Mumps virus F gene and HN gene sequencing as a molecular tool to study mumps virus transmission

Various mumps outbreaks have occurred in the Netherlands since 2004, particularly among persons who had received 2 doses of measles, mumps, and rubella (MMR) vaccination. Genomic typing of pathogens can be used to track outbreaks, but the established genotyping of mumps virus based on the small hydrophobic (SH) gene sequences did not provide sufficient resolution. Therefore, we expanded the sequencing to include fusion (F) gene and haemagglutinin-neuraminidase (HN) gene sequences in addition to the SH gene sequences from 109 mumps virus genotype G strains obtained between 2004 and mid 2015 in the Netherlands. When the molecular information from these 3 genes was combined, we were able to identify separate mumps virus clusters and track mumps virus transmission. The analyses suggested that multiple mumps virus introductions occurred in the Netherlands between 2004 and 2015 resulting in several mumps outbreaks throughout this period, whereas during some local outbreaks the molecular data pointed towards endemic circulation. Combined analysis of epidemiological data and sequence data collected in 2015 showed good support for the phylogenetic clustering.

[Bleeding in patients receiving dual antiplatelet therapy after acute coronary syndrome - significance, prevention and interdisciplinary management]

For secondary prevention of acute coronary syndrome, guidelines recommend dual antiplatelet therapy with acetylsalicylic acid and a P2Y12 receptor antagonist such as clopidogrel, prasugrel or ticagrelor for a period of 12 months. Premature discontinuation of dual antiplatelet therapy is associated with an increased risk of ischaemic events. However, antiplatelet therapy is also associated with an increased risk of bleeding that should not be under- or overestimated. To ensure an optimal care of patients receiving dual antiplatelet therapy after an acute coronary syndrome, an interdisciplinary group of experienced experts in the fields of cardiology, cardiac surgery, gastroenterology, anaesthesiology, intensive care and haemostaseology gathered bleeding-related information and developed recommendations relevant to daily clinical practice. These include the significance of bleeding events in the course of treatment, measures for bleeding prevention and the adequate care of patients with bleedings.

Ongoing transmission of hepatitis B virus in rural parts of the Netherlands, 2009-2013

Background

Reported acute hepatitis B incidence in the Netherlands reached its nadir in 2013. However, regional signals about increased number of hepatitis B cases raised the question how hepatitis B incidence was distributed over the country. In this study, regional differences in hepatitis B epidemiology were investigated using epidemiological and molecular data.

Methods

Acute hepatitis B virus (HBV) infections, reported between 2009–2013, were included. If serum was available, a fragment of S and C gene of the HBV was amplified and sequenced. Regional differences in incidence were studied by geographical mapping of cases and cluster analysis. Regional differences in transmission were studied by constructing regional maximum parsimony trees based on the C gene to assess genetic clustering of cases.

Results

Between 2009 and 2013, 881 cases were notified, of which respectively 431 and 400 cases had serum available for S and C gene sequencing. Geographical mapping of notified cases revealed that incidences in rural border areas of the Netherlands were highest. Cluster analysis identified two significant clusters (p<0.000) in the South-western and North-eastern regions. Genetic cluster analysis showed that rural border areas had relatively large clusters of cases with indistinguishable sequences, while other regions showed more single introductions.

Conclusion

This study showed that regional differences in HBV epidemiology were present in the Netherlands. Rural border regions showed higher incidences and more ongoing transmission, mainly among MSM, than the more urban inland areas. Therefore, preventive measures should be enhanced in these regions.

Two major mumps genotype G variants dominated recent mumps outbreaks in the Netherlands (2009–2012)

During three seasons of mumps outbreaks in the Netherlands (September 2009–August 2012), 822 mumps cases were laboratory-confirmed at the National Institute for Public Health and the Environment (RIVM). Most patients were vaccinated young adults. Given the protracted endemic circulation, we studied the genetic diversity and changes of mumps virus over a period of 3 years. Phylogenetic analysis of the small hydrophobic (SH) gene (316 bp) was performed on a representative set of 808 specimens that tested positive for mumps via PCR. Additionally, the haemagglutinin/neuraminidase (HN) gene (1749 bp) and fusion (F) gene (1617 bp) were sequenced for a subset of samples (n = 17). Correlations between different sequence types and epidemiological and clinical data were investigated. The outbreaks in the Netherlands were dominated by two SH gene sequence types within genotype G, termed MuVs/Delft.NLD/03.10 (variant 1) and MuVs/Scheemda.NLD/12.10 (variant 2). Sequence analysis of the HN and F genes indicated that the outbreaks were initiated by separately introduced genetic lineages. The predominance of variant 2 by the end of the first outbreak season could not be explained by any of the epidemiological factors investigated. Orchitis was more frequently reported in males infected with variant 2, irrespective of age and vaccination status. These findings illustrate genetic heterogeneity of an emerging mumps genotype, and raise questions about the mechanisms driving mumps epidemiology and immunity in relation to vaccination.