(especially of diseases) tending to spread from one person to another

contagious (disease)

(of disease) that can be spread by means of bacteria carried in the air or in water

catching, spreading

having poison; causing death or injury

harmful

causing, caused by infection (with disease germs)

harmful

(of a person) strong; (of ill-feeling, hatred) very strong; (of words etc) full hatred; (of a disease etc) very dangerous

poisonous, lethal