pes·tif·er·ous 
(pĕ-stĭfər-əs)
(pĕ-stĭfər-əs)adj.
1.
a. Producing or breeding infectious disease.
b. Infected with or contaminated by an epidemic disease.
2. Morally evil or deadly; pernicious.
3. Bothersome; annoying.
[Middle English, from Latin pestiferus, variant of pestifer : pestis, pestilence; see PEST + -fer, -fer.]
pes·tifer·ous·ly adv.
pes·tifer·ous·ness n.