Understanding COVID-19 in the light of epidemic disease described in Unani medicine.

Unani system of medicine is based on the humoral theory postulated by Hippocrates, according to him the state of body health and disease are regulated by qualitative and quantitative equilibrium of four humours. Amraz-e-Waba is an umbrella term which is used in Unani medicine for all types of epidemics (smallpox, measles, plague, Hameer Saifi, influenza, Nipaha, Ebola, Zika, and 2019 novel coronavirus, etc.) mostly fatal in nature. The coronavirus disease 2019 (COVID-19) is a severe acute respiratory infection, and the pathogenesis and clinical features resemble with those of Nazla-e-Wabaiya (influenza) and Zatul Riya (pneumonia) which were well described many years ago in Unani text such as high-grade fever, headache, nausea and vomiting, running nose, dry cough, respiratory distress, alternate and small pulse, asthenia, foul smell from breath, insomnia, frothy stool, syncope, coldness in both upper and lower extremities, etc. The World Health Organization declared COVID-19 as a global emergency pandemic. Unani scholars like Hippocrates (370-460 BC), Galen (130-200 AD), Rhazes (865-925 AD), and Avicenna (980-1037 AD) had described four etiological factors for Amraz-e-Waba viz., change in quality of air, water, Earth, and celestial bodies, accordingly mentioned various preventive measures to be adopted during epidemics such as restriction of movement, isolation or "quarantena", and fumigation with loban (Styrax benzoin W. G. Craib ex Hartwich.), sandalwood (Santalum album L.), Zafran (Crocus sativus L.), myrtle (Myrtus communis L.), and roses (Rosa damascena Mill.) and use of vinegar (sirka) and antidotes (Tiryaq) as prophylaxis, and avoiding consumption of milk, oil, sweet, meat, and alcohol. This review focuses and elaborates on the concept, prevention, and probable management of COVID-19 in the light of Amraz-e-Waba.