292 Cattle

IRWIN H.ROBERTS AND N. G. COBBETT

SCABIES is a contagious disease laying eggs. The entire cycle takes no caused by minute parasitic organisms more than 12 days. known as . It affects cattle of all Psoroptic mites attack the hairy parts ages and breeds. Sometimes it is of the body. They generally begin an referred to as scab, , or barn over the withers, but some- . Similar infections attack other times also over the back or around the classes of livestock, wild , and tailhead. The mites prick the skin to birds, as well as people. obtain food. Tissue fluids ooze from Scabies, the medical term for which the wounds. After many mites have is , is common throughout the fed, the fluids dry, become mixed with world. It generally causes a severe in- tissue debris, and form scabs. flammation of the skin and itching. The lesions made by the mites spread Mites are related to , spiders, as the parasites increase in number and scorpions, and are not true in- and involve large areas of the back and sects. Unlike , adult mites have sides. The condidon may advance over 4 pairs of legs instead of 3. They are practically the entire body if it is not wingless and usually are so small that checked. As the disease worsens, hair they can barely be seen with the naked falls out, and the body is covered with eye. thick, rough crusts. The skin becomes Of the thousands of known kinds of hard and thickened and it takes on mites, four are commonly parasitic to a corrugated look. cattle. Each of the four produces a different type of skin reaction. Two, CHORIOPTIC SCABIES occurs chiefly in known as psoroptic and chorioptic farm herds. It is widely distributed mites, live on the surface of the skin from the Atlantic coast to the States and cause a condition generally spoken east of the Rocky Mountains. A per- of as scabies. Two others, the sarcoptic sistent disease, it spreads slowly over and the demodectic mites, burrow the infected , but may travel under the surface of the skin and pro- from one animal to most of the animals duce mange. in a small herd in a year. The responsible for it is Chori- PSOROPTIC SCABIES, also known as optes bovis var. bovis. Like the psoroptic common scab, was prevalent in range mites, it lives on the surface of the skin. cattle in the Western States until about Its life history is similar to that of the 1938. It is caused by Psoroptes equi var. psoroptic mites, and it obtains nourish- hovis, a whitish mite, which can be ment in the same way. seen as a minute speck if it is placed Chorioptic scabies mites do not usu- against a dark background. It spends ally produce such extensive and prom- its entire life cycle on the animal. inent lesions as psoroptic mites, and Female mites deposit about 20 eggs on the injury they cause is less severe. the surface of the skin. The eggs hatch This form of scabies usually begins on in about 4 days, and minute larvae, the inside surface of the hind legs in each with three pairs of legs, emerge. the fetlock region, high on the rear These molt, or shed their , become surface of the udder or scrotum, or nymphs, molt again, become adults, on the inside of the flanks and thighs. reach maturity, and mate, and the The infection is known commonly as females of the new generation begin leg or foot mange. Cattle Scabies 293 Chorioptic mites produce an infec- eggs, which are almost as large as she tion by piercing the skin. The serum, is. The mature female usually stays in or tissue fluid, that exudes from this the burrow her entire life. The mite wound forms a minute blister. The begins laying eggs within a few hours mites multiply, the blisters unite and after starting her burrow. She deposits break, and their dried contents slowly the eggs every second or third day for build up into little scabs or crusts, as long as 2 months, stringing the eggs beneath which the skin is raw and out behind her as she lengthens her bleeds easily. burrow. She usually lays about 30 eggs The mites live in colonies under the in her lifetime. scabs. If a scab is removed with the The eggs hatch in about 5 days, fingers and placed on a dark surface after which the larvae leave the chan- in some warm place, the flesh-colored nels. They move about on the skin, mites will be seen, just about visible where they molt, become nymphs, to the naked eye, crawling rapidly and molt again to become adult males away in every direction. A reading or immature females. glass will help one find the parasites. Larvae and nymphs can be found in The mites from one small lesion the skin follicles. The adult males and spread after a few months to various young females make short burrows, in places about the hindquarters, estab- which they remain briefly. Mating lishing new colonies. The disease takes place on the skin. After mating, eventually may involve large portions the fertilized female burrows into the of the underparts, side, and back. skin to lay her eggs and start a new Sometimes the disease progresses so generation. The full cycle takes about slowly that scabs the size of a