Assessing the quality of data for drivers of disease emergence.

Drivers are factors that have the potential to directly or indirectly influence the likelihood of infectious diseases emerging or re-emerging. It is likely that an emerging infectious disease (EID) rarely occurs as the result of only one driver; rather, a network of sub-drivers (factors that can influence a driver) are likely to provide conditions that allow a pathogen to (re-)emerge and become established. Data on sub-drivers have therefore been used by modellers to identify hotspots where EIDs may next occur, or to estimate which sub-drivers have the greatest influence on the likelihood of their occurrence. To minimise error and bias when modelling how sub-drivers interact, and thus aid in predicting the likelihood of infectious disease emergence, researchers need good-quality data to describe these sub-drivers. This study assesses the quality of the available data on sub-drivers of West Nile virus against various criteria as a case study. The data were found to be of varying quality with regard to fulfilling the criteria. The characteristic with the lowest score was completeness, i.e. where sufficient data are available to fulfil all the requirements for the model. This is an important characteristic as an incomplete data set could lead to erroneous conclusions being drawn from modelling studies. Thus, the availability of good-quality data is essential to reduce uncertainty when estimating the likelihood of where EID outbreaks may occur and identifying the points on the risk pathway where preventive measures may be taken.

Les facteurs d'émergence sont des éléments ayant le potentiel direct ou indirect d'influencer la probabilité d'émergence ou de réémergence d'une maladie infectieuse. Il est probablement rare qu'une maladie infectieuse émergente apparaisse en raison d'un seul facteur ; c'est plutôt un faisceau de sous-facteurs (éléments pouvant avoir une influence sur un même facteur) qui contribue à ce que les conditions soient réunies pour qu'un agent pathogène puisse (ré)émerger et s'établir. Les concepteurs de modèles ont donc utilisé les données relatives aux sous-facteurs pour identifier les zones sensibles où les prochaines maladies infectieuses émergentes pourraient survenir, ou pour faire une estimation des sous-facteurs ayant la plus grande influence sur la probabilité de leur occurrence. Les chercheurs ont besoin de données de qualité pour décrire ces sous-facteurs, afin de minimiser le risque d'erreur et de biais lors de la modélisation de l'interaction entre les différents sous-facteurs, et de contribuer ainsi à mieux prédire la probabilité d'apparition d'une maladie infectieuse émergente. Les auteurs présentent une étude de cas qui a consisté à évaluer la qualité des données disponibles relatives aux sous-facteurs d'émergence du virus de la fièvre de West Nile au regard de différents critères. Il est apparu que la qualité des données était variable au regard des critères examinés. Le paramètre dont le score était le plus bas est celui de la complétude - le fait que suffisamment de données soient disponibles pour répondre à toutes les exigences du modèle. Il s'agit pourtant d'un paramètre important car des données incomplètes peuvent inciter à tirer des conclusions erronées des études de modélisation. La disponibilité de données de bonne qualité est essentielle pour réduire l'incertitude lors de l'estimation de la probabilité d'apparition de maladies infectieuses émergentes dans des zones déterminées, ainsi que pour identifier les points critiques de concrétisation du risque où des mesures préventives pourraient être mises en place.

Los inductores o factores de inducción [drivers] son aquellos que, directa o indirectamente, pueden influir en la probabilidad de que surjan o resurjan enfermedades infecciosas. Todo indica que rara vez una enfermedad infecciosa emergente aparece por efecto de un solo factor de inducción, sino que es probable que haya más bien una combinación de "subfactores de influencia" [sub-drivers] (factores que pueden influir en un inductor) que cree condiciones propicias para que un patógeno (re)surja y logre asentarse. Los creadores de modelos, por consiguiente, se han servido de datos sobre estos subfactores de influencia para localizar aquellas zonas donde con mayor probabilidad puedan aparecer próximamente enfermedades infecciosas emergentes o para determinar cuáles son los subfactores que más influyen en la probabilidad de que ello ocurra. Para reducir al mínimo los errores y sesgos al modelizar la interacción entre los subfactores y ayudar así a calcular la probabilidad de que surja una enfermedad infecciosa emergente, los investigadores necesitan datos de buena calidad para caracterizar estos subfactores. En el análisis expuesto por los autores se utilizó el virus del Nilo Occidental como ejemplo de estudio para evaluar, con arreglo a diversos criterios, la calidad de los datos existentes sobre los subfactores que inciden en la aparición de este virus. Lo que se constató, en relación con el grado de cumplimiento de los criterios, es que esos datos eran de calidad variable. La característica o parámetro que deparó la puntuación más baja fue la completud, es decir, la existencia de datos suficientes para aportar al modelo toda la información requerida para que este funcione bien. Se trata de una característica importante, pues un conjunto incompleto de datos podría llevar a extraer conclusiones erróneas de los estudios de modelización. Por ello, para reducir la incertidumbre a la hora de calcular la probabilidad de que en cierto lugar surjan brotes de enfermedades infecciosas emergentes y de determinar, dentro de la cadena de materialización del riesgo, aquellos eslabones en los que cabe adoptar medidas preventivas, es indispensable disponer de datos de buena calidad.

