Some Defintions to Keep In Mind

Antibody

An antibody is a protein that recognises a microbe by its antigenic coating. It then attaches to the microbe. This then becomes a signal or a tag for the immunes system to identify and destroy the microbe.

Antigen

Antigens are molecules on the surface of a microbe, including virus, that the immune system recognizes and mounts a response. The reponse is in the form of an antibody.

Disease

A disease is any abnormal condition of an organism that may cause discomfort, harm or death of the organism.

Infection

An infection is the invasion and occupation of the host organism by a foreign microbial organism, a pathogen. The pathogen utilizes the host resources for nutrition, reproduction and residence. This may often be detrimental to the host. The pathogen may emit toxins, cause malfunctions in normal cell operation and rob the host of it's nutrients.

Pathogen

A pathogen is an biological organism that causes harm to its host. Some bacteria, protozoans, viruses and prions are among of microbes that can cause infectious disease in their human hosts. Pathogenicity refers to the ability of the pathogen to cause infection of disease in the host organism. is the ability of an organism to

Pathogenesis

Pathogenesis describes the development of a disease episode from first etiological contact to the establishment of the disease state in the organism.

Pathology

Pathology is the study of disease including the origins of disease, the identification of the disease, the organism's reaction to the disease including destructive traits of the disease, the course of disease and any immune response.

Virulence

Virulence describes, qualitatively, the degree to which a pathogen can cause infectious disease and the severity of the diseaes.

Virus

A virus is composed of nucleic acid package enclosed in a protein capsule. It may be further enclosed in a bilipid membrane and have glycoprotein outer layer. The nucleic acid may be DNA or RNA and may be single or double stranded. The nucleic acid contains enough genetic information to take over the machinery of the host, forcing it to make copies of the virus and release them. The orthomyxoviruses of which the influenza strains are members are RNA based viruses.