Disease Brief Description Epidemiology Pathogenesis Clinical Signs Lesions Differential Diagnosis

Diagnosis Treatment Control & Prevention

Epitheliogenesisimperfecta (aplasia cutis)(aplasia cutis)

*A congenital skin deformity. Foals are born with small to extensive areas where skin is missing. Secondary infection is common*The condition is fatal when extensive

*One or more hooves may be deformed or absent

*Obvious at birth as glistening red,well-demarcated discontinuities in the skin or mucous membranes

*Small defects can be surgically corrected

Nevus *This term is used for any area where skin is malformed, including abnormally pigmented spots. Some forms of nevi displace the normal structures of the skin, including hair follicles; thus, these patches are hairless

*Defect occur in all species

*Alopecic, with pigmented ,pitted surfaces

*When not extensive, it can be surgically removed; otherwise there is no effective treatment

Dermoid sinuses or cysts *These cysts are lined with skin. Exfoliated skin, hair, and glandular debris accumulate in the cysts, which can lead to infection. The cysts are found on the midline of the back and in rare cases are associated with spinal cord deficits

*Occur in Thoroughbred horses

*They are caused by failure of complete separation of the neural tube from the epidermis during embryogenesis

*The lesions may be lateral or bilateral

*Can be removed by surgical excision

Follicular cystsPeriauricular (dentigerous) cysts

*Develop by abnormal hair follicle growth and by retention of follicular or glandular products*They may be congenital when the hair follicle does not develop normally*Although they are present at birth, they may not be recognized until adulthood

Albinism *Always associated with pink or pale irises and with visual defects and increased risk of skin damage from solar radiation. Albinism is different from extreme white spotting.*Some animals with extreme piebaldism (spotted or blotched with black and white) or dominant white have associated neurologic anomalies or deafness in one or both ears.

*Lethal white foal syndrome is one that results from breeding 2 Overo Paints.

Vitiligo *Hereditary but not noticeable at birth. Complete remission may occur but is rare. It causes no other health problems.

*Mostly seen in Arabian horses (Arabian fading syndrome, pinky syndrome).

*There is no accompanying systemic or cutaneus pathology

*Affected animals develop bleached splotches of skin that occasionally also affect the hair coat and hooves.

*Most lesions are on face ,especially the muzzle or planumnasale or around the eyes

*No treatment is available

*Treatments used in people with vitiligo are unlikely to help

*The onset is usually in young adulthood

Most splotches are on the face, especially the bridge of the muzzle or around the eyes. Color loss may wax and wane

animals

Hereditary equine regional dermal asthenia (HERD)

*A condition in which the skin produces abnormal collagen and/or elastin.

*Common in Quarter horses and Arabian cross horses.

*The condition is often first noticed during training, at the time saddles and tack are first placed on a young horse.

*Handling of the skin elicited a painful response and superficial trauma led to skin wounds.The skin was thinner than normal in affected areas,with thickened borders and harder fibrotic masses.The collagen fibrils were thinner and smaller,which created a loose arrangement of collagen within the deep dermis which contains a distinctive horizontal linear zone

*Patches or large areas of loose, stretchy, fragile skin*Joint problems

*Clinically there were bilateral asymmetrical lesions of the trunk and lumbar regions,where the skin was hyperextensible

*Based on visible signs and testing of the collagen structure.

*Wounds heal slowly or not completely

Epidermolysisbullosa syndromes

*These are a group of hereditary congenital defects that affect the attachments between the outer and inner layers of the skin.*Skin trauma results in dermal-epidermal separation and blisters that soon rupture, leaving glistening, flat ulcers. Blisters may be present at birth or develop within the first weeks of life. The most severe blisters are on the lower legs (with sloughing of hooves), mouth, face, and genitals.

* Except for the simplex form, most occurrences of the disease are fatal. All 3 forms of epidermolysisbullosa have been reported in Belgian foals.

*Most common on the gingivae,palate,lips,tongue,and feet*Most severe lesions are on feet with sloughing of hooves, claws of footpads and oral mucous membrane and facial and perigenital skin(erosions)

Airborne Allergies (Atopy) *While the horse's immune system normally provides protection for the animal, the immune system of some horses overreacts to the presence of one or more airborne allergens.*Airborne allergens can adversely affect the skin.

*Allergy testing is also available in some areas. Allergy testing identify the specific allergens

*Avoiding the allergen, if possible*Corticosteroids to control the inflammatory reaction. If a horse is allergic to dust in the environment*Feeding the horse hay lage or some other feed with little

dust may also help.*Conversely, if the horse has seasonal pollen allergies, it can be kept inside during the months when pollen is normally present.

Food Allergies *Although documented cases are rare. For example, there are reports that certain types of grains or hay have caused hives in horses. In some cases, the food allergies were associated with high-protein food concentrates.

- - *Trial or elimination diet

*Strict avoidance of the food.

ECTOPARASITES

Parasite Brief Description Epidemiology Pathogenesis Clinical Signs LesionsDifferential Diagnosis Diagnosis Treatment

Control & Prevention

The biting midges, “no-see-ums,” or punkies belong to the family Ceratopogondiae.

*Culicoid hypersensitivity in Canada*Queensland itch in Australia *Kasen in Japan*Sweat itch*Sweet itch*Summer dermatitis

*Culicoides spp are vicious biters and can cause intense irritation and annoyance. In large numbers, they can cause livestock to be nervous and interrupt their feeding patterns. These gnats tend to feed on the dorsal or ventral areas of the host; feeding site preference depends on the species of biting gnat.

*They fly only in the warm months of the year and are most active before and during dusk. They feed often on the mane, tail, and belly of horses.

*These flies also serve as the IH for Onchocercacervicalis; the microfilariae of this nematode are found in the skin of horses.

*These flies also transmit the bluetongue virus in sheep and cattle.

*Horses often become allergic to the bites, scratching and rubbing these areas, causing alopecia, excoriations, and thickening of the skin

*Onchocerciasis

*Nonseasonaldermatosis that is similar to sweet itch but usually is less pruritic and affects the head, neck, and belly.

*Most often collected in the field and not found on the animals

*Identification is probably best left to an entomologist.

*Larvae may be attacked in their breeding grounds. Extension entomology personnel should be contacted for the latest approved recommendations.

*Permethrin for the spraying of stables and horseboxes.

*Topical insecticides such as pyrethrins (eg, cypermethrin or cyfluthrin), especially in pour-on formulations, may also be used to control these adult pests in large animals.

*Black flies *Black flies feed on all classes of livestock, wildlife, birds, and people.

*Distributed throughout the world in areas where conditions permit development of the immature forms. *Larvae nearly always are found in

-Because of their tiny,serrated mouthparts, female black flies inflict painful bites.The ears,neck,head, and abdomen of cattle are favorite feeding sites

swiftly flowing, well-aerated water; shallowmountain torrents are favored breeding places. *They are particularly abundant in the north temperate and subarctic zones, but many species are found in the subtropics and tropics where factors other than seasonal temperatures affect their developmental and abundance patterns.

