Diseases of the Skin

Papillomas (Warts) Papilloma viruses are small, double-stranded DNA viruses of the Papovaviridae family. Some mammals have several distinct papilloma viruses—humans have >20; cattle, 6. Multiple papillomas (papillomatosis) of skin or mucosal surfaces generally are seen in younger animals and are usually caused by viruses. Papillomatosis is most common in cattle, horses, and dogs.

In cattle, warts commonly are found on the head, neck, shoulders and teats, and occasionally on the back and abdomen

Papillomatosis Management is controversial Wart vaccines NOT effective for several types Vaccines can prevent, not cure BPV1, BPV2 Topical meds unproven Sx useful but $$$

Dermatophytosis Ringworm • Affects mostly goats and cattle • Due to a fungus which is spread by contact or air currents • Can affect people

Etiology Trichophyton verrucosum is the usual cause of ringworm in cattle, but T mentagrophytes , T equinum , Microsporum gypseum , M nanum , M canis , and others have been isolated. Dermatophytosis is most commonly recognized in calves, in which nonpruritic periocular lesions are most characteristic, although generalized skin disease may develop.

Lesions Circular areas lesions are characteristically discrete, scaling patches of hair loss with gray-white crust formation, but some become thickly crusted with suppuration.

Zoonotic disease

Diagnose You can diagnose ringworm on sight, or take a skin scraping, or examine plucked hairs for fungal elements. This is examined under a microscope, or put on an agar plate in a microbiology laboratory and allowed to grow. Some of the fungi fluoresce under a black light examination, often with a Wood's lamp.                                Specialized agar plate, called Dermatophyte Test Medium is used to culture and identify ringworm organisms

Treatment • Treatment options depend on the limitations on the use of some agents in animals meant for slaughter. Agents reported to be of use include washes or sprays of 4% lime sulfur, 0.5% sodium hypochlorite (1:10 household bleach), 0.5% chlorhexidine, 1% povidone-iodine, natamycin, and enilconazole. Recovery to normal is slow and animals are considered contagious until hair starts to grow around the outside edge of the hairless area.

Dermatophilus rain scaled Rain scald is a skin disease seen in all ages of cattle, but particularly youngstock. It is caused by the bacteria Dermatophilus congolensis. It is commonly associated with wet weather (hence the name). The same organism causes mud fever in horses

Clinical Signs Begins as a moist circular patch, often with matted hairs which give a characteristic paint brush appearance Typically seen on muzzle, tips of ears, withers, but rapidly spreads - can involve up to half the skin area in severe cases Cattle are usually otherwise heathy, there are no systemic effects.

Diagnosis On the clinical signs described Smears from freshly affected skin will contain bacteria which can be identified under the microscope

Treatment There is no completely effective treatment, particularly for severe cases. Many antibiotics are effective, particularly penicillins. Keeping the skin dry (i.e. bringing the cattle indoors) is often more effective than any treatment. Injections of anti-inflammatories significantly improve cow well-being and help to restore the cow to normal production more quickly Local disinfection and treatment are necessary in more severe cases

Prevention The disease usually disappears in dry weather, but weather is not something over which there is much control. Providing shelter can significantly reduce the risk of rain scald.