Answer to Question 1
Red leg is a disease of frogs (anurans) and is caused by aeromonas bacteria. (Response may be non-specific, such as poor husbandry, poor water quality, etc. Both would also be true.)
Answer to Question 2
To prevent skin oils, lotions and soap from being absorbed through the amphibian's skin and to prevent amphibian toxins from coming into contact with human skin.