Association of environmental surface contamination with hand hygiene and infections in nursing homes: a prospective cohort study.

BACKGROUND: Little is known about the presence of infections in nursing home residents, the causative micro-organisms, how hand hygiene (HH) influences the presence of infections in residents, and the extent to which environmental contamination is associated with the incidence of infection among residents. AIMS: To establish if environmental contamination can be used as an indicator for HH compliance, and if environmental contamination is associated with the incidence of infection. METHODS: Environmental surface samples (ESS) were collected in an exploratory study as part of a HH intervention in 60 nursing homes. ESS results from three distinct surfaces (nurses' station, communal toilet and residents' shared living area) were compared with nurses' HH compliance and the incidence of infection among residents. Real-time polymerase chain reaction assays were used to detect norovirus genogroup I and II, rhinovirus and Escherichia coli. HH compliance was measured by direct observation. The incidence of infection was registered weekly. FINDINGS: Rhinovirus (nurses' station: 41%; toilet: 14%; living area: 29%), norovirus (nurses' station: 18%; toilet: 12%; living area: 16%) and E. coli (nurses' station: 14%; toilet: 58%; living area: 54%) were detected. No significant (P<0.05) associations were found between HH compliance and the presence of micro-organisms. An association was found between E. coli contamination and the incidence of disease in general (P=0.04). No other associations were found between micro-organisms and the incidence of disease. CONCLUSION: Rhinovirus, norovirus and E. coli were detected on surfaces in nursing homes. No convincing associations were found between environmental contamination and HH compliance or the incidence of disease. This study provides reference data about surface contamination.

The effect of a hand hygiene intervention on infections in residents of nursing homes: a cluster randomized controlled trial.

BACKGROUND: The primary goal of hand hygiene is to reduce infectious disease rates. We examined if a nursing home's participation in a hand hygiene intervention resulted in residents having fewer healthcare associated infections (HAIs) when compared to nursing homes without the hand hygiene intervention. METHODS: This study is a part of a cluster randomized controlled trial (RCT) in 33 nursing homes to improve hand hygiene (HANDSOME). The incidence of five illnesses was followed over 13 months: gastroenteritis, influenza-like illness, pneumonia, urinary tract infections and infections from methicillin-resistant Staphylococcus aureus (MRSA). Incidence rates per study arm were reported for baseline (October-December 2016) and two follow-up periods (January-April 2017, May-October 2017). HAI rates were compared in a Poisson multilevel analysis, correcting for baseline differences (the baseline infection incidence and the size of the nursing home), clustering of observations within nursing homes, and period in the study. RESULTS: There was statistically significantly more gastroenteritis (p < 0.001) and statistically significantly less influenza-like illness (p < 0.01) in the intervention arm when compared to the control arm. There were no statistically significant differences or pneumonia, urinary tract infections, and MRSA infections in the intervention arm when compared to the control arm. In a sensitivity analysis, gastroenteritis was no longer statistically significantly higher in the intervention arm (p = 0.92). CONCLUSIONS: As in comparable studies, we could not conclusively demonstrate the effectiveness of an HH intervention in reducing HAIs among residents of nursing homes, despite the use of clearly defined outcome measures, a standardized reporting instrument, and directly observed HH in a multicenter cluster RCT. Trial registration Netherlands Trial Register, trial NL6049 (NTR6188). Registered October 25, 2016, https://www.trialregister.nl/trial/6049 .

