What is Lungworm Infection?
Donkeys and mules are natural hosts for lungworms; they are infected by the parasite but show no clinical symptoms. They are usually the main source of equine lungworm infections.
All horses can be infected by lungworm but young horses are more susceptible to the parasite. If your horse or foal is coughing, he should be seen by a veterinarian. If left untreated, lungworm infection can cause respiratory distress. Additionally, untreated lungworm infections in foals can be fatal.
Lungworm infection in horses is caused by the parasite Dictyocaulus arnfieldi. The lungworm larvae is ingested by the horse, which then travels through the gastrointestinal tract into the bloodstream, making its way to the respiratory system.
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Symptoms of Lungworm Infection in Horses
Symptoms of lungworm in horses may include:
- Persistent cough
- Labored breathing
- Loss of appetite
- Weight loss
Causes of Lungworm Infection in Horses
Lungworm in horses is caused by the parasite Dictyocaulus arnfieldi. Dictyocaulus arnfieldi can live off a host for 6-7 weeks. The parasite is transmitted by:
- The horse grazing and ingesting infected forage
- Horses and donkeys that are not de-wormed grazing in the same pasture
- A pasture not cleaned of infected manure
- Not using feeding trays; feeding the horse on the ground where Dictyocaulus arnfieldi larvae may be found
Diagnosis of Lungworm Infection in Horses
The medical history of your horse is an important part of the diagnostic process. The veterinarian will need to see the patient’s vaccination and deworming records. Advise the veterinarian of the symptoms you have observed and when they started. Let your veterinarian know if your horse has been grazing in a pasture with donkeys or mules.
The veterinarian will then perform a full physical exam, listening to the equine’s heart, lungs and gastrointestinal tract with a stethoscope. The veterinarian will also palpate the patient’s abdomen, lymph nodes, limbs, and muscles. The color of your horse’s gums may be checked. The diagnostic exam may also include taking your horse’s temperature, blood pressure, and pulse, allowing the veterinarian to evaluate the patient’s overall condition.
The veterinarian may suggest a complete blood count (CBC), to make sure the platelets, and red and white blood cell counts are all within the normal range. A complete blood count can also help determine if your horse has a bacterial infection or if he is anemic. If during the physical evaluation process the veterinarian heard wheezing or any fluid in the lungs, he will recommend taking chest x-rays. A fecal exam of the patient and of any donkeys or mules that share the stall or pastures may be recommended.
Treatment of Lungworm Infection in Horses
If the diagnosis is determined as a lungworm infection the veterinarian will prescribe the de-wormer ivermectin or moxidectin. Usually, a second dose of the de-wormer is administered two weeks after the first. Horses that are experiencing persistent coughing may be prescribed anti-inflammatory drugs such as corticosteroids. In cases with lung tissue inflammation, prednisone may also be recommended. Prednisone has side effects; it may cause the horse to urinate more often and it can also increase the appetite of the patient.
If the horse or foal experience weight loss, the veterinarian may recommend vitamins and dietary supplements. In the case of a secondary bacterial infection, your horse will be prescribed antibiotics.
Recovery of Lungworm Infection in Horses
It is important to follow the treatment plan the veterinarian has prepared for your horse. Follow-up visits will be required to monitor the recovery progress. If your horse had fluid in the lungs or was experiencing severe coughing, the veterinarian may recommend re-taking chest x-rays. He may also suggest a repeat complete blood count to rule out a bacterial infection.
To avoid a re-infestation of the parasite Dictyocaulus arnfieldi, preventative measures should be taken. Your horse will need to be on a regular de-worming schedule. If you also own donkeys or mules, they should also be regularly de-wormed. The veterinarian can help you decide what de-worming product works best and how often it should be administered. Stalls and paddocks should be cleaned daily. Pastures should be maintained and kept clean of manure. Your horse should not be fed on the ground; his hay and grain should be placed in feeder trays.
Recovery of lungworm infection in horses has a good prognosis, although young horses with a heavy infestation of lungworm may have a guarded prognosis.
Lungworm Infection Questions and Advice from Veterinary Professionals
My horse and donkey have been wormed with Ivermectin twice a year for years. My horse fecal still showed up lung worms. What is the treatment?
His symptoms are labored breathing, fast respiratory rate , lethargy, exercise resistant.
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I have a 20 year old Arab gelding. He came to me last year in the most amazing condition and bouncing with health. Since then he has steadily lost weight. He is bright and comes to me at the gallop with no coughing. Under the vet he has been on a worming program, had teeth done and blood tests taken. We put him on a course of prednicilone. The only time he coughs is when he puts his head down to feed from his bucket but it is only an occasional cough and is not persistant. Last year I lost a 7/8 Arab which I had owned for 20 years with the same symptoms. My horse is grazing with two ponies, also wormed regularly, who are fat and fit. He is the boss in the field and hay is provided ad lib and he has extra feed and supplements but is only just holding weight condition reading about 2/3 with ribs and pin bones prominant. He has a rug on and is out 24/7 with a large field shelter which he uses. HAY IS FED IN THE FIELD SHELTER from corner feeders.
COULD THERE BE SOMETHING IN MY GROUND THAT IS CAUSING THIS?
My vet as I am at a loss. have you any suggestions?
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I have an 11 year old grey arab gelding who has food coming out of his nose, he's still eating, drinking, normal bowel movements, no fever, as well as shallow breaths, no panic or depression. we brought the vet out, tubed him for partial obstruction, felt resistance were the esophagus and the stomach meet. removed the tube which caused the worse nosebleed the vet has ever seen. next day...hes still the same. I did some research and found similar symptoms as lung worms, he's been dewormed in the last 30 days.
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