Buffalo flies, Haematobiairritansexigua

*The buffalo fly is a primary pest of cattle and water buffalo but occasionally feeds on horses, sheep, or wildlife.

*It is distributed throughout northern Australia and New Guinea and is found in parts of southern, southeastern, and eastern Asia as well as Oceania; it is not found in New Zealand.

* Its life cycle is similar to that of the horn fly; the adult leaves the host long enough to oviposit on fresh manure, where development occurs. The life cycle may take as few as 7–10 days, depending on weather conditions.

*Buffalo flies irritate and annoy animals, usually biting about the shoulders and withers. Bite wounds may provide a site for screwworm (Chrysomyiabezziana) infection. During hot weather, the flies move to shaded parts of the body. Affected animals suffer blood loss and are irritated by the flies; feed efficiency and production may be affected adversely.

*It can be identified by their dark color, size (approximately half that of a stable fly), and bayonet-like proboscis that protrudes forward from the head.

*Insecticides should be avoided in the treatment of buffalo fly populations. Many of the chemicals used to treat these flies result in meat residues. Buffalo flies have developed resistance to the synthetic pyrethroids and to some of the organophosphates.

The eye gnats or the eye flies (Hippelates spp)

*They are very small (1.5–2.5 mm long) flies that frequently

*In the desert and foothill regions of

*These gnats quietly approach

*These small flies have sponging type

*Repellents, such as those recommended

congregate around the eyes as well as mucous and sebaceous secretions, pus, and blood.They gather in deep shade, such as among densely planted shrubs or in the shade of a dwelling

southern California, adult Hippelates flies are present throughout the year; they are annoying from April through November. During the peak months, they are noticeable in the early morning and late afternoon.

*Hippelates flies also serve as vectors forArcanobacteriumpyogenes (summer mastitis) and Moraxella bovis

*The eggs are ~0.5 mm long, fluted, and distinctly curved. They are deposited on or below the surface of the soil. The larvae hatch and feed on decaying organic matter, including excrement. The larval stage lasts 7–11 days. During the winter months, the larval and pupal stages may persist for many weeks. Pupation occurs close to the surface of the soil and lasts ~6 days. The entire life cycle lasts ~21 days. The adults are generally strong flyers, flying both with and against the wind.

their mammalian hosts. They usually alight some distance from their feeding site and then crawl over the skin, or fly intermittently and alight, thus avoiding annoyance to the host. They are persistent and, if brushed away, quickly return to continue engorging themselves.They are nonbiting flies; however, the labellae have spines that scarify host tissue and allow entrance of pathogenic organisms. Hippelates flies often hover around the body orifices of calves, yearlings, pregnant heifers, and lactating cows. They feed on lacrimal fluid, fatty body secretions, milk droplets, and on secretions at the tips of the teats of animals.

mouthparts. Although eye gnats have much smaller mouthparts, they closely resemble house flies in form and structure and have short aristate antennae.

for mosquitoes, provide temporary relief from eye gnats.

*Applications of insecticides on a community-wide basis (as would take place with mosquito abatement) may provide temporary control of adults, but more adults invade the treated area after the insecticide has dissipated.

Face flies, Muscaautumnalis *They gather around the eyes and muzzles of livestock, particularly cattle. They may also be found on the withers, neck, brisket, and sides. Their mouthparts are adapted for sponging up saliva, tears, and

*Face flies are found on animals that are outdoors and usually do not follow animals into barns.

*They follow blood-feeding flies, disturb them during the feeding process, and then lap up the blood and body fluids that

*Sanitation

mucus. Face flies are usually not considered blood feeders because their mouthparts are a sponging type and not piercing or bayonet-like, as are those of Stomoxyscalcitrans.

accumulate on the host's skin.

Filth-Breeding flies *Filth-breeding flies: Muscadomestica (the house fly); Calliphora, Phaenicia, Lucilia, and Phormia spp (the blow flies or bottle flies);Sarcophaga spp (the flesh flies); Fannia spp (the little house flies); Muscina spp (the false stable flies);Hermetiaillucens (the black soldier flies).

*The house fly is commonly found around livestock operations, where it readily breeds in accumulating manure sources.

*It is a medium-sized (as large as 9 mm), grayish fly with four dark thoracic stripes and sponging, nonbiting mouthparts designed for sucking semiliquid food (there are no mandibles or maxillae). The labium is expanded into two labellae that can transfer fluids and semifluids.

*The life cycle of M domestica will be used as a representative example of the life cycles of the assorted filth-breeding flies.

*Large populations of these adult flies are often found around facilities associated with animal feces

*Have been implicated in the transmission of numerous pathogens (helminth, protozoan, bacterial, and viral) of people and other animals.

*Larval stages may be associated with skin wounds contaminated with bacteria or with a matted hair coat contaminated with feces

* The identification of adult flies is probably best left to a specialist.*House flies are medium-sized, grayish flies with four dark thoracic stripes. A preliminary identification of blow flies or bottle flies may be made on the basis of the metallic coloring of the adults. Flesh flies are medium-sized, grayish flies with a checkerboard abdominal pattern.

*Thorough sanitation program to control fly populations in and around livestock and facilities.

*All manure accumulations should be removed at least twice a week or handled properly, if stored on the premises, to minimize fly breeding.

*Residual sprays providing 2–4 wks control with one treatment may be applied to fly-resting surfaces. Space sprays, mists, or fogs with quick knockdown but no residual action can be used for immediate reduction of high numbers of adult flies.

*Use of insecticide resin strips or various fly baits.

Horse Flies *Tabanus spp (horse flies) are large (up to 3.5 cm long), heavy bodied, robust dipterans with powerful wings and very large eyes. They are swift fliers. These flies are the largest in the dipteran group in which only the females feed on vertebrate blood. Horse flies are larger than deer flies; many horse flies are highly colored.

* Adults are seen in summer, particularly in sunlight. Adult females feed in the vicinity of open water and have reciprocating, scissor-like mouthparts, which they use to lacerate tissues and lap up the oozing blood.

*Restless when the flies are present. Site preferences include the underside of the abdomen around the navel, the legs, or the neck and withers.

*These flies can be identified by their large size, powerful wings, compound eyes, and lacerating scissor-like mouthparts. Species identification of intact adult and larval horse and deer flies is probably best left to an

*Horse fly traps have been effective when used around cattle confined to manageable areas.

*Manipulation of these flies' aquatic habitat has been attempted by removing unnecessary woody

*Horse flies feed a number of times in multiple feeding sites before they become replete. When disturbed by the animal's swatting tail or by the panniculus reflex, the flies leave the host, yet blood continues to ooze from the open wound.

