Flystrike in sheep is a

myiasis Myiasis is the parasitic infestation of the body of a live animal by fly larvae (maggots) which grow inside the host while feeding on its tissue. Although flies are most commonly attracted to open wounds and urine- or feces-soaked fur, some spe ...

condition, in which domestic

sheep Sheep or domestic sheep (''Ovis aries'') are domesticated, ruminant mammals typically kept as livestock. Although the term ''sheep'' can apply to other species in the genus '' Ovis'', in everyday usage it almost always refers to domesticated ...

are infected by one of several species of flies which are external parasites of sheep. Sheep are particularly susceptible to flystrike because their thick

wool Wool is the textile fibre obtained from sheep and other mammals, especially goats, rabbits, and camelids. The term may also refer to inorganic materials, such as mineral wool and glass wool, that have properties similar to animal wool. ...

, if sufficiently contaminated with urine and faecal material, can provide effective breeding ground for

maggot A maggot is the larva of a fly (order Diptera); it is applied in particular to the larvae of Brachycera flies, such as houseflies, cheese flies, and blowflies, rather than larvae of the Nematocera, such as mosquitoes and crane flies. ...

s even in the relative absence of wounds.

Causes

Flystrike in sheep is a condition where parasitic flies lay eggs on soiled wool or open wounds. After hatching, the

maggots A maggot is the larva of a fly (order Diptera); it is applied in particular to the larvae of Brachycera flies, such as houseflies, cheese flies, and blowflies, rather than larvae of the Nematocera, such as mosquitoes and crane flies. Entom ...

bury themselves in the sheep's wool and eventually under the sheep's skin, feeding off their flesh. Once the larvae develop, flies continue to deposit eggs on to new or already infected sheep, starting the infection process over again. Sheep display symptoms such as agitation, loss of appetite, odour and matted wool, many of which further encourage the attraction of flies. Fly strike can be lethal for sheep due to ammonia poisoning. Fly strike is problematic, not only causing loss or degradation of stock, but also requiring expenditure of both money and time for effective management. In Australia, ''

Lucilia cuprina ''Lucilia cuprina'', formerly named ''Phaenicia cuprina'', the Australian sheep blowfly is a blow fly in the family Calliphoridae. It causes the condition known as "sheep strike"'. The female fly locates a sheep with ideal conditions, such as an ...

'' causes about 90% of infestations, and '' Chrysomya rufifacies'' is the most common secondary pest that targets wounds caused by ''L. cuprina''.

Identification of infected sheep

Flystruck sheep are identified in the flock by characteristic green or wet-looking patches in the sheep's fleece, usually around the haunches or tail, or at the site of an open wound, where wool can create a damper area which is more attractive to flies. In male sheep the penile region is also a common area for fly strike to occur. When the flock settle, infected sheep will display signs of agitation, such as foot stamping or turning to nibble their body. Flystruck animals often have a strong characteristic odour and in severe cases, the wet-looking wool can begin to shed. Fly strike is more likely to be found in favorable environmental conditions such as temperatures between , recent rain, and wind speeds below . The peak UK green bottle fly breeding season tends to be in late June or July, but fly strike can occur at any time warm damp conditions prevail and green bottles are active.

Prevention

There are several preventative measures which are used to reduce the occurrence of flystrike in sheep flocks, these include: * Controlling intestinal parasites to prevent scours and a suitable surface for flystrike * Scheduled shearing and

crutching Crutching refers to the removal of wool from around the tail and between the rear legs of a sheep for hygiene purposes. It can also refer to removing wool from the heads of sheep (''wigging'' or ''eye-wooling''). It does not refer to the proces ...

* Removing the tails of lambs at weaning *

Mulesing Mulesing is the removal of strips of wool-bearing skin from around the breech (buttocks) of a sheep to prevent the parasitic infection flystrike (myiasis). The wool around the buttocks can retain feces and urine, which attracts flies. The scar t ...

* Preventative chemical treatments before fly infestation risk is high * Breeding for traits that reduce the likelihood of infestation * Removing or avoiding large manure heaps or other sites attractive to the flies * Using fly traps near the flock to attract and kill any local flies, helping to minimise the local populations. NB: Traps often emit a pungent smell and are best placed away from human activity. None of these measures completely stop the occurrence of fly strike in sheep, and regular treatment is still necessary.Fahy, L., Lauber, M., & Suter, R. (2011). Flystrike. Retrieved 10 2013, from Department of Environment and Primary Industries

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References

{{Reflist Flies and humans Sheep and goat diseases Arthropod infestations Veterinary entomology Parasitic infestations, stings, and bites of the skin

Causes

Identification of infected sheep

Prevention

See also

References