Astanga Hrudaya
काले यथास्वं सर्वेषां प्रवृत्तिर्वृद्धिरेव वा। निदानोक्तानुपशयो विपरीतोपशायिता यथास्वं लिङ्गसंसर्गे ज्वरः संसर्गजः अपि च॥२३॥
The onset and exacerbation of all of them (kinds of fevers) happens at their own respective time when the dosha causing the fever is predominant i.e.; specific period of the day, night, season, digestion of food etc. Factors enumerated as causes (of each kind of fever) are anupashaya (unsuitable, cause discomfort) to each of them (fevers) whereas the factors opposite of the cause are upasashya (suitable, give comfort). Presence of respective signs and symptoms of any two doshas simultaneously is the feature of fevers caused by two doshas generally.
english translation
kAle yathAsvaM sarveSAM pravRttirvRddhireva vA। nidAnoktAnupazayo viparItopazAyitA yathAsvaM liGgasaMsarge jvaraH saMsargajaH api ca॥23॥
hk transliteration by Sanscript