*These flies may act as mechanical transmitters of anthrax, anaplasmosis, tularemia, and the virus of equine infectious anemia.

entomologist. plants from residential areas or draining wet areas.

* Application of insecticides in the water may have detrimental environmental effects.

Mosquitoes *Mosquitoes are members of the family Culicidae.Important genera include Aedes, Anopheles, Culex,Culiseta, and Psorophora.

*Although they are tiny, fragile dipterans, mosquitoes are perhaps some of the most voracious of the blood-feeding arthropods.

*Mosquitoes lay their eggs either on the surface of standing water (eg, Aedes and Psorophora spp) or on a substrate (such as damp soil) where the eggs hatch after inundation from rainfall, irrigation, snow melt, etc. Larval mosquitoes are known as wrigglers, whereas pupal mosquitoes are known as tumblers. These stages are always aquatic and are found in a wide variety of habitats. Large numbers of mosquitoes can be produced from eggs laid in relatively small bodies of water. Some species have several

*About 300 species have been described worldwide, with ~150 species found in the temperate regions of North America.Mosquitoes are found in such diverse areas as salt marshes of the coastal plains to snow pools above 14,000 ft (4,300 m) to the gold mines of India 3,600 ft (1,100 m) below sea level

*Only female mosquitoes actively take a blood meal so that they can lay eggs. Males feed on nectar, plant juices, and other liquids. Mosquitoes annoy livestock, cause blood loss, and transmit disease. Also, the toxins injected at the time of biting may cause systemic effects. The feeding of large numbers of swarming mosquitoes can cause significant anemia in domestic animals. Although they are known for spreading malaria, yellow fever, dengue, and elephantiasis in people, mosquitoes are probably best known in veterinary

*Adult mosquitoes are most often collected in the field and are not found on animals. Adults are 3–6 mm long and slender, with small, spherical heads and long legs. The wing veins, body, head, and legs are covered with tiny, leaf-shaped scales. The long, filamentous antennae have 14–15 segments and are plumose in the males of most species. They also have proboscides designed for lacerating tiny blood vessels and sucking up pooled blood. Identification of the plethora of mosquito species (adult, larval, and pupal stages) is

*Drainage o collections of still surface water or destruction of the larvae by the addition of any one of a number of insecticides

generations per year. The flight habits of adult mosquitoes vary with the species; some Aedessp migrate many miles for their aquatic, larval habitat. In strong winds, mosquitoes may be carried great distances. Some species overwinter as eggs, while others overwinter as adults.

medicine as the intermediate host for the canine heartworm,Dirofilariaimmitis, and as the vectors of the equine viral encephalitides, including West Nile virus.Anopheles quadrimaculatus is the intermediate host for malaria (Plasmodium spp) in people and other primates. Aedesaegypti is the yellow fever mosquito, transmitting this virus among people. Psorophoracolumbiae is a severe pest of both livestock and people in the rice fields of Louisiana and Arkansas.Culextarsalis is an important vector of Western equine encephalitis and is found in the western, central, and southern USA. Aedesvexans is an important nuisance species found in the midwest.Aedesalbopictus is a recently introduced Asian species that also spreads yellow fever, dengue, and equine encephalitis. Certain Mansonia spp are severe pests of livestock in Florida. In Central and South America, the adult female bot fly Dermatobiahominis fastens her eggs to a species

probably best left to an entomologist.

of Psorophoramosquito, which then transmits them to the mammalian host during feeding.

Stable Flies *The stable fly, Stomoxyscalcitrans, is often called the biting house fly. It is about the same in size and general appearance as Muscadomestica, the house fly. It is brownish gray, the outer of four thoracic stripes is broken, and the abdomen has a checkered appearance. It has a bayonet-like, needle-sharp proboscis that, when at rest, protrudes forward from the head. The wings, when at rest, are widely spread at the tips.

* Stable flies are mechanical vectors of anthrax, surra, and equine infectious anemia. They are the intermediate host for Habronemamuscae, a nematode found in the stomach of horses.

*These flies are found throughout the world. In the USA, they are found in the midwestern and southeastern states.The larval and pupal forms develop in decaying organic matter, including grass clippings and seaweed along beaches. In the midwestern USA, larvae can be found in wet areas around the edges of hay stacks and silage pits. Where cattle are fed hay, breeding can occur at the edge of the feeding area where hay has become mixed with urine and feces. The life cycle in the field can be completed in 2–3 wk, and adults may live ≥3–4 wk.

*Both male and female stable flies are avid blood feeders, feeding on any warm-blooded animal. Stable flies stay on the host for short periods of time, during which they obtain blood meals. This is an outdoor fly; however, in the late fall and during rainy weather, it may enter barns.Horses are the preferred hosts. The fly usually lands on the host with its head and proboscis pointed upward and inflicts painful bites that puncture the skin and bleed freely. It is a sedentary fly, not moving on the host. Stable flies usually attack the legs and ventral abdomen and may also bite the ears. They can be a problem in cattle feedlots in the midwestern USA. The damage inflicted to cattle is caused by the painful bite and blood loss, and the irritation results in a reduced efficiency in converting feed to meat or milk. In pets, stable flies prefer to feed on the tips of the ears of dogs with pointed

*Stable flies are easily identified by their size (about the same as that of the house fly), coloration, and bayonet-like proboscis that protrudes forward from the head.

* Sanitation*A combination of two compounds, imidacloprid and permethrin, works to repel S calcitrans. Monthly application of this product repels these flies and prevents their blood feeding on dogs, but the product does not kill this type of biting fly.

ears, especially German Shepherds.

Tse-Tse flies *The tsetse flies, Glossina spp, are important blood-feeding flies found in Africa (latitude 5°N to 20°S). Tsetse flies are narrow bodied, yellow to dark brown, and 6–13.5 mm long. When resting, their wings are held over the back in a scissor-like configuration. The thorax has a dull greenish color with inconspicuous spots or stripes. The abdomen is light to dark brown.* Both sexes are avid blood feeders. One copulation renders a female fly fertile for her lifetime, during which she can produce as many as 12 larvae. She produces one larva at a time, retaining it within her uterus; after ~10 days, the larva is deposited on loose, sandy soil, where it digs in and begins pupation within 60–90 min. This pupation period averages ~35 days, after which the adult emerges. Adult flies feed avidly on vertebrate blood approximately every 3 days.

*Tsetse flies serve as the intermediate hosts for several species of trypanosomes that cause fatal diseases of both domestic animals (nagana) and people (African sleeping sickness). Trypanosomes invade the blood, lymph, CSF, and various organs of the body, such as the liver and spleen. Nagana, a related complex in cattle caused by Trypanosomabrucei, has occurred throughout enormous areas estimated to be as great as one quarter of the African continent. The disease is fatal to horses, mules, camels, and dogs. Cattle, sheep, and goats usually survive, except when parasitized by certain strains. Many wild ungulates native to Africa show no evidence of harm.

