Fly Strike

Fly strike, or blowfly strike, is a serious condition, mainly affecting rabbits, that occurs during summer months.

The cause of flystrike

Fly strike is caused by flies; attracted to damp fur, urine, faeces or the odour of rabbit scent gland, lay their eggs on or around the rabbit’s rear end where they hatch within hours into a seething bunch of maggots that eat into the rabbit’s flesh, eating it alive and releasing toxins in the process.

Greenbottles are one of the main culprits when it comes to rabbit fly strike, also infect sheep and so are more likely to occur in sheep farming areas. However they are not the only flies that are attracted to rabbits and cause fly strike.

To understand the severity of this problem and recommendations for veterinary treatment, see vet Glen Cousquer’s flystrike article on the World Wide Wounds site or check out Google Images for Fly Strike (very unpleasant).

Prevention is better than cure

Overweight and arthritic rabbits, rabbits with heavy dewlaps, those prone to sticky bottom or suffering from a urinary infection are most at risk from fly strike but all rabbits should be checked for fly strike at least twice daily in summer and treated with one of the veterinary licensed products such as Xenex or Rearguard.

Glen Cousquer’s article recommends the natural plant based product Xenex Ultra Spot On (made by Genitrix) as a preventative. The product is applied every 2 weeks and is formulated from coconut oil triglycerides.

Just dining on too much fresh, rich grass can make even an otherwise healthy bunny produce too many soft droppings. The garden is not just a place for your rabbit to exercise, if it’s got a great lawn then it’s a food fest! Let your rabbit out for short periods initially and then increasingly long periods if there’s a lot that’s good for rabbits to eat in the garden.

Rearguard contains cyromazine, an insect growth inhibitor affecting the chitin mechanism the larvae have to use to shed their skin in order to grow. It gives 8 – 10 weeks protection when applied to the rabbit’s rear and has a good safety record, although there is some evidence then when fed to poultry, the flies do eventually develop a resistance. Rearguard should not be used on broken skin.

Insect repellents do not do the same job as Rearguard although Neem, (Azadirachtin indica), often included in natural insect repellent shampoos, also interferes with the chitin mechanism and is used in organic farming as a pesticide in the US. In the UK and Canada, however, it is not yet licensed for that purpose and so cannot be sold as such.

What to do if your rabbit becomes “flyblown”

If you find maggots on your rabbit then take it to the vet immediately. A flyblown rabbit can get ill from fly strike very quickly. Some sources say you should dip the rabbit’s bottom in water to remove the maggots but damp rabbit fur is not only almost impossible to shave off but also a potent attractor of the flies that laid the eggs in the first place.

Fly strike is one of those “Get to the Vet NOW!” conditions that you don’t mess around with. It looks awful and it is but vets know it can happen very quickly so don’t worry that they’ll think you’re an awful rabbit owner. Eggs can turn into maggots in just a few hours in warm weather. Your vet will be glad you’re bringing your rabbit in as soon as you spotted the fly strike, which is a serious medical condition requiring immediate veterinary treatment!

Treatment

The preferred method of treatment for rabbit fly strike is to remove the maggots using tweezers and shave off any damp or dirty fur. Although you can remove the maggots you can get hold of as a first aid measure, rabbit skin is very thin and tears easily. Your vet will not only have skilled and experienced staff on hand but they will also be able to administer sedation or an anaesthetic to make the process easier.

Rabbits who have had fly strike will also often need antibiotics to prevent infection, anti-inflammatory/pain killing drugs and sometimes fluids.

Prevention of fly strike is not easy, but fly mesh over the front of the hutch, insect repellents, fly strips and preventing the conditions that make a rabbit prone to fly strike in the first place will obviously contribute. Rearguard, Xenex and vigilance together with these measures provide the best protection.