Is This an Outbreak? A retrospective evaluation of syndromic surveillance for emerging infectious disease

In the last decade, worldwide several major infectious disease events occurred — like the anthrax attacks in the USA in 2001, the SARS epidemic in 2003 and the 2009 influenza pandemic. As a result, public-healt

Evaluation of Syndromic Surveillance in the Netherlands: Its Added Value and Recommendations for Implementation

In the last decade, syndromic surveillance has increasingly been used worldwide for detecting increases or outbreaks of infectious diseases that might be missed by surveillance based on laboratory diagnoses and notifications by clinicians alone. There is, however, an ongoing debate about the feasibility of syndromic surveillance and its potential added value. Here we present our perspective on syndromic surveillance, based on the results of a retrospective analysis of syndromic data from six Dutch healthcare registries, covering 1999–2009 or part of this period. These registries had been designed for other purposes, but were evaluated for their potential use in signalling infectious disease dynamics and outbreaks. Our results show that syndromic surveillance clearly has added value in revealing the blind spots of traditional surveillance, in particular by detecting unusual, local outbreaks independently of diagnoses of specific pathogens, and by monitoring disease burden and virulence shifts of common pathogens. Therefore we recommend the use of syndromic surveillance for these applications

Tekenradar.nl, een webplatform over tekenbeten en de ziekte van Lyme

Tekenradar.nl is een webplatform voor onderzoek naar teken en tekenoverdraagbare aandoeningen zoals de ziekte van Lyme. Het RIVM en Wageningen University hebben de website in 2012 gezamenlijk opgericht. Tekenradar.nl geeft informatie over tekenbeten en de ziekte van Lyme en een actuele voorspelling van de tekenactiviteit. Mensen kunnen hun tekenbeet of erythema migrans en de vermoedelijke geografische locatie waar de beet is opgelopen melden op de site. Tot voorjaar 2013 konden deze melders van een tekenbeet worden uitgenodigd de teek op te sturen voor onderzoek, om gedurende anderhalf jaar periodiek vragenlijsten in te vullen waarin wordt gevraagd naar hun gezondheid. In één van de nog lopende onderzoeken wordt onderzocht in hoeverre een eenmalige preventieve dosis antibioticum na een tekenbeet helpt om het ontstaan van de ziekte van Lyme te voorkomen. In dit artikel geven wij een overzicht van het bereik van Tekenradar.nl onder het Nederlands publiek, en een samenvatting van lopende onderzoeken en eerste resultaten

Do intensive care data on respiratory infections reflect influenza epidemics?

Objectives Severe influenza can lead to Intensive Care Unit (ICU) admission. We explored whether ICU data reflect influenza like illness (ILI) activity in the general population, and whether ICU respiratory infections can predict influenza epidemics. Methods We calculated the time lag and correlation between ILI incidence (from ILI sentinel surveillance, based on general practitioners (GP) consultations) and percentages of ICU admissions with a respiratory infection (from the Dutch National Intensive Care Registry) over the years 2003–2011. In addition, ICU data of the first three years was used to build three regression models to predict the start and end of influenza epidemics in the years thereafter, one to three weeks ahead. The predicted start and end of influenza epidemics were compared with observed start and end of such epidemics according to the incidence of ILI. Results Peaks in respiratory ICU admissions lasted longer than peaks in ILI incidence rates. Increases in ICU admissions occurred on average two days earlier compared to ILI. Predicting influenza epidemics one, two, or three weeks ahead yielded positive predictive values ranging from 0.52 to 0.78, and sensitivities from 0.34 to 0.51. Conclusions ICU data was associated with ILI activity, with increases in ICU data often occurring earlier and for a longer time period. However, in the Netherlands, predicting influenza epidemics in the general population using ICU data was imprecise, with low positive predictive values and sensitivities

Q fever outbreaks: a syndromic approach for detection of hidden clusters.

