Infectious disease is a term used to encompass a range of infections caused by pathogenic microorganisms. Viruses, fungi, bacteria and parasites can all be responsible for a variety of diseases; including HIV, aspergillosis, tuberculosis and malaria respectively. Whilst many individuals believe that only certain species of microorganisms are pathogenic, there are in fact naturally-occurring, “friendly” organisms that can also cause harm. These traitors can alter themselves to become pathogenic in response to sensing a change in their host. So just to make everyone feel that bit more vulnerable; you’re never entirely safe from the ambition of the tiny terrors that live inside you. However rest easy- if you’re healthy and your immune system is competent, they’re unlikely to cause any major problems.
So how do we acquire these infections? Transmission may occur through air, consumption of contaminated food, water, physical contact, by exchange of bodily fluids or by animal bites. The possibilities are sadly, almost endless. The Ebola virus requires direct contact to spread. In West Africa, hands on burial techniques and a motile population resulted in rapid spread of the virus; largely contributing to the 2014 epidemic. Evidence suggests human habits are largely influential to pathogen transmission. Despite education, we usually make the same mistakes twice (or more) and microorganisms take full advantage of this.
Why do these microorganisms make us sick? Pathogens aim to survive long enough to reproduce. Pathogens are therefore capable of generating a range of symptoms to enhance replication and transmission. The influenza virus upon infection damages the respiratory tract; causing symptoms such as coughing and sneezing. Sneezing expels viral particles from the host into the surrounding area; increasing the likelihood of transmission to a new host. In this case, simple hygiene practices may halt flu attacks.
A pathogenic army ready to take over the world.
Contrary to science-fiction beliefs, fatal pathogens are at a disadvantage and accordingly uncommon. Host mortality prevents pathogenic spread; consequently fatal strains are usually short-lived. Some scientists believe that overpopulation encourages transmission of potentially fatal pathogens. However, the most successful pathogens are typically less severe. Influenza remains infectious by annually altering its genetic material. Whilst changes are not largely dissimilar, they are enough to cause symptoms, allowing spread. Pathogenic success therefore depends not only on virulence, but also on transmission ability. Community intervention efforts may further inhibit pathogenic armies (humans, fight back!).
In summary, the pathogen-host relationship is a love-hate one. Although counter-productive for pathogens to kill their hosts, this does happen in some cases. The 2014 Ebola outbreak killed over 11,000 people; epidemics such as this highlight a need for increased research and education to advance the understanding of infectious diseases. Unfortunately, humans are ignorant of the fact that such diseases do not spread on their own. We play a crucial role within a pathogens life-cycle, therefore outbreaks are OUR responsibility to control. Current attitudes suggest a need for improved education; helping communities to minimize pathogenic transmission. Consequently, like it or not, infectious diseases should be everyone’s concern.