Network visualization for outbreak response: Mapping the Ebola Virus Disease (EVD) chains of transmission in N'Zérékoré, Guinea.

BACKGROUND: During the 2014-2015 Ebola Virus Disease (EVD) outbreak in N'Zérékoré, Forested Guinea, modes of transmission remained unexamined for a number of new cases. We used network visualization to investigate EVD transmission chains (TC) in seven sub-prefectures of N'Zérékoré in order to adapt outbreak response. METHODS: Between August 2014 and February 2015, the EVD outbreak response team including the World Health Organization (WHO) and local health authorities routinely collected information among new cases regarding hospital visits, cases within a household, participation in burials, as well as dates of symptom onset, serial intervals (SI) and exposure to EVD. SI's were defined as the interval between symptom onset in an index case and symptom onset in a secondary case infected by that index case. Cases who reported hospital visits, contact with a case in the household or participating in burials were attributed to these exposures. RESULTS: We identified seven TC (two urban and five rural) gathering characteristics of 109 probable/confirmed cases. Overall, 61% (66 cases, SI range: 7-20 days) were household related, 32% (35 cases, SI range 8-30 days) were household or burial related and 7% (8 cases, SI range: 4-20 days) were hospital-related. In the urban chains (18 cases, SI range: 7-20 days), 12 cases were household related and 6 cases were hospital related, none where household or burial related. In the rural chains (84 cases, SI range: 7-30 days), 60% (50 cases) were household related, 1% (1 case) was hospital related and 39% (34 cases) were household or burial related. No cases reported multiple exposures. CONCLUSIONS: Network visualization during field response is crucial in enhancing local control strategies, refining outbreak response and aiding rapid response teams in insuring psychosocial and socio-economic recovery. Urban settings need to focus on reducing hospital EVD transmission whereas rural settings should focus on raising awareness of transmission within a household and safeguarding EVD burials.

Human-Dromedary Camel Interactions and the Risk of Acquiring Zoonotic Middle East Respiratory Syndrome Coronavirus Infection.

Middle East respiratory syndrome coronavirus (MERS-CoV) cases without documented contact with another human MERS-CoV case make up 61% (517/853) of all reported cases. These primary cases are of particular interest for understanding the source(s) and route(s) of transmission and for designing long-term disease control measures. Dromedary camels are the only animal species for which there is convincing evidence that it is a host species for MERS-CoV and hence a potential source of human infections. However, only a small proportion of the primary cases have reported contact with camels. Other possible sources and vehicles of infection include food-borne transmission through consumption of unpasteurized camel milk and raw meat, medicinal use of camel urine and zoonotic transmission from other species. There are critical knowledge gaps around this new disease which can only be closed through traditional field epidemiological investigations and studies designed to test hypothesis regarding sources of infection and risk factors for disease. Since the 1960s, there has been a radical change in dromedary camel farming practices in the Arabian Peninsula with an intensification of the production and a concentration of the production around cities. It is possible that the recent intensification of camel herding in the Arabian Peninsula has increased the virus' reproductive number and attack rate in camel herds while the 'urbanization' of camel herding increased the frequency of zoonotic 'spillover' infections from camels to humans. It is reasonable to assume, although difficult to measure, that the sensitivity of public health surveillance to detect previously unknown diseases is lower in East Africa than in Saudi Arabia and that sporadic human cases may have gone undetected there.

Food-borne diseases associated with frozen berries consumption: a historical perspective, European Union, 1983 to 2013.

