Public Health and Communicable Diseases - SA Health - SA.Gov.au
Public Health and Communicable Diseases - SA Health - SA.Gov.au Public Health and Communicable Diseases - SA Health - SA.Gov.au
In the early 1800s Chadwick identified the appallingliving conditions of industrial England as causes of illhealth in workers, resulting in their inability to perform inthe workplace as well as they otherwise might. At thistime the miasma theory of disease was predominantand environment was ascribed the status of agent.With Koch’s discoveries from the mid-1870s, cameconcerted attention upon the diad of biological agentand host with less emphasis on the environment. Thusbegan an era where the emphasis of public health was(rightly) communicable disease. These are illnessesdue to specific infectious agents or their toxic productstransmitted from another infected host or from ananimate or inanimate reservoir.The recognition that an understanding of diseasedynamics could be usefully described by the triadhost-agent-environment arose in the 1920s withthe development of social and holistic medicine. Italso came to be the basis of training by AlexanderLangmuir and the Epidemic Intelligence Service and theconcept of ‘shoe leather epidemiology’ was promoted.Importantly, this required investigators to go into thefield to interview cases, their families, industry andother informants such as local health workers andgovernment officials.However, it was always necessary to view theenvironment as a multi-level construct ranging fromcellular interactions, to person to person interactions andto the influences at community and country level. Therehas been an evolving process of developing theory thateffectively integrates these multiple levels of factors thatcan all be viewed as causes of disease 1 .Classical epidemiology is being integrated with socialor cultural investigations as this theory evolves. This isimportant for several reasons. Firstly it reinforces theneed to fully understand the nature of a problem beforedesigning a solution and we see an increasing emphasison introducing ethnographic techniques into traditionalcommunicable disease investigations 2 . Secondly thisinvolves a mix of research methods – quantitative andqualitative to reach that understanding with betteranalytic methods to handle the data from mixed methodresearch becoming available. Finally, just as illness anddisease can be better understood with this paradigm, sotoo can appropriate means of intervention be devised.Clearly, the overwhelming message is that appropriateresources must be invested for adequate fieldinvestigations to secure reliable research findings whichcan be translated into feasible policy.References1. Kreiger N. Theories for social epidemiology in the 21 stcentury: an ecosocial perspective. Int. J Epidemiol.2001;30:668-677.2. Weiss MG. Cultural epidemiology: an introduction andoverview. Anthropology and Medicine 2001;8(1):5-29.Public Healthsurveillance forCommunicable Diseasesin South AustraliaIntroductionCameron MoffattEpidemiology Registrar,Communicable Disease Control BranchDepartment of HealthMaster of Applied Epidemiology ProgrammeAustralian National UniversityCommunicable disease control remains a high priorityfor population health. In Australia, many of the controlsfor communicable diseases already exist outside of thehealth system. These include things such as education,clean water, secure food sources, systems for disposalof refuse and sewage and adherence to regulationssuch as building codes. Disease surveillance helps toidentify cases when breakdowns in these systems mayhave occurred, however the pathogens responsible forthese diseases are frequently evolving, readily exploitingopportunities for change and transmission. In particularviruses transmitted in the air or by respiratory secretionshighlight the need for systems capable of detecting andmonitoring the presence of such pathogens.This paper examines public health surveillance with aparticular focus on notifiable conditions, using wherepossible relevant South Australian examples. Includedis an examination of effective public health surveillanceand its core aims; the main types of surveillancesystems used for monitoring communicable diseases;discussion of the importance of notifiable conditions;specific reporting systems and surveillance; the analysisand dissemination of surveillance data; and concludingremarks.What is public health surveillance?Public health surveillance is the systematic and on-goingassessment of the health of a community, including thetimely collection, analysis, interpretation, disseminationand subsequent use of that data. 1An effective public health surveillance system collectsrelevant data on a problem of public health importance,allowing users of the system to classify and interpretthat data to enable appropriate interventions to beapplied. All surveillance systems need to include thiscapacity for data collection and analysis as well astimely distribution of that data to those responsible forimplementing prevention and control measures.
