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CONTRIBUTOR(S): Claire Speight, Abigal Edis,

Fly strike

Fly strike

With the arrival of spring and summer, the risk of flystrike increases. This is a deeply distressing condition for owners, the veterinary team. However, with some preventative measures, hopefully your guinea pig will never have to endure this condition, or if they are unlucky enough to, you will be able to act quickly.

©Gustavo Fring / Pexels

What is flystrike?

Flies require the correct environment to lay their eggs, most commonly in dustbins and rubbish where there is rotten meat or faeces. If an animals fur becomes soiled with faecal matter or they have an infected or open wound, then flies will be attracted to this to feed on an lay larvae.

Flies will be attracted to any fur or skin which is soiled with faeces and/or urine, usually the back end and any open or infected wound.

Once eggs are laid they will hatch into maggots within 12-36 hours and begin burrowing into the guinea pigs flesh. This causes tissue damage and pain, which can prove to be fatal even with prompt veterinary treatment.

What time of year does flystrike affect guinea pigs?

The months of April to October are the months when animals are more susceptible to flystrike, but it has been reported to have occurred as early as January or as late as November, so owners need to be vigilant throughout the whole year, but extra vigilant during the ‘flystrike season’ of April to October.

What guinea pigs are affected by flystrike?

Any guinea pig can be affected, even those kept inside who keep themselves beautifully clean; it only takes one area of soiled fur/skin or scratch, and one fly.

However, those guinea pigs most at risk of flystrike will fall into one or more of the following risk categories:

  • Overweight: unable to keep themselves clean
  • Dental problems: causing dribbling and sores around the mouth
  • Arthritic: will be unable to physically clean themselves
  • Guinea pigs on poor diets leading to diarrhoea
  • Skin wounds: these will attract flies. This may be from fighting, scratching excessively due to mites or caused by a sharp object
  • Long-haired breeds: these are more likely to matt and have faeces and urine accumulate around their back end
  • Anal impaction: old males often develop a condition called impaction. The muscles of these guinea pigs have weakened and they are no longer able to expel the soft caecal pellets that accumulate in the perineal sack, which if left will attract flies
  • Living in dirty/cramped housing: the smell from the urine and faeces will attract flies.

How do I prevent my guinea pig from getting flystrike?

As far as flystrike goes, prevention really is better than cure and cannot be stressed enough; even if your guinea pig doesn’t fall into any of the risk categories.

Preventative methods

  • Treat any condition which places the guinea pig in a ‘high risk’ category.
  • Ensure that your guinea pig isn’t overweight and is fed a correct diet.
  • Check the whole guinea pig, paying special attention to the back end, at least twice a day, going through the fur to check for soiled/wet fur or maggots.
  • If the guinea pig has a dirty bottom, clean it for them immediately.
  • High risk guinea pigs may be safer inside the house, but must still have their bottom checked twice daily.
  • Older males suffering from anal impaction will need assistance each day to clear the impaction
  • Remove all soiled bedding from hutches daily.
  • Staple net curtains over the hutch/run to reduce the risk of flies.

What should I do if I suspect my guinea pig has flystrike?

Sometimes you may not be able to see any actual maggots as they may be concealed in fur or wounds, but if you do, they are very tiny white specks which look like grains of rice before they hatch. Maggots will grow in size as they develop. If you suspect flystrike or you can see maggots or eggs then you should take your guinea pig to your vet immediately – this is an emergency and cannot wait until the following day or later. If you suspsect flystrike and your vets is closed, then you should phone an emergency on-call vet.

If you can see some maggots remove them with tweezers immediately, but do not put the guinea pig into water in an attempt to wash them off.

The longer a guinea pig is left, the more damage the maggots will cause to the tissues.

Is flystrike treatable?

Cases of flystrike can be successfully treated if caught early, but this is dependant on the amount of damage caused by the maggots. In severe cases, sometimes the kindest thing to do is to have the guinea pig euthanased.

If your vet feels that your guinea pig has a reasonable chance of recovery then treatment usually consists of:

  • Analgesia to help with the pain
  • Clipping the fur from the affected area to assess the damage
  • Washing and removing all visible maggots
  • Surgery to remove any concealed maggots, necrotic (dead/infected) tissue and repair tissue damage
  • An injection of an antiparasitic drug to kill any maggots which remain hidden
  • Antibiotics to prevent or treat infection
  • Fluid therapy to replace the fluid lost from the wound
  • Syringe feeding to try and keep the gastrointestinal tract moving if your guinea pig is not eating
  • Identifying the cause as to why the guinea pig was affected with flystrike and treatment to correct any underlying problem.

Wounds from maggots can take weeks to heal and during this time they will be at an increased risk of further bouts of flystrike, so careful nursing by the owner will be required and preventative treatment measures must be stepped-up.

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Claire Speight

Abigal Edis

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