A rather dangerous and often underestimated parasite is the fly larvae.
Fly strike primarily affects older, sick, or weakened rabbits during the summer months. Rabbits that have wounds, feces, or urine stuck in their fur, are unable to groom themselves properly, or are weakened, are highly vulnerable. Healthy, vigorous rabbits are not typically affected. Common victims include rabbits with diarrhea or dirty hindquarters (e.g., those that cannot groom themselves, as is often the case with joint problems or obesity).
An infestation is visible through small, white, oval eggs and the maggots themselves, which are laid in the anal region or in a wound. The maggots can hatch as soon as eight hours after being laid. The eggs often resemble clumps in the fur and are sometimes difficult to find in the undercoat. The maggots themselves are extremely small and inconspicuous (see photo). They are often hidden in the dark skin folds to the right and left of the genital area (inguinal glands, perineal glands, genital corners).
They burrow into the tissue, causing severe internal damage, sometimes even to the organs. Additionally, internal bleeding and infections occur, and the skin often becomes intensely irritated and inflamed. In advanced stages, the fur or skin may begin to peel away.
Affected rabbits typically appear lethargic, eating less or not at all, and show little movement. Some rabbits become restless, twitch, and groom excessively.
Contents
First Aid
- Before visiting the veterinarian, visible maggots should be removed. By placing the rabbit in a warm water bath, the maggots can be encouraged to come out. They flee from light and can be lured out by darkness and warmth. However, caution is required! If there are any open wounds, do not bathe the rabbit, as water could enter its body.
- We recommend keeping Nitenpyram (Capstar® 1mg/kg orally) in the emergency first aid kit and using it in an emergency. This medication causes the maggots to quickly flee the rabbit. Some veterinarians may not have this medication on hand, and it could potentially save the rabbit’s life.
Treatment
Only immediate veterinary treatment can save the rabbit (preferably by an experienced emergency vet). The longer you wait, the worse the chances of successful treatment, as the rabbit will continue to be eaten alive from the inside during this time.
Fly Maggot Wounds
The vet will first remove all externally visible maggots and eggs, often shaving or trimming the fur to access them. The rabbit will then be bathed with an antibacterial shampoo or a wound solution such as Rivanol solution, and the wound will be disinfected. It is highly recommended to apply coconut oil to the affected skin area, as it helps to soothe the skin quickly, protects it, and combats inflammation (avoid applying it to open wounds!). Maggots flee from light and are attracted to warmth, so a blow dryer can be used after the bath to encourage them to come out. They particularly like to hide in the genital corners, as these areas are dark and warm. Additionally, the vet will administer an antiparasitic treatment such as Ivomec® or Dectomax®, or a spot-on treatment like Stronghold®. This medication will kill any remaining maggots. Even better is Nitenpyram (Capstar®, 1mg/kg orally), which causes the remaining maggots to quickly flee the rabbit and die within half an hour.
Fly Strike Necrosis
Rabbits with fly maggot infestations need to be carefully monitored, as the extent of internal damage is often unclear. Depending on the severity, medications may be needed to address the consequences (e.g., Meloxicam (e.g., Metacam) for pain relief, wound care, etc.), and often the circulatory system must be stabilized (infusions). An antibiotic may be required depending on the extent of the infestation. It is recommended to check the rabbit for overlooked maggots three times a day and keep it under strict observation to monitor its general well-being.
Fly maggot infestations are often fatal, especially if not detected and treated in time. In such cases, the rabbit often has to be euthanized. The underlying condition causing the infestation should always be addressed, or a new maggot infestation will soon follow.
Prevention
The following measures can help prevent or reduce the risk of a fly strike infestation:
Cleanliness: During the summer months, litter boxes should be cleaned at least every one to two days, ensuring that heavy soiling is removed. Diarrhea or any substances that attract flies should be cleaned up multiple times a day. The entire enclosure should be thoroughly cleaned weekly. Urine and feces attract flies, so it’s a good idea to wipe down the enclosure with vinegar essence and clean up any diarrhea, as this strongly repels flies.
Inspections: Sick and elderly rabbits, especially those who cannot groom themselves (such as weak rabbits, rabbits with arthritis or other diseases that limit movement), as well as those with diarrhea, urine or other soiling, or wounds in their fur, should be kept indoors (with fly screens) or cleaned several times a day and checked for maggots. Long-haired rabbits should have the area around their anus shaved. Weak rabbits with diarrhea are particularly vulnerable.
