Contribution of Pasteur and Koch to our understandings of infectious diseases
Louis Pasteur, through his famous swan-neck flask experiment, disproved “spontaneous generation” as a theory by showing that meat would go off only because there were bacteria in the air that we cannot see with the naked eye, discovering the “Germ theory of disease”. This made way for pasteurization which kills the bacteria in milk so it is safe to drink and does not change taste or properties. Robert Koch developed the agar plate technique, determined that each disease is caused by a certain micro organism and the nature of infectious diseases (Koch’s postulates).

Prion: Non-cellular organism that is a protein capable of causing disease.
Virus: Non-cellular pathogen with living and non-living characteristics and contain, basically, DNA.
Bacteria: Single-celled prokaryotic organism with a single large chromosome. Divides by binary fission.
Protozoan: Single-celled eukaryotic organism. Most do not cause disease but some are pathogenic.
Fungi: Eukaryotic organism with a cell wall and cannot supply themselves like plants. Vary greatly.
Macro-parasites: Parasites visible to the naked eye. Some cause disease directly, some via vector transmission

Malaria is caused by a parasite named plasmodium which uses the Anopheles Mosquito as a vector to be transmitted into humans. To stop malaria artemisinin-based combination therapies need to be used prior or soon after infection or prevented by insecticides or nets.

First line of Defence
The skin is a physical barrier which is dry and uninhabitable by most pathogens. Mucous membranes in the genital area and mouth trap microbes and get them prepared to be spit out later. Acids such as sweat and tears kill many microbes that it touches as well as any other foreign particles.

Antigens are specific to the organism that created the cell. The body will detect these antigens from all cells and either classify...