avirulence

Avirulence refers to the lack of virulence, meaning an organism is not capable of causing disease. Virulence, on the other hand, is the degree of toxicity or injury-producing potential of a microorganism. This can involve factors like toxins that kill cells or enzymes that break down host tissues.1234

While some pathogens are highly virulent, others, like certain strains of Salmonella or viruses, are avirulent. This means they cannot infect or cause illness in a host. The development of disease, or pathogenesis, depends on a complex interplay between the pathogen's virulence factors and the host's resistance.23