Fly Screens: Fly screens can be easily installed on enclosures. A fly screen placed on windows (for indoor housing) or over the aviary mesh (for outdoor housing) prevents flies from getting near the rabbits. Large fly screens or meter-long strips can also be used to cover the aviary mesh.
Insecticides: Depending on the type of housing, insecticide-coated window adhesives, fly traps, fly strips, insect sprays, and UV light traps are all effective. However, rabbits must never come into contact with the insecticides. These should only be applied outside the enclosure in areas where the rabbits cannot reach. If using airborne insecticides, the rabbits must be removed during application and can only be returned once the area is well-ventilated and the insecticide has dissipated. A popular product is Ardap spray, but it should not be applied to surfaces that the rabbits may lick.
Plants: Some plants have a natural repellent effect, such as lavender, tomato leaves, and geraniums. Walnut tree leaves are especially effective in repelling flies.
Health: Healthy, active rabbits are generally not affected. Always address any health issues in sick rabbits promptly. Rabbits with wounds, urine-soaking, feces on their hindquarters, weakened rabbits, or those struggling to groom themselves (e.g., due to obesity or joint disease) are at much higher risk.
Spot-on Treatment for Preventing Fly Strike in Vulnerable Rabbits
These products are applied to the back of the rabbit’s neck and help ensure that any maggots that infest the rabbit will die quickly, causing minimal damage or even preventing fatal consequences. These treatments are available from your veterinarian.
Recommended Products:
Permethrin & Imidacloprid (Advantix®): Available over-the-counter, see the link. Apply 10-30 mg/kg every two weeks to the skin on the neck (part the fur). Be careful not to apply too much to one spot! A 40mg spot-on is suitable for rabbits weighing 1.3 to 4kg. Alternatively, a spot-on with a higher mg dosage can be applied at 0.1 ml/kg. Some rabbits may experience mild skin reactions (hair loss, irritation). This product is toxic to cats (e.g., if you have cats that may lick the rabbits).
Other Options:
Fluralaner (Bravecto®): Lasts about 2 months.
Selamectin and Sarolaner (Stronghold Plus®).
Pyrethrum (Ixotan®).
Pyrethrum (Inuzid-Spray®): Apply daily to your hand or cloth and rub against the fur, especially in vulnerable areas.
Permethrin (Exspot®).
Deltamethrin (Butox® Protect 7.5 mg/ml pour-on): Apply evenly along the rabbit’s backline from the base of the skull to the tail base, refreshing every 35 days.
Vectra 3D (Dinotefuran, Pyriproxifen, Permethrin): Use in the dog dosage. Be cautious as this is toxic to cats—choose a different product if you have close contact with cats.
Nexgard Spectra (Afoxolaner and Milbemycinoxim) or FRONTPRO (Afoxolaner) in the dog dosage, refreshing every 4 weeks.
In some countries, additional products may be available, such as Dicyclanil (CLIK 5% pour-on) (30–100 mg/kg Spot-on, applied once in the spring for 16 weeks of protection) or Cyromazin (Reaguard rabbits).
Discuss with your veterinarian whether preventive treatment is appropriate and necessary in your specific case.
Important
The best prevention is to check the rabbits twice daily to ensure they are moving normally, eating properly, and displaying their usual behavior. Any changes in behavior, reduced appetite, or signs of retreat should prompt an immediate thorough inspection. Rabbits with diarrhea or wounds must also be checked twice daily (including the genital areas!) and treated by a veterinarian right away. Diarrhea can generally be treated. This way, you can spot fly maggots before they cause any harm!
Sources include:
Beck, W., & Pantchev, N. (2012): Praktische Parasitologie bei Heimtieren: Kleinsäuger-Vögel-Reptilien-Bienen. Schlütersche.
Ewringmann, A. (2016): Leitsymptome beim Kaninchen: diagnostischer Leitfaden und Therapie; 33 Tabellen. Georg Thieme Verlag.
Kraft, W., Emmerich, I. U., & Hein, J. (2012). Dosierungsvorschläge für Arzneimittel bei Kleinnagern, Kaninchen und Frettchen. Schattauer Verlag.
Zinke, J. (2004): Ganzheitliche Behandlung von Kaninchen und Meerschweinchen: Anatomie, Pathologie, Praxiserfahrungen; 14 Tabellen. Georg Thieme Verlag.