Emphasis on particular goals of public healthsurveillance may vary between different levels of publichealth responsibility. Some goals are achieved mosteffectively by a regional public health unit while othermore strategic aims are best managed by state-baseddisease surveillance units or the CommonwealthDepartment of Health and Ageing. In South Australia,data generated through communicable diseasesurveillance is most typically used as a prompt foroutbreak investigation, monitoring of disease trends andfor initiating disease control initiatives. This does notpreclude the use of such data for other means includingepidemiological research and programme development.Table 1 lists the goals seen in effective public healthsurveillance.Table 1: Goals of effective public health surveillanceGoals of Surveillance• To detect cases or clusters of cases thereby enablinginterventions to be implemented that preventtransmission or reduce morbidity and mortality.• To assess the public health impact of a health eventor determinant and measure trends.• To demonstrate the need for public healthintervention programmes and resources.• To monitor the effectiveness of disease preventionand control measures and intervention strategies.• To identify high-risk populations or geographic areasto target interventions and guide analytical studies.• To develop hypotheses leading to analyticstudies about disease causation, transmission ordevelopment.Types of surveillance systemsPublic health surveillance systems have traditionallybeen classified as being passive, active or sentinel,and all three types are utilised in the surveillance ofcommunicable diseases in SA. 2Passive surveillancePassive disease surveillance usually refers tomonitoring of data supplied to health authorities bydoctors and laboratories as a requirement under law.Communicable disease surveillance is heavily reliant onpassive surveillance, using both clinical and laboratorynotifications, however these systems are likely tounderestimate the true burden of illness as many peoplewith notifiable conditions may only have mild illnessand do not seek care, while others may be incorrectlydiagnosed or may not receive laboratory testing toconfirm a diagnosis. For example Campylobactergastroenteritis, with over 15,000 notifications nationally,is the most common notifiable cause of foodbornedisease in Australia, with SA having the highest statenotification rate (173 per 100,000). 2 Yet estimates ofits true prevalence in Australia are thought to exceed200,000 cases per year. 3 Nevertheless the patternsseen over time are informative and provide the basis forpublic health action.Active surveillanceTo preclude issues with under reporting, particularlyfor more serious conditions, more vigorous means ofdetection may be used. In SA additional laboratorytesting of all bloody stools for the presence of Shigatoxigenic Escherichia coli is undertaken, 4 as cases wouldnot be detected via routine microbiological examinationor a specific clinical diagnosis. This supplementarysurveillance was implemented in response to a largeoutbreak of Haemolytic Uraemic Syndrome (HUS)caused by fermented sausage contaminated with E.Coli. 5 This type of surveillance is particularly useful inestablishing prevalence rates for conditions where theremay be a lack of data or where cases occur sporadically.Another illustration of active surveillance is theprocess of case ascertainment during an outbreakinvestigation. If a hospital intensive care doctornotified two cases of HUS a likely response would beto contact other intensive care unit and renal units toactively find more cases. Active systems can validatethe representativeness of passive systems, enablemore complete reporting of conditions or be used inconjunction with or part of specific epidemiological oroutbreak investigations.Sentinel surveillance systemsSentinel surveillance systems are established for thepurpose of enabling simple, early detection of disease.Animals are often used to provide this early warning. InAustralia, the Sentinel Chicken Surveillance Programmewas established to detect increases in flavivirus activity. 6The programme involves regular testing of a numberof chicken flocks across Australia for seroconversion toMurray Valley encephalitis virus and Kunjin virus in orderto determine levels of risk to human populations fromthese viruses.Sentinel healthcare providers are another example, withclinicians collecting data on selected indicators to assistin estimating the size of a problem among the generalpopulation. The Australian Sentinel Practice Research andEvaluation Network is one such example, with GeneralPractitioners (GP) collecting data on presentations forinfluenza-like illness (ILI). Such presentations couldpossibly represent an early expression of increasedinfluenza activity. In SA this data is combined withlaboratory reporting of influenza and ILI presentationsto emergency departments, to provide evidence of theimpact of seasonal influenza activity (Figure 1 next page).
