What disease primarily affects amphibian species, with early signs including anorexia and lethargy?

Chytridiomycosis is a disease caused by the chytrid fungus, Batrachochytrium dendrobatidis, which has had devastating effects on amphibian populations worldwide. Early signs of the disease include anorexia (lack of appetite) and lethargy (decreased activity levels), which are common indicators of distress in amphibians. This fungal infection affects the skin of amphibians, disrupting their ability to absorb water and regulate electrolytes, leading to significant physiological stress and, ultimately, increased mortality.

The other listed diseases, while they can affect various animals, do not primarily target amphibians or exhibit the same early symptoms. Salmonellosis is primarily a bacterial infection associated with reptiles and birds. Dermatitis refers to inflammation of the skin, which can be caused by various factors, but is not specific to amphibians as the primary disease. Aspergillosis is a fungal infection that can affect multiple animals, including birds and mammals, but again, it does not exhibit the distinct early signs characteristic of chytridiomycosis in amphibians. Thus, the focus on anorexia and lethargy as early signs uniquely identifies chytridiomycosis as the disease in question.