F770
Skin Problems

Bacterial Skin Infections:

Fungal Skin Infections:

1. Dermatophytosis (Ringworm, lumpy wool, club lamb fungus): Dermatophytes are a "keratinophilic" (skin-loving) species of fungi which are responsible for the commonly known syndrome "ringworm." Because the disease is not caused by a worm at all, this term is rather misleading.
   
   Causative Agents: The following are different species of dermatophytes that have been found to infect sheep and goats: Microsporum canis, Trichophyton verrucosum, T. gypseum, and T. mentagrophytes.
   
   Clinical Signs: Generally, these fungal infections appear as areas of hair loss, with flaky, crusty, irritated skin. The face, ears and neck are commonly involved. These infections usually cause some degree of discomfort to the animal, resulting in pruritus (itching).
   
   Transmission: Sheep and goats can get ringworm from several sources. They can get the fungi directly from other animals or from the soil. They can also be exposed to fungi found on surfaces, such as contaminated equipment, feeders, and bedding. The aggressive shearing and washing of show lambs makes these animals very susceptible to fungal infections.
   
   Diagnosis: A dermatophytosis infection is diagnosed by performing a culture of the hair and skin from an affected individual. This is accomplished by taking hair samples from the outside edge of a few of the lesions. The hair is then placed on fungal specific media and any dermatophytes are allowed to grow. Most cultures can be performed and interpreted by a veterinarian. Results may take up to 10-14 days to provide an accurate answer. Other techniques commonly used include a Wood’s lamp test and direct microscopic examination of hair and scales of affected animals. Wood’s lamp testing involves close examination of the skin of the animal with a special light which causes the hair and skin to fluoresce a bright apple-green color if the animal is infected with a dermatophyte. Wood’s lamp testing is not accurate in all cases. Direct microscopic examination with the aid of potassium hydroxide preparations can also be performed.
   
   Treatment (choose one of the following):
   • Chlorhexidine (diluted 1:4 in water) applied 3 times a day until resolved.
   • Topical iodine compounds (2-5%) can be applied to the lesions.
   • Captan, a plant fungicide, (mixed 1 ounce of the 50% powder to a gallon
   • of water) applied daily for 3 days and then weekly until resolved.
   • Allow the animal as much exposure to sunlight as possible.
      
   Prevention and Public Health Concerns: Dermatophytosis is "zoonotic," which means that the disease is contagious to people. Care should be taken when an animal is diagnosed with dermatophytosis. Follow the veterinarian’s instructions when treating ringworm. If ringworm is identified as the cause, all bedding, clippers, brushes, and pens must be thoroughly cleaned and disinfected. A 1:10 dilution of household bleach can be used. The fungal spores remain viable for up to 18 months in the environment. Frequent washing of hands and clothing that comes into contact with the affected animal is very important.

1. Lice (Pediculosis):
   Introduction and Causative Agents: Most lice (louse = singular) infestations occur during the winter months. The infections are often more severe in sick or weak animals. There are basically two categories of lice: ones that bite or chew and ones that suck when obtaining their nourishment. Biting lice can be identified by their round head, while sucking lice have a narrow head. This table identifies the common biting and sucking lice associated with sheep or goat infestations:
   
    

   Species of Animal Affected	Common Biting Lice	Common Sucking Lice
   Sheep	Damalinia ovis	Linognathus ovillus L. pedalis
   Goats	Damalinia caprae D. crassiceps D. limbata	Linognathus stenopis

   
   Clinical Signs: Lice are parasites of the skin which cause mostly superficial skin inflammation and itching. Many times the itching is so intense that the animal may suffer wool or hair loss, weight loss, and even lameness.
   
   Diagnosis: Diagnosing an infestation of lice is made by identifying the parasite using a microscope. Careful observation of the anatomy of the louse will aid a professional in identifying the specific species causing the infection.
   
   Treatment: Treatment of lice infections in sheep and goats is accomplished with the use of dips, dusts, or sprays including lime sulfur, coumaphos, and phosmet (see page B620 for additional details). Injectable products, such as ivermectin and doramectin, can also be used to treat the sucking lice infestations.
   
