Home » Blog » What You Need to Know About Eyeworms

What You Need to Know About Eyeworms

What You Need to Know About EyewormsAs a pet owner, you’re probably familiar with intestinal worms, like tapeworms and roundworms. But, have you ever encountered eyeworms? They’re not as common as parasitic intestinal worms, but they’re definitely nastier and more dangerous. They can infect dogs, cats, and sometimes even humans, causing severe eye problems that can lead to blindness if left untreated.

Read on to learn more about this creepy crawly and how to protect yourself and your pet from becoming infected.


What Are Eyeworms?

Eyeworms, scientifically known as Thelazia californiensis and Thelazia callipaeda, are parasitic worms that cause an infection called Thelaziasis in various animals, including dogs, cats, and humans. Commonly found in the western parts of the United States and Asia, these worms are thin and resemble cooked spaghetti in color. In length, they can range from 10 to 19 millimeters.


What Do Eyeworms Do?

What You Need to Know About EyewormsOnce the eyeworms enter a host, they settle and multiply in the tear ducts, the inner lining of the eyelids, and underneath the layers of the skin lining the eyeballs.

For the infected animal, the sensation of the eyeworms moving around can be extremely uncomfortable and even painful. This is because the body of the slithering worms are lined with teeth-like protrusions, which can cause a lot of irritation and damage to the tissues surrounding the eyes.

As a result, the eyes become inflamed and swollen. This leads to excessive tearing, eye discharge, squinting, difficulty opening the eyes, itching of the eyes or areas around it, reddening of the white portion of the eye (conjunctiva), inflammation of the eyelids, and sometimes, blindness.


How Are Eyeworms Transmitted?

Eyeworms are spread by flies. In the United States, the culprit is said to be canyon flies, although other species of flies can also carry and transmit the worms.

They pick up eyeworm larvae when they feed on the tears of an infected animal. The larvae then grow and mature inside the fly.

After reaching full maturity, they position themselves on the fly’s mouth, where they wait to be deposited on the eyes of the next animal the fly feeds on.


How Is Eyeworm Infection Treated?

What You Need to Know About EyewormsThe main way of getting rid of eyeworms is physically removing them. Veterinarians apply a local anesthetic to numb the eye area before carefully pulling out the worms using sterilized forceps or flushing them out using a sterile saline rinse.

After the procedure, your veterinarian may prescribe an anthelmintic medication, such as ivermectin, selamectin, and moxidectin, to make sure all the worms are eradicated. The kind of anthelmintic will depend on your pet’s health status and medical history.

They may also give you an anti-inflammatory medication to help with the swelling and make your pet’s recovery faster and more comfortable. Before letting you and your pet go, your veterinarian will talk to you about the medications and give you instructions on proper dosage and administration.

While your pet is recovering, make sure to monitor them at all times and give them their medications on time. To be safe, it’s best that they stay indoors throughout the time of their recovery. If you notice that they’re not healing or that their symptoms are getting worse, contact your veterinarian immediately.


How Can Eyeworm Infection Be Prevented?

Since eyeworms are spread by flies, the best way to prevent infection is to minimize your chances of encountering the little buggers. Here are a few ways you can get rid of flies in and around your home, and protect yourself and your pet from contracting eyeworms:

1. Invest in an electronic bug zapper

Electronic bug zappers take advantage of the fact that flies are naturally attracted to bright lights. Not only are they incredibly effective in getting rid of flies, but they kill mosquitoes, too! Plus, they come in indoor and outdoor variations.

2. Burn citronella candles

While burning citronella candles doesn’t exactly kill flies, it does a great job of making them go away. However, citronella candles have a really strong scent, so only burn them outside and not indoors.

3. Wear insect repellent

Of course, let’s not forget the classic way to repel flies: insect repellents. Whenever you’re going out, it’s best to wear some. Be sure to get a pet-safe one for your pet, too! Pet-safe insect repellents don’t contain DEET, a chemical that’s extremely toxic to animals but is normally found in insect repellents made for humans. You can check out our favorite pet-safe insect repellents here!

4. Don’t leave food out

The smell of food attracts flies BIG TIME, so avoid leaving food out on the counter or outside. If you feed your pet outside, make sure to bring it inside and wash it with soap and water to remove the food particles, as well as the scent.

5. Cover garbage bin and compost pits

The smell of trash and rotting food may deter humans, but not flies! So, always remember to cover your outdoor garbage bins or compost pits, if you have those. Don’t let trash overflow and make sure to regularly disinfect both your outdoor and indoor trash cans to prevent the growth of bacteria, fungus, and molds. Feel free to view our top disinfectant and non-liquid bleach picks here!


Have you heard about, or encountered, eyeworms before?