2010i-265 2011a-510 2012i-549 2017j-091 administration bacteria communicablediseases communityhealthservices control disasterplanning diseaseoutbreaks diseasesandhistory emergencies epidemics epidemiologicmethods epidemiologie epidemiology ethics gezondheidszorg healthpromotion history hivinfections human influenza jurisprudence legislation onderzoek onderzoeksmethoden organization organizations pandemics pathogenicity plague poliomyelitis politicalaspects prevention riskassessment smallpox socialaspects socialmedicine southafrica wa105w3672011 wa11hu5p559e2012