Date Published: March 25, 2008
Publisher: Public Library of Science
Author(s): Jean-Paul Chretien, Howard S Burkom, Endang R Sedyaningsih, Ria P Larasati, Andres G Lescano, Carmen C Mundaca, David L Blazes, Cesar V Munayco, Jacqueline S Coberly, Raj J Ashar, Sheri H Lewis
Abstract: The tools and strategies of syndromic surveillance, say the authors, hold promise for improving public health security in developing countries.
Partial Text: Surveillance, according to the World Health Organization (WHO), “is the cornerstone of public health security” . In many developing countries, human, laboratory, and infrastructure limitations impede effective surveillance [2–5]. Such countries likely do not meet core surveillance and response capacities under the new International Health Regulations (IHR 2005) , which require detection of elevated disease and death rates, immediate implementation of control measures, and reporting to WHO of any event that may constitute a public health emergency of international concern . (The previous IHR covered only cholera, plague, and yellow fever.)
Syndromic surveillance offers a useful adjunct to diagnosis-based surveillance of emerging infections in developing countries. Where laboratory confirmation is not routinely used, syndromes associated with diseases of public health importance, such as influenza-like illness caused by multiple epidemic-prone tropical infections, could indicate outbreaks requiring laboratory-based investigation and control. Also, syndromic surveillance can identify outbreaks that do not fall into pre-established diagnostic categories, a capability essential for prompt control of new or changing diseases.
There is cause for optimism that syndromic surveillance approaches can feasibly be adapted to developing settings. First, they fit naturally with and could enhance existing strategies for outbreak detection and situational awareness in tropical areas. For example, with the goal of containing epidemics within two weeks of onset, WHO and African countries are implementing Malaria Early Warning Systems that use health data and climatology to forecast and detect epidemics . Pre-diagnostic data have been evaluated as indicators for dengue outbreaks in French Polynesia , French Guiana , Puerto Rico , and elsewhere.
Some developing countries have overcome resource constraints to establish effective electronic syndromic surveillance systems. The Indonesian Ministry of Health, together with a US laboratory it hosts in Jakarta, Naval Medical Research Unit-2, developed a simple but flexible syndromic surveillance system, Early Warning Outbreak Recognition System (EWORS), in 1998. For patients presenting to selected provincial hospitals, data on 29 signs and symptoms are collected and analyzed daily. Health authorities have used EWORS to detect outbreaks of dengue, diarrhea, influenza-like illness, and many other diseases.
Syndromic surveillance tools and approaches are not appropriate for all developing settings. Where no health data are routinely collected, developing basic surveillance capacities , including laboratory-based surveillance, should be a high priority for local and national health authorities. Where electronic syndromic surveillance systems may be feasible, a combination of technical, financial, political, ethical, cultural, and societal factors all may contribute to successful implementation and should be considered from the outset of planning (Box 2).
By helping to rapidly detect and characterize unusual morbidity trends, syndromic surveillance holds promise as an early line of defense against new and emerging infections in developing settings. Considering the poor state of public health surveillance in those areas, syndromic surveillance tools and approaches may provide greater additional benefit than in high-income countries that already have other types of effective surveillance programs.