half 14 days. dollar, in various places about the A female theoretically could have hindquarters, may go unnoticed for a more than a million descendants in year or two. six generations, or go days. In highly susceptible animals, the When huge numbers of mites are condition may eventually spread to present on an animal, they are rather the underparts of the body, forward easily found under scabs, which can along the midline, around the outer be removed from the skin with the surface of the legs, and over the sides fingers or a dull knife edge. Their and back. burrowing habits in the early stages make it rather hard to find the mites. SARCOPTIG MANGE used to be con- However, skin scrapings made with a sidered of no economic importance in knife edge, deep enough to draw the cattle in the United States. By 1950, blood, will usually disclose the active however, 30 percent of the scabies- parasites. They are barely visible, but infested cattle in one Northeastern a reading glass will show them as State were infested with the sarcoptic moving specks if they are placed variety ot the disease, either alone or against a dark background. in combination with chorioptic scabies. Sarcoptic mange mites may produce As in chorioptic scabies, sarcoptic lesions anywhere on the body of cattle. mange often is found in purebred They appear to adapt themselves best herds and may be spread about the in locations where the skin is thin and country with the sale of breeding tender and the haircoat is thin. They stock. are commonly found high on the rear The mite that causes it is surface of the udder or scrotum, and scahiei var. bovis. It spends its entire life on the rear and inner surfaces of the cycle on the body of the animal. The thighs, where the lesions they produce mature female makes long channels may exist side by side with those within the horny surface of the skin. caused by chorioptic mites. In the burrows the female deposits her Sarcoptic mites may also start infes- 294 Yearbook of Agriculture 1956 tations at the root of the tail or the ance during the fall, winter, and lower parts of the neck and brisket. spring. Owners have observed that the Before many months a large portion of lesions appear to clear up and disap- the body surfaces may be involved. pear spontaneously when an infested Itching is more intense than in other herd is turned out to pasture. Some forms of scabies or mange. mites, however, survive the summer, Shortly after the onset of the disease, and almost invariably be- hairless spots appear, dandruff is come serious again when the weather abundant, and the skin may become gets cool. thickened, hard, and covered with Often there is much less change in crusts or scabs. The skin may crack the status of infestations on animals and ooze blood and pus. It may bleed that remain housed or in close contact where the scabs become detached. with each other during the summer. The disease may spread rapidly—from The presence of oils in the skin, the in- one cow to practically every animal creased activity of skin glands, and the in a dairy barn in a winter. improved nutritional state of the ani- mals when they are on pasture may be DEMODEGTIG, or follicular, mange of responsible for the diminished activity cattle is widespread in the United of the mites in summer. States, but few cattlemen are aware of Demodectic mange shows no re- its existence. sponse to the change of seasons. The It is caused by the mite DemodexJolli- nodules almost invariably discharge culorum bovis, a microscopic, cigar- their contents or are reabsorbed on shaped, sluggish organism that lives the body, regardless of time of year. within the skin. The lesions in the skin take the form THE SPREAD OF SCABIES and mange of nodules, usually in the region of the mites from one animal to another neck, shoulders, and brisket, and some- nearly always takes place through times on other parts of the body. The direct contact. Infection in a herd size of the nodules may vary from that usually starts when an animal with of a match head to that of a hazelnut. scabies lesions too small to be noticed The nodules appear to result from the is introduced into a clean herd. Mites formation of pus, which accompanies spread most rapidly in a herd when the mite. Frequently the nodules are the dairy barn, feed lot, or barnyard pitted. Sometimes they break and dis- are crowded. A bull that has mites charge their cheesy-white contents may infect many animals, even on the over the surrounding hair. range. The mite occasionally can be found Mites parasitic on cattle can live in this material, but often one has to apart from their hosts for varying lance the nodule and extract the con- periods. The length of life varies ac- tents. It can be seen only with a micro- cording to species, humidity, and the scope. Dairymen sometimes become temperature. When the weather is aware of the swellings or nodules on damp and cool, the scabies mites may the neck or brisket, which usually can survive up to 3 weeks, but direct sun- be felt more easily than they can be light and dryness may destroy them seen. Little is known about the life in 48 hours or less. history of this strange, wormlike mite. The eggs may persist on barn walls, stanchions, fence posts, railway cars, THE SEASONAL OGGURRENGE of psor- and cattle trucks, but it is not very optic and chorioptic scabies and sar- likely that cattle will acquire infection coptic mange follows a similar pattern. in that way. It is possible, though, The mites multiply the most rap- that infection may be spread by such idly, produce the most severe skin objects as currycombs, brushes, and lesions, and cause the greatest annoy- halters. Cattle Scabies 295