*Tsetse flies can be identified by their honeybee-like appearance, the long proboscis with its onion-shaped bulb at the base, and the unique wing venation with the characteristic cleaver- or hatchet-shaped cell in the center of the wing.

*Catching and trapping (tsetse traps), bush clearing, fly screens, repellents, insecticides, and sterile male release techniques.

Lice *Horses and donkeys may be infested by 2 species oflice,Haematopinusasini, the horse sucking louse, and Damaliniaequi, the horse biting louse. Both species are worldwide in distribution. Normally, H asini is found at the roots of the forelock and mane, around the base of the tail, and on the hairs just above the hoof. D equi prefers to oviposit

*Lice live within the microenvironment provided by the skin and its hair or feathers, and are transmitted primarily by contact between hosts.In temperate regions, lice are most abundant during the colder months and often

*Pediculosis is manifest by pruritus and dermal irritation with resultant scratching, rubbing, and biting of infested areas.*A generally unthrifty appearance, rough coat

*Skin lesions due to rubbing,fleces have tufts protruding and lose their brightness

*Separate from allergic dermatitis

*Based on the presence of lice. The hair should be parted, and the skin and proximal portion of the coat examined with the aid of light if indoors. The hair of large animals should be parted on the face, neck, ears, topline, dewlap,

*Organophosphates,syntheticpyrethroids and macrocylic lactones

*Premises recently vacated by infested stock should be disinfected before being used for clean stock.* Wipe-on formulations of permethrin, permethrin plus diflubenzuron, and pyrethrins are available for lice control

on the finer hairs of the body and is found on the sides of the neck, the flanks, and the base of the tail.

are difficult to find in the summer. Lice are largely host-specific, living on one species or several closely related species. Anoplura are parasites of mammals. However, Mallophaga infest both mammals and birds.

*Transmission usually occurs by host contact. Lice dropped or pulled from the host die in a few days, but disengaged ova may continue to hatch over 2–3 wk in warm weather.

*Lowered production in farm animals are common.

* In severe infestations, there may be loss of hair and local scarification. Extreme infestation with sucking lice can cause anemia.

escutcheon, tail base, and tail switch. The head, legs, feet, and scrotum should not be overlooked.

on horses.* Horses may also be dusted with coumaphos.

MANGE IN HORSES

Sarcoptic Mange *Sarcoptesscabieivarequi is rare in the USA but is the most severe type of mange in horses

*Female mites from shallow burrow in the lower stratum corneum of the skin in which they deposit eggs.Development for both sexes includes the larval stage,two nymphal stages prior to the molting to the adult

*Later papules and vesicles occur and the skin becomes thickened,coveredwih pale scabs and the hair is lost

*The first sign is intense pruritus due to hypersensitivity to mite products. Regions protected by long hair and lower parts of the extremities are usually not involved.

*Early lesions appear on the head, neck, and shoulders.

*Lesions start as small papules and vesicles that later develop into crusts. Alopecia and crusting spread, and the skin becomes lichenified, forming folds. If untreated, lesions may extend over the whole body, leading to emaciation, general weakness, and anorexia.

*The horses may be affected by psoropticor chorioptic mange but the lesions are most common at the base of the mane and tail and at the back of the pastern respectively

*Skin scrapings*Biopsy

*Macrocylic lactone endectocides are preffered products*Prefarrowing treatment with Ivermectin to prevent transmission

*Organophosphate insecticides or lime-sulfur solution can be used by spraying, sponging, or dipping. Treatment should be repeated at 12- to 14-day intervals at least 3–4 times. Alternatively, the oral administration of ivermectin or moxidectinat 200 μg/kg can be attempted. Several treatments are required 2–3 wk apart. It is important to treat all contact animals.

Psoroptic Mange *Pruritus is characteristic.*Psoroptesequi rare in horses; Pcuniculi can sometimes cause

*Spread of ear mite in the horses can occur by grooming

*The mites migrates to all parts of the skinand prefers

*Production of a large,thick crust on the part of the body

*It produces lesions on thickly haired regions of the body,

*Lesions start as papules and alopecia and

-ELISA test has been developed

Treatment is as for sarcoptic mange

*Affected ears should be cleaned of all wax and ear

otitis externa in horses and may cause head shaking.

or by the use of infected harness

areas coveredwith hair or foal.Salivary secretions and mite excreta contain proteinases that result in a severe allergic pruritis

carrying long hair,the base of the hair and hairless areas such as the udder, prepuce and axilla

*Severe irritation in the ear,shaking of the head,rubbing of the head, tenderness of the poll

such as under the forelock and mane, at the base of the tail, under the chin, between the hindlegs, and in the axillae.

develop into thick, hemorrhagic crusts. Mites are more easily recovered from skin scrapings compared with sarcoptic mange.drawn to the condition because of the horse rubbing its head,by swelling around the base of the ear,or by resentment to the bridle passing over the ears.In some horses the affected ear may droop

preparations containing benzene hexachloride should be used a weekly intervals

Chorioptic Mange (Leg Mange) *Chorioptic mange is common in heavy breeds of horses.

*Widespread*Mostly draft and other working horse*Most horses in group affected

*Causes an allergic, exudative dermatitis*The yellowish serous exudates coagulates and breaks as the hair grows so that the small scabby lessons are seen on the hair

*Papules are seen first, followed by alopecia, crusting, and thickening of the skin. A moist dermatitis of the fetlock develops in chronic cases.

*Lesions caused by Chorioptesequi start as a pruritic dermatitis affecting the distal limbs around the foot and fetlock.

*Greasy heel *“Greasy heel” in draft horses

-washing encrusted areas with oil of salicylic acid and later removal of crust with a stiff brush,eradication was achieved

Topical treatments recommended for other manges are effective

Demodectic Mange *Demodexequi is rare in horses. The mites live in the hair follicles and sebaceous glands; D equi lives on the body, and D caballi in the eyelids and muzzle

*Spread via grooming tools and rugs*Rare

*Invasion of hair follicles and sebaceous gland leads to chronic inflammation,loss of the hair fiber and many instances the development if secondary staphyloccocal

*Patchy alopecia and scaling or as nodules.

*Lesions appear on the face, neck, shoulders, and forelimbs. Pruritus is absent. This disease has been reported in association with chronic corticosteroid treatment.

*The commonest error is to diagnose the disease as a non-specific staphyloccocal infection

*Deep-seated ringworm in horses has much common with demodicosis

*Unknown *This disease has been reported in association with *Chronic corticosteroid treatment

*No effective treatment regimens have been developed. Amitraz, used in other species, is contraindicated in horses because it can cause severe colic and death.

