Having a disease that can be transmitted to another person.
Easily transmitted to others.
Easily passed on to others.
Of a disease or disease-causing agent: malignant, able to cause damage to the host.
Of a pathogen: replicating within its host cell, then immediately causing it to undergo lysis.
Extremely hostile or malicious; intensely acrimonious.
Of animals, plants, or substances: extremely venomous or poisonous.