Scabies in Sheep and Goats

Scabies in Sheep and Goats 403 No satisfactory medicinal treatment ment of the thread lungworm larva and for the destruction of thread lung- the intermediate hosts of the hair lungworms is known. Inhalants and intra- worm and the red lungworm. tracheal injections of various drugs It is desirable to rotate animals to have been tried, but frequently they clean pastures whenever practicable. are more injurious than beneficial to The use of dry feed, in racks designed the host and they are hard to give. to prevent contamination with drop- The hair lungworm can be killed by pings, and uncontaminated water will an intramuscular injection of emetine minimize the acquisition of parasites. hydrochloride, but such a treatment Sick animals and heavily infected should be administered by a veterinar- ones should be kept from contaminat- ian. Emetine hydrochloride is a po- ing pastures with their droppings. They tent drug, and an overdose may result should be removed to dry lots to pre- in serious damage or death. Care must vent additional infection with lung- be used to keep it from contact with worms. the eyes, as it is highly irritant. It An adequate diet, and removal of should not be used near shearing time gastrointestinal parasites by anthel- because it may cause sheep to shed. mintics, remedies for worm infections, Preventing infection is the best are deemed to be of considerable value means of combating lungworms. The in building up the vigor of the animal general measures recommended for and consequently counteracting the ef- keeping livestock healthy apply. fects of lungworm infection. The following measures are especially important in minimizing lung- AARON GOLDBERG is a parasitologist worm infection. The use of wet areas in the Helminth Parasite Section^ Animal for pastures should be avoided as they Disease and Parasite Research Branchy are favorable habitats for the develop- Agricultural Research Center at Beltsville. Scabies in Sheep and Goats H. E. KEMPER AND H. O. PETERSON FIVE KINDS of parasitic mites cause The mites live on blood serum that scabies, or scab, in sheep and goats. oozes from skin punctures, which the Common scabies, or psoroptic sca- mites make with their sharp mouth bies, is highly contagious to all classes parts. Into the tiny wounds they prob- of sheep. It is transmitted readily and ably secrete a poisonous substance. quickly from one animal to another Bluish-red, inflamed, swollen areas by direct contact. surround the puntures. The serum on It is caused by tiny, ovoid, pearl- the skin becomes mixed with debris, white mites, Psoroptes equi var. ovis. which soon dries, hardens, and forms The female mite is about one-fortieth a crust, or scab. As the lesion develops, of an inch long. A hand lens should the skin becomes thickened, hard, and be used when one examines infested wrinkled. It might crack and bleed animals for the mites. The adults have when it is manipulated with the fin- four pairs of brownish legs and sharp, gers. The uniformly thickened condi- pointed, brownish mouth parts. tion of the diseased skin is readily 404 Yearbook of Agriculture 1956 detected by comparing it with the but they may become infested from pHable, healthy skin. premises or bed grounds very recently Chronically diseased areas become occupied by infested sheep. Premises hardened and covered with a tightly that have been vacant for about a adhering, scaly, grayish crust. The month arc safe for use by clean sheep. grayish color results from the accumu- Freshly dipped sheep do not become lation of dried flakes of skin. The wool infested from contaminated premises falls out and leaves bare areas, which and therefore may be safely held there enlarge as the disease advances and between the first and second dippings. make the sheep look naked. The mites It is a good sanitary practice, however, seek the healthier skin at the outer to avoid old bed grounds and unclean edges of a lesion, produce more punc- corrals. tures, and thereby cause the lesions to The disease may be contagious at all spread. The mites can be found most seasons, but new infestations are un- easily at the outer edges of the lesions. common in summer. Scabies often re- The mites cause intense irritation mains dormant during hot, dry weath- and itching. Infested sheep become er and may seem to be cured, but usu- restless and furiously scratch, rub, kick, ally it becomes evident again with the and nibble at their wool. The fleece arrival of cold, rainy weather. soon has a broken, disturbed appear- An attack does not give immunity. ance. From the fleece hang tags or A flock may become infested any num- tufts