    

2. Melophagus ovinus (Sheep ked):
   Introduction: Sheep keds (Melophagus ovinus) are wingless parasites that feed on the blood of animals. Though commonly called sheep ticks, they are not actually ticks. The ked is reddish to grey in color, about 1/4 of an inch long, and has six legs. Most infections occur in the winter months; however, problems can occur year-round.
   
   Clinical Signs: The parasite moves rapidly from animal to animal, with moderate to heavy infections causing severe damage to the wool. It is spread by direct contact between animals. The ked causes damage to the wool in two ways. First, if the parasite load is great enough, the keds will suck enough blood to severely affect the nutritional health of the sheep. This will cause poor wool growth. Secondly, the excrement of the keds will stain the wool a reddish color and pupal stages of the ked can be found in the wool. The ked also causes damage to the skin (often called "cockle") and a pungent smell.
   
   Treatment: Controlling this parasite can be accomplished by dipping, spraying, dusting, and using certain pour-ons (see page B620 for additional details). Treatments should be repeated every 14-21 days.
   
    
3. Mites or Mange:
   Introduction: Scabies, mange, scab, or itch are all terms referring to mite infections that cause inflammation and irritation of the skin and itching (pruritus). Although most species of domestic animals are susceptible to scabies, each species of mites prefer a certain host animal. This prevents a permanent transfer of parasites between different host species. For example, the mite Psoroptes ovis prefers sheep as its host and will not permanently spread to cattle. This fact validates the separate control and eradication programs for sheep and cattle. Both sheep and goats are susceptible to mite infestations. Mange is more common in goats than in sheep, but is considered basically eradicated in the United States (except for demodectic mange). However, in many countries of the world, mange persists and remains a concern for the sheep/goat industry. These infections are most commonly spread by direct contact between animals.
   
   Generalized mite infections in sheep and goats are sometimes grouped under the common disease term of "mange." Mange is then more specifically broken down based on the species of mite which is responsible for the infection. In sheep and goats, the four types of mange most commonly encountered are psoroptic mange (caused by Psoroptes ovis), sarcoptic mange (caused by Sarcoptes scabiei), chorioptic mange (caused by Chorioptic ovis and C. caprae), and demodectic mange (caused by Demodex ovis and D. caprae).
   
   Impact of Mite Infections: These diseases cause significant losses and waste to the sheep and goat industry wherever they are a problem. Economic losses result from a reduction in the amount of meat and quality of wool/fiber produced. Control and prevention programs are a significant cost to the producer. On a larger scale, mite infections impact the local and international trade of animals.
   
   Causative Agents: The following are some of the most common mites that infect sheep and goats:
    
   1. Psoroptes communis ovis (psoroptic mange, sheep scab, common scabies, or Psoroptes cuniculi):
      Introduction: This mite is an important cause of mange in sheep and goats. It can occur at any age, but tends to be more common in adult animals. Most cases in sheep occur in the winter months, but milder infections can occur during the summer. The economic importance of common scabies exceeds any other type and possibly all other types combined. Psoroptic scabies is prevalent in the more temperate climatic zones of the world, including Iceland, Europe, Africa, Middle East, Balkans, Pakistan, India, and South and Central America. Australia, New Zealand, Canada, and the United States have eradicated the disease.
      
