When his boss called to complain that the time-sensitive documents he was waiting for still hadn't arrived, Victor worried that the courier responsible for delivery may secretly be on their competitor's payroll and had sabotaged them on purpose.
Virulence factors are molecules produced by pathogens (bacteria, viruses, fungi and protozoa) that contribute to the pathogenicity of the organism and enable them to achieve the following: 1  colonization of a niche in the host (this includes attachment to cells). 2  immunoevasion, evasion of the host's immune response.
1 Invasion. 2  Some virulent bacteria produce proteins that either disrupt host cell membranes or stimulate their own endocytosis or macro-pinocytosis into host cells. 3  These virulence factors allow the bacteria to enter host cells and facilitate entry into the body across epithelial tissue layers at the body surface. Colonization. 2  Some virulent bacteria produce special proteins that allow them to colonize parts of the host body. 3  Helicobacter pylori is able to survive in the acidic environment of the human stomach by producing the enzyme urease.