7.1.3 Fungal diseases

. . Fungal diseases Fungi was recognized as a causative agent of human diseases much earlier than bacteria. Dermatomycosis is a cutaneous infection caused by fungi belonging to the genera Trichophyton , Microsporum and Epidermophyton . Ringworm is one of the most common fungal disease in humans (Fig. . ) . Appearance of dry, scaly lesions on the skin, nails and scalp are the main symptoms of the disease. Heat and moisture help these fungi to grow and makes them to thrive in skin folds such as those in the groin or between XII Std Zoology Chapter XII Std Zoology Chapter Human Health and Diseases and diarrhoea. A heavy infection can cause nutritional deficiency and severe abdominal pain and causes stunted growth in children. It may also cause enteritis, hepatitis and bronchitis. Filariasis is caused by Wuchereria bancrofti , commonly called filarial worm. It is found in the lymph vessels and lymph nodes of man (Fig. . ) . Wuchereria bancrofti is sexually dimorphic, viviparous and digenic. The life cycle is completed in two hosts, man and the female Culex mosquito The female filarial worm gives rise to juveniles called microfilariae larvae . In the lymph glands, the juveniles develop into adults. The accumulation of the worms block the lymphatic system resulting in inflammation of the lymph nodes. In some cases, the obstruction of lymph vessels causes elephantiasis or filariasis of the limbs , scrotum and mammary glands (Fig. . ) .