      Clinical Signs: The mites live on the skin surface and pierce the epidermis to feed on lymph. Small pustules develop at the puncture sites and these rupture exuding serum that forms a hard, yellow crust. In sheep, this lifts from the skin together with the wool. Often there is a hypersensitivity reaction to the presence of active mites that causes a significant amount of itching (pruritus). In goats, these mites like to infect areas with less hair such as the ears. These areas may experience hair loss (alopecia) and crusting. Sheep often have pieces of wool stuck between their teeth as a result of nibbling. A "nibble reflex," similar to that elicited in sheep with scrapie, may be obtained when rubbing the affected area. There is extensive loss of fleece and the exposed skin is thickened with raw patches. These raw patches are often secondarily infected with bacteria. The lesions occur particularly over the shoulders and sides but can spread over the whole body. The mites are found mostly at the edge of the expanding lesion which is characteristically moist. The lesions observed are the result of a combination of factors, including damage caused by the mites during feeding, the host’s immune responses to the mites, secondary bacterial infection, and self-inflected trauma in response to the irritation. In sheep, three phases of the infection are described:
      • Active winter scab - At peak severity this affects up to three-quarters of the body surface and occurs 6-12 weeks after the initial infection.
      • Active summer scab - This is a slowly progressive disease with increasing severity as winter approaches.
      • Latent scab - This describes a recovery phase following the onset of warmer summer weather. Often all the lesions are completely gone by mid-summer. Unless an effective treatment program has been started, relapse will occur the following winter.
         
      Diagnosis: In severe, active cases with large numbers of mites present, it is possible to actually see the mites at the edges of lesions. Placing suspected mite infested material on a dark background (i.e. carbon paper, black felt, etc.) will help in observing the tiny, light-colored mites. Unless there is known contact with another infected flock, microscopic confirmation will be required from skin scrapings taken from the animal. Because the mites live on the skin surface, the sample needs to be taken from the superficial or very top layers of skin. The sample should be taken from the edge of the lesion after removing any excess wool/hair. This skin scrapping can be done by using the edge of a scalpel blade with a drop or two of mineral oil on it. The oil will help the mites and debris adhere to the blade. If there is any uncertainty about the sample collected, take another sample from a different area. It is appropriate to include portions of the wool/hair fibers and any skin crusts or flakes in the sample. Once collected, the scraping should be placed in a mite-proof glass or plastic container for transmission to the lab.
      
      Treatment: Treatment for this problem involves dips and sprays including lime sulfur, coumaphos, and phosmet (see page B620 for additional details).
      
      * A Psoroptes ovis infection is a reportable disease. If this disease is suspected, local, regional, state, or federal veterinarians should be contacted.
       
   2. Sarcoptes scabiei (Sarcoptic mange, head scabies):
      Introduction: Sarcoptic mange is not found in the United States, but occurs in Europe, Africa, Middle East, Balkans, India, South America, and Central America. The disease generally develops in malnourished animals during late winter and persists for long periods of time. These mites like to infect areas with less hair such as around the eyes and ears. Itching (pruritus) is usually severe, with areas of hair loss (alopecia) and crusting as a result of self-trauma. Goats can have infections that involve the entire body. If the problem has been going on for a long period of time, the skin may appear thickened and raised. Weight loss is not uncommon for animals that suffer severe problems.
      
      Diagnosis: Diagnosing sarcoptic mange usually requires multiple deep skin scrapings. In challenging cases, specific mite treatment products (ivermectin or 1% lime sulfur dips) are often administered and the animal observed to see how it responds to the treatment. If the sheep/goat responds favorably to the treatment, a diagnosis of sarcoptic mange infestation can be made.
      
      Treatment: Treatment of sarcoptic mange is usually successful. Weekly lime sulfur dips can be very helpful; usually treatment for 4-12 weeks is sufficient for resolution. Ivermectin is a very effective drug which may be used either orally or as a series of subcutaneous injections.
      
      Like a Psoroptes ovis infection, this is a reportable disease. If Sarcoptes scabiei ovis is suspected, a local, regional, state, or federal veterinarian should be contacted.
       
   3. Chorioptes ovis and C. caprae (Chorioptic mange, foot mange) - This type of mite occurs commonly in sheep and goats, but is not considered to be of great economic or pathological importance. In sheep, the mites are found mainly in the interdigital spaces (between the toes), but can extend up the legs to the knees and scrotum. In goats, the mites infect the lower limbs, hindquarters, and abdomen. They can also be found around the scrotum, brisket, and eyes. The disease is generally mild, with some inflammation and pustule development.
      
      Like a Psoroptes ovis infection, this is a reportable disease. If a Chorioptes infection is suspected, a local, regional, state, or federal veterinarian should be contacted. Treatment is similar to the other mange infections.
       
