epidemic
疫 centers on widespread illness: an epidemic that spreads through a population.
疫 combines 疒 (sickness) with 殳, which likely contributes the sound and may suggest a striking or spreading action, together conveying a spreading disease.
The sickness enclosure 疒 wraps around 殳, like a disease striking and spreading through a crowd. Picture an epidemic sweeping through a village.
For エキ, imagine an epidemic spreading through a city, and everyone is saying 'eck!' in disgust: eck -> エキ.
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immunity; immunization; immunisation
epidemic; plague; pestilence
god of pestilence; god who spreads infectious diseases
quarantine; medical inspection
epidemiology
communicable disease control (e.g. by quarantine, disinfection, etc.); prevention of epidemics
god who spreads infectious diseases; god of pestilence
epidemic
African horse sickness
human immunoglobulin
human immunodeficiency virus; HIV
humoral immunity
primary immunodeficiency syndrome
immunoglobulin
immune system
immunodeficiency
immunodeficiency disease
antibody
immune strength; immunity
immunogenicity