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parasitic disease Sheep

Psoroptic mange (body scabies)

Under the word “scabies”, breeders actually group together several different diseases, caused by different mites, which do not live in the same places and are not treated in the same way. The general sheet on sheep scabies presents this set...

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Definition Signs Causes Transmission Diagnosis Treatment Prevention Complications When to see a vet Prognosis FAQ Sources Affected species

What is it?

Psoroptic mange is scabies of the body: its mite lives on the surface of the skin, under the wool, on the flanks, shoulders, back and base of the tail - that is to say precisely where the fleece is thickest and most precious. Sarcoptic mange attacks the head and areas with little wool; Chorioptic mange remains confined to the legs and lower limbs. Three diseases, three locations, three behaviors.

What distinguishes the psoroptic form is its violence and speed. The mite does not burrow into the skin: it lives on it and triggers an intense skin reaction that oozes, forms scabs and makes the animals crazy with itching. An entire batch can tip over in a matter of weeks.

Key point

It is the most contagious of sheep skin diseases: it can invade an entire flock in a few weeks and destroy all the fleece of the year. In many countries, it is subject to specific health measures which regulate movements and sales. Faced with animals that rub and lose their wool in patches, call the veterinarian instead of buying a product at random.

Commonly observed signs

These signs are neither exhaustive nor specific. Only a veterinarian can establish a diagnosis.

Related signs — each one links to its page:

Itching Rubbing against decor Hair loss Scabs and skin lesions Thickened or darkened skin Skin redness Weight loss Seizures Fatigue Reduced herd feed intake

Intense and permanent itching, day and night: animals rub against walls, stakes, feeders, trees, violently bite their sides, scratch with their horns and hind legs.

Very characteristic reflex: scratching the back or side of an affected animal triggers a movement of the neck, a twisting of the head and biting in space with the lips. This is a strong warning sign, but it does not replace the veterinarian's diagnosis.

Locks of wool raised, loosened, torn off, leaving bare patches which grow larger week after week, especially on the sides and shoulders.

On the periphery of these plaques, at the base of the wool, yellowish moist then dry, adherent crusts, under which the skin is red and oozing.

Skin that thickens, wrinkles and dulls in old areas.

Tufts of wool hanging everywhere in the sheepfold, on the fences, on the corners of the walls: often the first clue noticed by the breeder.

Restless animals, which no longer lie down, no longer graze properly, visibly lose weight in a few weeks.

In neglected forms, certain animals present, during an attack of itching, brief convulsions or a fall, and become exhausted until they no longer get up.

The signs become significantly worse under long wool in winter, and become more discreet in summer in wearers who nevertheless continue to contaminate others.

When to consult without delay

This list does not replace veterinary advice. It gathers situations that justify a prompt consultation.

Causes and risk factors

The responsible mite lives on the surface of the skin, under the wool, without digging a tunnel. It feeds on skin secretions and multiplies very quickly in the moist heat of the fleece.

It is not the bites that make the animal suffer, but the reaction of its skin to the droppings and secretions of the parasite: an intense inflammation which oozes and forms the typical scabs.

The lesion spreads step by step, in a circle, from a starting point, because the mites flee the damaged areas and colonize the healthy skin around them.

A few mites are enough to cause the disease to spread to an animal, then to an entire flock.

Outside the animal, on a strand of wool, in a crack in a feeder or on equipment, the parasite survives for a certain time - enough to contaminate subsequent animals, which explains the relapses after a well-conducted treatment.

Purchase of animals without quarantine, fairs and markets, loans of rams, returns from transhumance and common routes.

Winter groupings in sheepfolds, high density, close-packed animals.

Long wool and cold season, which provide the parasite with the environment it needs.

Mowing equipment shared between farms without cleaning or disinfection.

Treatment limited to only animals that scratch themselves, leaving discreet carriers in the group: this is the first cause of failure.

Buildings reused without cleaning after an episode.

Absence of declaration and dialogue with the buyer or seller: the disease travels with the animals, in silence.

Transmission

By direct contact between animals: this is the main method, and it is extremely effective in sheepfolds in winter, when the animals are crowded together at the trough.

By the wool left on fences, feeders, feeders, walls and rubbing posts, where the mite survives outside the animal.

Through shearing equipment, combs, livestock trailers, sorting yards, clothing and the hands of the workers.

By the introduction of an animal purchased, loaned or returned from a gathering: a carrier in summer, without visible lesions, is enough to relaunch an epidemic in a sanitized herd.

This sheep scab does not take a lasting hold on humans.

Diagnosis and care

Diagnosis is the veterinarian's responsibility, based on clinical examination and laboratory tests. Care is decided case by case.

The diagnosis is not made by eye, and this is a point on which we must not compromise. Lice, sheep louse, ringworm, dermatophilosis and other skin diseases give similar effects when seen from a distance, and are not treated in the same way.

The veterinarian scrapes the skin at the edge of an active lesion, where the mites are most numerous, and identifies them under a microscope. A scraping carried out in the center of an old plate can be falsely negative: it is the border that counts.

He examines the whole lot, animal by animal, removing the wool, and not just those that are scratching. The actual proportion of carriers is almost always higher than the breeder imagines.

He assesses the general condition: a herd that has been scratching for weeks is emaciated, weakened and often carrying other parasites.

Finally, it provides information on the obligations in force. In many countries, this scabies is subject to specific health measures which govern the movements, sales and sometimes the treatment of an entire area. The veterinarian and local veterinary services are the right people to contact.

