Sterile Biobag Larvae (maggots) for use in the removal of unwanted tissue

How do the larvae work?

The contents of a fly’s egg are sterile (clean) although the outer surface is heavily contaminated with bacteria. Sterilising the outer surface of the fly eggs and then allowing them to hatch in a sterile environment produces sterile larvae.

Larvae are living organisms that move over the surface of the wound. As they do so they secrete a powerful enzyme that breaks down dead or unwanted tissue. The larvae digest the dead/unwanted tissue. Any bacteria or microorganisms in the wound will also be digested by the larvae or killed by the enzymes that they secrete.

The larvae will not eat or burrow into healthy tissue and they will not lay eggs or turn into flies while in your wound.

What do the larvae look like?

Larvae are very small and look like an uncooked grain of rice. They will be in a sterile biobag where they remain sealed in the dressing throughout the treatment. This also ensures they will not escape.

When the larvae are removed, they will be about the size of a cooked grain of rice.

The larvae may be left in your wound for up to 5 days, and if necessary, replaced with a new sterile biobag.

Will the larvae smell?

It is quite normal for you to find an increase in the smell or amount of fluid coming from your wound as the larvae break down the unwanted tissue. To help reduce this the outer dressing will be changed regularly by a nurse on the ward or if you are at home by a community nurse.

Having larvae in your wound should not alter your day-to-day routine and activities. However, you should not take a bath or shower as this can make the dressing too wet and kill the larvae. Also, you should not get the wound too hot, as this may cause the larvae to dry out and die.

When are larvae used?

Sterile larvae are only placed in open wounds that are infected or contain sloughy (unwanted) or necrotic (dead) tissue.

Larvae can be used in many different types of wounds including leg ulcers, pressure ulcers, burns, abscesses and infected surgical wounds.

Before the larvae are put onto your wound, a thorough assessment of your wound will be made. Your doctor or nurse will then discuss the treatment and any alternative treatments with you. If you agree to the larvae, they will be put on either at an out-patient clinic or on the ward if you are already an inpatient.

Alternative treatments

There are other ways of debriding wounds, these include:

• ‘Sharp’ debridement - using a scalpel (sharp blade to remove dead tissue).
• Wound dressings - some dressings can be slow to act. You may have tried them before being offered larvae therapy.

Reminder

• The dressing consists of sterile fly larvae (maggots).
• Larvae are not harmful.
• Larvae will clear your wound of unwanted and dead tissue.
• They will not burrow into or eat healthy skin. They will not lay eggs or turn into flies in your wound.
• It is unlikely that you will feel them moving in your wound.
• It is quite normal to find an increase in the smell or amount of fluid coming from the wound. Do not worry about this.
• Do not take a bath or shower while the larvae are in the wound, as this would make the dressing too wet and might kill the larvae.
• Try not to get the wound too hot, for example sitting too close to the fire or radiator, as this may cause the larvae to dry out and die.
• If you notice bleeding through your dressing please inform your healthcare professional as soon as possible.

Contact information

If you experience any problems which you think may be due to the larvae, please contact the nurse who applied them.

If you have any other concerns or questions about larvae treatments, please discuss these with your hospital doctor, consultant or the nurse who applied them to your wound.

Further information

The Bio Surgical Research Unit has a good website which gives useful information about larvae therapy and case studies of larvae in use, including pictures:

BioMonde

Website: www.biomonde.com