Transmission of SARS-CoV-2 among healthcare workers and patients in a teaching hospital in the Netherlands confirmed by whole-genome sequencing.

AIM: To investigate the sources of infection among healthcare workers (HCWs) and patients in a teaching hospital in the Netherlands during the early stages of the coronavirus disease 2019 (COVID-19) pandemic using epidemiological and whole-genome sequencing data. METHODS: From 3rd April to 11th May 2020, 88 HCWs and 215 patients were diagnosed with COVID-19. Whole-genome sequences were obtained for 30 HCWs and 20 patients. RESULTS: Seven and 11 sequence types were identified in HCWs and patients, respectively. Cluster A was the most common sequence type, detected in 23 (77%) HCWs; of these, 14 (61%) had direct patient contact and nine (39%) had indirect patient contact. In addition, seven patients who were not hospitalized in the COVID-19 cohort isolation ward who became positive during their admission were infected with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) cluster A. Following universal masking of all HCWs and emphasis on physical distancing during meals and breaks, no further evidence was found for patient-to-HCW or HCW-to-HCW transmission or vice versa. CONCLUSION: The finding that patients and HCWs were infected with SARS-CoV-2 cluster A suggests both HCW-to-HCW and HCW-to-patient transmission.

[Rise and threat of infectious diseases]. / Opkomst en dreiging van infectieziekten.

In 2019, 1 in 4 deaths was caused by infectious diseases. In addition to the big 3 - HIV, malaria and tuberculosis - these diseases are mainly respiratory infections, infectious diarrhoea and sepsis. The burden of disease caused by infections also remains high in the Netherlands. This could still get worse because of several factors: ageing, 'vaccination doubts', increased use of immunosuppressive drugs, increased mobility of people and globalisation of food chains. Global warming also affects the spread of pathogens and disease vectors. Pathogens have an impressive ability to adapt and, for example, to develop resistance to antimicrobial agents. In order to cope with these threats, we would do well to consider the emergence of new infectious diseases as well as the threat of old ones. What can we learn from decades past? Why do new infections keep emerging? What does the future look like?

Global status of Middle East respiratory syndrome coronavirus in dromedary camels: a systematic review.

Dromedary camels have been shown to be the main reservoir for human Middle East respiratory syndrome (MERS) infections. This systematic review aims to compile and analyse all published data on MERS-coronavirus (CoV) in the global camel population to provide an overview of current knowledge on the distribution, spread and risk factors of infections in dromedary camels. We included original research articles containing laboratory evidence of MERS-CoV infections in dromedary camels in the field from 2013 to April 2018. In general, camels only show minor clinical signs of disease after being infected with MERS-CoV. Serological evidence of MERS-CoV in camels has been found in 20 countries, with molecular evidence for virus circulation in 13 countries. The seroprevalence of MERS-CoV antibodies increases with age in camels, while the prevalence of viral shedding as determined by MERS-CoV RNA detection in nasal swabs decreases. In several studies, camels that were sampled at animal markets or quarantine facilities were seropositive more often than camels at farms as well as imported camels vs. locally bred camels. Some studies show a relatively higher seroprevalence and viral detection during the cooler winter months. Knowledge of the animal reservoir of MERS-CoV is essential to develop intervention and control measures to prevent human infections.

Microarray profile of the humoral immune response to influenza vaccination in breast cancer patients treated with chemotherapy.

BACKGROUND: Patients treated with chemotherapy have an impaired response to influenza virus vaccination compared to healthy controls. Little is known about the broadness of the antibody response in these patients. METHODS: Breast cancer patients on FEC (5-fluorouracil, epirubicin and cyclophosphamide) chemotherapy regimens were vaccinated with influenza virus vaccine. Sera were obtained before and three weeks after vaccination. In addition to the determination of virus-specific antibody titres by hemagglutination inhibition assay, the broadness of the response was assessed by the use of a protein microarray and baseline titres were compared with an age-matched reference group. RESULTS: We included 38 breast cancer patients and found a wide variety in serum antibody response after vaccination. Patients with a history of influenza vaccination had higher pre-vaccination titres, which were comparable to the reference group. Increasing number of cycles of chemotherapy did not have a negative effect on influenza array antibody levels, nor on the HI antibody response. CONCLUSIONS: Overall there was a broad serum antibody response to the influenza virus vaccine in patients treated with chemotherapy for breast cancer.

