Screw Worm Fly Surveillance

Screw-worm fly is an insect parasite of warm-blooded animals. The fly has red eyes and a shiny blue-green body and looks similar to Australian blowflies. Flies lay eggs on the edge of open wounds from scratches, injury, branding, dehorning or castration. Larvae (maggots) hatch and feed on the underlying flesh causing extensive tissue damage. Left untreated, animals can die from infection and loss of tissue fluid.

There are two species of screw-worm fly:

• Old world screw worm fly- Chrysomyabezziana
• New world screw worm fly - Cochliomyia hominivorax

Old world screw worm fly (SWF) is present throughout south-east Asia and Papua New Guinea and is one of the most serious emergency animal disease threats to the northern livestock industry.

SWF is a notifiable disease in the NT.

Monitoring wounds in livestock

To ensure early detection of a screw-worm fly incursion, it is important to check wounds on livestock for maggots. If you find maggots

1. Collect up to 10 maggots from deep in the wound
2. Drop them in HOT water. This causes them to extend
3. Place maggots in three parts methylated spirit to one part water
4. Contact your regional office to identify magogts

Northern Australia Quarantine Strategy (NAQS) conducts targeted quarantine surveillance along the northern coastline which includes

• Fly trapping at airports, seaports and other risk areas
• Inspection of livestock vessels returning to Australia from overseas
• Sentinel cattle herds to monitor wounds for maggots

Further information

• Animal Health Australia
• NAQS