Parasites in horses - Types, symptoms and treatments

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The‌ ‌big‌ ‌most‌ ‌of‌ ‌the‌ ‌species‌ ‌of‌ ‌kingdom‌ ‌animal ‌can ‌to be‌ ‌affected ‌for‌ ‌diseases‌ ‌parasitic,‌ ‌Y‌ ‌the‌ ‌equines‌ ‌do not‌ ‌are‌ ‌the‌ ‌exception.‌ ‌The‌ ‌parasites‌ ‌are‌ ‌organisms‌ ‌what‌ ‌of‌ ‌form‌ ‌permanent‌ ‌or‌ ‌temporary‌ ‌Y‌ ‌of‌ ‌way‌ ‌obligatory,‌ ‌must‌ ‌nurture‌ ‌to‌ ‌expenses‌ ‌of‌ ‌other‌ ‌organism‌ ‌(what‌ ‌do not‌ ‌belong‌ ‌to‌ ‌its‌ ‌species),‌ ‌what‌ ‌is‌ ‌called‌ ‌host.‌ ‌This‌ ‌relationship‌ ‌do not‌ ‌it implies‌ ‌in‌ ‌everybody‌ ‌the‌ ‌cases‌ ‌the‌ ‌death‌ ‌of‌ ‌host,‌ ‌reason‌ ‌for‌ ‌the‌ ‌which‌ ‌the‌ ‌parasitism‌ ‌do not‌ ‌is‌ ‌classified‌ ‌What‌ ‌predation.‌ ‌ ‌

In‌ ‌this‌ ‌Article‌ ‌of‌ ‌Expert‌Animal ‌we will develop‌ ‌the‌ ‌generalities‌ ‌of‌ ‌the‌ ‌organisms‌ ‌plus‌ ‌important‌ ‌what‌ ‌parasitize‌ ‌horses,‌ ‌the‌ ‌diseases‌ ‌what‌ ‌produce,‌ ‌its‌ ‌prevention‌ ‌Y‌ ‌its‌ ‌possible‌ ‌treatment.‌ Read on to discover all the types of parasites in horses and the symptoms they produce.

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  1. Types of parasites in horse
  2. Internal parasites in horses
  3. External parasites in horses
  4. How to eliminate parasites in horses? - Treatment

Types of parasites in horse

A parasitic disease is one caused by parasites. Parasites adapt to the different habitats that the host can provide (blood, skin, subcutaneous tissue, organs, cavities, etc.), which is why they can be classified according to the affected area. Since there are millions of genera and species of parasites, the taxonomic categories are used to facilitate their study a little. Taxa are nothing more than groups in which biology scientifically classifies living beings, associating them by their similarities and their phylogenetic proximity. The correct taxonomic classification of the parasitic species helped science to better group the diseases they produce, thus facilitating both medical and teaching work..

However, more generically, we can classify parasites in horses into two large groups:

  • Internal parasites
  • External parasites

Within each group we find different types of parasites that affect horses, as we will see in the following sections.

Internal parasites in horses

Internal parasites, also called endoparasites, are organisms that live inside the animal (organs, blood, intestines, etc.). They also receive a classification according to the internal space in which they develop their life. They are the cause of many diseases that can endanger the life of the animal. The internal parasites that are of most clinical importance in equines are the following:

Intestinal parasites in horses

As we have already mentioned, one of the ways to classify parasitic diseases is by the host organ or system affected. In this case, that we are talking about the intestines, these diseases have great clinical relevance, since they are the cause of diarrhea, Colic, peritonitis and many other digestive conditions.

The major intestinal parasites they are called strongyles, which are the cause of equine strongylosis (parasitosis caused in horses by nematodes of the order Strongylida) and are the protagonists of most intestinal parasite diseases in horses. Although there is a classification of large and small strongyles, we will talk about the most important. Some of the large strongyles are capable of migrating and affecting organs far from the intestine. The most common strongyles are:

  • Strongylos vulgaris: it is located in the large intestine causing injuries that reduce the horse's quality of life. One of the most outstanding characteristics of this parasite is that in some cases it can migrate through the arteries, managing to adhere and weaken the endothelium, an action that ends up causing verminous aneurysm.
  • Strongylos equinus: It is part of the large strongyles and also has the characteristic that it can migrate. In this case, it is the cause of pancreatitis and severe liver lesions in horses..
  • Strongylus edentatus: this parasite is associated with peritonitis in horses, although it has also been described that it can lead to liver damage.

