The chain of infection

Covid-19

During the past year, Covid has dominated our lives and rightly so given the devastating effects on health, both physical and mental and the livelihood of millions on a worldwide scale. Staying safe and the prevention of cross-infection has been “the watchword” of governments not only in the UK but elsewhere in the world with various slogans being utilised to encourage the population to comply with the UK scientists recommendations. There are a variety of potentially nasty bugs out there, not just Covid, that these simple measures prevent in further contamination.

MICROBES

These are found from the floor of the Amazon to the internal digestion (the gut bacteria often referred to in pre and pro biotic advertising) and the human race would not be able to survive without them, nor would our planetary ecosystem. Microbes include bacteria, viruses, fungi and protozoa and while we generally think of such as a health problem the vast majority of them are harmless and some can even have beneficial effects such as assisting in the production of essential nutrients and of course, gut health.
However some are less kind to our bodies and are often referred to as “opportunistic” and/or as “pathogenic” meaning they can cause disease, especially if the human host has a depressed immune system or one that is unable to mount a suitable defence.

ENDOGENOUS or EXOGENOUS.

These terms are used to describe where microbes are found. Endogenous are micro-organisms found inside and on the body and are usually referred to as “normal flora” and as stated previously, not all detrimental to human health although some such as Staphylococcus Epidermis can be unpleasant.
Exogenous micro-organisms live outside the body and for example found in water or in buildings e.g. Legionella Pneumophila, or in soil e.g. Tetanus Bacilli.

THE CHAIN OF INFECTION

The method by which micr-organisms spread is known as “The chain of infection” and consists of the following pathway:

* A source and /or reservoir – in the case of Covid, an infected person
* An exit point – eg via the mouth or nose if the hosts coughs or sneezes
* A means of delivery – in this case, air droplets or a contaminated surface
* An entry point – eg by inhaling or touching an infected surface then for example, the mouth
* A susceptible host – especially somebody with a compromised immune system

HOW DO WE BREAK THE CHAIN?

A source is where micro-organisms can live permanently, and normally reside inside the human body. A reservoir is where they can survive temporarily and multiply. We can create these reservoirs unintentionally for example through unsafe or poor hygiene practices i.e. unwashed hands. Hence the advice to WASH HANDS FREQUENTLY.

As the human body has several entry and exit sites, these are the obvious locations to break the chain. Infections can be spread by contact that is described as being direct or indirect.
Direct involves body to body contact, as with skin diseases such as impetigo. Indirect is mostly via the hands, hence why hand decontamination is so vital with regard to preventing the spread of infection, with areas of frequent contact being the most vulnerable e.g. supermarket trolley handles. Hence the advice to SHOP AS INFREQUENTLY AS POSSIBLE.

Droplet spread is obviously through coughing, sneezing or even talking where the droplets can land on someone else or the objects that we touch. Under normal conditions the common cold is the most easily spread disease, but in the current situation Covid is the obvious reason to WEAR A MASK if you are out and about in an enclosed space and KEEP YOUR DISTANCE as infectious particles are so small that they easily can be carried in air currents, such as provided by air conditioning units and to those within a relatively short distance.

Additionally anything that weakens the immune system places the individual at more risk of infection to usual infections, let alone in these Covid times. These include:
* The elderly or the very young
* Underlying diseases eg cancer, chronic respiratory conditions and heart problems
* Medication that interferes with the normal functioning of the immune system
* Radiotherapy/ Chemotherapy
* Surgical wounds
* Medical devices especially those with external exit/entrance eg feeding tubes and catheters
* Obesity, primarily due to skin folds and poor mobility

THE WAY FORWARD.

It is well known that the vaccine is the way forward with regards to returning to an albeit new normal. In the meantime while we await our turn, breaking the chain of infection is all we can do – as the September government campaign stated HANDS. FACE. SPACE.