Trombiculidiasis (Chiggers, Harvest Mite)

*Trombiculid mites can parasitize the skin of horses, especially during the late summer and fall. The adult mites live on invertebrates and plants; the larvae normally feed on small rodents, but they can opportunistically feed on humans and domestic animals including horses.

*Lesions consist of severely pruritic papules and wheals.

*Specific treatment is not required

*The pruritus can be controlled with glucocorticoids. Repellents may help prevent infestation.

Straw Itch Mite (Forage Mite) *These mites usually feed on organic material in straw and grain and can opportunistically infest the skin of horses.

*Papules and wheals appear on the face and neck if horses are fed from a hay rack, and on the

*Pruritus is variable and can be controlled with glucocorticoids.

muzzle and legs if fed from the ground.

URTICARIA*Hives*Nettle rash

*It is an allergic condition characterized by the appearance of wheals on the skin surface

Caused by:Exogenous hives

>Toxic irritating substance of the stinging nettle>Stings or bites of insects>Medications/Chemicals(Carbolic acid, Turpentine, Carbon disulfide or Crude oil)

Endogenous/Symptomatic hives>Young horses>Inhalation or absorption of ingested allergens

>May be associated with intestinal parasite

*Though they can occur during any season, it is a common problem during the summer months.

Immunologic causes include insect bite hypersensitivity caused by stable flies, mosquitoes, culicoides (biting midges), horse flies, and chiggers.

*The lesions of urticaria are characteristic of an allergic reaction. A primary dilatation of capillaries causes erythema of the skin. Exudation from the damaged capillary walls results in local edema of the dermis, which swelling and pallor due to compression of the capillaries. The lesion usually remains red in the edges. Only the dermis, and sometimes the epidermis, is involved.

*Wheals or plaques appear within a few minutes or hours of exposure to the causative agent

*Cutaneous eruptions are preceded by fever, anorexia, or dullness in severe cases

*Often become excited and restless

*Elevated, round, flat-topped, and 0.5-8in (1-20cm) in diameter, may be slightly depressed in the center

*Develop on any part of the body but occur mainly on the back, flanks, neck, eyelids and legs. In advance cases, they may be found on the mucous membranes of the mouth, nose, conjunctiva, rectum and vagina.

*Angioneurotic edema-involves subcutaneous tissue rather than the skin and the lesions are much larger and more diffuse

-In urticaria, the lesions can be palpated in the skin itself

*Based on clinical signs

*Acute Urticaria

>Glucocorticosteroids(Hydrocortisone sodium succinate; Prednisolone sodium succinate or Hemisuccinate

>Dexamethasone (0.1mg/kg)

>Epinephrine: may be given in life- threatening situations

*ChronicUrticaria

>Antihistamine hydroxyzine (0.4-0.8 mg/kg, bid, or the tricyclic antidepressant doxepin (which have antihistaminic properties) at 3mg/5kg, bid

*Eradication of the causalInsect and plants*Keeping horses stalledat dawn and dusk wheninsects are at their peak

Dermatophilosis*Dematophilus infection*Cutaneous streptothricosis

****erroneously called Mycotic Dermatitis

*The infection is caused by a species of actinomycete, a microorganism that resembles bacteria and funguses. Factors such as prolonged wetting by rain, high humidity, and high temperature, increase the occurrence of dermatophilosis. The organism can live in the skin quietly until infection is stimulated by climatic conditions. High humidity and moisture increases the release of spores and spreads the infection. Epidemics usually occur during the rainy season.

*It is seen worldwide but is more prevalent in tropical environments where rain is frequent and humidity is high.

* Seen in all ages but most prevalent to young, in animals chronically exposed to moisture and in immune-suppressed host

Transmission:>Direct contact between animals through contaminate environments or possibly via biting

*In chronic infections, scabs and crusts can spread over a large portion of the body, particularly along the back. Itching is variable. Some wounds may be painful.

*Lameness and loss of performance may occur in horses that are severely affected around the pasterns.

*Horses with long Winter hair coats:=Developing matted hair and paint brush lesions leading to crust or scab formation with yellow green pus present under can larger scabs

Short Summer Hair:=matting and scab formation is uncommon; loss of hair with fine paint brush effect can be extensive

*Depends on the appearance of wounds in diseased animals and the finding of the actinomycete in skin smears or culture

*Diagnostic test is microscopic examination of scabs or impression smears of the underside of fresh wounds.

*Infected horses should be isolated from other animals to reduce spread of the disease.*Careful attention to the cleanliness of living areas, tack, blankets, grooming tools, and other accessories is required and can help control spread of the disease.* Control insects

insects

Reservoir:>Asymptomatic chronically infected animals

Equine eosinophilic granuloma

*Nodular necrobiosis or collagenolytic granuloma with collagen degeneration

*It is the most common nodular skin disease in horses. There are many proposed causes; however, insect bite reactions are the most likely. Trauma and other environmental allergies may also be involved. Many collagenolytic granulomas occur during the warmer months of the year and may recur seasonally. Some may persist year round or distinctively occur under tack and saddle areas where pressure and trauma occur.

*Lesions vary in size and number from less than ¼ inch (0.5 centimeter) to larger than 2 inches (5 centimeters) and usually occur over the neck, trunk and back. Some horses can develop a generalized form with hundreds of pea-sized nodules over most of the body. The overlying skin is usually normal but on occasion may open and ulcerate. More chronic lesions may calcify and become “rock hard;” such lesions are often the most difficult to treat effectively.

BENIGN, NONVIRUS-ASSOCIATED PAPILLOMATOUS LESIONS

Epidermal hamartomas (nevi) *Are rare proliferations identified only in dogs, most often in the young.

*They are benign, but their appearance is unpleasant, and the extensive hyperkeratosis is prone to secondary bacterial infection.Some forms are associated with pustules and acantholytic cells.

*Epidermal nevi appear as pigmented, hyperkeratotic, vaguely papillated papules and plaques that are occasionally arranged in a linear pattern.

*Localized lesions can be excised; dogs with multiple lesions or lesions too large to be surgically removed may be responsive to isotretinoin or etretinate.

*Use of topical keratolytic shampoos and emollients.

HELMINTHS OF THE SKIN

CUTANEOUS HABRONEMIASIS*Summer sores*Jack sores*Bursatti

*Is a skin disease of Equidaeaused in part of by the larvae of the spirurid stomach worm

*When the larvae emerge from flies feeding on pre-existing wounds or on moisture of the genitalia or eyes,they migrate into and irritate the

*Non healing, reddish brown, greasy skin granulomas that contain yellow calcified material the size of rice grains

*The lesions become chronic and healing is protracted

*Skin scraping of the lesions

*Based on finding nonhealing, reddish brown, greasy skin granulomas that contain

*Symptomatic treatment, including; >use of insect repellents, may be of benefit, and organophosphates applied topically

*Control of fly host and regular stackingOf manure, together with anthelminthic therapy

tissue yellow, calcified material the size of rice grains.

to the abraded surface may kill the larvae.