Chronic norovirus infection among solid organ recipients in a tertiary care hospital, the Netherlands, 2006-2014.

OBJECTIVES: Immunocompromised patients can suffer prolonged norovirus symptoms and virus shedding for many years. Little is known about the prevalence of chronic norovirus infection among solid organ transplant (SOT) recipients. In this study, 2182 SOT recipients were retrospectively tested for chronic norovirus infection. METHODS: The first and last norovirus positive faecal samples of SOT recipients were sequenced to distinguish between persisting infection and re-infection. Patient charts were reviewed to obtain data on health status and treatments. RESULTS: In all, 101 of 2182 (4.6%) recipients were norovirus infected and 23 (22.8%) of these developed chronic norovirus infection. Chronic norovirus infection was found among allogeneic heart, kidney and lung transplant recipients. The median shedding period at the end of the study period was 218 days (range 32-1164 days). CONCLUSIONS: This study shows that chronic norovirus infection is not a rare phenomenon among SOT recipients in a tertiary-care hospital. Further research is needed to study the risk of norovirus transmission to other immunocompromised patients in the hospital and to the general population.

A Serological Protein Microarray for Detection of Multiple Cross-Reactive Flavivirus Infections in Horses for Veterinary and Public Health Surveillance.

The genus Flavivirus in the family Flaviviridae includes some of the most important examples of emerging zoonotic arboviruses that are rapidly spreading across the globe. Japanese encephalitis virus (JEV), West Nile virus (WNV), St. Louis encephalitis virus (SLEV) and Usutu virus (USUV) are mosquito-borne members of the JEV serological group. Although most infections in humans are asymptomatic or present with mild flu-like symptoms, clinical manifestations of JEV, WNV, SLEV, USUV and tick-borne encephalitis virus (TBEV) can include severe neurological disease and death. In horses, infection with WNV and JEV can lead to severe neurological disease and death, while USUV, SLEV and TBEV infections are mainly asymptomatic, however, and induce antibody responses. Horses often serve as sentinels to monitor active virus circulation in serological surveillance programmes specifically for WNV, USUV and JEV. Here, we developed and validated a NS1-antigen protein microarray for the serological differential diagnosis of flavivirus infections in horses using sera of experimentally and naturally infected symptomatic as well as asymptomatic horses. Using samples from experimentally infected horses, an IgG and IgM specificity of 100% and a sensitivity of 95% for WNV and 100% for JEV was achieved with a cut-off titre of 1 : 20 based on ROC calculation. In field settings, the microarray identified 93-100% of IgG-positive horses with recent WNV infections and 87% of TBEV IgG-positive horses. WNV IgM sensitivity was 80%. Differentiation between closely related flaviviruses by the NS1-antigen protein microarray is possible, even though we identified some instances of cross-reactivity among antibodies. However, the assay is not able to differentiate between naturally infected horses and animals vaccinated with an inactivated WNV whole-virus vaccine. We showed that the NS1-microarray can potentially be used for diagnosing and distinguishing flavivirus infections in horses and for public health purposes within a surveillance setting. This allows for fast, cheap, syndrome-based laboratory testing for multiple viruses simultaneously for veterinary and public health purposes.

A novel hepatitis B virus subgenotype D10 circulating in Ethiopia.

