IMMUNOLOGY

Detailed explanation-1: -The host–pathogen interaction is defined as how microbes or viruses sustain themselves within host organisms on a molecular, cellular, organismal or population level. This term is most commonly used to refer to disease-causing microorganisms although they may not cause illness in all hosts.

Detailed explanation-2: -(b) A biological vector carries a pathogen from one host to another after becoming infected itself. Biological transmission occurs when the pathogen reproduces within a biological vector that transmits the pathogen from one host to another (Figure 4).

Detailed explanation-3: -Each pathogen is made up of several subparts, usually unique to that specific pathogen and the disease it causes. The subpart of a pathogen that causes the formation of antibodies is called an antigen. The antibodies produced in response to the pathogen’s antigen are an important part of the immune system.

Detailed explanation-4: -A pathogen interacts with the host and causes infection, leading to the development of disease in the host. A pathogen may be any harmful microbial agent such as a bacterium, virus, protozoa, fungus or helminth etc.

Detailed explanation-5: -A host in the context of infectious disease refers to an animal or plant that acts as a biological refuge in which another-often parasitic-organism may dwell. The host usually provides shelter or nourishment to the other organism, which may use the host to partially/completely sexually develop 1.