*Surgical removal or cauterization ofthe excessive granulation tissue may be necessary.

>Ivermectin (200 μg/kg) has been effective, and although there may be temporary exacerbation of the lesions (presumably in reaction to the dying larvae), spontaneous healing may be expected.

*Moxidectinat 400 μg/kg also appears to be active against Habronemasppinthe stomach.

Onchocerciasis *O cervicalis is found in the ligamentumnuchae and possibly other sites in Equidae

*Adults are associated with connective tissues; they are very thin and 3–60 cm long. Microfilariae are found in the dermis and on rare occasions circulating in peripheral blood. The microfilariae lack a sheath and are 200–250 μm long with a short, sharply pointed tail.

*Culicoidessppare the intermediate hosts for O cervicalis, and Simuliumspp for O gutturosaand O lienalis

*O cervicalis has been associated with fistulous withers, poll evil, dermatitis, and uveitis in horses.

*Adults in the ligamentumnuchae induce inflammatory reactions ranging from acute edematous necrosis to chronic granulomatous changes, resulting in marked fibrosis and mineralization. Mineralized nodules are more common in older horses. Although lesions are found in these areas, presumably associated with dead parasites, it is generally agreed that fistulous withers and poll evil are not caused by O cervicalis infections.

*These lesions may be pruritic and often

*Full thickness Skin biopsy >6mm

*No treatment is effective against the adults

>Ivermectin, Moxidectin is efficacious against microfilariae

include areas of scale, crusts, ulceration, alopecia, and depigmentation.

PARAFILARIA MULTIPAPILLOSA *P multipapillosa is found in the subcutaneous tissues of horses in various parts of the world

*It is similar in size, appearance, life cycle, and development to P bovicola. Blood-sucking Haematobiaspp are thought to be the invertebrate hosts.

*It is especially common in the Russian steppes and eastern Europe.

*Skin nodules, particularly on the head and upper forequarters.

*These bleed transiently but often profusely (“summer bleeding”) and then resolve; other hemorrhaging nodules develop as the parasite moves to a different site.

*Occasionally, the nodules suppurate. The nodules and bleeding are unsightly and interfere with harnesses of working horses but generally are of little consequence. The clinical signs are pathognomonic.

*Carcass lesions can be differentiated from bruising by the presence of numerous eosinophils in Giemsa-stained impression smears made from the lesions.

*In addition, affected tissue has a characteristic, disagreeable, metallic smell.Usually, only small numbers of worms are present in affected carcasses and are often difficult to find because of their color and the accompanying inflammatory reaction.

*Microscopic examination of the sediment

*Affected tissues can be incubated in warm saline to facilitate the recovery of parasites.

*An ELISA for the detection of antibodies against P bovicola has been developed.

*No satisfactory treatment has been reported

Ivermectin (200 μg/kg) or nitroxynil (20 mg/kg) given by SC injection reduces the number and surface area of Parafilaria lesions.

Animals should be treated at least 70–90 days before slaughter to provide sufficient time for lesions to resolve. The treatment-to-slaughter interval should not be >120 days because unaffected larval forms of the parasite may induce fresh lesions as they mature.

*Fly control may reduce the incidence.

PHOTOSENSITIZATION *Photosensitization occurs when skin (especially areas exposed to light and lacking significant protective hair, wool, or pigmentation) becomes more susceptible to ultraviolet light due to the presence of photodynamic agents. Photosensitization differs from sunburn and photodermatitis, as both of these conditions result in pathologic skin changes without the presence of a photodynamic agent.

*Most compounds that are important causes of photosensitivity in veterinary medicine are plant-derived.

*Photosensitization occurs worldwide and can affect any species, but is most commonly seen in cattle, sheep, goats and horses.

*Inphotosensitization, unstable high-energy molecules are formed when photons react with a photodynamic agent. These high-energy molecules initiate reactions with substrate molecules of the skin, causing the release of free radicals that in turn result in increased permeability of outer cell and lysosomalmembranes. Damage to outer cell membranes allows for leakage of

*Dermatologic signs associated with photosensitivity are similar regardless of the cause. Photosensitive animals are photophobic immediately when exposed to sunlight and appear agitated and uncomfortable. They may scratch or rub lightly pigmented, exposed areas of skin (eg, ears, eyelids, muzzle). Lesions initially appear in white-haired,

*Severe phylloerythrinemia and bright sunlight can induce typical lesions even in black-coated animals

*Evaluation of serum liver enzymes and liver biopsies*Examination of blood,feces and urine for porphines

*Diagnosis of photosensitization is based on clinical signs, evidence or history of exposure to photosensitizing agents or hepatotoxins, and characteristic lesions. Photophobia in combination with erythema and edema of hairless, nonpigmented areas of skin is strongly suggestive of the disease. The period from exposure to photodynamic or hepatotoxic agents

*The prognosis for animals with hepatogenous photosensitization and porphyria is poor, however the prognosis for animals with primary photosensitization is generally good. Treatment involves mostly palliative measures. While photosensitivity continues, animals should be shaded fully or, preferably, housed and allowed to graze only during darkness. The

*Unknown

Primary PhotosensitizationPrimary photosensitization occurs when the photodynamic agent is either ingested, injected, or absorbed through the skin. The agent enters the systemic circulation in its native form where it results inskin cell membrane damage after the animal is exposed to ultraviolet light. Examples of primary photosensitizing agents include hypericin (from Hypericumperforatum [St. John's wort]) and fagopyrin (fromFagopyrumesculentum [buckwheat]). Plants in the families Umbelliferae and Rutaceae contain photoactive furocoumarins (psoralens), which cause photosensitizationin livestock and poultry.Ammimajus (bishop's weed) and Cymopteruswatsonii (spring parsley) have produced photosensitizationin cattle and sheep, respectively. Ingestion of A majus and A visnaga seeds has produced severephotosensitizationin poultry. Species of Trifolium, Medicago (clovers and alfalfa), Erodium, Polygonum, and Brassica have been incriminated as primary photosensitizing agents. Many other plants have been suspected, but the toxins responsible have not been identified (eg, Cynodondactylon [bermudagrass]). Additionally, coal tar derivatives such as polycyclic aromatic hydrocarbons, tetracyclines, and some sulfonamides have been reported to cause primary photosensitization. Phenothiazine anthelmintics have been reported to cause

cellular potassium and cytoplasmic extrusion. Lysosomal membrane damage releases lytic enzymes into the cell. This can lead to skin ulceration, necrosis, and edema. The time interval between exposure to the photodynamic agent and the onset of clinical signs depends on the type of agent, its dose, and the exposure to sunlight.

