In order to control pathogens and help our bodies defend against them, we have created a variety of tools.

Antiseptics and Disinfectants

Antibiotics and Antimicrobials

Fungicides and Antifungals

Antivirals

Antiprotozoan and Antihelminthic drugs

Antiseptics are used on the skin to kill pathogens. Antiseptics such as Dettol contain a number of different chemicals which affect microorganisms.

• 70% ethanol
• (breaks down lipids and denatures proteins)
• Hydrogen peroxide
• Oxidising agent
• Detergents
• Disrupts cell membrane
• Iodine
• Binds to proteins

Disinfectants are used to kill pathogens on objects. Disinfectants can contain:

• Chlorine
• Oxidising agent
• Phenols
• Denatures proteins
• Ammonium compounds
• Disrupts the plasma membrane
• Copper sulfate
• Precipitates proteins

Antimicrobials are a group of chemicals which inhibit the growth of microbes.

They affect bacterial cell walls, cell membranes, synthesis of proteins or nucleic acids.

A key requirement of Antimicrobials is selectivity. By this I mean the ability to destroy pathogens but not host cells.

Antibiotics are a form of Antimicrobials. Antibiotics are naturally occurring substance produced by microorganisms (Penicillin).

There are two types of antibiotics:

Broad spectrum (affective against a wide range of bacteria)   

Narrow spectrum (affective against one or a few microbes).

Antibiotics do not act like antibodies. Antibotics affect the metabolism of pathogenic organisms. Since viruses rely on a host cell, antibiotics arn’t effective.

Fungicides and Antifungals are used to treat fungal infections. Since fungal cells are Eukaryotes, they have similar properties too us. This limits the ways we can attack them.
This is why most Antifungals are spray, creams or shampoos, as opposed to oral consumption.

Most Antifungals work by disrupting the fungus cells, cell wall.

Antivirals are extremely intricate. This is because it is difficult to kill a virus, without killing the host cell.

Antivirals will either, affect the un-coating process of a virus, interfere with the binding process, prevent nuclear synthesis and prevent assembly and release of viral particles.

The video to the right shows steps taken to prevent the spread on HIV in cells.

These treatments are used to kill invading worm and protozoa.