Based on the 9-Keel Unified Theory and the core D(t) steady-state imbalance formula, this paper focuses on interpreting the pathogenesis and lethal mechanism of the Black Death (Plague) and Smallpox, the two deadliest infectious diseases in human history. Combined with the core viewpoint of “Cellular Innate Duty No Error Theory”, this study verifies that regardless of bacterial infection (Black Death) or viral infection (Smallpox), regardless of acute explosive onset or subacute progressive deterioration, the ultimate lethal essence is consistent with the core law of the D(t) formula: when the pathological driving force (D) in the body continuously exceeds the self-regulatory resistance (R) of the organism, the multi-system physiological steady-state, with core parameters including core body temperature, systolic blood pressure, heart rate as core parameters, gradually deviates, and eventually breaks through the critical survival threshold, leading to systemic collapse and death. This paper further confirms the universal applicability of the D(t) formula across disease types, pathogenic factors and time dimensions, supplements the historical typical cases for the 9-Keel Unified Theory system, and provides a unified theoretical framework for understanding the essential law of acute lethal diseases.
FOO SENG ANG (Tue,) studied this question.