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Physical Preventative Measures

Biology (Year 12) - Pathogen Management Strategies

Ben Whitten

What are physical preventative measures? Prior to the mid-19th century, transmission of pathogens was not an area which many understood; surgeons were extremely unhygienic, not washing their hands and the rates of post-op infection were massively high. Joseph Lister had read Louis Pasteur's theory (germ theory) that microorganisms cause disease. Certain hygiene practices were experimented with, and the strategies were a success! The main measures which you need to be aware of include:

  • Handwashing

  • Using clean, filtered water and clean food

  • Sanitation

  • Coughing/sneezing into elbow

  • Barriers

How does handwashing prevent disease? Regular handwashing is effective in preventing individuals from contracting infections, in particular ones which are spread via direct contact or faecal-oral routes. On a global scale, handwashing can significantly reduce the mortality rate of certain infections. Handwashing is most effective if warm water alongside soap or antiseptic handwash is used. An antiseptic handwash contains antimicrobial substances, which effectively inactivate microorganisms or inhibit their growth. The technique of handwashing is important. Both sides of the hands and in between the fingers should be washed, followed by a thorough rinse and drying of the hands. Washing removes or kills pathogens, which hence prevents the spread of disease.

How does using clean, filtered water and clean food prevent disease spread? For water to be safe for use, it should be treated prior to being supplied. In a number of areas in the world, such as third-world countries, water is unclean and carries waterborne diseases such as Cholera. Pathogens have the ability to be carried long distances in water, which further increases the spread of infectious disease. Sometimes, food products are washed in unclean water which means that those pathogenic agents are transferred to that food and then consumed. Some pathogens are foodborne, which is usually because the food they occupy is either undercooked (for example, a very raw steak) or out of date when consumed.

How does sanitation prevent the spread of disease? Sanitation is defined as the safe disposal of human excrement, including both faeces and urine. The safe removal of these waste products can easily prevent the oral entry of a number of infectious diseases, which slows the spread of those diseases significantly. Approximately 2.6 billion people in the world however lack adequate sanitation, which leads to the spread of diseases which are mainly diarrhoeal (such as Cholera).

How does sneezing/coughing into the elbow prevent disease spread? The elbow can be used as a barrier to any airborne droplets that exit an infected host during a cough or a sneeze, which is effective in preventing the spread of disease. SARS-CoV-2 (COVID-19), influenza and tuberculosis are all diseases which have the capability of being transmitted through coughs and sneezes. The elbow is used to capture the pathogen. If the hand is used, then it is highly likely that the hand will become a fomite or a 'vector' for a pathogen, providing an alternative mode of transmission. How do barriers prevent the spread of disease? The different types of barriers include:

  • Mosquito nets

  • Kitchen gloves

  • Surgical masks

Mosquito nets have been made more effective when they are sprayed with insecticide. Protection against mosquito-borne diseases such as malaria can last for maths, however susceptible individuals must be smart in using their nets. Infected hosts with tuberculosis can use masks to stop exhaled droplets from being generated or projected. Healthcare workers can wear masks which are specially designed to protect them from inhaling droplet nuclei, helping protect these individuals from becoming infected when in close contact with a person with TB, which is highly infectious. The use of masks has been increasingly prevalent in reducing the spread of COVID-19.

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