Ringworm

local names, definition, etiology,epidemiology lifecycle, pathogenesis, clinical findings, necropsy finding, diagnosis,treatment, control and prevention

1. Faculty of Veterinary Science Infectious Diseases II (Fungal Diseases) RINGWORM 6 th ,May ,2016 SHAFI’I. A. M. SHEIKH

2. Ring Worm Synonyms: Tinea infection, Trichophytosis , Dermatophytosis . It is contagious fungal infection that can affect any part of the body. The name comes because of characteristic red ring that appears due to infection. Ringworm is caused by invasion of keratinized epithelial cells and their fibers by dermatophytosis

3. Etiology Causative agent are fungi that grow on hair or skin or both. The common fungi that occur in each species are

4. Host Dermatophytes Cattle, T. verrucosum ; T. mentagrophytes ; T.rubrum Buffalo , T. verrucosum ; T. mentagrophytes ; Horse T. equinumM.gypseum , T. verrucosum ; T. M Pig M.nanum ; T. verrucosum ; T. mentagrophyte Dog, Cat M.canisM.gypseum , T. mentagrophytesM.distorum Camel , T. verrucosum ; T. mentagrophytes

5. These fungi are strict anaerobes and asexually spores producing. They die out under the crust in centre of lesions. These are ectothrix type, characterized by mycelia invasion within hair in stratum corneum of epidermis with arthrospores on outside of hair shaft. Trychophyton Spp. Produce large chains

6. Microsporum Spp. Produce spores in mosaic pattern. High humidity being conducive to multiplication of fungus. Resistance depends largely on immunological status of animals.

7. Ringworms occurs in every part of the world. Affecting human and animal population. Individual dermatophytes may have different geographical distribution. Zoophiles dermatophytes may cause human infection. Trychophyton verrucosum cause suppurative type of ringworm lesion in man in rural areas. Some dermatophytes have geographical restrictions.

8. Epidemiology T. semii infection is restricted to India whereas T. concentricum in Africa. Dermatophytes have seasonal distribution and related to the high rainfall and humidity outbreaks has been noted in pet animals during summer months in close confinement with in adequate nutrition. Disease occurs with less morbidity and zero mortality. Infection spreads with direct contact, indirect contact with fomites and animal attendant

9. Pathogenesis Dermatophytes never invade living tissues. Dermatophytes attack the keratinized layer of skin, hair and nail to cause autolysis of the fibrous structures that break the hairs and produce alopecia. They produce skin lesions through excretion of toxin and allergens, which affect the basal layers and there will be increased proliferation of cells of malphagian layers. These toxins and allergens also act as on the vascular components

10. As a capillary dilatation, hyperemia, and edema takes places that cause spongiosis of the epithelium and thus, interfere with keratinization resulting in parakeratosis . There are scales encrustation. The hair is complete until the follicles are destroyed by secondary bacterial infection. Secondary bacterial infection may produce micro-abscess in the superficial epidermis together with suppurative folliculitis

11. Clinical findings Ringworm usually appears 10 to 14 days after contact. Different dermatophytes affect different parts of the body to cause the various type of lesions. Ringworm of the scalp Ringworm of the foot Ringworm of the body Ringworm of the nails

12. The affected area of the skin become erythematous , discrete and almost circular with raised borders have thick grayish crusts. The lesions grow peripherally with central healing. The lesion look like asbestosis. The lesion coalesce. The lesion are mostly present at the head, around the eyes, neck, ears and dewlap. Generalized distributions of lesion are also seen occasionally

13. Diagnosis The epidemiological history and diagnosis of dermatophytes is made on the basis of characteristic lesion. The confirmation is scrapping, hair, nails, etc.are subjected to direct microscopic examination. Collect materials are soaked in few drops of 10% KOH salution in a petridish and after 30 minutes make slide and examine under the microscope. The presence of fungal elements and spores may be noted.

14. Clinical materials may be cultured on sabaurauds dextrose agar medium. Antibacterial agents and antidione may be added to prevent most of the laboratory contaminants and growth may be obtained at 22-30c. Dermatophytes grow within 5-10 days

15. The skin biopsy from the suspected lesions may be done and stained for observing fungus. Haematoxyline and eosin stain is widely used for histopathological examination of animal tissues. Many fungi take this stain. Special fungal stains such as Gomorismethanamine silver technique (GMS). gridleys fungus stain (GF). And periodic acid Schiffs technique (PAS). May also be used

16. Certain stains of M. canis and M. audouninii produce a yellow green colour fluorescence is due to tryptophan metabolite produced by the fungi. The fungal antigen can be given subcutaneously for allergic test and reaction can be noted after 24 to 48 hours for any hot, painful doughy swelling.

17. Treatment Spontaneous remission occurs in dermatophytosis within three months by anatomical barrier of the skin and mucus membrane. Good general nutrition and health. Besides, neutrophils play an important role in the inflammatory response. The drug used in dermatophytosis can be broadly divided into categories of local and systemic drugs.

18. Irritants,keratolytics , fungicide, and fungistatic drugs are used to check the ring worm. Medicines of ring worm can be either locally applied in the form of ointment or lotion or systemically given. Phenol. Salicyclic acid, benzoic acid, iodine and miconazole are used as 2-5% as ointment

19. Cotrimazolehaloproquine , risorcinole and tolnaflateare generally used as 1% preparations. Systemic antifungal agents are arise otulyinethialbendazole , nystanine and ketoconazole . Systemic antifungals are used in generalized infection of severe nature. Support of ant-inflammatory and anti-histaminic drugs are always required for early recovered.

20. Control The infected animals should be identified and treated at the earliest possible. Spread can be prevented by rearing them at isolated place. Contaminated utensils, grooming articles, feeding trough etc. should be properly cleaned. The wooden doors, windows, gaits or chain, rope should be treated with disinfectants animal handler should wash their hands properly before handling the non-infected ones

21. Various vaccines have been tried and T. verrucosum infection in cattle has been controlled, but any commercial vaccine is not yet available

22. Conclusion Although ringworm is not tracked by animal owners, infections appear to be increasing steadily especially among pet animals. Early recognition and treatment are needed to slow the spread of infection and to prevent reinfection