Equine biosecurity: Germ warfare on the home front

December 16, 2009


Are visitors to your property - including vets, dentists, and friends - aware of biosecurity practices?

A sick horse can be costly to get well. Neil Clarkson offers some simple strategies to keep the bad bugs at bay.

Mention biosecurity and most New Zealanders will conjure up images of quarantine stations and people getting around in biohazard suits.

The country is thankfully free of the world's most serious horse diseases, but that is no reason to disregard good hygiene and think your equine friends are bulletproof.

The outbreak of strangles in several parts of the country last spring, and more recent cases in the Hawke's Bay in September, serve as a reminder to horse owners that they need to remain vigilant.

Even if your horses escape something as serious as strangles, who wants the potential cost of vet bills, lost riding time and the general misery that can result from snotty noses or a nagging cough?

Biosecurity is about doing everything you reasonably can to prevent your horse catching something from another horse, be it viral, bacterial or fungal.

Home biosecurity means putting in place strategies to deal with the two key means of transmission - either close contact with other horses or through a person or other object carrying the organism from one property to another.

There are many inanimate objects potentially able to transmit bugs if shared. It could be a horse float, shared brushes, sponges, feed buckets, covers, a saddle cloth or tack. There is even a name for such vectors: fomites.

People are just as risky. The germs can come in on hands, hair, lurk in nasal secretions or hitch a ride on clothes and boots.


Shared brushes and other grooming gear can transmit bugs.
The overall risk to any horse will come down to a handful of factors:

In some countries, with endemic equine influenza and others diseases capable of causing serious illness or even death, biosecurity is a big deal.

New Zealand's social equine scene and comparative freedom from disease means many horse owners take a pretty relaxed approach. Why go "over the top" when the risk in many cases may be low?

The key is to be aware of the major threats and exercise sound judgment. For example, if snotty noses are doing the rounds or you've been alerted to a strangles outbreak, lift your home biosecurity until the greatest risk has passed.

First, let's consider off-property excursions. Ideally, you don't want to share a horse float. If you must, make sure the owner of the other horse confirms the animal is well. It is likely you will know the person and the horse, so make your own assessment over how conscious the owner is about their own animals' biosecurity.


The secret to disinfection

Disinfection isn't rocket science and it isn't expensive, either. The biggest investment will be the time involved.

There's no need to spend up large on expensive chemicals.

One part of household bleach to 10 parts water is a good general-purpose disinfectant. It's ideal for the likes of floats, grooming gear, footwear and some tack. Citric acid cleaners are also effective, as are soap and water. Putting it in a pump-action sprayer will make application a breeze.

Brushes and other plastic grooming gear can be dipped in the solution.

There are two secrets to disinfection. First, make sure the item to be disinfected has been cleaned of dirt and manure, which can shield germs from the disinfectant. Second, be thorough.

There are plenty of commercial disinfectants available which will likewise work fine - they're just more expensive.

Anti-bacterial wipes or waterless hand cleaners can be very handy to have around, especially at shows, but again, be thorough with them.

Be extra careful with leather gear. Follow the manufacturer's instructions for cleaning.


But there is another factor to consider. What horses have used the float before? Has the owner loaned it out? Has it been thoroughly cleaned?

Essentially, you don't want to move your horse on anyone else's float unless it has been thoroughly cleaned and disinfected (more on that later).

Those without access to a float will have to use a commercial horse transporter. This obviously poses additional risks.

The best course is to use a reputable operator. Such firms should have protocols in place to ensure regular disinfection of their trucks.

The United States Department of Agriculture offers the view that if a float or truck smells horsey, it has not been cleaned properly.

Once at an event, the chances of your horse catching something will be reduced if you can prevent the animal making nose-to-nose contact. No equine socialising, you ask? Again, common sense applies.

Obviously, the risk will be lower if you can keep your horse's contact with other equines to a minimum. And be conscious that people can carry germs between horses, so be careful.

