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—from the Epidemiological Bulletin, Vol. 21 No.1, March 2000— An integrated approach to Communicable Disease Surveillance
Effective communicable disease control relies on effective response systems and effective response systems rely on effective disease surveillance. A functional surveillance system is essential in providing information for action on priority communicable diseases; it is a crucial instrument for public health decision-making in all countries. Surveillance data provide information, which can be used, for priority setting, policy decisions, planning, implementation, resource mobilization and allocation, and prediction and early detection of epidemics. A surveillance system can also be used for monitoring, evaluation and improvement of disease prevention and control programs. Disease surveillance is thus a critical component of the health system since it provides essential information for optimal health care delivery and a cost-effective health strategy. Current situation Outdated surveillance systems, in which new surveillance targets have been added but old ones never removed, often lead to central bodies collecting huge amounts of data with little or no analysis and use of the corresponding information. Feedback to the data collectors is rarely provided. The surveillance system becomes driven by the need to collect and move data while scant attention is given to using the data at each level of the health service for decision-making. National surveillance data on infectious diseases is usually collected by programs under different authorities, inclu-ding the ministry of health (diseases and health system moni-toring), the ministry of agriculture (environment, animals, plants and food products) and the ministry of the interior (central statistics offices). In addition, academic or research institutes may conduct specific surveillance activities while the private sector and nongovernmental organizations (NGOs) may also run surveillance systems in their area of interest. Within the health sector, multiple surveillance systems may operate in parallel, sometimes in complete independence. This problem can be exacerbated by the influence of strong outside donors who may support specific surveillance and control programs. Establishing surveillance activities within vertical programs allows the surveillance and control functions to remain closely linked. On the other hand, the overall surveillance function in a country may become badly disjointed and inefficient, with field workers participating in multiple complicated systems, which use different surveillance methodologies, terminology, and reporting frequencies and forms. This leads to extra costs and training requirements, and often results in health workers becoming overloaded and demotiva-ted. Furthermore, new priorities such as surveillance of antimicrobial drug resistance need to be addressed across vertical programs. Paradigm shift – An integrated approach to surveillance One national surveillance system Specialized surveillance systems are important, especially where surveillance is complex and has specific data needs. For example, eradication and elimination programs require strong surveillance systems aimed at detecting every case. Yet although specific disease control programs require different surveillance data, they all require similar core activities (case detection, reporting, investigation, confirmation, ana-lysis, interpretation and action) and support functions (surveillance standards, epidemiology training, supervision, geographical mapping, communications, laboratory support and financial resources). It should thus be possible to envisage a holistic approach, which takes into consideration all core activities and support functions, in order to strengthen the national surveillance system through coordination, prioritization and streamlining of all surveillance activities. On the basis of an inventory of surveillance activities and the prioritization of surveillance targets, a gap analysis can be carried out, possible synergies identified, and existing activities reoriented as needed, while at the same time recognizing the special needs of individual programs. Integration should focus particularly on the support functions of all individual surveillance systems. One national network of people It is essential that feedback loops be built into national surveillance systems. This may be a regular epidemiological bulletin or website with tables and graphs showing trends, progress towards targets, and reports on the investigation and control of outbreaks. To maintain the momentum for the surveillance effort, it is crucial that the personnel involved in surveillance activities regularly see the impact of their work, since at the peripheral level it is usually done in addition to a heavy clinical workload. Participants in the surveillance system should be pro-perly trained for their surveillance tasks, through both initial and ongoing inservice training. In an integrated multi-disease approach, field or intervention epidemiology training will provide general surveillance and response skills, which can be, applied almost anywhere in the system and for any disease surveillance and response needs. General surveillance and response skills are crucial in the event of the emergence of diseases not anticipated by the surveillance system. Short-term and long-term training courses in field epidemiology should be available in all countries. Training in laboratory techniques should also take an integrated multidisease approach where the same or a similar technique (e.g. microscopy, serological assay) is used to diagnose various diseases. The integrated approach to training should also encourage basic laboratory training for epidemiologists and some epidemiology training for laboratory technicians, in order to ensure that both groups understand each other’s needs and approach to surveillance. National coordination At the regional level, coordination of all national surveillance systems is also required through regional prioritization, standardization and the strengthening of integrated multidisease epidemiological and laboratory