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Background: Climate change may contribute to higher incidence and wider geographic spread of vector borne diseases (VBDs). Effective monitoring and surveillance of VBDs is of paramount importance for the prevention of and timely response to outbreaks. Although international regulations exist to support this, barriers and operational challenges within countries hamper efficient monitoring. As a first step to optimise VBD surveillance and monitoring, it is important to gain a deeper understanding of system characteristics and experiences in to date non-endemic regions at risk of becoming endemic in the future. Therefore, this study qualitatively analyses the nature and flexibility of VBD surveillance and response in Beijing., Methods: In this qualitative study, eleven experts working in Beijing's vector-borne diseases surveillance and response system were interviewed about vector-borne disease surveillance, early warning, response, and strengths and weaknesses of the current approach., Results: Vector-borne disease surveillance occurs using passive syndromic surveillance and separate vector surveillance. Public health authorities use internet reporting networks to determine vector-borne disease risk across Beijing. Response toward a vector-borne disease outbreak is uncommon in this setting due to the currently low occurrence of outbreaks., Conclusions: A robust network of centralised institutions provides the continuity and flexibility needed to adapt and manage possible vector-borne disease threats. Opportunities exist for population-based health promotion and the integration of environment and climate monitoring in vector-borne disease surveillance.

Measles is a notifiable disease, but not everyone infected seeks care, nor is every consultation reported. We estimated the completeness of reporting during a measles outbreak in The Netherlands in 2013-2014. Children below 15 years of age in a low vaccination coverage community (n = 3422) received a questionnaire to identify measles cases. Cases found in the survey were matched with the register of notifiable diseases to estimate the completeness of reporting. Second, completeness of reporting was assessed by comparing the number of susceptible individuals prior to the outbreak with the number of reported cases in the surveyed community and on a national level.We found 307 (15%) self-identified measles cases among 2077 returned questionnaires (61%), of which 27 could be matched to a case reported to the national register; completeness of reporting was 8.8%. Based on the number of susceptible individuals and number of reported cases in the surveyed community and on national level, the completeness of reporting was estimated to be 9.1% and 8.6%, respectively. Estimating the completeness of reporting gave almost identical estimates, which lends support to the credibility and validity of both approaches. The size of the 2013-2014 outbreak approximated 31 400 measles infections.

Background: Since 2009, the incidence of meningococcal serogroup W disease has increased rapidly in the UK because of a single strain (the so-called original UK strain) belonging to the hypervirulent sequence type-11 clonal complex (cc11), with a variant outbreak strain (the so-called 2013 strain) emerging in 2013. Subsequently, the Netherlands has had an increase in the incidence of meningococcal serogroup W disease. We assessed the temporal and phylogenetic associations between the serogroup W outbreaks in the Netherlands and England, and the historical serogroup C outbreaks in both countries., Methods: For this observational cohort study, we used national surveillance data for meningococcal serogroup W and serogroup C disease in the Netherlands and England for the epidemiological years (July to June) 1992-93 to 2015-16. We also did whole genome sequencing and core genome multilocus sequence typing (1546 loci) on serogroup W disease isolates from both countries for surveillance years 2008-09 to 2015-16. We used Poisson regression to compare the annual relative increase in the incidence of serogroup W and serogroup C between both countries., Findings: In the Netherlands, the incidence of meningococcal serogroup W disease increased substantially in 2015-16 compared with 2014-15, with an incidence rate ratio of 5·2 (95% CI 2·0-13·5) and 11% case fatality. In England, the incidence increased substantially in 2012-13 compared with 2011-12, with an incidence rate ratio of 1·8 (1·2-2·8). The relative increase in the Netherlands from 2014-15 to 2015-16 was 418% (95% CI 99-1248), which was significantly higher than the annual relative increase of 79% (61-99) per year in England from 2011-12 to 2014-15 (p=0·03). Cases due to meningococcal serogroup W cc11 (MenW:cc11) emerged in 2012-13 in the Netherlands. Of 29 MenW:cc11 cases found up to 2015-16, 26 (90%) were caused by the 2013 strain. For both the current serogroup W outbreak and the historical serogroup C outbreak, the increase in incidence started several years later in the Netherlands than in England, the rate of increase was higher in the Netherlands, and age distributions were similar in both countries., Interpretation: Given the historical similarities of meningococcal serogroup W with meningococcal serogroup C emergence, the rapid expansion of the MenW:cc11 2013 strain in the Netherlands, its high case fatality, and the availability of a safe and effective vaccine, urgent consideration is needed for public health interventions in the Netherlands and other affected countries to prevent further serogroup W cases and deaths., Funding: National Institute for Public Health and the Environment (Netherlands), Academic Medical Center (Netherlands), and Public Health England., (Copyright © 2017 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY NC-ND 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Despite vaccination coverage over 95%, a measles outbreak started in May 2013 in the Netherlands. As of 28 August, there were 1,226 reported cases, including 82 hospitalisations. It is anticipated that the outbreak will continue. Most cases were orthodox Protestants (n=1,087/1,186; 91.7%) and unvaccinated (n=1,174/1,217; 96.5%). A unique outbreak control intervention was implemented: a personal invitation for measles-mumps-rubella (MMR) vaccination was sent for all children aged 6–14 months living in municipalities with MMR vaccination coverage below 90%.

