Page 18 - Timeliness of Infectious Disease Notification & Response Systems - Corien Swaan

16 Chapter 1
1.1 Infectious disease surveillance and response: capacities for emergency preparedness
Public health surveillance is defined as the ongoing, systematic collection, analysis, interpretation, and dissemination of data regarding a health-related event for use in public health action to reduce morbidity and mortality and to improve health (1).
Historically, in the 19th century the first systematic sentinel surveillance systems developed in the large cities in Europe, requiring physicians to report number of cases and deaths (2). This was related to the cholera outbreaks that occurred in these regions. In the Netherlands, mandatory reporting of individ- ual cases was installed for physicians in 1865. During that period, the country was confronted with typhoid and smallpox epidemics besides cholera. In 1872, the ‘law on epidemics’ entitled local authorities to install control measures for cholera, typhoid, smallpox, scarlet fever, diphtheria, measles and dysentery (3). In the 20th century, the notifiable diseases were adjusted in successive laws de- pending on actual public health threats. Following developments in microbio- logical confirmation technologies, also laboratory surveillance was installed re- quiring heads of laboratories, like physicians, to notify infectious diseases to the local municipal health services or local health departments (MHS or LHD, in the Netherlands called ‘Gemeenschappelijke Gezondheidsdiensten’, GGDs). In the Netherlands, the purpose of notification of diseases is early warning of outbreaks or emerging infections for which control measures by public health authorities might be necessary. In addition, infectious diseases are notifiable for which pre- ventive vaccination is included in the National Immunisation Programme (Rijks- vaccinatie-programma, RVP), in order to monitor potential vaccine failure. In the latest Law on Public Health from 2008, the list of notifiable diseases was adjust- ed to be in line with the newly installed International Health Regulations (IHR) of the World Health Organization (WHO) (4). To date, cholera, diphtheria, typhoid fever, and (bacillary) dysentery are still on the list of notifiable diseases (5).
Mandatory notification systems are a traditional form of Indicator Based Surveillance (IBS), which is defined as the systematic collection, monitoring, analysis, and interpretation of structured data, i.e. indicators, produced by a number of well-identified, predominantly health-based formal sources (6). Data in IBS are routinely collected, according to established case definitions, which are either disease-specific or syndromic. Conventional notification systems us- ing postal mail, telephone, and fax are more and more replaced by electronic reporting systems such as electronic laboratory reporting (ELR) and automated ELR, which can lead to more timely and more complete notifications on local,