capacity. Specific regional capacity may be needed, such as regional reference laboratories, regional epidemic response teams and regional stocks of supplies (e.g. vaccine and drug storage). At the international level the need to coordinate surveillance and response activities is growing with the increasing globalization of trade and travel. Global surveillance standards for communicable diseases are recommended by WHO 1 to support the global analysis of surveillance data through common terminology, common case definition and common surveillance methods. Assessing the national surveillance system Any assessment should aim to develop or update a national plan for communicable disease surveillance so that the national surveillance and response system is improved overall. In a given country, it should bring together all those who have responsibility for surveillance of communicable dis- eases and assess systematically the national surveillance activities as one system. There should be participation where possible from those working in public sectors other than the health sector, such as the agricultural sector. In addition, the private sector and other relevant partners such as NGOs should be included in the assessment. The integrated or multidisease approach to assessment of the national surveillance system may be based on the WHO protocol developed and field-tested in several countries 1 and may complement the assessment of individual systems as developed by CDC. More specific multidisease assessment guidelines have also been developed by WHO for vaccine- preventable diseases and are under development for antimicrobial resistance surveillance. Taking advantage of news tools Thanks to electronic databases, data can be analyzed more easily and rapidly and when geographical information is available, they can be linked to geographical information systems (GIS).1 The joint WHO-UNICEF HealthMap project, initially developed and successfully used by the program for eradication of guinea-worm disease, has evolved into a multidisease tool for data collection, mapping and geographical analysis. It provides a unique possibility for multidisease, multilevel and multisectoral surveillance. The dissemination of surveillance data and their presentation to a wider audience, as well as internal feedback, are now also achieved through dedicated websites and compact disks. The difficulties related to the timely collection of disease specific data have led to the concept of collecting information about syndromes. This syndromic approach is used successfully by the poliomyelitis eradication program, which collects data on acute flaccid paralysis (AFP) caused by several infectious or non-infectious diseases, but that will trigger an immediate response from the poliomyelitis surveillance system. The same approach could be applied in areas where rapid laboratory diagnosis cannot be obtained (such as at the periphery of many health systems). Although lacking specificity, the syndromic approach offers: a simple and stable case definition; reliability (as it reports what is actually seen); immediate reporting (as there is no laboratory delay); a wider surveillance coverage allowing for the detection of emerging diseases; and, in some cases, the avoidance of disease-associated stigma. This approach is complementary to a disease-specific list of notificable diseases, and is also being considered in the context of the revision of the International Health Regulations. Investing in surveillance In 1999, the Director-General of WHO issued a call to invest in healthy development, which should also translate into investing in disease surveillance.2 Disease surveillance is a long-term effort that requires investment in national capacity-building, such as laboratory strengthening and field epidemiology training. Short-term and relatively low investment can rapidly have a visible impact in the specific area of epidemic surveillance and response. However, the overall strengthening and sophistication of routine surveillance systems is critical but necessarily more costly, and can only produce tangible results on a mid- or long–term basis. Investing in surveillance should take into account the investment already made to support specific control, elimination or eradication programs, and transform these time-li- mited efforts into a long-term undertaking, capitalizing on special efforts such as the onchocerciasis control program in the African Region and the global poliomyelitis eradication program. Since disease surveillance is a basic component of a health information system, and thus also of a national health system, partnership with development agencies (whether international, governmental or nongovernmental) is essential to improve national surveillance and response systems. This is particularly true in the context of health sector reform and other long-term development projects. Lessons learnt and conclusion In the area of epidemic surveillance and response, public health authorities should give more attention to information from sources other than the public health sector, including NGOs and the media. The capacity of public health authorities to rapidly respond to outbreak-related information from any source is essential for the efficiency and credibility of the entire surveillance effort. In order to achieve such credibility, building an integrated multidisease response capacity should be the first step towards improving national and regional surveillance systems, the second step being to build on existing and successful surveillance activities. A special effort is needed to design quality indicators for a multidisease surveillance and response system. It should take into account not only the need for generic universal indicators, but also the diversity of national surveillance systems and their specific situations. Overall, the commitment of all interested parties, including health and other sectors such as agriculture and commerce, whether public or private, and the resolute support of the highest national authorities, are essential for the success of an integrated multidisease national surveillance and response system.
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