Epidemiological investigations of outbreaks of hepatitis A virus (HAV) and norovirus (NoV) infections in the European Union/European Economic Area (EU/EEA) in the last five years have highlighted frozen berries as a vehicle of infection. Given the increasing berry consumption in the EU over the last decades, we undertook a review of the existing evidence to assess the potential scale of threat associated with this product. We searched the literature and four restricted-access online platforms for outbreak/contamination events associated with consumption of frozen berries. We performed an evaluation of the sources to identify areas for improvement. The review revealed 32 independent events (i.e. outbreak, food contamination) in the period 1983­2013, of which 26 were reported after 2004. The identified pathogens were NoV, HAV and Shigella sonnei. NoV was the most common and implicated in 27 events with over 15,000 cases reported. A capture­recapture analysis was performed including three overlapping sources for the period 2005­2013. The study estimated that the event-ascertainment was 62%. Consumption of frozen berries is associated with increasing reports of NoV and HAV outbreaks and contamination events, particularly after 2003. A review of the risks associated with this product is required to inform future prevention strategies. Better integration of the available communication platforms and databases should be sought at EU/EEA level to improve monitoring, prevention and control of food-borne-related events.

Event-based surveillance of food- and waterborne diseases in Europe: urgent inquiries (outbreak alerts) during 2008 to 2013.

During 2008 to 2013, 215 outbreak alerts, also known as 'urgent inquiries' (UI), for food- and waterborne diseases were launched in Europe, the majority of them (135; 63%) being related to salmonellosis. For 110 (51%) UI, a potential food vehicle of infection was identified, with vegetables being the most reported category (34;31%). A total of 28% (n = 60) of the outbreaks reported had an international dimension, involving at least two countries (mean: 4; standard deviation: 2; range:2­14). Participating countries posted 2,343 messages(initial posts and replies, excluding updates), with a median of 11 messages per urgent inquiry (range:1­28). Of 60 multicountry UI, 50 involved between two and four countries. The UI allowed early detection of multicountry outbreaks, facilitated the identification of the suspected vehicles and consequently contributed to the timely implementation of control measures. The introduction of an epidemic intelligence information system platform in 2010 has strengthened the role of the Food- and Waterborne Diseases and Zoonoses network in facilitating timely exchange of information between public health authorities of the participating countries.

Changing hepatitis A epidemiology in the European Union: new challenges and opportunities.

This perspective on hepatitis A in the European Union and European Economic Area (EU/EEA) presents epidemiological data on new cases and outbreaks and vaccination policies. Hepatitis A endemicity in the EU/EEA ranges from very low to intermediate with a decline in notification rates in recent decades. Vaccination uptake has been insufficient to compensate for the increasing number of susceptible individuals. Large outbreaks occur. Travel increases the probability of introducing the virus into susceptible populations and secondary transmission. Travel medicine services and healthcare providers should be more effective in educating travellers and travel agents regarding the risk of travel-associated hepatitis A. The European Centre for Disease Prevention and Control (ECDC) endorses the World Health Organization's recommendations on vaccination of high-risk groups in countries with low and very low endemicity and on universal vaccination in countries with intermediate endemicity. Those recommendations do not cover the use of hepatitis A vaccine to control outbreaks. ECDC together with EU/EEA countries should produce evidence-based recommendations on hepatitis A immunisation to control outbreaks. Data about risk behaviours, exposure and mortality are scarce at the EU/EEA level. EU/EEA countries should report to ECDC comprehensive epidemiological and microbiological data to identify opportunities for prevention.

Investigation of travel-related cases in a multinational outbreak: example of the Shiga-toxin producing E. coli outbreak in Germany, May-June 2011.

Early investigation of travel-related cases in an outbreak of an emerging infectious disease can provide useful information to epidemiologists to characterize the exposure, while they may differ in demographic profiles from cases reported in the country where the outbreak has occurred. During the spring 2011 E. coli outbreak in Germany, we proposed a methodological approach to collect a minimal set of demographic and clinical data that are relatively easy to obtain and available at an early stage of an outbreak investigation. Ninety-eight STEC O104 travel-related cases were reported in a survey by seven EU countries, Switzerland, Canada and the USA. We found a mean incubation period (n = 50) of 8·5 days, which confirmed previous estimations communicated by the Robert Koch Institute. No significant association was found between the duration of the incubation period and possible demographic and clinical factors, although the older the age, the shorter the incubation period that was observed. Such approach and observations are informative for further investigations of outbreaks of enterohaemorrhagic E. coli or other emerging infectious diseases.

