"virulence" refers to the ability of a pathogen (like bacteria or viruses) to cause harm or disease in a living organism. The more virulent a pathogen is, the more severe the illness it can cause. Full definition
«Although we must be careful in drawing this conclusion, as other factors, such as increased virulence of bacterial pathogens [in warmer] conditions may well tip the balance for corals the other way.» (bbc.com)
Excess labile carbon promotes the expression of virulence factors in coral reef bacterioplankton — Anny Cárdenas, ISME (microbiomedigest.com)
The building block, called the Passenger - associated Transport Repeat (PATR), has been found in virulence factors of many major harmful bacteria including Salmonella, Shigella, and Meningococcus as well as bacteria that cause infections in cystic fibrosis and burns patients. (sciencedaily.com)