Hardly a year goes past without some new scare over some newly emerging high virulent virus or bacteria that seems set to cause mayhem and havoc yet again amongst the population. Some of the concern raised in relation to these new diseases is generated or at least encouraged by sensationalist journalism. A recent example of that would be the widespread scares in the UK over the new flesh-eating bug. This particular organism (Streptococcus pyogenes) has long been recognised as causing a necrotising fasciitis (severe infection of tissues underneath the skin). However, once a couple of clusters were reported sensationally, it became news and multiple outbreaks were being described. The condition still occurs with the same frequency, but it is interesting to note that the newspapers have lost interest in it, and it's no longer reported. Other diseases then, are genuinely new. For example, the new strain of BSE capable of infecting humans. The HIV virus could also be considered in this category, although there is convincing evidence that it has been around for at least 20 years before it became so widespread.

lt is well known that organisms like bacteria viruses and parasites do mutate and change as they go through life cycles. -->