About Horse’s Parasites: Other Worms, Bots, and Filarial Parasites

Does your horse exhibit symptoms which the previous article on strongyles and roundworms did not describe yet? That is possibly because the parasite responsible for it has not been mentioned yet. Here are the rest of the most common parasites that pester our equine friends.

Other Worms

These invade specific areas, such as the intestine for the tapeworms, lungs for the lungworms, the skin near the anus for the pinworms, the stomach for the stomach worms and the hair worms, and the lungs and the small intestine for the threadworms. Usually, the most dangerous of these are the tapeworms, for they absorb the nutrients which are needed by your horse for growth and other bodily functions. As a result, you will notice slow growth and rough skin coat if your equine friend has tapeworms residing within the intestinal walls. It can also cause colic. Other worms are less dangerous – the lungworms can cause coughing and other respiratory difficulties, while the pinworms can cause extreme itchiness on your horse’s anus. Another worm to be wary of is the stomach worm, for it can cause a very serious sickness called the “swamp cancer” or the “summer sore” if it gets the chance of reaching your horse’s open wound or near its eyes. If it does, chances are that it will progress into what is called a granuloma, which is very itchy and does not heal. That is why it is very important to maintain an extensive horse grooming every day, especially for those that go through strenuous physical activity on a regular basis. On top of that, consistent deworming is a must, especially an ivermectin-based one.


Short term for botfly larvae, these do not enter the horse’s system through unclean food and contaminated water. Instead, the bot flies lay their eggs around our equine companions’ lips, forelegs, jaws, and shoulders. Once these eggs hatch, they crawl toward the mouth and hide within the tissues of the tongue and gums. It is here where they mature. After some time, they go deeper into the stomach and intestines, and after a year, they go with the manure, and finish the transformation into adult bot flies, to repeat the cycle over again.

One should not underestimate these, for they can cause tissue damage to your equine friend’s mouth and intestines, as well as cause gastric ulcers. Thankfully, bot flies cannot stand cold temperature, so you won’t have to worry about them during winter. What you have to do is to regularly deworm your horse to make sure that no bot fly larvae is not hiding within the walls of the stomach and intestines, as well as the skin of the jaws and tongue.

Filarial Parasites

Somehow, you can be thankful that these do not invade the intestines and the stomach – one less parasite to deworm. But be wary of your horse’s skin and neck, because these are the target locations of these parasites. They can be very itchy, and can result to intense irritation and hair loss for those areas that have been infected.  Regular horse grooming is required, as well as wormer, specifically an Ivermectin-based one.

These are the most common of the parasites that can harm our equine friends. With regular horse grooming, clean food and water, pest-free environment, and regular deworming, you can make sure that they won’t torment your horse.


Leave Comment