Numerous health issues can cause a dog's eyes to appear inflamed, reddened, and teary. While injuries, infections, allergies, structural defects, and debris on the eye's surface are frequent culprits, have you considered the possibility of an eyeworm infestation? Dive deeper to discover the intricacies of eyeworms in canines and the measures to address and deter them.
Causes of Eyeworms in Dogs
Eyeworms, with Thelazia californiensis being the most prevalent species, spread to dogs when they come in contact with specific fly varieties. Studies indicate that in the western United States, canyon flies (Fannia benjamini complex) are the main carriers of eyeworms. However, in different regions, other flies might play this role. Thelazia californiensis, among other eyeworm types, has been identified globally.
Understanding the lifecycle of the eyeworm is relatively simple. Mature eyeworms residing in an infected animal's eyes reproduce and produce eggs. When a fly approaches to feast on the animal's tears, it ingests the newly hatched larvae. These larvae then grow inside the fly, moving to its mouthparts. They are transferred to another animal's eyes when the fly feeds again. Besides dogs, eyeworms can afflict cats, wildlife, livestock, and even humans.
Symptoms of Eyeworms in Dogs
It's no shock that a worm in a dog's eye causes significant discomfort. Thelazia, with its distinct sharp edges, can harm the delicate parts of a dog's eye. This invasion prompts an inflammatory response, manifesting as eye and tissue redness, conjunctiva swelling (the mucous layers encircling the eye), profuse tearing, itchiness, and frequent blinking. The cornea (the eye's transparent outer layer) might sometimes develop ulcers or scars. Dogs with minimal eyeworm infestation may show negligible eye changes, whereas those heavily affected generally exhibit pronounced symptoms.
Upon a detailed eye inspection, these worms often become apparent. They display a white to creamy hue, are slender, and stretch between 10 to 15 millimeters (about half an inch) in size. While Thelazia can be spotted on the eye's surface, they're also seen beneath eyelids, including the third one, and within the tear ducts.
Diagnosing Eyeworms in Dogs
Typically, veterinarians can identify eyeworms through a simple physical inspection. However, to thoroughly examine under the eyelids, applying a local anesthetic to the dog's eyes or even mildly sedating the animal might be essential.
Treatment Of Eyeworms in Dogs
The most prevalent method to address eyeworms in dogs is their direct removal. A veterinarian will use a local anesthetic on the eye's surface and might also opt for sedation. With the help of forceps or a sterile saline solution, the worms can be delicately extracted or washed away. Additionally, veterinarians could recommend specific medicines to eliminate these parasites, such as ivermectin, moxidectin, imidacloprid, and selamectin. The vet will decide the most suitable treatment depending on the circumstances.
For dogs experiencing intense eye inflammation due to eyeworms, topical or systemic anti-inflammatory drugs might be needed to alleviate swelling, redness, and discomfort. In some cases, antibiotics for dogs could be given either to combat or prevent subsequent bacterial infections.
Preventing Eyeworms in Dogs
Maintaining pets indoors during high fly activity can shield dogs from eyeworm infestations. Studies indicate that flies capable of transmitting eyeworms are active throughout the year in Southern California. However, the pattern of fly activity might vary in different regions.
If keeping flies at bay isn't feasible, regularly applying a fly repellent designed for dogs or administering a parasiticidal medication (like oral milbemycin) might be recommended. Consult your vet to determine the best and safest preventive actions for your canine companion.