Eyeworm (Thelazia californiensis) in Dogs


What is Eyeworm (Thelazia californiensis)?

The Thelazia californiensis types of pet eyeworms are whitish worms discovered in the eyes of domestic dogs and felines. Human beings have actually been known to end up being contaminated, however it is extremely uncommon. The eyeworms noticeably cross the pet’s eyes in a fast, serpentine movement. As numerous as a 100 worms might exist in the tear ducts, on the conjunctiva (the mucous membrane that covers the front of the eyes) and under the eyelids. This types of eyeworm is most frequently discovered in western The United States and Canada and is more widespread throughout fly season (late spring through early fall).

Eyeworms are parasites of the orbits of the eye, discovered on the conjunctiva and under the covers and nictitating membrane. This illness is frequently known as thelaziasis.

Signs of Eyeworm (Thelazia californiensis) in Dogs

Several of the following signs are normally discovered throughout an infection of pet eyeworms: 

  • Extreme tearing of the eyes
  • Irritated conjunctiva (conjunctivitis)
  • Nontransparent corneas of the pet’s eyes
  • Slow recovery sores or ulcers on the corneas of the eye
  • Loss of sight (uncommon)
  • Itching of the pet’s eyes
  • Excess of capillary on the whites of the eyes
  • Little, white to cream colored, active worms on the pet’s eyes, looking comparable to nylon fishing line
  • Light level of sensitivity to the eyes
  • Inflamed eyes 
  • Pus in the eyes


Thelazia californiensis is a types of parasitic roundworm that impacts dogs, felines, and often human beings. It was very first found in California throughout the 1930s and was acknowledged as a brand-new types of eyeworm at that time. There are roughly a lots types of eyeworms, however Thelazia californiensis is the most widespread type that happens in domestic animals such as dogs. 3 to 4 years of age, big dogs are most likely to end up being contaminated than more youthful, smaller sized dogs.

Reasons For Eyeworm (Thelazia californiensis) in Dogs

Transmission of face fly, housefly, or dirt fly larvae is the reason for infection of the Thelazia californiensis types of pet eyeworm. The adult female eyeworm lays eggs in the tears of the eyes. Once in the tears, the eggs develop into larvae, which a face fly will then consume. Inside the fly, the larvae develop for roughly 30 days at which time they will transfer to the mouth of the fly. When the adult flies are feeding near a pet’s eyes, the larvae vacate the fly’s mouth and transfer to the eyes of the pet. It takes about 3-9 weeks for the larvae to develop into grownups and duplicate the cycle.

Medical Diagnosis of Eyeworm (Thelazia californiensis) in Dogs

Your vet will take a look at and assess the pet’s eyes and tissues near the eyes. The eyes might be flushed (rinsed) to clean the infection and assistance to avoid secondary bacterial infection. The matter gathered throughout the rinsing of the eyes might likewise be taken a look at for existence of the worm. The pet eyeworms are normally extremely active and simple to see, making the medical diagnosis apparent. Your vet might select to eliminate the eyeworms. Probably your pet will simply be treated with medication. The medication will be sent out house with guidelines for ongoing treatment.

Treatment of Eyeworm (Thelazia californiensis) in Dogs

The technique of treatment to remove the Thelazia californiensis eyeworm need to be figured out by your vet. Appropriate usage of these medications is required to accomplish total removal of the eyeworm infection. The following are a couple of approaches that might be suggested or administered.

Anesthetic might be administered to the pet’s eyes by your vet. Then forceps will be utilized to thoroughly eliminate the worms from the eyes.

Anti-parasitic topical eye options and lotions such as selamectin, moxidectin and levamisole options, or levamisole and morantel lotions might be recommended. In some cases administering eye treatments to your pet can be tough. It needs your pet to be still for a short time, which might require some help, specifically if your pet is experiencing a great deal of discomfort and pain from the infection.

Injected anti-parasitic medication such as moxidectin is often administered by the vet. This will be injected into the muscle of the pet.

Anti-parasitic oral medication such as ivermectin tablets, moxidectin tablets, or milbemycin oxime tablets are oftentimes recommended. This is a simple way to deal with the illness.

Healing of Eyeworm (Thelazia californiensis) in Dogs

In order to avoid eyeworms of the dogs, the fly population requires to be managed. Managing or removing the fly population and the chance for the face flies to feed upon the pet’s eyes will considerably decrease the spread of the eyeworms. Waste management is required by eliminating build-ups of trash, scraps, manure, and other matter and dirt where flies like to live will assist significantly. While taking your pet for a walk in a location with a big fly population, utilizing a fly repellent might be recommended.

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