nonpigmented, or hairless areas such as the nose and udder. However, severe phylloerythrinemia and bright sunlight can induce typical skin lesions, evenin black-coated animals. Erythema develops rapidly and is soon followed by edema. If exposure to light stops at this stage, the lesions soon resolve. When exposure is prolonged, lesions may progress to include vesicle and bulla formation, serum exudation, ulceration, scab formation, and skin necrosis. The final stage involves skin sloughing. In cattle, and especially in deer, exposure of the tongue while licking may result in glossitis, characterized by ulceration and deep necrosis. Irrespective of coat color, cattle may develop epiphora, corneal edema, and blindness.Depending on the initial cause of the accumulation of the photosensitizing agent, other clinical signs may be seen. For example, if the photosensitivity is hepatogenous, icterus may be present. In bovine congenital erythropoietic

to the onset of clinical signs can vary from several hours up to 10 days. Clinical signs; elevated serum biochemical measurements including sorbitol dehydrogenase, gamma glutamyltransferase, alkaline phosphatase, and direct bilirubin; and gross or histologic signs of liver disease help support a diagnosis of hepatogenous photosensitization. A presumptive diagnosis of porphyria is based on signalment (sex, breed, age) combined with clinical signs, and a definitive diagnosis can be made by measuring porphyrin levels in blood, feces, and urine.

severe stress of photosensitization and extensive skin necrosis can be highly debilitating and increase mortality. Corticosteroids, given parenterally in the early stages, may be helpful. Secondary skin infections and suppurations should be treated with basic wound management techniques, and fly strike prevented. The skin lesions heal remarkably well, even after extensive necrosis.

primary photosensitivity in cattle, sheep, goats, and swine.

Aberrant Pigment MetabolismType II photosensitivity due to aberrant pigment metabolism is known to occur in both cattle and cats.In this syndrome, the photosensitizing porphyrin agents are endogenous pigments that arise from inherited or acquired defective functions of enzymes involved in heme synthesis. Bovine congenital erythropoietic porphyria and bovine erythropoieticprotoporphyriaare the most commonly reported diseases in this category.

Secondary (Hepatogenous) PhotosensitizationSecondary or type III photosensitization is by far the most frequent type of photosensitivity observed inlivestock. The photosensitizing agent, phylloerythrin (a porphyrin), accumulates in plasma due to impaired hepatobiliary excretion. Phylloerythrin is derived from the breakdown of chlorophyll by microorganisms present in the GI tract. Phylloerythrin, but not chlorophyll, is normally absorbed into the circulation and is effectively excreted by the liver into the bile. Failure to excrete phylloerythrin due to hepatic dysfunction or bile duct lesions increases the amount in the circulation. Thus, when it reaches the skin, it can absorb and release light energy, initiating a phototoxic reaction.Phylloerythrin has been incriminated as the phototoxic agent in the following conditions: common bile duct occlusion; facial eczema; lupinosis; congenital photosensitivity of Southdown

porphyria, discoloration of dentin, bone (and other tissues), and urine often accompanies the skin lesions. Photodermatitis is the sole manifestation observed in bovine erythropoieticprotoporphyria.

and Corriedale sheep and poisoning by numerous plants including Tribulisterrestris (puncture vine), Lippiarehmanni, Lantana camara, several Panicumspp (kleingrass, broomcorn millet, witch grass), Cynodondactylon,Myoporumlaetum (ngaio), and Nartheciumossifragum (bog asphodel).Photosensitization also has been reported in animals that have liver damage associated with various poisonings: pyrrolizidine alkaloid (eg, Seneciospp, Cynoglossumspp, Heliotropiumspp, Echiumspp; cyanobacteria (Microcystisspp, Oscillatoriaspp), Nolinaspp (bunch grass), Agave lechuguilla (lechuguilla), Holocalyxglaziovii, Kochiascoparia, Tetradymiaspp (horse brush or rabbit brush), Brachiariabrizantha, Brassica napus, Trifoliumpratense and T hybridum (red and alsike clover), Medicago sativa, Ranunculus spp, phosphorus, and carbon tetrachloride. Phylloerythrin is likely the phototoxic agent in many of these poisonings.

Type IV PhotosensitivityPhotosensitivity where the pathogenesis is unknown or the photodynamic agent is not identified is classified as type IV. One such example involves a case of primary photosensitivity in cattle presumed to be caused by Thlaspiarvense (field pennycress) even though field pennycress had not been reported to cause photosensitization. Outbreaks of photosensitization have been reported in cattle exposed to water-damaged alfalfa hay,

moldy straw, and foxtail-orchardgrass hay. These cases were suspected to be hepatogenous in origin. Ranunculus bulbosus (buttercup) has also been presumed to be a cause of hepatogenous photosensitization. Other plants associated with photosensitizationinclude winter wheat (cattle), Medicagospp (alfalfa), Brassica spp (mustards), and Kochiascoparia(fireweed). Many of these plants are believed to be type I photosensitizers. Forages such as oats, wheat, and red clover have been suspected in cases of photosensitization and may be associated with specific environmental conditions such as heavy rainfall.

DERMATOPHYTOSIS*Ringworm

*It is an infection of keratinized tissue (skin, hair, claws)

*The agents >Trichophytonequinum ; T. mentagrophytes-main

>Microsporumgypseum; M. canis; T.verrucosumAre zoonotic

*Transmission:>Direct contact>Contaminated fomites>Grooming implements>Tack

*Dermatophytes can survive solely on outer cornified layers of the skin. Natural infection is acquired by the deposition of viable arthrospores or hyphae on the surface of the susceptible individual. After the inoculation in the host skin, suitable conditions favor the infection to progress through the stages of adherence and penetration. Development of host response is mostly by a T-cell mediated response of delayed-type hypersensitivity. Antibody formation does not seem to be protective. Natural defenses against dermatophytes depend on both immunological and

*Consist of one or more patches of alopecia

-Erythema-Scaling-Crusting

*EARLY:- May resemble papularurticaria but progress with crusting and hair loss within a few days*Most lesions are seen in the saddle and girth areas (“girth itch”)

*Dermatophilosis

*Pemphigus foliaceus

*Bacterial Folliculitis

*Fungal culture-most accurate

*Wood’s lamp examination

*Direct microscopy of hair or skin

*Topical (because systemic therapy is expensive and of unproven efficacy)

*Whole body rinses

*Individual lesions: Clotrimoxazole/Miconazole preparations

*Grooming implements and tack should bedisinfected, and affectedhose should be isolated.

nonimmunological mechanisms

SADDLE SORES COLLAR GALLS *The area of riding horses that is under saddle, or the shoulder area of those driven in harness, is frequently the site of injuries to the skin and deeper soft and bony tissues.

