Botflies in Cats: Diagnosis, Treatment, and Prevention

Botflies in cats are Cuterebra larvae that develop under the skin, typically causing a firm lump with a small breathing hole. While most cases aren’t emergencies, a veterinarian can remove the botfly completely to help prevent infection and promote proper healing. 

If you notice a lump with a small opening—especially around your cat’s head or neck—contact your veterinarian for an appointment.  

Seek emergency veterinary care if your cat develops serious symptoms such as seizures, blindness, or difficulty breathing. 

What Are Botflies in Cats?

The scientific name for botflies in cats is Cuterebra. Specifically, Cuterebra are the North American rabbit or rodent botfly. When a cat gets botflies, the condition is sometimes called warbles or cuterebriasis. 

Botflies are found throughout North America, Central America, and parts of South America. These botflies prefer to live on rabbits or rodents but occasionally end up on cats. 

Botfly larvae usually develop under the skin. There’s usually a swollen bump that feels like a firm cyst, with a visible opening at the top of the lump. This bump is called a warble. The opening is the botfly larva’s breathing hole. 

The larvae are usually whitish, yellowish, or dark and look like a ribbed, worm-like grub. 

Botflies are not usually a medical emergency. Rarely, abnormal movement of botfly larvae in parts of the body, like the brain or lungs, can cause blindness, seizures, or respiratory difficulty. In these cases, seek emergency care. Otherwise, it’s OK to immediately contact a veterinarian for an ASAP appointment or take your pet to a walk-in clinic.  

Symptoms of Botflies in Cats

The following are symptoms of botflies in cats: 

• Lump under the skin with a small hole, usually around the cat’s head or neck 
• Thin liquid oozing from a hole in a bump 
• A visible larva within the hole  
• Licking or scratching at the lump 
• Reddened or irritated skin around the lump 

Rarely, abnormal movement of larvae can cause clinical signs like blindness, seizures, or breathing difficulty. 

After the botfly leaves the cat’s body, some cats will get a deep abscess or skin infection in the space left behind. 

Causes of Botflies in Cats

Cats are considered accidental hosts for botflies. This means that they aren’t the preferred host species, which include rabbits and rodents. 

Adult botflies lay their eggs near the burrows of rabbits or rodents. A cat nosing around the burrow or hunting prey can get botfly larvae through their nose, mouth, or an open wound. 

The larvae will move through the host body and develop a cyst in the skin, with a breathing hole for the larvae as they continue developing. They’re usually in the skin for about a month before falling out to continue the life cycle. 

All ages and sexes of cats can be affected by botflies, but they’re far more common in cats who go outside. In areas with cold winters, botflies are more common in the late summer and early fall.  

Otherwise, botflies in cats can occur year-round.  

How Veterinarians Diagnose Botflies in Cats

The veterinarian can usually diagnose botflies with a simple visual inspection. Occasionally, the veterinarian may recommend imaging or blood work, especially if there are signs of abnormal larval movement. They won’t see the larvae on these tests, but they can rule out other health conditions that may show similar signs. 

Make sure to let the veterinarian know whether your cat goes outside, what their travel history is, and if the cat is on parasite preventives. 

Treatment of Botflies in Cats

Botflies in cats should be physically removed from the cystic area.  

Removal should be performed by a veterinarian.  

This can be done with or without anesthesia, depending on how easily the botfly can be reached and whether the cat is responding painfully to examination of the area.  If the cat doesn’t react painfully, the veterinarian may attempt removal without anesthesia. 

In some cases, a liquid or salve can be placed over the hole to stop the larva from getting air. Once it starts to come out to breathe, it can be grasped and pulled out. 

It’s important that the veterinarian removes the entire body of the larva. If a piece of the larva is left behind, an infection is likely to start. Rarely, a pet may have anaphylaxis or a severe allergic response as a result.  

If there is a lot of damage to the underlying tissue or a large abscess, surgical removal of the area may be recommended. 

The veterinarian is likely to prescribe antibiotics, such as Clavamox, for one to two weeks.  

Anti-inflammatories like meloxicam may also be recommended for a few days to help with discomfort. 

If there is a concern for an allergic reaction, antihistamines like diphenhydramine and steroids like prednisolone may be recommended.  

Steroids like prednisolone and non-steroidal anti-inflammatories like meloxicam should not be given at the same time. 

Recovery and Management of Botflies in Cats

It usually takes two to three weeks for the skin to heal after a botfly is removed. If hair loss has occurred around the area, hair will likely take longer to regrow. 

Most cats do very well with recovery. If the site is itchy, your cat may need a recovery cone, like the Supet Cone, or a recovery suit (like the Suitical Recovery Suit) to prevent licking and scratching. 

Prevention of Botflies in Cats

The best thing you can do to prevent botflies in cats is keep your cats indoors. Botfly infestations are very rare in indoor cats who live in clean and sanitary homes.  

It’s also possible that some preventives, like selamectin, may help to prevent warbles, but this would be an off-label use.