Hepatitis B virus (HBV) is genetically highly divergent and classified in ten genotypes and forty subgenotypes in distinct ethno-geographic populations worldwide. Ethiopia is a country with high HBV prevalence; however, little is known about the genetic variability of HBV strains that circulate. Here, we characterize the complete genome of 29 HBV strains originating from five Ethiopian regions, by 454 deep sequencing and Sanger sequencing. Phylogenetically, ten strains were classified as genotype A1 and nineteen as genotype D. Fifteen genotype D strains, provisionally named subgenotype D10, showed a novel distinct cluster supported by high bootstrap value and >4% nucleotide divergence from other known subgenotypes. In addition, the novel D10 strains harboured nine unique amino acid signatures in the surface, polymerase and X genes. Seventy-two per cent of the genotype D strains had the precore premature stop codon G1896A. In addition, 63% genotype A and 33% genotype D strains had the basal core promoter mutations, A1762T/G1764A. Furthermore, four pre-S deletion variants and two recombinants were identified in this study. In conclusion, we identified a novel HBV subgenotype D10 circulating in Ethiopia, underlining the high genetic variability of HBV strains in Africa.

Performance evaluation of a rapid molecular diagnostic, MultiCode based, sample-to-answer assay for the simultaneous detection of Influenza A, B and respiratory syncytial viruses.

BACKGROUND: Clinical signs and symptoms of different airway pathogens are generally indistinguishable, making laboratory tests essential for clinical decisions regarding isolation and antiviral therapy. Immunochromatographic tests (ICT) and direct immunofluorescence assays (DFA) have lower sensitivities and specificities than molecular assays, but have the advantage of quick turnaround times and ease-of-use. OBJECTIVE: To evaluate the performance of a rapid molecular assay, ARIES FluA/B & RSV, using laboratory developed RT-PCR assays (LDA), ICT (BinaxNOW) and DFA. METHODS: Analytical and clinical performance were evaluated in a retrospective study arm (stored respiratory samples obtained between 2006-2015) and a prospective study arm (unselected fresh clinical samples obtained between December 2015 and March 2016 tested in parallel with LDAs). RESULTS: Genotype inclusivity and analytical specificity was 100%. However, ARIES was 0.5 log, 1-2logs and 2.5logs less sensitive for fluA, RSV and fluB respectively, compared to LDA. In total, 447 clinical samples were included, of which 15.4% tested positive for fluA, 9.2% for fluB and 26.0% for RSV, in both LDA and ARIES. ARIES clinical sensitivity compared to LDA was 98.6% (fluA), 93.3% (fluB) and 95.1% (RSV). Clinical specificity was 100% for all targets. ARIES detected 10.6% (4 fluA, 8 fluB, 11 RSV) and 26.9% (7 fluA, 3 fluB, 22 RSV) more samples compared to DFA and ICT, all confirmed by LDA. CONCLUSION: Although analytically ARIES is less sensitive than LDA, the clinical performance of the assay in our tertiary care setting was comparable, and significantly better than that of the established rapid assays.

Diagnostic performance of influenza viruses and RSV rapid antigen detection tests in children in tertiary care.

BACKGROUND: Rapid antigen detection tests (RADTs) are increasingly used to detect influenza viruses and respiratory syncytial virus (RSV). However, their sensitivity and specificity are a matter of debate, challenging their clinical usefulness. OBJECTIVES: Comparing diagnostic performances of BinaxNow Influenza AB(®) (BNI) and BinaxNow RSV(®) (BNR), to those of real-time reverse transcriptase PCR (RT-PCR), virus isolation and direct immunofluorescence (D-IF) in paediatric patients. STUDY DESIGN: Between November 2005 and September 2013, 521 nasal washings from symptomatic children (age <5 years) attending our tertiary care centre were tested, with a combination of the respective assays using RT-PCR as gold standard. RESULTS: Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of BNI were 69% (confidence interval [CI] [51-83]), 96% [94-97], 55% [39-70] and 98% [96-99] respectively. Of eleven false-negative samples, RT-PCR Ct-values were higher than all RT-PCR positive test results (27 vs 22, p=0.012). Of twenty false-positive samples, none were culture positive and two tested positive in D-IF. Sensitivity, specificity, PPV and NPV for BNR were 79% [73-85], 98% [96-99], 97% [93-99] and 88% [84-91]. Of the 42 false-negative samples the median Ct-value was higher than that of all RT-PCR positive samples (31 vs 23, p<0.0001). Five false-positive samples were detected. Three of these tested positive for RSV in virus isolation and D-IF. CONCLUSIONS: RADTs have a high specificity with BNR being superior to BNI. However, their relative low sensitivity limits their usefulness for clinical decision making in a tertiary care paediatric hospital.