Sarcoptic mange is the most con- THE HISTORY of efforts to control tagious of all forms of scabies and scabies in the United States by Federal mange on cattle. The way in which and State agencies emphasizes the demodectic mange is transmitted from enormous effort required to keep animal to animal is not known. scabies from becoming a catastrophe. Scabies was widespread throughout THE DAMAGE done by parasitic mites the Western States by 1900. A bulletin to cattle depends on the extent of the describing the disease and methods disease. Scabies causes noticeable and for its control, issued by the United sometimes intense itching in its early States Department of Agriculture in stage. Cattle may be so annoyed and 1902, described psoroptic scabies as a spend so much time rubbing that they serious disease, chorioptic scabies as a fail to eat properly or to gain weight. less important one, and sarcoptic mange When the affected areas of the body as being almost unknown in cattle. become extensive and the skin takes on The Department of Agriculture, a thickened, wrinkled appearance re- with the cooperation of stockmen and sembling elephant hide, there is loss the State livestock sanitary officials, in of condition and weight. Emaciation 1904 inspected more than a million and weakness may happen in severe, head of cattle in the West and super- chronic cases. vised the dipping of nearly 160,000 Under range conditions or in any diseased or exposed animals. A large environment in which the injury is force of veterinarians was placed in compounded by poor nutrition and the field by the Department in 1905. exposure to cold, heavily infested ani- Federal quarantines were imposed in mals may die from psoroptic scabies. areas in which the disease was preva- Rubbing and scratching by milking lent, but cattle scabies increased rap- cows that have sarcoptic mange may idly in many States until about 1911. cause mastitis or inflammation of the Progress thereafter was slow but milk-producing glands. Severe itching encouraging. The disease was reported may also cause the animals to rub so in 1926 to be increasing in only three vigorously that abscesses develop on Western States. More than 3 million the shoulders and rump. A serious head were inspected that year, and economic result of mange is the loss in half that many were dipped. The milk production. Another evil is that work continued until 1937, when it the mites can transfer from dairy ani- was finally reported that the psoroptic mals to people. In the Northeastern scabies was confined chiefly to Ne- States that has been a matter of some braska. concern, because children particularly After 1938, with control in sight, the suffer from mites they get from cows. numbers of animals annually inspected The injury caused by demodectic and dipped gradually diminished. In mange is of greatest concern to the 1942 with infection present only in leather industry. The nodules produced Nebraska and Kansas, i .5 million head in the skin by demodectic mites ap- were inspected in the entire West, 85 pear in the tanning process as deep thousand were dipped, and known in- pits or holes in the hide. Because the fected herds contained only 12,000 disease may attack animals of all animals. breeds and classes, the annual loss in The inspection of 1.5 million head terms of damaged leather is high. in 1948 revealed only 550 cases of The total annual loss to our cattle scabies. Many were chorioptic infec- industry from the four species of mites tions that had been introduced into was estimated in 1954 to total more the Western States from the East. than 4 million dollars. That figure More than 300,000 inspections in does not include the sums spent to keep the W^est in 1950 disclosed fewer than scabies under control. 