Bot eggs

The bot (stomach worm) is not a worm but the larvae of Gasterophilus flies.

The adult horse bot fly emerges a during the summer or fall season. After the fly emerges from the pupa, it quickly finds a mate, lays the eggs on the horse's coat and, on grooming, the eggs make their way to the mouth where they hatch in mouth as larvae.

Over winter the larvae burrow into the stomach lining (where they spend 8-10 months) and are then passed out via the faeces and will hatch in the summer.

Significant trauma and ulceration of the stomach can occur following infection.

Disease is also caused by the larvae in mouth. Larvae here create borrowing holes, which in turn become infected. The 3rd stage larvae are passed in the faeces and over winters to develop the following summer.

Infected horses can often show no signs, which is why treatment should be given over the winter months to kill them.

Large Roundworms (ascarids)Photo kindly provided by University of Liverpool Diagnosteq Lab

Ascarids, (also known as roundworms) are parasites which are mainly a problem to foals. However, small numbers can also be carried by adults.

The adult worms are very large and can be up to 40cm in length. Once the larvae of this parasite are swallowed, they pass through the gut wall, via the liver to the lungs. Heavy infestations can cause coughing as the larvae travel through the lungs.

Adult worms can cause intestinal impaction. They pose a considerable threat to young horses and their developing immune systems, and they have to potential to kill by triggering colic. Even if a young horse escapes colic, a heavy ascarid burdened young horse will appear depressed and its normal growth will be affected.

The most common ascarid to infect horses is Parascaris equorum.The eggs laid by the large females pass out into pasture protected by a tough shell which equips them well for survival.  They can withstand drying conditions and even freezing; waiting for that moment when a passing horse ingests them with grass.

Symptoms of Ascarid Infection In Foals

It goes without saying that the migratory habits of ascarids cause damage. However, the impact of ascarids in the horse will depend upon the degree of infection and the whether the larvae are in their migratory phase.

• When migrating, a horse may well show signs of respiratory problems. It may have a nasal discharge or a cough and possibly a fever. Antibiotics will make no difference as they are not effective against ascarids.
• A heavy burden in the gut will likely show in the classic signs of a poor coat, a loss of weight, a pot-bellied appearance and sluggishness.
• Ascarids present one other notable danger. Their size is such that collectively they have the ability to block the intestinal tract of a young horse and trigger a potentially fatal bout of colic.

Ironically, this colic can be triggered by a dose of drench. The worms are killed, fall away from the intestinal lining and cause a blockage. This is the primary reason that you not only need to drench young horses, but do so regularly to ensure there is no potentially fatal build-up of mature ascarids in the gut.

Symptoms of Ascarid Infection In Adult Horses

Adult horses are symptomless but can carry them and provide a reservoir for infestation to foals.

Which Actives Treat Large Roundworms (Ascarids)?

Worming your horse can seem a daunting task. However, our guide is here to take the stress and confusion out of worming for you.

In-Feed medication tips from Bimeda Equine, ao you & your horse can get back in the saddle.

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Rachel Mallet, BVM&S MRCVS, is a qualified Veterinary Surgeon, who now works as a Professional Services Vet; providing technical support to vets, SQPs and horse owners in the UK. Rachel is passionate about animal health and about promoting best practice among animal health professionals and horse owners. Here, Rachel talks about the best-practice approach to addressing a parasite which all horse owners will be familiar with tapeworm.

Rachel Mallet, BVM&S MRCVS, is a qualified Veterinary Surgeon, who now works as a Professional Services Vet; providing technical support to vets, SQPs and horse owners in the UK. Rachel is passionate about animal health and about promoting best practice among animal health professionals and horse owners. Here, Rachel talks about the best-practice approach to addressing a parasite which all horse owners will be familiar with tapeworm.

For horse owners, the arrival of Spring is synonymous with tapeworm treatment. In general, horse owners in the UK have willingly adopted a strategic approach to worming based on faecal eggs counts (FEC).  However, many are reluctant to adopt the same approach to tapeworms and continue to treat twice annually in spite of not having information about the infection status of their animal. On continuation, I provide some information about this common parasite, and best practice methods to address it.

The Equine Tapeworm

There are a number of species of tapeworm in the UK which are capable of infecting horses; however most of these are rare. The tapeworm species most commonly found in the horse is Anoplocephala perfoliata. It can reach up to 8cm in length and attaches itself to the intestinal lining at the ileocaecal junction which is where the small intestine meets the large intestine. It Is a perfect location for the tapeworm because the digestive juices found here are rich in the nutrients which it needs to thrive.

How Common is Tapeworm Infection?

It is impossible to be certain of infection rates due to the difficulty in detecting infection but studies suggest up to 69%¹ of horses in the UK are infected at any given time.

A horse can become infected at any age; however tapeworm tends to have a bigger impact on very young and very old horses as their immune systems are not as robust.