Zika virus and the current outbreak: an overview.

Zika virus (ZIKV), a mosquito-borne flavivirus closely related to yellow fever virus and dengue virus, is currently causing a large outbreak in the Americas. Historically, ZIKV infection was considered a sporadic, relatively mild disease characterised by fever, maculopapular rash, conjunctivitis and often arthralgia. However, current observational studies suggest that ZIKV may cause more severe neurological sequelae such as Guillain-Barre syndrome, and birth defects, mainly microcephaly, in babies of whom the mother was infected with ZIKV during pregnancy. This article provides a clinically focussed overview of ZIKV, with emphasis on the current outbreak, clinical manifestations, diagnostic tools and caveats.

The sample of choice for detecting Middle East respiratory syndrome coronavirus in asymptomatic dromedary camels using real-time reversetranscription polymerase chain reaction.

The newly identified Middle East respiratory syndrome coronavirus (MERS-CoV), which causes severe respiratory disease, particularly in people with comorbidities, requires further investigation. Studies in Qatar and elsewhere have provided evidence that dromedary camels are a reservoir for the virus, but the exact modes of transmission of MERS-CoV to humans remain unclear. In February 2014, an assessment was made of the suitability and sensitivity of different types of sample for the detection of MERSCoV by real-time reverse-transcription polymerase chain reaction (RT-PCR) for three gene targets: UpE (upstream of the E gene), the N (nucleocapsid) gene and open reading frame (ORF) 1a. Fifty-three animals presented for slaughter were sampled. A high percentage of the sampled camels (79% [95% confidence interval 66.9-91.5%, standard error 0.0625]; 42 out of 53) were shown to be shedding MERS-CoV at the time of slaughter, yet all the animals were apparently healthy. Among the virus-positive animals, nasal swabs were most often positive (97.6%). Oral swabs were the second most frequently positive (35.7%), followed by rectal swabs (28.5%). In addition, the highest viral load, expressed as a cycle threshold (Ct) value of 11.27, was obtained from a nasal swab. These findings lead to the conclusion that nasal swabs are the candidate sample of choice for detecting MERS-CoV using RT-PCR technology in apparently healthy camels.

Des travaux de recherche approfondis sont encore nécessaires concernant le coronavirus responsable du syndrome respiratoire du Moyen-Orient (MERSCoV), un virus identifié récemment et qui provoque des troubles respiratoires sévères en particulier chez les individus atteints de pathologies multiples. Les études effectuées au Qatar et ailleurs ont démontré que les dromadaires font office de réservoirs du virus ; toutefois, les modalités précises de la transmission du MERS-CoV à l'être humain demeurent obscures. En février 2014, une équipe de chercheurs a évalué l'adéquation et la sensibilité de plusieurs types d'échantillons pour détecter le MERS-CoV en utilisant l'amplification en chaîne par polymérase couplée à une transcription inverse en temps réel (RT-PCR) spécifique pour trois cibles génétiques, à savoir la séquence UpE (en amont du gène E), le gène N (nucléocapside) et le cadre de lecture ORF1a. Pour ce faire, divers prélèvements ont été effectués sur 53 dromadaires destinés à l'abattage. Un fort pourcentage de ces dromadaires (79 % [intervalle de confiance à 95 % compris entre 66,9 et 91,5 %, erreur standard : 0,0625], soit 42 sur 53) excrétaient le MERSCoV au moment de l'abattage, mais aucun ne présentait le moindre signe clinique. Les échantillons dans lesquels le plus de cas positifs ont été détectés étaient les écouvillons nasaux (97,6 %). Venaient ensuite les écouvillons oraux, qui ont détecté 35,7 % de cas positifs, puis les écouvillons rectaux (28,5 % de cas positifs détectés). Par ailleurs, ce sont les écouvillons nasaux qui ont permis d'obtenir l'intensité la plus élevée de la réponse de la RT-PCR, exprimée en une valeur du seuil de cycles de 11,27. Ces résultats permettent de conclure que les écouvillons nasaux sont les échantillons à privilégier pour la détection du MERS-CoV par RTPCR chez les dromadaires asymptomatiques.

