Jwara (fever) is described first among disorders because temperature (or body heat) is a life-sustaining force, and is the first condition (afflicting patients of somatic conditions).
[Vata dominant jwara: Causes] Excess use of rough, light to digest, and cold (food), over administration of therapeutic emesis and therapeutic purgation, asthapana (non-unctuous enema), shirovirechana (head evacuation), overexertion, suppression of urges, anashana (fasting), injury, copulation, agitation, lamentation, excessive blood-letting, night vigils and improper/odd posture of body – cause vitiation of vayu
[Pathogenesis] This vitiated vayu, when it gets into the amashaya (stomach), afflicts agni and vitiates the first dhatu (rasa) created through this vitiated digestion process. This (vitiated admixture of vayu and rasa) blocks the channels associated with rasa and sweda (sweat), adversely affecting the digestive processes and moving that heat out of its locus into other parts of the body. This excess heat leads to jwara.