Within exotic animals there are two types of disease; pathogenic and non-pathogenic. Pathogens are disease causing organisms including bacteria, viruses and fungi. Bacteria can cause conditions such as mouth rot, viruses can cause herpes and fungi can cause Chytridiomycosis. Pathogens can be spread directly and indirectly as well as airborne. These diseases are usually caused from improper living conditions including incorrect humidity and temperature. Non-pathogenic diseases such as metabolic bone disease and dysecdysis can be caused from incorrect nutrition and poor husbandry.