免疫【めんえき】
immunity, immunization, immunisation, being hardened (to), being unaffected (by), being accustomed (to)
検疫【けんえき】
quarantine, medical inspection
防疫【ぼうえき】
communicable disease control (e.g. by quarantine, disinfection, etc.), prevention of epidemics
疫病【えきびょう】
epidemic, plague, pestilence