   4. Demodex ovis and D. caprae (Demodectic mange, follicular mange) - This infection occurs in sheep, but clinical disease is rare and often of little significance. However, it may be the most common cause of mange in goats. The mites invade and live in hair/wool follicles and sebaceous glands of the neck, shoulders, and body. They cause the development of nodules with exudate. In a few cases, some intense irritation can occur. In kids the infection may spread rapidly. Deep skin scrapings are necessary to provide a diagnosis. Treatment involves weekly dipping (see page B620 for additional details).
       
   5. Psorergates ovis (Psorergatic scabies, sheep itch mite or mange) - Itch mange has occurred among the Merino breeds in Australia, New Zealand, Argentina, South Africa, and the United States of America. They feed by piercing the surface of the skin (epidermis) and ingesting the exuding fluids. The infected skin is dry, and flaky. Hair and wool fibers break easily, and remaining wool becomes cotted and matted. Like the other forms of scabies, intense itching causes infected sheep to bite, kick, and rub the parasitized areas.

Lumps and Masses

1. Squamous cell carcinoma:
   Introduction/Causative Agents: Squamous cell carcinoma (SCC) is probably the condition most frequently associated with the term "skin cancer." SCC arises from the most superficial layer of skin and is associated with exposure to excessive sunlight, old scars, and chronic skin irritation. This tumor is more common in older animals and in the Merino breed of sheep. The masses occur on the face, ears, and vulva.
   
   Clinical Signs: Skin in which squamous cell carcinoma arises may appear as an open sore or wound that does not heal, or may occur as cauliflower-like nodules of varying size.
   
   Diagnosis/Treatment: Histopathology is necessary for a diagnosis. Treatment of SCC most often includes surgical removal of the cancer. Many animals are culled early from the flock or herd. In all cases, it is important to avoid additional exposure to sunlight.
    
2. Melanoma and Hemangioma:
   Introduction/Clinical Signs/Diagnosis/Treatment: Both melanomas and hemangiomas are uncommon tumors found in small ruminants. They most often appear as raised lesions that vary in color. Histopathology is the primary method of diagnosis, and aggressive surgical removal of the tumor is the treatment of choice.
    
3. Warts (Papillomatosis)
   Cause: Warts in sheep are caused by papilloma viruses. Viruses have not been associated with warts in goats, however.
   
   Clinical Signs: Warts can be found on the head, neck, teats, ears, and penis. The lesions are white to grey, firm and raised. These lesions are harmless in almost all situations, except where mastitis or pain is involved. These warts are most common in animals under 2 years old.
   
   Disease Transmission: Warts are spread by direct contact from animal to animal. They can also be spread when contaminated equipment such as shearing, ear tagging, or tattooing instruments are not cleaned properly between animals.
   
   Treatment: Small warts can be crushed, pinched off, frozen (cryosurgery), or surgically removed. Many of the warts found in sheep and goats are often left alone until the body recognizes the lesions and the immune system clears the problem. This can take many months.
   
   Prevention: When an animal has a wart infection, it should be isolated from other animals. Any infected animal should also be kept from rubbing on feeders and posts that may be used by other animals. Cleaning of shearing, tagging, and tattooing equipment with a product like chlorhexidine is essential for preventing the spread of warts.
   
    

Introduction: A number of nutritional deficiencies or excesses can lead to skin disease. Notably among these are deficiencies of vitamin A, zinc, iodine, and copper.

Introduction/Clinical Signs: Wool slip is a term that has been coined to describe a problem that is associated with shearing housed ewes in the winter months. Wool slip usually occurs several weeks after shearing and can affect a single animal or a large percentage of the flock. The wool falls out usually leaving a pink bald lesion over the back of the ewe. It is common to see from 1/4 to 1/2 of the ewe’s back without any wool. This unsightly lesion causes much concern to producers who often wonder if their feed or mineral rations are lacking. Wool break is a condition where the wool stops growing and becomes weak. The wool will be lost in a few days to a few months.