Life Cycle

The tapeworm has an indirect life cycle which means that it requires more than one host to reach adulthood and reproduce.

The intermediate host for the most common equine tapeworm (A.perfoliata) is the forage mite (Oribatid mite). Forage mites are found on pasture and play a vital role in maintaining good quality grazing. The mites themselves pose no threat to your horse but the tapeworm cysts which they carry can.

Your horse can ingest forage mites when grazing at pasture or from conserved forage such as hay. If these forage mites are infected they can transmit the tapeworm cyst to your horse. The cyst is then ‘digested’ to free the infective tapeworm which attaches to the intestinal lining at the ileocaecal junction.

As the tapeworm grows it develops body segments, andonce it reaches sexual maturity these segments fill with eggs and are shed in the faeces.  It takes 6-10 weeks after the horse ingests the cyst for the tapeworm to begin shedding eggs.

Clinical Signs of Tapeworm Infection

It benefits the tapeworm to cause as little damage to its host as possible, in order to ensure it maintains its source of nutrition. For many years it was believed that tapeworms cause no real problems in horses. However, more recent studies have shown that they can be linked to spasmodic colic, impaction at the ileocaecal junction, ileocaecal intussusception, intestinal ulcers and peritonitis.

Your horse may be infected with tapeworm and show no symptoms at all. In more severe infections they may have some of the following clinical signs:

• Diarrhoea
• Dull Coat
• Poor Growth
• Intermittent Colic Episodes
• Poor performance
• General Lethargy

Diagnostics

We know from the tapeworm life cycle that when the tapeworm sheds its eggs they are dispersed in a segment of its body called the proglottid. If the proglottid remains intact then no eggs will be found in the faeces in spite of the horse being infected. As a result tapeworm eggs are rarely detected in faecal egg counts (FEC) even if the horse is infected.

The best approach is to carry out a test called an ELISA antibody test. When a horse becomes infected with tapeworm it will produce antibodies to try and protect itself. The ELISA test is capable of detecting these antibodies. It could previously only be carried out on a blood sample but can now be carried out on saliva making it much more accessible and cost effective. The antibodies persist for months after an infection so a positive result tells us that the horse has been exposed to tapeworm recently. A positive result and a lack of recent tapeworm treatment allows us to assume that the horse is infected. 

Treatment

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Ideally you should carry out an ELISA test before treating for tapeworm to help protect our wormers from resistance.

If you are unable to test you should carry out tapeworm treatment once in the Spring and once in the Autumn.

The two active ingredients which can treat tapeworm infection are Pyrantel Embonate (double dose) and Praziquantel. Table 1 details the activity of the anthelmintics which are available to treat tapeworm in horses.

Remember to give your horse the correct dose for its weight- you can use a weigh bridge or a weigh tape to determine the dose required.  Repeatedly exposing parasites to the same class of anthelmintic is known to speed up the rate of resistance so try to rotate the class of active ingredient which you use. Remember to consider which parasites you are trying to target and select the most appropriate active ingredient based on that.

If you are uncertain please speak to your vet or SQP as they will be able to give you the best advice for your circumstances.

Table 1

References

1. D.W.Jagger et el (1988). “Prevalence of Anoplocephala perfoliata in horses and ponies in Clwyd, Powys and adjacent English marches” Vet Record 123 562-3
2. Traversa D et al (2008). A comparison of coprological, serological and molecular methods for the diagnosis of horse infection with Anoplocephala perfoliata (Cestoda, cyclophyllidea), Vet Parasitology 152: 271-277.
3. M.K.Nielson (2015). “Equine Tapeworm Infections: Disease, Diagnosis and Control”, Equine Veterinary Education, DOI: 10.1111/eve.12394
4. 4. C J Proudman et al. (1998) “Tapeworm Infection is a Significant Risk Factor for Spasmodic Colic and Ileal Impaction Colic in the Horse” Equine Vet Journal, 30 p194-199.

Bimeda supports the responsible use of anthelmintics.

Care should be taken to avoid the following practices because they increase the risk of development of resistance and could ultimately result in ineffective therapy:

• Too frequent and repeated use of anthelmintics from the same class, over an extended period of time.
• Under dosing; this may be due to underestimation of body weight or mis-administration of the product.

This information was provided by Bimeda- makers of Bimectin Equine¹ and Embotape^2
1Bimectin Equine (18.7mg/g Ivermectin) is a POM-VPS medicine.
²Embotape (11.4g/syringe Pyrantel Embonate) is a POM-VPS medicine.
For full product information including dose rates, see the SPC data sheet on the VMD website or the data sheet on the Bimeda Website 
Use Medicines Responsibly. Noah.co.uk

50% Dextrose es una solución hipertónica de dextrosa en agua como fuente de reposición de fluidos y nutrientes.

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