One of the lesser known gods in the Saiva pantheon is called Jvaradeva – god of fever. He is depicted as three-armed, three-legged and when he would attack an individual their body temperature would increase to uncomfortable levels. Later on jvara deva was paired with Sitala or goddess of smallpox. The story of his origin goes this way that when the terrifying lord Rudra was engaged in great Tapas, Jvara was created from a drop of his sweat and then became a part of the Saiva demigods. In the Vedic hymns to Rudra he is often regarded as the greatest of healers due to his perfect control over all disease-causing entities. Additionally, he was identified with the Self which is the curer of all maladies.
There were specific mantras and rituals to propitiate Jvara in case the deity afflicted any individual.
Later Vaishnava texts like Harivamsa gives a sectarian view of Krishna encounter with Jvara deva wherein the leader of the Vrishnis created a Narayana-jvara to fight against the original Jvara deva. In old South Indian Shiva temple one can still find the icon of Jvara adorned in the walls.