch in to prepare. “We know … to be sure they have lots of hay and water in case it’s hard to get to them.”

Natural disaster threats are a normal part of island life, says Moniz. “We just learn to roll with the punches,” he says.

Water and Air Travel

When Taal erupted, owners dragged their horses onto fishing and motorboats to get them across the sea to safety, says Arreola.

Fortunately, most island horses have experienced travel by air and/or boat—a different experience from land travel, says Catherine Ramsingh-Pierre, president of Equestrian Bahamas. “There’s no opportunity for rest stops when you’re crossing the sea,” she says. Horses often arrive on boats from the import/export center in Miami “dehydrated, disoriented, and a little trembly,” she adds, and they typically need sedation during the 13-hour trip.

Travel to Hawaii from mainland U.S. takes five hours by plane or five days by boat, Moniz says. Between-island barge trips—for competitions and rodeos, for example—can take up to 19 hours.

Hay, Feed, and Veterinary Care

While some islands, such as Iceland, are self-sufficient for forage, many depend on imports to provide hay for all their horses. Even when they do produce hay, a volcanic eruption can contaminate it with ash, says Arreola.

Hay and feed transported over water can be prohibitively expensive, says Ramsingh-Pierre. “Your classic rectangular bales cost us $48 each.” And because weather conditions can interrupt cargo shipments, islanders know they must always keep an abundant supply on hand.

Veterinary care can also be costly—and hard to come by. “We don’t have any equine vets on the island,” Ramsingh-Pierre says. Owners of the approximately 100 horses in the Bahamas work together to schedule regular visits with veterinarians, farriers, and chiropractors (who make) the 45-minute flight from Florida for routine care. For emergencies, though, they often rely on “self-doctoring,” she says.

Even if an equine veterinarian is on an island, the procedures he or she can perform might still be limited because of a lack of equine hospitals. Ramsingh-Pierre says she had to take her own images with a portable X ray unit of her Thoroughbred mare’s back after a spinal injury and email them to Florida—but, in the end, the only treatment option she had was putting the mare on strict stall rest for six months. 

Horse owners can struggle with veterinary care options on larger islands, as well, says Björnsdóttir. “We don’t have a veterinary college in Iceland,” she says, adding that veterinary students study abroad and return home to practice. “So we do have limitations.”

The Water Paradox

Because islands are surrounded by beaches and seawater, many lack freshwater sources. Hawaii and the Philippines have vast irrigation systems bringing water from lakes and occasional springs throughout their agricultural land areas. On smaller islands, though, drinking water can be harder to come by.

“There are wells and desalination, but most drinking water comes from collected rainwater,” says Masters McDowell. “Captured water is collected on our traditional Bermuda roofs and stored in tanks under our houses and electrically pumped out—which is why generators are so important. Before a hurricane we fill lots of buckets in case the electricity is affected.”

Still, abundant seawater offers a significant advantage to island horses, says Masters McDowell. “Soaking their legs in the ocean salt water can be really therapeutic after a tough show jumping competition,” she says. Equestrians can ride to the ocean (outside of tourist season) for some “beach therapy,” and the local hunt club often organizes events that take members along the shores.

Take-Home Message

Island horses have the same health and welfare needs as any horse, but where they live presents a unique set of advantages and disadvantages for their owners and veterinarians. While they benefit from the built-in biosecurity that isolation affords, owners might not have the access to feed and forage and veterinary care that owners on larger land masses enjoy. The geological and geographical nature of these horses’ habitats also predisposes them to natural disasters such as volcano eruptions, earthquakes, and hurricanes. With careful planning and risk management, however, island horses can enjoy healthy lives.