- Page 1: Edition 4 /2006 South AustraliaPubl
- Page 6 and 7: References1. Teutsch SM. Considerat
- Page 8 and 9: H5N1 is not yet readily transmissib
- Page 10 and 11: number of people living in areas of
- Page 12 and 13: Infections, kidneyand cardiovascula
- Page 14 and 15: living conditions and health status
- Page 16 and 17: Hepatitis C virusinfection in priso
- Page 18 and 19: population). Data collection commen
- Page 20 and 21: 31 Weild AR, Gill ON, Bennett D, Li
- Page 22 and 23: avoidance strategies. To promote po
- Page 24 and 25: cancer among aboriginal women. This
- Page 26 and 27: coverage had dropped by 21% and mum
- Page 28 and 29: CASE STUDY 2Parents’ experiences
- Page 30 and 31: Chlamydia -closing thestable doorDr
- Page 32 and 33: Sexually transmittedinfections in C
- Page 34 and 35: Early treatment of infections is es
- Page 36 and 37: Australian hospitals, the optimum r
- Page 38 and 39: Figure 3: Relationship between new
- Page 40 and 41: While ongoing monitoring and analys
- Page 42 and 43: InfluenzaSouth Australian influenza
- Page 44: Notifiable Diseases in South Austra
In the early 1800s Chadwick identified the appallingliving conditions of industrial Engl<strong>and</strong> as c<strong>au</strong>ses of illhealth in workers, resulting in their inability to perform inthe workplace as well as they otherwise might. At thistime the miasma theory of disease was predominant<strong>and</strong> environment was ascribed the status of agent.With Koch’s discoveries from the mid-1870s, cameconcerted attention upon the diad of biological agent<strong>and</strong> host with less emphasis on the environment. Thusbegan an era where the emphasis of public health was(rightly) communicable disease. These are illnessesdue to specific infectious agents or their toxic productstransmitted from another infected host or from ananimate or inanimate reservoir.The recognition that an underst<strong>and</strong>ing of diseasedynamics could be usefully described by the triadhost-agent-environment arose in the 1920s withthe development of social <strong>and</strong> holistic medicine. Italso came to be the basis of training by Alex<strong>and</strong>erLangmuir <strong>and</strong> the Epidemic Intelligence Service <strong>and</strong> theconcept of ‘shoe leather epidemiology’ was promoted.Importantly, this required investigators to go into thefield to interview cases, their families, industry <strong>and</strong>other informants such as local health workers <strong>and</strong>government officials.However, it was always necessary to view theenvironment as a multi-level construct ranging fromcellular interactions, to person to person interactions <strong>and</strong>to the influences at community <strong>and</strong> country level. Therehas been an evolving process of developing theory thateffectively integrates these multiple levels of factors thatcan all be viewed as c<strong>au</strong>ses of disease 1 .Classical epidemiology is being integrated with socialor cultural investigations as this theory evolves. This isimportant for several reasons. Firstly it reinforces theneed to fully underst<strong>and</strong> the nature of a problem beforedesigning a solution <strong>and</strong> we see an increasing emphasison introducing ethnographic techniques into traditionalcommunicable disease investigations 2 . Secondly thisinvolves a mix of research methods – quantitative <strong>and</strong>qualitative to reach that underst<strong>and</strong>ing with betteranalytic methods to h<strong>and</strong>le the data from mixed methodresearch becoming available. Finally, just as illness <strong>and</strong>disease can be better understood with this paradigm, sotoo can appropriate means of intervention be devised.Clearly, the overwhelming message is that appropriateresources must be invested for adequate fieldinvestigations to secure reliable research findings whichcan be translated into feasible policy.References1. Kreiger N. Theories for social epidemiology in the 21 stcentury: an ecosocial perspective. Int. J Epidemiol.2001;30:668-677.2. Weiss MG. Cultural epidemiology: an introduction <strong>and</strong>overview. Anthropology <strong>and</strong> Medicine 2001;8(1):5-29.<strong>Public</strong> <strong>Health</strong>surveillance for<strong>Communicable</strong> <strong>Diseases</strong>in South AustraliaIntroductionCameron MoffattEpidemiology Registrar,<strong>Communicable</strong> Disease Control BranchDepartment of <strong>Health</strong>Master of Applied Epidemiology ProgrammeAustralian National University<strong>Communicable</strong> disease control remains a high priorityfor population health. In Australia, many of the controlsfor communicable diseases already exist outside of thehealth system. These include things such as education,clean water, secure food sources, systems for disposalof refuse <strong>and</strong> sewage <strong>and</strong> adherence to regulationssuch as building codes. Disease surveillance helps toidentify cases when breakdowns in these systems mayhave occurred, however the pathogens responsible forthese diseases are frequently evolving, readily exploitingopportunities for change <strong>and</strong> transmission. In particularviruses transmitted in the air or by respiratory secretionshighlight the need for systems capable of detecting <strong>and</strong>monitoring the presence of such pathogens.This paper examines public health surveillance with aparticular focus on notifiable conditions, using wherepossible relevant South Australian examples. Includedis an examination of effective public health surveillance<strong>and</strong> its core aims; the main types of surveillancesystems used for monitoring communicable diseases;discussion of the importance of notifiable conditions;specific reporting systems <strong>and</strong> surveillance; the analysis<strong>and</strong> dissemination of surveillance data; <strong>and</strong> concludingremarks.What is public health surveillance?<strong>Public</strong> health surveillance is the systematic <strong>and</strong> on-goingassessment of the health of a community, including thetimely collection, analysis, interpretation, dissemination<strong>and</strong> subsequent use of that data. 1An effective public health surveillance system collectsrelevant data on a problem of public health importance,allowing users of the system to classify <strong>and</strong> interpretthat data to enable appropriate interventions to beapplied. All surveillance systems need to include thiscapacity for data collection <strong>and</strong> analysis as well astimely distribution of that data to those responsible forimplementing prevention <strong>and</strong> control measures.
Change language