of wool, which the sheep have ber of times. pulled out with their mouths or Goats and cattle herded with sheep scratched out with their hind feet. may be temporary carriers and may Their discomfort is especially notice- even develop lesions of short duration. able after they have been active. The Therefore they should be included wool on afifected areas within reach of when the flock is treated. the animals' mouths may be dirty and We used to think that psoroptic wet with saliva. Licking the lips and mites of sheep were not transferable to champing the jaws while scratching cattle or to any other class of livestock. are characteristic movements of sheep Tests at the Animal Disease and affected with scabies. Parasite Research Laboratory at Albu- The first lesions usually are on the querque, N. Mex., showed, however, back or sides, but may start on any that common sheep scabies could be part of the body. transmitted from sheep to cattle and The only way to be sure that a sheep then back to clean sheep. Lesions con- has scabies is to find the mites. Any taining psoroptic mites were found on condition that causes the sheep to bite December 27, 1950, on a cow that had and scratch themselves should be in- been kept with 10 scabies-infested vestigated at once. sheep for 15 months. Six months later As the wool is parted over a lesion, the disease appeared on a bull that also the mites move away from the light had been with the sheep. The original and may be picked up on the edge of a infestation on the cow and bull was knife blade. The best way to find mites maintained continuously on them for is to scrape the outer edge of the lesion more than 4 years. Skin scrapings con- with a blunt blade of a pocketknife, taining live psoroptic mites were re- transfer the scrapings to a sheet of moved from the cow every day for 2 black paper, and examine the material weeks and placed in the wool of scabies- under bright light. If the material is free sheep. Live mites became estab- slightly warmed by sunlight or a lamp, lished in the wool 4 days after the first the mites become active. They are transplant. Small lesions and some loss plainly visible with a hand lens. of wool were observed during the first Clean sheep do not commonly con- month. The sheep developed extensive tract scabies from infested premises. and typical scabies within 3 months. Scabies in Sheep and Goats 405 FOOT SCABIES, also called chorioptic shoulders. They also occur over the or symbiotic scabies, is caused by mites back, hips, flanks, ears, and jaws. To known as Chorioptes bovis (of the variety find them, one must run his hands over ovis^ if they are on sheep, or the variety the animal's body. caprae^ if they infest goats). The contents of some nodules can be The mites resemble the common squeezed out between the fingers, but scab mites and live in groups on the sometimes they must be incised. In surface of the skin, usually on the lower order to see the mites, the material parts of the legs and around the feet. from the nodules must be examined They spread to the inner surfaces of under a microscope. They look quite the thighs and to the udder and ab- different from other mites that infest domen in severe cases. livestock. The elongated body is di- Chorioptic scabies is much more vided into the anterior part, which common in goats than in sheep. The bears the head; thorax, with legs at- visible lesions usually occur initially tached; and the abdomen. About lOO around the feet and are most pro- or 125 of them measure an inch. The nounced during cold weather when legs are short and stout. The mites the flock is housed. have sucking mouth parts. SARGOPTIC SCABIES, often known as PSORERGATIC SCABIES was first found head scab or black muzzle, has been in the United States on sheep in Ohio found on sheep in Europe but not in in 1951. It had been reported on the United States. It is caused by the Merino sheep in Australia in 1941. mite Sarcoptes scahiei var. ovis. The mite causes a mild irritation and The mite burrows into the skin on itchiness like that caused by lice. The the head and face, where there is little sheep bite and scratch the parts most or no wool. Like common scabies, it easily reached, such as the sides, flank, causes intense itching and irritation. and rump. Tags of wool are pulled out, The infested animals rub and scratch and the fleece has a ragged, tangled the affected parts and hard, firmly at- appearance. The tips of the wool fibers tached scabs are formed. arc twisted or curled into locks or Sarcoptic scabies may be told from matted and hang loosely from the sides.

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