Apart from strongyles, we must mention other species of intestinal parasites in horses with great relevance:

  • Parascaris equorum: Causing colic due to obstruction and characterized by causing high mortality in foals.
  • Oxiurys x: cause of pinworm in equines, characterized by producing itching at the level of the anus and tail, restlessness and subsequent loss of appetite due to stress.
  • Habronemiasis: it is a pathology caused by nematodes of the order Habronema and, although nematodes parasitize intestines, this species is capable of causing equine cutaneous haryonemiosis, one of the most studied skin conditions in horses. Within this order we can name Habronema megastoma, Habronema muscae and Habronema microstoma.

Hemoparasites in horses

As the word says, hemoparasites are nothing more than parasitic organisms that they make life in the blood of the host. They tend to have a preference for certain cells depending on the species, although some have been reported that can remain free in the bloodstream. In the equine, the most studied are:

  • Trypanosomes: causing equine trypanosomiasis, they cause anemias that can become quite serious. The species that parasitizes equines is called Trypanosoma evansi.
  • Babesias: causing equine piroplasmosis. Some species of Babesia can parasitize the horse through vectors (in this case a tick). In the horse we can find the species Babesia caballi and Babesia equi.

Lung parasites in horses

There are parasites in horses that develop their evolutionary cycles in the respiratory tract. In the case of the equine, the most important is a nematode called Dictyocaulus arnfeldii, causing equine pulmonary verminosis. Its main symptoms are cough and runny nose, especially on cold days. Its prognosis is generally favorable, but if the infestation is severe, it can cause from respiratory distress to pneumonia. It can also favor the environment for a bacterial infection that can endanger the life of the animal, especially foals.

Kidney parasites in horses

There are some parasites capable of making life in the kidney. In the case of horses, we must take into account Klossielia equi, responsible for equine renal coccidiosis. This pathology can lead to the animal suffering from kidney infections and alterations in the architecture of the kidney.

External parasites in horses

External parasites, or ectoparasites, are organisms that live outside the host's body, are generally found on the skin and can cause very dangerous diseases for the animal that hosts them. We can name insects, mites, arachnids, etc., but the most important external parasites in horses can be classified as follows:


  • Horseflies: they are species of flies belonging to the Tabanidae family. They are hematophagous, that is, they feed on blood and some species are related to equines. Its sting is quite painful, which causes stress problems for the specimen..
  • Stomoxys calcitrans: it is commonly called stable fly and it also possesses blood-sucking habits. It is interested in practically any warm-blooded animal (including humans), which is why it should be considered an important external parasite in the study of equines..
  • Gasterophilus: flies belonging to this genus have the peculiarity of causing myiasis in different parts of the body. They can grow their larvae in the intestines or in the nasal cavity, depending on the species. The most important that affect equines are: G. haemorroidalis, G. intestinalis and G. nasalis.

Ticks on horses

The most common tick species on horses are the following:

  • Dermacentor nitens: it is a species belonging to the Ixodidae family (hard ticks) and it is one of the ticks that parasitize equines. This tick serves as a vector for other parasites (such as babesia), causing different systemic diseases such as equine piroplasmosis.
  • Amblyiomma Cajennense: it also belongs to the family of hard ticks and is one of the species most commonly found in equines. It causes anemia problems and is well known worldwide for being responsible for Rocky Mountain fever..

We will notice that the horse has ticks if we observe that it feels itchy in a certain area. When analyzing this area, we can perfectly see the tick, which we will have to remove with tweezers, being very careful, or going to the vet.

How to eliminate parasites in horses? - Treatment

For obvious reasons, each parasitic species will have a control and treatment totally different. It is important to carry out an efficient sanitary control and for the veterinarian to evaluate the animal from birth. The antiparasitic medication in the opinion of the doctor will be the most favorable for the animal, however, the management recommendations should also be followed to avoid subsequent infections. It is recommended, in addition to the sanitary plan, some traps for flies if the situation warrants it or if the animal is located in a very favorable area for diptera insects..

The prognosis, most of the time, is favorable if the aforementioned is taken into account from the beginning, in fact, a minimal parasite load is allowed that does not trigger signs and symptoms of any disease. In the event that mishandling is carried out and the reproduction of parasites is excessive, of course the life of the specimen is put at risk..

Then, ¿how to eliminate parasites in horses? The antiparasitic products will be chosen according to the parasite in question. On the other hand, once eliminated, the vet will set a peventive deworming schedule, that is, to avoid future infestations. This calendar will include both internal deworming, through tablets or syrups, and external, through topical or ingested products..
Of course, in addition to taking deworming into account, we recommend taking it into account in the vaccination plan for horses established by the specialist.

This article is merely informative, at we do not have the power to prescribe veterinary treatments or make any type of diagnosis. We invite you to take your pet to the vet in the event that it presents any type of condition or discomfort.

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