If you regularly go to horse events - even as a spectator - why not have footwear designated only for off-farm equine activities? This eliminates the chance of carrying something nasty into your paddocks once you get home. Who wants to deliver a bunch of drug-resistant worm eggs to your pasture if you stood in some horse dung at a show?

Try not to share equipment - and we're not just talking tack. Shared water buckets, feed containers, brushes and sponges all run the risk of carrying bugs. Before leaving, clean and disinfect any gear that may have picked up bugs. Brush off any manure before using disinfectant.

If your brushes and other gear haven't made contact with anything other than your horse and your float, you're safe enough. But if they've been put down in a shared tie-up area or you've used a stall at the local showgrounds, disinfection is a must.

You'll naturally want to take special care with your expensive saddle and other tack. Follow the manufacturer's recommendations for cleaning. There are several different finishes put on leather and you don't want to mess it up.

Generally, a very gentle wipe with a lightly damp rag and a little mild disinfectant shouldn't do any harm, but you would be foolish not to test it on an out-of-the-way spot first.


Designate footware from off-farm equine activities only. And once you're home from an event, throw your clothes in the wash.
Once home, throw your clothing straight in the wash. Wash your hands thoroughly and blow your nose with a tissue and dispose of it (germs can survive a good while in your nasal secretions). You're no doubt dying for a hot, soapy shower, so why not have it before you head into your paddocks? Overalls are good value and work a treat.

Overseas, advice on visitors is pretty stark: If they don't need to be around your stable area or paddocks, then keep them away. If they have horses of their own - clean shoes (wash and disinfect them if need be) and no unwashed clothing they've worn around their own animals.

Kiwis will find all that a hard pill to swallow. However, a polite inquiry to ensure their own horses are well would be sensible, and washing hands if they're going to satisfy an equine itch is not too much to ask.

Having only one entrance to your property helps you manage visitors more easily. Why not put up a sign asking visitors to report to the house?

Vets should be practicing good hygiene in any case. Make sure other visiting practitioners such as farriers, equine chiropractors and dentists, are equally vigilant about hygiene. Don't be afraid to ask if their equipment has been cleaned properly after their previous job.

It's a good idea to keep a written record of people who have contact with your horses at home.

Don't forget vehicles. Tyres can carry just as many nasties as shoes. Preferably keep them parked away from areas where your horses graze.

New horses arriving at your property pose an obvious risk. Where possible, check that their vaccinations are up to date and dose them with a broad spectrum wormer (check that they weren't wormed before arriving at your place and, if so, what with). Clean up and compost their dung.


Competitions can be a great place for horses to mingle - and pick up germs.
Keep new arrivals away from your other horses for a while. The US Department of Agriculture recommends 30 days, but the Americas have a wider array of nasties than New Zealand.

You're probably safe in following the guideline suggested by Australian authorities, which is seven days - with the proviso that the horse remains well throughout.

Have grooming gear, feed buckets and the like specially marked for use only with new arrivals.

Where possible, make the new arrival the last horse you either handle or feed each day, to reduce the risk of spreading anything.

Make sure you record and keep your horses' vaccinations up to date. Diary when boosters are needed.

No-one enjoys a sick horse - and the horse won't be too keen on the idea, either.

Most biosecurity measures are simple and highly effective. Cleaning may ultimately prove tedious and repetitive, but it's a lot cheaper than a vet visit.

If a horse becomes unwell, isolate the animal immediately to reduce the chances of it spreading an infection to others.


Threats aplenty

It's easy to be complacent about biosecurity in New Zealand because, by world standards, we are mercifully free from the biggest threats.

The world is full of scary horse diseases. African horse sickness, for example, which has spread north into Europe, kills most of the horses it infects. There are fears an outbreak in Britain could decimate its horse industry.

We have only to look across the Tasman to see how expensive and disruptive an outbreak of equine influenza can be in a population never before exposed to the disease.


