Rabbits: Fly Strike

What is fly strike?

Fly strike is maggot infestation of wounds, skin irritations, or feces stuck to hair around the rectum. Sometimes the rabbit is said to be “fly blown”. It often occurs during the summer months in pet rabbits that are allowed to run outdoors. Healthy and cared-for rabbits are typically not affected by fly strike.

For a rabbit to develop fly strike, a fly must first lay its eggs on the rabbit’s skin. Attractive sites, for a fly, are skin wounds or areas of soiled and matted fur — especially fur that is soiled by blood, urine, or feces. A rabbit that cannot or does not groom itself around the base of the tail and anus may leave feces or urine-contaminated hair, which can become attractive to flies. Damp and soiled bedding is an ideal environment for flies to lay eggs, and for maggots to grow and develop.

When fly eggs hatch, the larvae are called maggots. If the rabbit cannot groom or clean itself, these fly larvae survive, thrive, and spread to local tissues on the rabbit. Maggots cause a tremendous amount of damage as they eat their way through the rabbit’s skin and invade deeper tissues.

How can I prevent my rabbit from getting fly strike?

You can prevent fly strike by ensuring your rabbit is healthy and their environment is clean.

• Ensure that bedding is dry and cleaned daily.
• Regularly check that the rabbit has no wounds or ulcerated areas of skin.
• Ensure there are no problems that prevent the rabbit from grooming.

Dental disease can impair a rabbit's ability to groom. An animal that has sharp hooks on its molars or cheek teeth may not be able to groom properly, allowing dirt, dander, or fecal-soiled hair to attract flies. Similarly, overgrown incisor teeth (at the front of the mouth) will prevent grooming. Your veterinarian should check your rabbit’s teeth regularly and give appropriate treatment, if necessary.

Rabbits with spinal arthritis or joint disease problems may not be able to turn around to groom properly. Any rabbit with diarrhea will be especially prone to fly strike and will have other problems associated with diarrhea.

Rabbits with cystic calculi (bladder stones), crystals or sludge accumulation in the bladder (hypercalcinuria), and/or a primary or secondary bladder infection (cystitis) are prone to having a wet hind-end and will attract flies. Any condition affecting the skin, such as fight wounds, skin mites and/or lice, ear mites, flea bite wounds, or botfly lesions will be very attractive to flies and will encourage them to lay eggs.

What is the treatment for fly strike?

Rabbits affected by fly strike will need to be sedated or anesthetized so that all the maggots can be removed and the whole area can be cleaned and clipped free of soiled hair. Any and all wounds will need to be thoroughly cleaned and debrided (dead or infected tissue is removed) by a veterinarian. Many veterinarians use the drug nitenpyram to help kill any live maggots that remain after the wounds have been cleaned. 

Most cases require sedation and administration of pain medications. The affected area will be disinfected with antiseptic solution and your rabbit will be placed on antibiotics, since there is a high probability of secondary bacterial infection.

In severe cases, hospitalization, intravenous fluids, vitamins, and other supportive care may be needed. Such intensive care may cure your rabbit of the maggot infestation but, in severe cases, extensive surgery may be needed to remove all the dead, maggot-ridden tissue.

After treatment, it is necessary to address the original problem(s) that led to the fly strike. Post-treatment, your rabbit should not be allowed outside for at least a month. If the initiating cause cannot be permanently resolved, it is recommended to keep your rabbit indoors except for supervised playtime outdoors.

Is there anything else I should know?

Ideally, you should take your rabbit to your veterinarian once a year for a routine health check, to ensure that dental disease, urinary issues, or back problems do not predispose your rabbit to this dangerous condition. Dry, clean, and well-ventilated indoor housing is an ideal, simple, and inexpensive way to minimize the possibility of fly strike.