Treatment

The rule is absolute and allows no exceptions: we treat the entire herd at the same time, never just the animals that scratch themselves. Carriers without visible lesions are the reason the disease keeps coming back.

Two main approaches exist, to be chosen with the veterinarian depending on the season, the length of the wool, the population, the equipment available and the presence of animals in lactation or at the end of gestation: injectable antiparasitics, or external treatments applied to the skin, as a spray or in a bath.

An external treatment only reaches its target if the product reaches the skin: on a long fleece, it slides on the fibers without effect. This is why the period following mowing is by far the most favorable, and why a poorly applied winter treatment gives the illusion of an ineffective product.

A second pass is almost always necessary to reach the hatched mites after the first treatment. The veterinarian sets the behavior and the interval: stopping after a single pass means starting again for a ride.

Treating animals is not enough. It is necessary to sanitize at the same time: clean and disinfect the sheepfold, the feeders, the feeders, the rubbing areas and stakes, the shearing equipment and the livestock trailers, and do not return treated animals to an unsanitized environment.

No dose or rhythm can be improvised. Products intended for other species, homemade preparations, diesel, waste oils and household products applied to the skin are ineffective, burn animals and are dangerous for the person handling them.

Bathing or collective spraying requires precautions: make the animals drink beforehand, never treat exhausted or overheated animals, protect the skin, eyes and respiratory tract of those involved, and eliminate wastewater without discharging it towards a water point or a grazed plot.

Waiting times for meat and milk differ depending on the product and must be requested from the veterinarian before any slaughter or milking.

Treatment depends on the cause and the animal's condition: it must be determined by a veterinarian. No self-medication.

Prevention

Systematic quarantine of any animal purchased, loaned or returned from a gathering, with examination of the skin under the wool and treatment decided by the veterinarian before introduction.

Avoid lending animals and sharing undisinfected mowing equipment; clean combs and clippers between flocks.

Mow healthy flocks before suspect flocks, never the other way around, and consider shearing as a time for systematic inspection of each animal.

Clean and disinfect the sheepfold between batches, as well as livestock trailers and sorting yards.

Intervene from the very first animals that scratch, without waiting for the entire flock to be affected: the disease costs infinitely less to treat on three animals than on a hundred.

Informing the buyer or seller in case of doubt and respecting the movement rules in force: this is what also protects your own herd from other people's animals.

Maintain a good nutritional state of the herd, which tolerates better and recovers more quickly.

Possible complications

Rapid weight loss and collapse of performance: animals spend their days rubbing instead of grazing.

Fleece destroyed, value of wool and skins entirely lost for the year.

Deep scratching wounds, secondary skin infections, abscesses.

Damaged and oozing skin which attracts flies as soon as the heat returns, with a high risk of myiasis.

Exhaustion, nervous attacks during attacks of itching and mortality in young or already weakened animals, in neglected forms.

Restrictions on movement and sales where the disease is regulated, with direct economic consequences.

Complete reinfestation of the herd when the treatment was partial, poorly applied to long wool, or the buildings were not sanitized.

When to see a veterinarian

One or more animals rub themselves violently and constantly against walls, fences or feeders.

Tufts of wool remain hanging everywhere in the sheepfold and on the fences.

Patches of wool fall off, leaving red, oozing, then crusty skin that spreads.

An animal reacts strongly, twists its head and nibbles when its back is scratched.

Animals lose weight significantly even though they are well fed.

You have just introduced or lent animals and itching appears in the following weeks: have the lot examined quickly.

An animal becomes exhausted, falls or convulses during an attack of itching: consult without delay.

Prognosis

The individual prognosis is good when the diagnosis is confirmed microscopically and the treatment is carried out on the entire herd, at the right time and with the necessary number of passages.

The wool, on the other hand, takes several months to grow back, and the year's fleece is lost whatever happens: the cost of the disease is already incurred on the day of diagnosis.

Very emaciated animals recover with good nutrition, but the most affected animals remain behind for a long time.

Failures almost always come from the same causes: treatment limited to visibly sick animals, product applied to too long wool, second pass not carried out, buildings not sanitized, or new animal introduced without quarantine.

Frequently asked questions

What is the difference with sheep scabies that we generally talk about?

“Sheep scabies” is a broad term that covers several different mites. The psoroptic form is the one which affects the body under the wool, on the sides, shoulders and back: it is the most contagious and the most destructive for the fleece. The sarcoptic form is mainly seen on the head and areas with little wool, the chorioptic form remains on the legs. The veterinarian identifies the mite under a microscope, because the course of action is not the same.

Can I treat only scratching sheep?

No, this is the mistake that causes almost all treatments to fail. Animals without visible lesions already carry the mite, especially in summer, and recontaminate the batch as soon as the treatment is finished. The entire herd is treated at the same time, according to the protocol defined by the veterinarian.

Can I get it from handling my animals?

This mite does not settle permanently on human skin. Prolonged contact may cause temporary itching, but there is no lasting illness in humans. Washing your hands and changing clothes after handling an affected flock remains a good practice, especially to avoid transporting the parasite to another herd.

Should I tell someone if my herd is affected?

Talk to your veterinarian right away. In many countries, this mange is subject to specific health measures that regulate the movement and sale of animals, and the veterinarian will tell you what applies to you. Notifying the buyer or the neighbor is not just a question of rules: it is what prevents the disease from returning to your home by another route.