OBJECTIVE: To explore - using syndromic data - whether there is evidence for local Q fever outbreaks before detection of the known 2007 outbreak in the Netherlands and whether syndromic surveillance could have accelerated their detection. BACKGROUND: For many years, Q-fever has been very rare in the Netherlands with around 15 notified cases per year, but since the end of May 2007, outbreaks of Q fever have been reported in rural areas in the southern part of the country, with 20-25% of the notified cases hospitalized. In 2007, 178 Q fever cases were notified, most of them occurring in May and June 2007. In 2008 and 2009 large outbreaks of Q fever recurred with increasing numbers of cases and in an expanding geographic area. Dairy goat farms are considered the most plausible source of infection for these outbreaks and Q fever has been first reported as cause of abortion waves on such farms in 2005. This triggered questions about possible undetected or misdiagnosed outbreaks preceding the 2007 outbreak, as most patients with severe acute Q fever present with pneumonia. In this study we explore retrospectively whether there is evidence for human Q-fever outbreaks in the Netherlands in 2005-2007, before detection of the 2007 outbreak. For this, we look for elevations in space and time of hospitalized patients with lower-respiratory infections (LRI) and other syndromes that can be associated with Q fever, and assess whether these local syndrome elevations could be due to Q-fever (or to other causes e.g. RSV/influenza). We then evaluate whether real-time syndromic surveillance on hospitalizations could have ac-celerated the detection of human Q-fever outbreaks. METHODS: Space-time scan statistics were used to look for clusters of lower-respiratory infections (LRI), hepati-tis and/or endocarditis in Dutch hospitalizations (2005-2007). We assessed whether these were plau-sibly due to Q fever, using criteria based upon age distribution and discharge diagnoses, overlap with notified Q fever cases, indications for other likely causes, and geographic overlap with contaminated farms. RESULTS: For seven out of twenty detected LRI clusters and one out of two hepatitis clusters, we considered Q fever a plausible cause. With real-time syndromic surveillance, two of these clusters could have been signaled in 2005, one in 2006, and four in 2007. CONCLUSIONS: We found substantial support for the occurrence of local Q fever outbreaks before detection of the 2007 outbreak and in a wider area. Real-time syndromic surveillance could have detected these clusters, prompting further investigations and additional labo-ratory tests. This might have resulted in up to two years earlier detection of Q fever outbreaks. Serology on historical blood samples from the detected cluster areas would be necessary to confirm that Q fever did cause these clusters. (aut. ref.

Decrease in tick bite consultations and stabilization of early Lyme borreliosis in the Netherlands in 2014 after 15 years of continuous increase

BackgroundNationwide surveys have shown a threefold increase in general practitioner (GP) consultations for tick bites and early Lyme borreliosis from 1994 to 2009 in the Netherlands. We now report an update on 2014, with identical methods as for the preceding GP surveys.MethodsTo all GPs in the Netherlands, a postal questionnaire was sent inquiring about the number of consultations for tick bites and erythema migrans diagnoses (most common manifestation of early Lyme borreliosis) in 2014, and the size of their practice populations.ResultsContrasting to the previously rising incidence of consultations for tick bites between 1994 and 2009, the incidence decreased in 2014 to 488 consultations for tick bites per 100,000 inhabitants, i.e., 82,000 patients nationwide. This survey revealed a first sign of stabilization of the previously rising trend in GP diagnosed erythema migrans, with 140 diagnoses per 100,000 inhabitants of the Netherlands. This equals about 23,500 annual diagnoses of erythema migrans nationwide in 2014.ConclusionsIn contrast to the constantly rising incidence of GP consultations for tick bites and erythema migrans diagnoses in the Netherlands between 1994 and 2009, the current survey of 2014 showed a first sign of stabilization of erythema migrans diagnoses and a decreased incidence for tick bite consultations.<br/

Validation of cellular tests for Lyme borreliosis (VICTORY) study

Contains fulltext : 207350.pdf (publisher's version ) (Open Access

Sensitivity of a point of care tick-test for the development of Lyme borreliosis

Background: A commercially available self-test for the detection of Borrelia burgdorferi sensu lato in ticks was evaluated for its ability to predict erythema migrans formation. Findings: The self-test was performed on 127 Ixodes ricinus from 122 humans that reported tick bites at enrolment and occurrence of symptoms during follow-up. The self-test gave negative results on all the 122 individuals, 14 of whom reported erythema migrans (EM) at follow-up of which 10 were confirmed by their GP. The estimated sensitivity of the self-test for prediction of EM formation is 0% (95% Cl: 0%-28%). Conclusions: This self-test is not suitable for reducing the number needed to treat in a post-exposure prophylaxis setting as it already missed all the obvious early Lyme borreliosis cases