diphtheria - jesus was there any last year ?
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/609001/hpr1317_dphthr2.pdf
yeah six-ish - four cutaneous ( where? - the skin)
96% of the population are vaccinated and the six werent
interesting dynamic system - the naughty bacterium is 'bigger' than the innocent sort and so in a vaccinated population the bigger naughty one trades at a disadvantage - and dies out !
( the toxic bacterium has longer DNA - to code for the toxin geddit? - than the innocent one and so requires more energy to multiply and is at an darwinian disadvantage )
[ sorry cant resist technical comments like this and the ensuing avalanche of:
wot dat den ? what means toxic den ? cant help dair den!
didnt do reading at skool den - and I can see why! Darwin - didnt he invent electricity? wot he doin here den? I blame Crick and What's on? yeah what's on later den ? ]