Es preciso investigar más a fondo el coronavirus del síndrome respiratorio de Oriente Medio (MERS-CoV), recién identificado, que provoca una grave enfermedad respiratoria, sobre todo en personas con afecciones concomitantes. Estudios realizados en Qatar y otros lugares han deparado pruebas de que los dromedarios son un reservorio del virus, pero aún no están del todo claros los modelos exactos de transmisión del MERS-CoV al ser humano. Los autores describen un análisis realizado en febrero de 2014 de la idoneidad y sensibilidad de distintos tipos de muestra para detectar el MERS-CoV mediante una reacción en cadena de la polimerasa acoplada a transcripción inversa en tiempo real (RTPCR) dirigida contra tres genes: el gen UpE (upstream of the E gene: en dirección 5' desde el gen E); el gen N (nucleocápside) y el marco de lectura abierto (ORF) 1a. Para ello se tomaron muestras de 53 animales enviados al sacrificio. Se comprobó que un elevado porcentaje de los dromedarios analizados (un 79% [intervalo de confianza al 95%: 66,9­91,5%; error estándar: 0,0625], esto es, 42 de 53) excretaban virus en el momento del sacrificio, pese a que todos los animales parecían estar sanos. Entre los ejemplares positivos para el MERS-CoV, las muestras que con más frecuencia arrojaban resultado positivo eran los frotis nasales (97,6%). Las segundas, por orden de frecuencia, eran los frotis bucales (35,7%), seguidos de los frotis rectales (28,5%). Además, la carga viral más alta, expresada por un valor de ciclo umbral (Ct) (o punto de cruce) de 11,27, se obtuvo a partir de un frotis nasal. Estos resultados llevan a la conclusión de que los frotis nasales son el tipo de muestra más adaptado para detectar el MERS-CoV en dromedarios aparentemente sanos mediante la técnica de RT-PCR.

Emergence of a novel GII.17 norovirus ­ End of the GII.4 era?

In the winter of 2014/15 a novel GII.P17-GII.17 norovirus strain (GII.17 Kawasaki 2014) emerged, as a major cause of gastroenteritis outbreaks in China and Japan. Since their emergence these novel GII.P17-GII.17 viruses have replaced the previously dominant GII.4 genotype Sydney 2012 variant in some areas in Asia but were only detected in a limited number of cases on other continents. This perspective provides an overview of the available information on GII.17 viruses in order to gain insight in the viral and host characteristics of this norovirus genotype. We further discuss the emergence of this novel GII.P17-GII.17 norovirus in context of current knowledge on the epidemiology of noroviruses. It remains to be seen if the currently dominant norovirus strain GII.4 Sydney 2012 will be replaced in other parts of the world. Nevertheless, the public health community and surveillance systems need to be prepared in case of a potential increase of norovirus activity in the next seasons caused by this novel GII.P17-GII.17 norovirus.

Seoul hantavirus in brown rats in the Netherlands: implications for physicians--Epidemiology, clinical aspects, treatment and diagnostics.

The recent discovery of Seoul hantavirus (SEOV) presence in wild rat populations in the Netherlands has direct implications for Dutch clinicians and hantavirus diagnostics. SEOV is amongst the Old World hantaviruses which cause haemorrhagic fever and renal syndrome (HFRS) in humans. HFRS is characterised by a classical triad of fever, acute kidney injury and haemorrhage, but can show different signs and symptoms in specific cases. SEOV is transmitted from infected rats to humans by inhalation of aerosolised excreta. When compared with the known circulating hantaviruses in the Netherlands, Puumala (PUUV) and Tula (TULV), SEOV causes a more severe form of HFRS. Data from cohort studies undertaken in China and Northern Europe show differences in signs and symptoms at onset of disease, (haemorrhagic) complications and mortality. Furthermore, routine diagnostics currently available for hantavirus diagnosis in the Netherlands are not optimised for SEOV detection. The clinical outcome of an SEOV and PUUV infection will greatly benefit from an early diagnosis which will reduce the costs of unnecessary tests and treatments as well. The discovery of SEOV circulation in the Netherlands follows recent findings of SEOV infections in both rodents and humans in England, Wales, France, Belgium and Sweden, indicating the emerging character of SEOV and a high importance of this hantavirus for Public Health in large areas of Europe. Here, we review the current knowledge on the clinical manifestation of SEOV versus PUUV infections in humans, the treatment of clinical cases and diagnostics.

