Warbles

Warbles are the larvae of the bot-fly (Cuterebra sp.) and can be found in outdoor rabbits during the spring and summer.

They appear as a swelling or lump just under the skin. On closer observation, you will see that there is a puncture or hole just above the lump. This is an air vent for the larva, which has burrowed into the skin.

They will usually be found around the neck and legs of the rabbit, but can be found anywhere on the body.

When the bot-fly lays her eggs on the rabbit, the eggs hatch into larva which then burrow into the skin. They wall of an area, and become a parasite living off the rabbit.

Larval development can take anywhere from 19 days to around 60 days. The pupa period can be as short as 28 days, or as long as 7-11 months, depending on the time of year and temperature.

The newly hatched larvae are usually 2-4 mm long and grayish white in color. As they grow, the color changes to reddish brown and then to dark brown. Fully-grown larva can be from 20-42 mm long and 7-10 mm wide.

When you find a lump or swelling on your rabbit, check to see if the class air vent is present. If so, you are probably dealing with warbles. If not your rabbit may have an abscess.

Removal of the Warble
If you find a warble on your rabbit, you should have it removed as soon as possible to prevent a secondary bacterial infection. Although the warble will eventually leave the animal, it is not a good idea to wait for this to happen.

As with all medical procedures, this should only be attempted after consultation with your veterinarian. This description is provided for informational purposes only.

Generally, the key to remember when removing a warble is that the larvae must be removed from the rabbit alive. If the larvae dies encysted in the animal, toxins can be released which can cause serious harm and in some cases death to the rabbit. So please exercise caution in removing them.

Supplies you will need: 

• Sterilized Tweezers (a hemostat is even better)
• Alcohol
• Hydrogen peroxide 
• Needle-less syringe to irrigate the wound 
• Antibiotic ointment 
• Container to hold the bot fly 
• An assistant is helpful to restrain the rabbit

First, enlarge the air vent and insert the tweezers into the opening. Once the opening is enlarged, back off a moment. The larvae often will poke his head out of the hole to investigate. (If not then you will have to go into the air vent with the tweezers) Once you visualize the larvae, grasp it firmly below the head with the tweezers and pull firmly. 

At first the larva will not budge - but if you keep pulling firmly but gently, taking care not to break the larva it will eventually pop out - sometimes quite suddenly. Place the larva into a container for possible examination by your vet. Don't forget to close the container - you don't want to set this creature free! 

Irrigate the wound with hydrogen peroxide for several minutes, or as long as it continues to bubble. Pack the wound with antibiotic ointment to help prevent a secondary infection.

Check the rabbit for other warbles - it is not uncommon for there to be multiple warbles on the same animal. It's also a good idea to check other rabbits, cats, dogs, and other animals as they can be infested with this parasite too. 

Check the wound daily until healed for signs of infection.