The symptoms are hair loss and excessive scratching of the infected areas. You need to get rid of the fleas first by using a flea collar, anti-flea shampoo, powder, spray or dip. You need to use a combination of these products as fleas are very persistent and recontamination may occur when the fleas in the environment hop onto your cat. It is necessary to engage pest control services to fumigate your house and garden against the fleas. Your vet will prescribe antibiotics to heal the sores and anti-inflammatory drugs to treat the skin inflammation.
Ringworm is contagious as it spreads through contact.
If your cat has them, it is likely you're infected too. Symptoms are circular bald patches with scabby lesions on the skin. Topical anti-fungal dips and washing reagents can be used to get rid of the parasitic fungus.