The Compendium of Caraka 2.1.35

2.1.35

jvarastu khalu maheśvarakopaprabhavaḥ, sarvaprāṇabhṛtāṃ prāṇaharo, dehendriyamanastāpakaraḥ, &prajñābalavarṇaharṣotsāhahrāsakaraḥ, śramaklamamohāhāroparodhasaṃjananaḥ; jvarayati śarīrāṇīti jvaraḥ, nānye vyādhayastathā dāruṇā bahūpadravā duścikitsyāśca yathā 'ayam/

Fever, indeed, originated from the anger of Maheśvara; it takes the life of all living beings, causes burning torment to the body, sense organs, and mind, diminishes intelligence, strength, complexion, joy, and enthusiasm, and produces fatigue, exhaustion, confusion, and obstruction to food intake. It is called jvara because it torments (jvarayati) the body; no other diseases are so dreadful, so full of complications, and so difficult to cure as this one.