Background: New variant strains of norovirus have emerged worldwide in recent years, evolving by mutation much like influenza viruses. These strains have been associated with a notable increase in the number of annual norovirus outbreaks. However, the impact of such increased norovirus activity on morbidity and mortality is not clear because norovirus infection is rarely specifically registered., Methods: We studied trends of gastroenteritis with unspecified cause in medical registrations (ie, general practitioner [GP] visits, hospitalizations, and deaths) and their association with known temporal trends in norovirus outbreaks in the Netherlands. Using weekly counts in the elderly (aged 65+ years) from 1999 through 2006, we applied Poisson regression analyses adjusted for additional pathogens and seasonal trends (linear, sine, and cosine terms)., Results: In the elderly, each notified norovirus outbreak was associated with an estimated 26 unspecified gastroenteritis GP visits (95% confidence interval = 17-34), 2.2 unspecified gastroenteritis hospitalizations (1.6-2.7), and 0.14 unspecified gastroenteritis deaths (0.08-0.21). For the heaviest norovirus season (2004-2005), these models attributed up to 3804 unspecified gastroenteritis GP visits, 318 unspecified gastroenteritis hospitalizations, and 21 unspecified gastroenteritis deaths to norovirus outbreaks among a total elderly population of 2.3 million., Discussion: The recent increase in norovirus outbreak activity is associated with increases of unspecified gastroenteritis morbidity and even deaths in the elderly. Norovirus should not be regarded as an infection with trivial health risks.

In 2006, in The Netherlands, an outbreak of Salmonella Typhimurium phage type 561 (STM DT7, corresponding to the rare DT7 in the international typing scheme) was detected, accumulating to over 200 cases. By telephone interviews, data were collected from all laboratory-confirmed cases. In addition, in August 2006, a case-control study was performed in a subset of cases. Environmental and microbiological investigation was performed on a suspected dairy farm. In the case-control study (51 cases, 105 matched controls), hard cheese purchased from a farm, specifically farm X, and from a market stall were found to be associated with infection. The dairy production room of farm X tested STM DT7-positive in August. However, it was only in November, after earlier unsuccessful attempts, that a low-level contamination was confirmed in the hard farmhouse cheese, triggering control measures. A timely and adequate response was hampered during this outbreak for several reasons. Measures for improvement in handling future similar incidents are discussed.

Objectives: To estimate the fraction of human cases of enterically transmitted illness by five major pathways (food, environment, direct animal contact, human-human transmission, and travel) and by 11 groups within the food pathway., Methods: Food safety experts were asked to provide their estimates of the most likely range for each of the parameters. Joint probability distributions were created by probabilistic inversion (PI)., Results: Sixteen experts participated in the study. PI resulted in good fits for most pathogens. Qualitatively, expert estimates were similar to earlier published studies but the estimated fraction of foodborne transmission was lower for most pathogens. Biologically less plausible pathways were given some weight by the experts. Uncertainties were smallest for pathogens with dominant transmission routes., Conclusions: Structured expert studies are a feasible method for source attribution, but methods need further development., Applications: These estimates can be combined with data on incidence, disease burden and costs to provide specific estimates of the public health impact of foodborne illness, and to identify the food groups that have the highest impact.

The main objectives of this pilot study were to test the potential use of the disease burden concept in the field of infectious diseases, including data quality and availability; to recommend future studies; and to stimulate a debate. The disease burden of seven infectious diseases (influenza, measles, HIV, campylobacteriosis, infection with enterohaemorrhagic Escherichia coli, salmonellosis and tuberculosis) in Europe was estimated by calculating Disability Adjusted Life Years (DALYs), a composite measure that attempts to combine mortality, incidence and sequelae, taking duration and severity into account. The results show that the relative burden of diseases as measured by DALYs differs from that only measured by incidence or mortality. Several limitations regarding data availability and quality have been identified, resulting in an underestimation of the true burden of disease in this pilot. Notwithstanding these, HIV-infection, tuberculosis (TB) and influenza are estimated to cause the highest burden in Europe among the selected diseases. The burden of foodborne diseases (campylobacteriosis, infection with enterohaemorrhagic Escherichia coli and salmonellosis) and in particular of measles is lower. A consideration of the relative comparison of burden between diseases can be useful when tackling the difficult, sensitive but necessary task of identifying priority actions. A low burden stresses the need for continued support for prevention and control whereas a high burden indicates the need for additional interventions. Following this pilot project, a generalised burden of disease study for infectious diseases in Europe is recommended. Such a study would benefit from an approach that identifies and combines several methods of investigation, including epidemiological modelling, and it should be done in collaboration with other international efforts in this field.