*Absolute rest of the affected parts is necessary. During the early or acute stages, astringent packs (Burow solution) are indicated. Chronic lesions and those superficially infected may be treated by warm applications and topical or systemic antibiotics. Hematomas should be aspirated or incised. Necrotic tissue should be removed surgically. In severe folliculitis and furunculosis, antibiotics, ideally chosen on the basis of culture and sensitivity, are always indicated. Scars and/or leukotrichia (white hairs) are common sequelae of healed areas. Recurrence of hematomas, seromas, and/or sloughing skin upon initial saddlings of a young Quarter horse or Paint horse should elicit suspicion of the genetic disease hereditary equine dermal asthenia.

*Emaciated horses are at increased risk. Chronic saddle sores are characterized by a deep folliculitis/furunculosis (boils) with fibrosis or a localized indurative and proliferative dermatitis. Lesions are usually caused by poorly fitting tack.

*Sores affecting only the skin are characterized by inflammatory changes that range from erythematous to papular, vesicular, pustular, and finally necrotic.

*Frequently, the condition starts as an acute inflammation of the hair follicles and progresses to a purulent folliculitis.

*Affected areas show hair loss and are swollen, warm, and painful. The serous or purulent exudate dries and forms crust. or moist necrosis.

*Clinical signs vary according to the depth of injury and the complications

*Advanced lesions are termed “galls.” When the skin and underlying tissues are more severely damaged, abscesses may develop.

*These are characterized as warm, fluctuating, painful swellings from which purulent and serosanguineous fluid can be aspirated.Severe damage to the skin and subcutis or deeper tissues results in dry

*A simple DNA test, performed on the hair bulbs of the tail, will confirm this diagnosis.

*Identification and elimination of the offending portion of tack is more important than any other treatment.

*Excoriations and inflammation of the skin of the saddles and harness regions are treated as any other dermatosis.

*Absolute rest of the affected parts is necessary.

*During the early or acute stages, astringent packs (Burow solution) are indicated.

*Chronic lesions and those superficially infected may be treated by warm applications and topical or systemic antibiotics.

*Hematomas should be aspirated or incised. Necrotic tissue should be removed surgically.

*In severe folliculitis and furunculosis, antibiotics, ideally chosen on the basis of culture and sensitivity, are always indicated.A simple DNA test, performed on the hair bulbs of the tail, will confirm this diagnosis.

SCRATCHES *Often associated with poor *Standardbreds : *Skin is itchy, *Removing of the

*Greasy heel*Dermatitis verrucosa

stable hygiene, but no specific cause is known.

frequently affected in the spring when tacks are wet

sensitive and swollen in acute stages; later it becomes thickened and most of the hair is lost.*Surface of the skin is soft, and the grayish exudate commonly has a fetid odor*Chronic: with vegetative granulomas*Lameness may or may not be present ; it can be severe and associated generalized cellulitis of the limb. As the condition progresses, there is thickening and hardening of the skin of the affected regions, with rapid hypertrophy of subcutaneous fibrous tissue

hairRegular washing and cleansing with warm water and soap to remove all soft exudates, drying and applying an astringent dressing.If granulomas appear, they can be cauterizedCellulitis require systemic antibiotic therapy and tetanus prophylaxis

DERMATOPHILOSIS*Dematophilus infection*Cutaneous streptothricosis

****erroneously called Mycotic Dermatitis

*Dermatophiluscongolensis *More prevalent in the tropics

Transmission:>Direct contact between animals through contaminate environments or possibly via biting insects

Reservoir:>Asymptomatic chronically infected animals

*Seen in all ages but most prevalent to young, in animals chronically exposed to moisture and in immune-suppressed host

*Horses with long Winter hair coats:=Developing matted hair and paint brush lesions leading to crust or scab formation with yellow green pus present under can larger scabsShort Summer Hair:=matting and scab formation is uncommon; loss of hair with fine paint brush effect can be extensive

*DermatomycosisDermatophytosisImmune-mediated scaling diseases oh horse

*Presumptive Diagnosis:Appearance of lesions in clinically diseased animals

Definitive Diagnosis:demonstration of organism in cytologic preparations

isolation via culture

skin biopsy

*Lesion should be gently soaked and removedTopical antibacterial shampoo therapy is Antimicrobials(erythromycin, spiamycin, penicillin G, ampicillin, chloamphenicol, streptomycin, amoxicillin, tetracycline, novobiocin

Wart infection *Infection with papilloma virus is relatively common in young horses kept in a large grot. Warts are usually self-limiting condition lasting 2-6 months, however warts are contagious to other horses sharing feeders and tack.

*Infectious to horses only and can be transmitted to or from man or other species

*Small, single or multiple, cauliflower-like, raised, rough lumps especially on the muzzle, eyelids and inner surface of the ears, jowl and chest

(rarely on the belly and hindlegs)

Equine Sarcoids *Most commonly diagnosed tumor of the equids

*No significant gender or age is predisposition

*6 distinct clinical entities are recognized:Occult-flat, gray, hairless and persistentVerrucous-gray, scabby or warty in appearance and may contain small, solid nodules; possibly surface ulceration; well-defined or cover large, ill-defined areas.Nodular-multiple, discrete, solid nodules of variable size; may ulcerate and bleedFibroblastic fleshy masses, either with a thin pedicle or a wide flat base, that commonly bleed easily; may have a wet, hemorrhagic surfaceMixed variable mixtures of 2 or more typesMalevolent-are extremely rare, aggressive tumor that spreads extensively through skin; cords of tumor tissue intersperse with nodules and ulcerating fibroblastic lesion

*The lesions are characteristically nodular growths of viable tissue and if there is no traumatic injury,with nodiscontinuity of the covering epidermis

*Can occur in single or multiple lesions in different forms; can occur anywhere on the body

TICKS OF HORSES *Are importance in the production of animal diseases

*Life cycles vary widely both in the number of hosts required and the hostsspecificity.Animals are infested by larval or nymphal states on the ground.

*The definitive sign of tick infestation is the presence of a tick on the animal. Ticks that have been on an animal only a short time (an hour to a few days) appear flat. Ticks that have been on an animal for several

*Skin damage due to biting and rubbing anemia

*Ticks easily found,should be identified to species

*Dipping,pour-ons and injectable acaricides

*Regular treatment at intervals dependenton the life cycle of the tick,pasture spelling to destroyfree living stages,(Kahn, 2010)the use of resistant and vaccination all play a part

hours or days appear much more rounded due to the blood they have consumed. Diagnosis is by appearance of tick bite marks on the animal and the presence of the offending pest.

References:Kahn, C. M. (2010). THE MERCK VETERINARY MANUAL 10th Edition. WhiteHouse Station.N.J.,USA: Merck & Co.,Inc.,.Radostits, O. (n.d.). Veterinary Medicine Diseases of Cattle, Horses, Sheep, Pigs, and Goats.

In Partial Fulfillment of the Requirements in Equine Medicine

Urinary Diseases of Horses

Submitted to: Dr. Karen B. Gaerlan

Submitted by: Dongga-as, Chester N.Payad, Bellamy