Shedding of norovirus in symptomatic and asymptomatic infections.

Norovirus is the most frequent cause of acute infectious gastroenteritis and it is difficult to control in crowded environments like hospitals and nursing homes. Transmission depends on oral intake of virus deposited in the environment by infectious subjects. Data from volunteer studies indicate that virus concentrations in stool are highly variable, but systematic studies of the time-course of shedding and its individual variation are lacking. This paper quantifies norovirus shedding in a large population of 102 subjects, including asymptomatic shedders, and uses a longitudinal model to generalize shedding patterns. Enhanced surveillance for studies of transmission of norovirus in hospital outbreaks has yielded a considerable number of faecal samples from symptomatic and asymptomatic shedders, both from patients and staff. Norovirus concentrations were determined by real-time PCR. A quantitative dynamic model was fitted to the shedding data, in a multilevel Bayesian framework, to study the time-course of shedding and its variation. The results indicate that shedding in asymptomatic subjects is similar to that in symptomatic infections, both showing considerable variation in peak levels (average 105-109 /g faeces) as well as duration of virus shedding (average 8-60 days). Patients appear to shed higher numbers of virus than staff, for slightly longer durations, but the differences are too small to be significant. Given equal shedding, the greater contribution of symptomatic cases to transmission must be caused by their higher efficiency in spreading these viruses. The results of this study will be helpful for risk studies that need to quantify the deposition of virus in the environment.

Ebola virus disease: a review on epidemiology, symptoms, treatment and pathogenesis.

Currently, West Africa is facing the largest outbreak of Ebola virus disease (EVD) in history. The virus causing this outbreak, the Zaire Ebolavirus (EBOV), belongs to the genus Ebolavirus which together with the genus Marburgvirus forms the family of the Filoviridae. EBOV is one of the most virulent pathogens among the viral haemorrhagic fevers, and case fatality rates up to 90% have been reported. Mortality is the result of multi-organ failure and severe bleeding complications. By 18 September 2014, the WHO reported of 5335 cases (confirmed, suspected and probable) with 2622 deaths, resulting in a case fatality rate of around 50%. This review aims to provide an overview of EVD for clinicians, with the emphasis on pathogenesis, clinical manifestations, and treatment options.

High seroprevalence of Borrelia miyamotoi antibodies in forestry workers and individuals suspected of human granulocytic anaplasmosis in the Netherlands.

Substantial exposure to Borrelia miyamotoi occurs through bites from Ixodes ricinus ticks in the Netherlands, which also transmit Borrelia burgdorferi sensu lato and Anaplasma phagocytophilum. Direct evidence for B. miyamotoi infection in European populations is scarce. A flu-like illness with high fever, resembling human granulocytic anaplasmosis, has been attributed to B. miyamotoi infections in relatively small groups. Borrelia miyamotoi infections associated with chronic meningoencephalitis have also been described in case reports. Assuming that an IgG antibody response against B. miyamotoi antigens reflects (endured) infection, the seroprevalence in different risk groups was examined. Sera from nine out of ten confirmed B. miyamotoi infections from Russia were found to be positive with the recombinant antigen used, and no significant cross-reactivity was observed in secondary syphilis patients. The seroprevalence in blood donors was set at 2.0% (95% CI 0.4-5.7%). Elevated seroprevalences in individuals with serologically confirmed, 7.4% (2.0-17.9%), or unconfirmed, 8.6% (1.8-23%), Lyme neuroborreliosis were not significantly different from those in blood donors. The prevalence of anti-B. miyamotoi antibodies among forestry workers was 10% (5.3-16.8%) and in patients with serologically unconfirmed but suspected human granulocytic anaplasmosis was 14.6% (9.0-21.8%); these were significantly higher compared with the seroprevalence in blood donors. Our findings indicate that infections with B. miyamotoi occur in tick-exposed individuals in the Netherlands. In addition, B. miyamotoi infections should be considered in patients reporting tick bites and febrile illness with unresolved aetiology in the Netherlands, and other countries where I. ricinus ticks are endemic.