Cuterebra in Cats and Dogs – AKA Warbles

April 22, 2020

cuterebra botflyIf your dog or cat is outside and chasing or hunting for rodents such as mice, rats or rabbits, he or she may accidentally pick up a nasty passenger – a cuterebra or botfly.

Cuterebra is the scientific name of the North American rodent botfly. Also known as “warbles” (sounds so cute but it really isn’t!), there are 26 different species in the U.S. and Canada and, can also be found in Mexico and other neo-tropical regions.

How Does My Cat or Dog Get Warbles?

botfly cuterebra larvaeThe botfly’s eggs develop parasitically in rodents and rabbits. So, in order to be close to their preferred hosts, adult female cuterebra lay their eggs – approximately 5-15 per site – around entrances to rodent dens or nests, as well as along runways used by the rodents.

So, when Fido or Kitty hunt for those pesky mice and get close to their hide-outs, they may brush against the eggs and accidentally pick them up in their fur. Then the fun begins.

The Life of the Cuterebra

The cuterebra eggs in your pet’s fur are stimulated by her body heat and hatch. Then the maggot or “warble” crawls around until it finds an opening into the body (mouth, nose, open wounds, etc.).

botfly aka horsefly

Depending on the type of species of botfly, it will migrate to a specific location in the subcutaneous tissue (the tissue beneath the skin). It forms a breathing hole through the skin and starts to grow. The breathing hole creates swelling and infection that you can actually see.

It takes about 30 days for it to mature and leave your pet, after which it burrows into the soil to finish its development into an adult fly.

Note that the possibility for cuterebra infestation is seasonal. In the northern U.S. and Canada, most cases occur in the summer and early fall when the adult flies are active. In warmer climates, infestations can occur during longer periods of the year.

Which Animals Are More Prone To Get Cuterebra Warbles?

Warbles in CatsBecause cats and terriers tend to hunt rodents, they are more likely to get the warbles. Most cases of warbles occur around the head and neck, because your pet is sniffing or digging around the rodent’s contaminated nest.

But even if your cat or dog doesn’t hunt, it’s still possible for them to brush against grass blades where cuterebra eggs have been laid and pick up the infestation. And even newborn kittens can be infected if the mother brings home cuterebra larvae in her fur.

What Are The Symptoms?

The most obvious symptom is a lesion or raised opening in the skin that contains the warble maggot. It’s usually about 1 cm in diameter. As the warble matures, the hole gets bigger. Sometimes you won’t see anything until after the maggot has left your cat or dog and the empty place becomes infected or develops into an abscess.

Depending on where the maggots migrate within your pet’s tissues, symptoms may also include:

  • Upper respiratory infections
  • Fever
  • Dizziness
  • Depression or lethargy
  • Seizures
  • Circling
  • Paralysis
  • Lesions in the eye / blindness

How Is Cuterebra Diagnosed?

If your vet sees that lesion with the maggot in it, the diagnosis is easier – s/he will be able to quickly determine if it’s a warble.

cuterebra in dogs

If the warble hasn’t become obvious, however, it’s harder to diagnose, as the other symptoms listed above could also be indicators of several different health issues. That’s why it’s important to take your pet to the vet.

If the symptoms are respiratory, the vet will have to consider allergies, other possible parasites, and other causes. If the symptoms are more neurological, there are many other conditions that could cause them (such as distemper, heart worms, and rabies) and need to be ruled out.

And quite often, your cat or dog may develop secondary bacterial infections in the empty cysts left in the skin after the warble has dropped off. These infections can sometimes be worse than the actual warble.

How Does a Vet Get Rid of Warbles?

If the warble can be seen in a lesion under the skin, eyes or nose, the vet can remove it. No stitches are usually required, but if there’s a severe infection, antibiotics may be prescribed.

treatment for cuterebra

Your vet may prescribe an anti-parasitic medication to kill the maggots that are still in the migrating stage.
If the infestation has migrated to the lungs, it can be treated with corticosteroids.

If the maggot infestation has progressed to the point where it’s done irreversible neurological damage, the prognosis is poor.

Cat and Dog Cuterebra Prevention

There are a few things you can do:

  • Keep your cat or dog from hunting rodents.
  • If your area has numerous mice, rats, rabbits or other small mammals, inspect your pet frequently for any sign of warbles. The earlier you get it removed, the less like it is to cause serious or permanent damage.
  • Finally, here is the easiest way to prevent this type of infection. Keep up with your parasite prevention treatments – heartworms, flea control, and topical flea and tick treatments. These help prevent the maggots from developing and even kill them before they have a chance to crawl inside your cat or dog.

And don’t forget that Banixx Pet Care is ideal for preventing secondary bacterial infections caused by warbles. Its anti-fungal and anti-bacterial formula is easy on tissue and helps aid in the recovery of any infection. It does not sting or burn, and its soothing properties go to work immediately. Just apply it 2-3 times daily to the affected site, for a period of 2-3 days or, as needed.

Go to our dog page or cat page to learn more about how to keep your pets happy and healthy!