Hendra virus a wake-up call

Queensland horse owners have been given a nasty reminder about just how careful they need to be in the care and management of their horses.

Rockhampton vet Dr Alister Rodgers died early in September after spending two weeks in critical condition in hospital with a case of Hendra.

His death followed a year after another Queensland vet, Ben Cunneen, died from the same cause.

Hendra was identified only 15 years ago and Dr Rodgers became the fourth person to have died from the virus. Three other people have survived the infection.

The disease is carried by Australian native fruit bats, but in rare cases can be transferred to horses, probably through contact with the bodily fluids of bats. People can catch it from horses.

The risk may be low, but it is very real. Authorities in Queensland warn horse owners against providing horses access beneath trees where the bats, which live in colonies, may gather. It warns about the dangers of placing water and feed troughs under trees, where bat fluids could fall.

Hendra first presents itself as a flu-like illness in horses, with severe lung damage and accumulation of massive amounts of fluid. In more severe cases, there is inflammation of the brain, called encephalitis.

Horses can survive the infection but Australian law requires them to be euthanized, because of the risk of reoccurrence and the potential for spreading the infection.

The latest death has made Queensland vets acutely aware of the risks associated with horses that may be coming down with Hendra.

The biosecurity precautions are simple. Those who fail to take them could pay the ultimate price.


An adult Flying Fox.
© Andrew Breed/Aust DAFF

The list of threats is depressingly long.

New Zealand has import health standards in place designed to prevent the introduction of a raft of horse diseases, including such delights as equine infectious anaemia, which arrived in a horse in 1999 but was contained before the virus could spread to other horses.

Several diseases have been identified as posing a greater threat of introduction here than others.

Equine influenza tops the bill. New Zealand, Australia and Iceland remain the only countries with significant equine populations still free of the disease.

The outbreak in Australia is estimated to have cost $A1 billion in lost earnings, as well as the cost of containment and eradication.

Other threats include contagious equine metritis, a venereal disease of horses caused by the scarily named Taylorella equigenitalis bacteria. A major containment effort has been going on in the United States in recent months, crossing 48 states. A good proportion of its spread can be put down to poor hygiene practices around artificial insemination.

Then there are the mosquito-borne diseases - the equine viral encephalomyelitis family - all of which can cause brain inflammation. No person or horse will want an encounter with Venezuelan Equine Encephalomyelitis, Western Equine Encephalomyelitis or Eastern Equine Encephalomyelitis. This group of diseases is a growing problem in the United States. People can catch these in the same way horses do - through a bite from an infected mosquito. The introduction of any of these diseases into this country would most likely result in the euthanizing of infected animals.

Then there is vesicular stomatitis, a viral infection that affects several species, including horses. It is a disease of the Americas and, in cattle, can produce symptoms similar to the dreaded foot and mouth disease. Texas and New Mexico recently endured a small outbreak involving a handful of cases among horses. Most US states slapped restrictions on stock movements faster than you could shut a stable door.

Another disease, equine viral arteritis, is currently in New Zealand, having arrived in 1988 in imported standardbreds from North America. The strain in New Zealand has not so far caused disease symptoms, but a control programme is in place, recognising that over time the virus can change, with the potential to cause more serious disease.

Authorities are monitoring stallions capable of spreading the virus, and New Zealand one day hopes to formally declare itself free of the disease.

The above diseases are arguably the biggest threats, but there are others that could still potentially arrive in New Zealand, although the risk is considered low. These include the aforementioned African horse sickness, dourine, equine lymphangitis, Australia's equine morbillivirus (more commonly known as the Hendra virus), equine paratyphoid, equine protozoal myeloencephalitis, glanders, horse pox, louping-ill, Lyme disease, piroplasmosis, Potomac fever, Q fever and surra.

If you're starting to feel unwell, just take an aspirin and lie down ...


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