Enhanced epidemic intelligence using a web-based screening system during the 2010 FIFA World Cup in South Africa.

The 2010 FIFA World Cup took place in South Africa between 11 June and 11 July 2010. The European Centre for Disease Prevention and Control (ECDC), in collaboration with the hosting authorities, carried out enhanced epidemic intelligence activities from 7 June to 16 July 2010 for timely detection and monitoring of signals of public health events with a potential to pose a risk to participants and visitors. We adapted ECDC's routine epidemic intelligence process to targeted event-based surveillance of official and unofficial online information sources. A set of three specifically adapted alerts in the web-based screening system MedISys were set up: potential public health events in South Africa, those occurring in the participating countries and those in the rest of the world. Results were shared with national and international public health partners through daily bulletins. According to pre-established ECDC criteria for the World Cup, 21 events of potential public health relevance were identified at local and international level. Although none of the events detected were evaluated as posing a serious risk for the World Cup, we consider that the investment in targeted event-based surveillance activities during the tournament was relevant as it facilitated real-time detection and assessment of potential threats. An additional benefit was early communication of relevant information to public health partners.

Multidisciplinary investigation of a multicountry outbreak of Salmonella Stanley infections associated with turkey meat in the European Union, August 2011 to January 2013.

Between August 2011 and January 2013, an outbreak of Salmonella enterica serovar Stanley (S. Stanley) infections affected 10 European Union (EU) countries, with a total of 710 cases recorded. Following an urgent inquiry in the Epidemic Intelligence Information System for food- and waterborne diseases (EPIS-FWD) on 29 June 2012, an international investigation was initiated including EU and national agencies for public health, veterinary health and food safety. Two of three local outbreak investigations undertaken by affected countries in 2012 identified turkey meat as a vehicle of infection. Furthermore, routine EU monitoring of animal sources showed that over 95% (n=298) of the 311 S. Stanley isolates reported from animal sampling in 2011 originated from the turkey food production chain. In 2004­10, none had this origin. Pulsed-field gel electrophoresis (PFGE) profile analysis of outbreak isolates and historical S. Stanley human isolates revealed that the outbreak isolates had a novel PFGE profile that emerged in Europe in 2011. An indistinguishable PFGE profile was identified in 346 of 464 human, food, feed, environmental and animal isolates from 16 EU countries: 102 of 112 non-human isolates tested were from the turkey production chain. On the basis of epidemiological and microbiological evidence, turkey meat was considered the primary source of human infection, following contamination early in the animal production chain.

Infectious diseases prioritisation for event-based surveillance at the European Union level for the 2012 Olympic and Paralympic Games.

In 2012, London hosted the Olympic and Paralympic Games (the Games), with events occurring throughout the United Kingdom (UK) between 27 July and 9 September 2012. Public health surveillance was performed by the Health Protection Agency (HPA). Collaboration between the HPA and the European Centre for Disease Prevention and Control (ECDC) was established for the detection and assessment of significant infectious disease events (SIDEs) occurring outside the UK during the time of the Games. Additionally, ECDC undertook an internal prioritisation exercise to facilitate ECDC's decisions on which SIDEs should have preferentially enhanced monitoring through epidemic intelligence activities for detection and reporting in daily surveillance in the European Union (EU). A team of ECDC experts evaluated potential public health risks to the Games, selecting and prioritising SIDEs for event-based surveillance with regard to their potential for importation to the Games, occurrence during the Games or export to the EU/European Economic Area from the Games. The team opted for a multilevel approach including comprehensive disease selection, development and use of a qualitative matrix scoring system and a Delphi method for disease prioritisation. The experts selected 71 infectious diseases to enter the prioritisation exercise of which 27 were considered as priority for epidemic intelligence activities by ECDC for the EU for the Games.

Taking stock of the first 133 MERS coronavirus cases globally--Is the epidemic changing?

