EPIDEMIOLOGY AND CONTROL OF FUNGAL INFECTIONS

1. EPIDEMIOLOGY AND CONTROL OF FUNGAL INFECTIONS Dr Igbinedion MBBS, MPH, FRSPH

2. SUPERFICIAL FUNGAL INFECTIONS • Affects the skin, nails and hair • Dermatophytes, yeast and mould are the main fungi that cause superficial skin infections • There are three genera of dermatophytes that cause superfical fungal infections and they are: • Microsporum (affects hair and skin) • Trichophyton(affects skin, hair and nails) • Epidermophyton (affects nails and skin)

3. The dermatophytes can be classified into three groups based on their habitats • Humans • Animals • Soil • It should be noted that the skin is a normal habitat for some of these fungi

4. Distribution • There is worldwide distribution • Commonly seen in daily practice • Geographic distribution of these dermatophytes varies with different presentations in different parts of the world • Migration, drug therapy, lifestyle and socioeconomic factors all influence the changes that have been observed in the epidemiology of these infections

5. Distribution (contd) • Affects all ages and sexes but more commonly found in children • Higher incidence in tropical countries and may be attributed to the warm climate (fungi thrive well in moist environments) and poor infrastructure (lack of water)

6. Determinants • Man is the main reservoir of infection but as mentioned earlier, animals and soil play a part • Transmission can be direct or indirect • Direct transmission e.g. during sexual intercourse, the moist surface of the lesion allows for easy transfer of the organism • Indirect transmission is by close body contact, sharing of clothing, towels, razors, hair clippers

7. Determinants (contd) • Incubation period 4-14 days • Host immunity is an important factor. Drug therapy, e.g. steroids or other immunosuppressive drugs can increase susceptibility to developing infections. Poor personal hygiene also increases susceptibility

8. Clinical Features • Affects the body, scalp, nails, moist skin of the feet or groin • Tineacorporis (ringworm) produces lesions on the skin that spread out from the centre with depigmentation • Tineacapitis affects the scalp and causes areas of baldness. More common in prepubertal children • Tinea (Pityriasis) versicolor caused by the yeast malassezia furfur can be mistaken for leprosy because of the blotchy hypopigmentation

9. Clinical Features (contd) • Tineapedis affects the feet and can cause scaling. Common in men who wear shoes and socks all day long • Tineacruris usually only found in the groins and occurs more in males. May extend to thigh and buttocks • Tineaunguium affects the nails, with toenails more affected than fingernails. Usually found along with tineapedis

10. Diagnosis • Clinical diagnosis is usually sufficient for diagnosis • Laboratory diagnosis can be done by staining or culturing scrapings of skin and scales, and plucked out diseased hairs (in cases of T. capitis)

11. Treatment • Topical antifungals- clotimazole, Whitfield’s ointment • Systemic antifungals- griseofulvin, terbinafine, fluconazole, itraconazole, ketoconazole • Anti bacterials in cases of secondary bacterial infection

12. Prevention and Control • Primary prevention • Health education on the cause of disease • Adequate housing facilities to prevent overcrowding • Adequate water supply • Adequate protective clothing and avoidance of moist feet • Avoid sharing clothes and other items

13. Prevention and Control (contd) • Secondary prevention • Early detection • Prompt treatment Advantages • Reduces rate of transmission and infectivity • Reduces morbidity and illness duration • Limits disability that may result from secondary bacterial infection

14. Prevention and Control (contd) • Tertiary prevention • Rehabilitation Surveillance is important and should be carried out especially in children to examine head, feet and groin.

15. CANDIDIASIS Dr Igbinedion MBBS, MPH, FRSPH

16. Caused by yeast of the genus Candida • There are about 20 Candida species that can infect man but the most common is Candida albicans • Candida yeasts are normally found in the skin and mucous membranes but problems arise when there is overgrowth of the organisms in predisposed conditions such as pregnancy, infancy, diabetes, moist environments, immunosuppression, etc.

17. Candida infection can be found in skin folds, moist areas such as webspaces, genitals and areas covered by diaper • Incubation period is 1 week • Can be transmitted directly or indirectly through sexual intercourse

18. Types • Oropharyngealcandisiasis aka Thrush- This causes white plaques on the oral mucosa which may bleed when removed • Vulvovaginal candidiasis- causes itching and soreness with resultant erythema and edema of the vulva and vagina

19. Diagnosis • Clinical • Laboratory- Gram staining of samples which shows yeasts with pseudohyphae, pathognomic of tissue invasion

20. Treatment • Topical or systemic antifungals depending on the extent of disease • Nystatin • Clotrimazole • Carnestin cream • Fluconazole • Itraconazole • Ketoconazole

21. References • Ameen, M. (2010). Epidemiology of superficial fungal infections. Clindermatol; 28(2): 197-201 • King-man, H.O. and Cheng, T. (2010). Common superficial fungal infections- a short review. The Hong Kong Medical Diary; vol 15: 23-27. • Webber, R. (2010). Communicable Disease Epidemiology and Control: A Global Perspective. 3rd edition.