Screw Worm Fly Surveillance & Preparedness Program
Screw-worm fly is an insect pest of warm blooded animals including people, livestock and wildlife. There are two commonly known screw-worm flies:
- Old world screw-worm fly (OWS) – Chrysomya bezziana
- New world screw-worm fly (NWS) – Cochliomyia hominivorax.
Suspicion of screw-worm fly infestation in animals is notifiable under state and territory animal health legislation.
Animal Health Australia (AHA) manages the Screw-worm Fly Surveillance and Preparedness Program (SWFSPP) in consultation with a committee of industry and government stakeholders. The program aims to detect an incursion early enough to ensure a high likelihood of success of an eradication program.
A program review was completed in 2015. The review reassessed the priority of OWS for targeted surveillance as moderate and reaffirmed that the highest risk pathways are still considered to be through Torres Strait or with returning livestock vessels. A revised program was initiated.
The SWFSPP comprises four areas of work:
- surveillance (Figure 1):
- by fly trapping in Western Australia (four locations), the Northern Territory (two locations) and Queensland (two locations)
- by targeted livestock wound surveys for myiasis in Western Australia (two locations), the Northern Territory (three locations) and Queensland (four locations)
- entomology training and development of reference resources
- awareness promotion to increase general surveillance for myiasis
- monitoring of the risk profile for screw-worm fly in Australia.
The screw-worm fly (Figure 2) lays eggs on wounds or moist body openings, which hatch to release aggressive flesh eating maggots (Figure 3).
Establishment of screw-worm fly in Australia would have major negative impacts including on northern livestock production, livestock export trade and public health.
Screw-worm fly is widespread through tropical regions (Figure 4). OWS is considered a greater threat to Australian livestock industries than NWS as it is endemic in a number of Australia’s closes northern neighbours.
Potential affected area in Australia
Screw-worm fly is most likely to enter through the Torres Strait or with returning livestock export vessels. Travellers returning from countries where the pest is endemic may also be infested.
Screw-worm fly would most likely establish in northern Australia, particularly in the Torres Strait islands and/or in the regions around livestock export ports in WA, NT and Qld (Figure 5).
How do I spot Screw-worm Fly?
Screw-worm flies look like blowflies found throughout Australia and fly traps are used in northern Australia to look for them.
Tissue damage caused by feeding screw-worm fly maggots, and the appearance of the maggots themselves, are more easily recognised than adult flies. Maggot identification requires specialist expertise.
If screw-worm fly occurrence in Australia is suspected please contact your local vet, a government animal health officer or stock inspector or call the Emergency Animal Disease Watch Hotline 1800 675 888.
Keeping Australia screw-worm fly free relies upon early detection, containment and eradication before it can spread to other areas. Regular sampling and laboratory examination of maggots from infested wounds anywhere in Australia is key to early detection. If you see an animal with maggots in a wound please support surveillance by sending some maggots to your government laboratory.
Send Your Maggots!
|Please mark Attn: Screw-worm fly surveillance|
|Northern Territory: (08) 8999 2249
|Berrimah Veterinary Laboratories,
Department of Primary Industry and Resources,
Reply Paid 83108,
DARWIN, NT 0801
|Queensland: (07) 3708 8762
|Biosecurity Sciences Laboratory,
Health and Food Science Precinct,
Reply Paid 87088,
ARCHERFIELD BC, QLD 4108
|Western Australia: (08) 9368 3351
|DAFWA Diagnostic Laboratories,
Department of Agriculture and Food WA,
Reply Paid 85028,
KENSINGTON, WA 6151
- Screw-Worm Fly brochure (pdf – 883 KB)
- Poster Screw Worm – Biology, Distribution and Identification (pdf – 958 KB)
- Screw-worm fly maggot collection kit
- Old World Screw-World Fly: A Manual for Diagnosis (pdf – 5.18)
- Chemicals for the control of the Old World screw-worm fly in Australia (pdf – 354 KB)
- Australian Veterinary Emergency Plan (AUSVETPLAN) – Disease Strategy Screw-worm Fly
- Animal Health in Australia