1,000 infected animals with not a 296 Yearbook of Agriculture 1956 single case of psoroptic scabies among containers. One difficulty associated them. with their use is the need to maintain Only 320 infected animals were a dipping solution temperature of ap- found in 1953. In that year, however, proximately 100^ F. In the case of cattle with chorioptic scabies and nicotine sulfate, temperatures higher sarcoptic mange w^ere reported in 11 than 105° may injure cattle. Midwestern and Eastern States and Two dippings 10 to 12 days apart undoubtedly were present in many will cure most cases of psoroptic and more. chorioptic scabies. Four dippings about An outbreak of psoroptic scabies of 6 to 10 days apart may be needed for unknown origin involved 6 Western sarcoptic mange. States in 1954. It was quickly arrested BHC and lindane applied in dip by prompt Federal and local action. form have given good results. They The existence of scabies and mange in- may be used in cold water. The solu- festations in midwestern and eastern tions are easily prepared. The animals herds of purebred beef animals and need not spend so much time in the dairy cows indicates the need for vats as when the older insecticides are constant vigilance against the return used. of the parasites into the range herds of BHC or lindane should be used at a the West. concentration of 0.075 percent of the active ingredient. A single dipping gen- THE CONTROL of scabies and mange erally is enough, but for unusually se- of cattle requires the external applica- vere, chronic cases, marked by heavy tion of chemicals capable of destroying scab formation, two dippings applied the parasites without harming the ani- 10 to 12 days apart are recommended. mals. For many years lime- and BHC is usually obtainable in the nicotine sulfate were used. form of wettable powders containing 6, Many infected animals have been 10, or 12 percent of the active ingredi- treated since 1948 with benzene hexa- ent, which is known as gamma isomer. chloride (BHC) and lindane, which are Lindane wettable powders usually con- better than the old chemicals. They are tain 25 percent of gamma isomer. deadlier to mites than lime-sulfur and less likely to injure cattle than nicotine THIS TABLE SHOWS the amounts of sulfate. wettable powder needed to prepare Another chemical, , seems roo gallons of dip: to be about as effective as BHC and Pounds per 100 gallons lindane for chorioptic scabies. It is in- Gamma isomer in product of water expensive and relatively harmless to 6 percent 10 cattle if properly used. I o percent 6 12 percent 5 DIPPING is the preferred method in 25 percent 2.5 treating cattle for scabies. The animals Cattle must spend at least 2 minutes are put into a tank or vat of medicated in the dipping solution if lime-sulfur or liquid. The animals are thoroughly nicotine sulfate is used. W^hen BHC wetted all over. Dipping plants are or lindane is used, 30 seconds to i min- usually so arranged that the cattle ute are enough. enter a narrow vat, one at a time, swim All the insecticides must be used with through it, and emerge into a draining care in the dipping vat. Newborn pen at the opposite end. Lime-sulfur calves and weak or emaciated animals and nicotine sulfate are effective only of any age should not be dipped. when applied in dip form. BHC and lindane are particularly Prepared concentrates of these chem- dangerous to calves of the dairy breeds. icals may be purchased and should be Dairy calves less than 2 wxeks old used in amounts recommended on the should not be dipped. Cattle Scabies 297 AU cattle should be well rested before part of the product of a milkshed, is dipping. mixed with large quantities of milk from untreated herds before it reaches SPRAYING CATTLE to control parasitic the consumers, any health hazard is mites is done in many places because probably eliminated. dipping vats are scarce. Spraying is less When treating producing milk cows, effective than dipping, because it is strict adherence to the manufacturer's harder to wet thoroughly the haircoat recommendations for the use of an and the skin on all parts of the body. insecticide must be followed; the addi- Scabies and mange can be cured, how- tion of too much of the insecticide con- ever, if generous amounts of liquid are centrate to the spray mixture may used and*if the work is done carefully. allow the chemical to show up in BHC and iindane at a concentration harmful amounts in the milk. of 0.075 percent gamma isomer, as Beef cattle that are intended for food recommended for use in dipping vats, for people should not be treated with are the insecticides of choice for this BHC or Iindane within 30 days of the purpose. date of slaughter. Two sprayings with either BHC or Leftover dips of BHC and Iindane Iindane, 10 to 12 days apart, are rec- should be disposed of carefully. Pools ommended. High-pressure, power-op- from which livestock may drink should erated equipment is usually necessary. not be allowed to collect. The insecti- A pressure of 200 to 400 pounds per cides should not be allowed to contam- square inch should be maintained. inate feed or the grass on which live- Newborn and sick or weak calves and stock may graze. BHC and Iindane are calves of the dairy breeds less than 2 poisonous to fish and should not be weeks of age should not be treated. emptied into streams or ponds. The amount of spray used depends on the size of the animals, the length of DEMODEGTIC MANGE of cattle does not the haircoats, the dimensions of the respond to any known treatment. If quarters in which the animals are con- the nodules are small, they will cause fined for treatment, and the type of no