Since June 2012, 133 Middle East respiratory syndrome coronavirus (MERS-CoV) cases have been identified in nine countries. Two time periods in 2013 were compared to identify changes in the epidemiology. The case-fatality risk (CFR) is 45% and is decreasing. Men have a higher CFR (52%) and are over-represented among cases. Thirteen out of 14 known primary cases died. The sex-ratio is more balanced in the latter period. Nosocomial transmission was implied in 26% of the cases.

Outbreak with a novel avian influenza A(H7N9) virus in China--scenarios and triggers for assessing risks and planning responses in the European Union, May 2013.

As part of the risk assessment and strategic planning related to the emergence of avian influenza A(H7N9) in China the European Centre for Disease Prevention and Control (ECDC) has considered two major scenarios. The current situation is the one of a zoonotic epidemic (Scenario A) in which the virus might be transmitted sporadically to humans in close contact with an animal reservoir. The second scenario is the movement towards efficient human to human transmission (a pandemic Scenario B). We identified epidemiological events within the different scenarios that would trigger a new risk assessment and a review of the response activities to implement in the European Union (EU). Further, we identified the surveillance activities needed to detect these events. The EU should prepare for importation of isolated human cases infected in the affected area, though this event would not change the level of public health risk. Awareness among clinicians and local public health authorities, combined with nationally available testing, will be crucial. A 'one health' surveillance strategy is needed to detect extension of the infection towards Europe. The emergence of a novel reassortant influenza A(H7N9) underlines that pandemic preparedness remains important for Europe.

Surveillance status and recent data for Mycoplasma pneumoniae infections in the European Union and European Economic Area, January 2012.

In January 2012, the European Centre for Disease Prevention and Control (ECDC) conducted an email based survey of European Union and European Economic Area countries to describe the existing surveillance activities for Mycoplasma pneumoniae infections, recent findings and existence of clinical guidelines for the treatment of M. pneumoniae infection. Of the 20 countries that participated in the survey, seven reported increases in M. pneumoniae infections observed during the autumn and winter of 2011.

Applicability of evidence-based practice in public health: risk assessment on Q fever under an ongoing outbreak.

With reference to the Q fever outbreak in the Netherlands in 2009-10, we tested if an evidence-based approach, comparable to the methodology used in clinical medicine, was appropriate for giving public health advice under time constrains. According to the principles of evidence-based methodologies, articles were retrieved from bibliographic databases and categorised by type and size, outcome, strengths and limitations. The risk assessment was conducted in two months and involved six staff members. We retrieved and read 559 abstracts and selected approximately 150 full text articles. The most striking finding was the lack of sound scientific evidence behind standard treatment regimes for Q fever in pregnancy. Difficulties in applying existing evidence rating systems and in expressing uncertainties were identified as problems during the process. By systematically assessing the evidence on several questions about Q fever, we were able to draw new conclusions and specify earlier statements. We found it difficult to grade the mostly observational studies with the known evidence-based grading systems. There is need to develop new methods for grading evidence from different sources in the field of public health. We conclude that an evidence-based approach is feasible for providing a risk assessment within two to three months.

Assessing the risk of a community outbreak of hepatitis A on blood safety in Latvia, 2008.

Post-transfusion hepatitis A virus (HAV) infection worldwide is considered a sporadic event. An outbreak of HAV infection occurred in Latvia between the end of 2007 and throughout 2008 with more than 2,800 confirmed cases reported over a 13-month period (incidence of 123 per 100,000 population). The majority of reported HAV infection cases were in people over 18 years of age and in people living in the capitalcity, Riga. We estimated that the crude risk for HAV contamination of whole blood supplies in Riga between February and October 2008 ranged from 1.4 to 10.6 per 10,000 donated units. In people under 40 years of age, the risk of receiving an infectious blood transfusion was more than 3.0 per 10,000 recipients between August and October 2008 during the peak of the outbreak. We conclude that there is a previously under-recognised impact of HAV on blood safety during widespread outbreaks of this disease. Estimating the risk of contamination of blood supplies during an infectious disease outbreak scenario is important for fine tuning risk assessments and potentially improving public health practices.