• Question: What is a pathogen?

    Asked by mariaa.s to Ceri, Marikka, Matt, Rob, Sally on 10 Nov 2014.
    • Photo: Sally Cutler

      Sally Cutler answered on 10 Nov 2014:

      This is a good question. Basically it is a microbe that is able to cause detrimental pathological effects (disease-causing). This actually gets more complicated when you think about it more in depth as we are not equal and nor are microbes, so you need to view the interaction between the two. A pathogen lives at the expence of its host and causes damage, but one microbe can be normal flora in one place of the body, but be a pathogen in another. An example is Staphylococcus epidermidis which lives without causing harm on our skin. If it gets into the blood and you have a susceptible heart valve it will cause endocarditis that could kill you! So is it a pathogen or not?

    • Photo: Ceri Dare

      Ceri Dare answered on 11 Nov 2014:

      A pathogen is a bug (like bacteria or virus) which makes you ill. Some bacteria can live in some parts of your body without causing any problems, but then they get in the wrong place and can make you very ill – for example the bacteria in your gut help you digest food, but if they got in your blood after an injury, you could become very unwell.

    • Photo: Robert Hampson

      Robert Hampson answered on 11 Nov 2014:

      Pathogen comes from two greek words. The first is ‘pathos’ which means ‘suffering’ or can also mean ‘passion’ or ‘suffering for others’. ‘Genes’ is the second and means ‘producer of’ (I believe this is the same as the root for genes like in DNA). So literally, pathogen means ‘producer of suffering’.

      Given this definition, you can only really use the term in relation to something else, the influenza virus is a pathogen in humans but not snails for example. Generally when used in terms of medicine it is assumed you are talking about a human pathogen unless you say something else.

      Some pathogens are known as obligate pathogens (obligate – they are obligated or they must be pathogenic to multiply and survive). Some pathogens are called opportunistic pathogens (they only infect you if they have a good enough opportunity), they can live in or on you perfectly happy without causing side effects until this happens.

    • Photo: Marikka Beecroft

      Marikka Beecroft answered on 11 Nov 2014:

      A pathogen is either a virus, bacteria, fungi or protozoa that can cause disease. Some pathogens aren’t pathogens all the time, it depends where they are and what’s happening around them, this can then make them cause disease and then we use the word pathogen to describe them.

    • Photo: Matt Bilton

      Matt Bilton answered on 11 Nov 2014:

      Something that causes disease! There are lots of microorganisms that don’t cause disease though. Things that might make a bacteria, or virus, pathogenic could be that they damage your cells, or release toxic molecules and/or trigger a dangerous immune response.

      The ‘best’ pathogens are perhaps those which don’t actually kill you, but keeps you alive so you can spread the bug. About 1/3 of the world’s population is infected with tuberculosis bacteria, yet most of those people will never know! TB bacteria cause a lot of people to get ill though – about 10 million people every year – so it is definitely a pathogen.

Comments