perceptible injury and may be ig- equipment. Large, heavily haired beef nored. cattle require 4 to 5 gallons or more BHC or Iindane washes containing each. All parts of the haircoat and skin 0.075 percent of the gamma isomer can must be wet. Particular attention be applied to open nodules to kill the should be paid to the hindquarters, the mites that may live in the pus dis- undersides of the body, and the inner charged onto the skin. surfaces of the legs. Total saturation Open nodules infrequently provides greatest assurance of success- become abscessed as a result of bac- ful treatment. terial infection. If the discharge per- Several health hazards must be con- sists, such abscesses, which occasionally sidered when BHC and Iindane are are as large as a pigeon's egg, may be used. Small amounts of both are ab- treated with local antiseptics. Accumu- sorbed through the skin and are de- lated pus can be expressed by means of posited in the tissues of treated animals. light pressure and flushed away with They are partly eliminated from the warm, soapy water. The abscess should body through the milk. then be swabbed, as deeply as gentle Sprays containing 0.075 percent of probing will allow, with tincture of Iindane may be applied to producing iodine appHed by means of a small dairy cows, but their milk is regarded piece of sterile absorbent cotton tightly as unfit for use by people for 3 to 4 wrapped around the end of a tooth- days after treatment. The milk may be pick. fed safely to calves, swine, and nonlay- ing poultry. Moreover, if such milk, as IRWIN H. ROBERTS is a parasitologist 298 Yearbook of Agriculture 1956 in the Department of Agriculture. He was Agriculture, Bureau of Animal Industry Bulletin 40, 23 pages. 1902. graduated from Alfred University in igjj F. Hutyra, J. Marek, and R. Manningcr: and received the degree of doctor of veterinary Special Pathology and Therapeutics of the medicine from Cornell University in igjy. Diseases of Domestic Animals, volume 3, N. G. GoBBETT, a veterinarian in the pages 610-661, Chicago, Illinois, Alex Eger. 1946. Department of Agriculture^ is stationed at H. E. Kemper and H. O. Peterson: Treat- Albuquerque, N, M ex. Upon graduation ment of Cattle Scabies with Lindane, Veterinary from Colorado Agricultural and Mechanical Medicine, volume 47, number 11, pages College in ig2i, he joined the Bureau of 453-455- 1952. H. E. Kemper and H. O. Peterson: Cattle Animal Industry. Scab and Methods of Control and Eradication, For further reading: U. S. Department of Agriculture Farmers' D. W. Baker: Cattle Mange and the Other Dis- Bulletin ICI7, Q6 pages. 1953. eases Known Commonly as Barn Itchy 36 pages, Frank Krai and Benjamin J. Novak : Veterin- Ithaca, N. Y., Cornell University, 1946. ary Dermatology, 325 pages, Philadelphia, Pa., E. W. Baker and G. W. Wharton: An Intro- J. B. Lippincott Company. 1953. duction to Acarology, 465 pages. New York, Rudolph Snyder: Cattle Scab and Its Control. Macmillan Company. 1952. U. S. D. A. Yearbook of Agriculture 1942, Joseph H. Camin and Wm. M. Rogoff: Keeping Livestock Healthy, pages 588-592. Mites Ajfecting Domesticated . South B. I. Sparr, J. C. Clark, E. E. Vallier, and Dakota Agricultural Experiment Station A. H. Baumhover: Studies on the Stability of Technical Bulletin 10, 11 pages. 1952. Toxaphene Emulsions in Dipping Vats, U. S. Richard W. Hickman : Description and Treat- Bureau of Entomology and Plant Quarantine ment oj Scabies in Cattle^ U. S. Department of publication E-849, ^^ pages. 1952.

Verminous

JOHN T. LUCKER

THE ONLY truly parasitic worm The causative parasite has been known to cause a specific dermatitis, found only in lesions in the skin of or skin diseasCj of cattle in the United cattle. Presumably the intermediate States is a small filarial roundworm, host inoculates the skin with the infec- Stephanofilaria stilesi. tive larvae of the parasite. The irrita- The adult worms live and move tion produced as they develop into about in the outermost, or epithelial, adults apparently starts the lesions. layer of the skin. Their progeny, An alternative possibility is that the known as larvae or microfilariae, are transmitter is attracted to already found mostly in the upper part of the existing sores or breaks in the skin and underlying dermal skin layer. inoculates infective larvae into them. The life cycle of the parasite has not At any rate, the presence of the adults been worked out, but an inter- and their microfilariae causes tissue mediate host probably is required for destruction. its completion. Transmission by one Stephanofilariasis, also known as or more of the many kinds of sucking stephanofilarial dermatitis and ste- insects that attack cattle is strongly phanofilarial dermatosis, the skin dis- suggested by the life cycles determined ease caused by this parasite, was first for related filarial roundworms. Such recognized in western cattle in 1934. dipteran insects as , "midges," and It has been found in 11 of the mosquitoes head the list of suspects. Eastern, Southern, and Midwestern