Estimation of the infection attack rate of mumps in an outbreak among college students using paired serology.

Mumps virus is a highly transmissible pathogen that is effectively controlled in countries with high vaccination coverage. Nevertheless, outbreaks have occurred worldwide over the past decades in vaccinated populations. Here we analyse an outbreak of mumps virus genotype G among college students in the Netherlands over the period 2009-2012 using paired serological data. To identify infections in the presence of preexisting antibodies we compared mumps specific serum IgG concentrations in two consecutive samples (n=746), whereby the first sample was taken when students started their study prior to the outbreaks, and the second sample was taken 2-5 years later. We fit a binary mixture model to the data. The two mixing distributions represent uninfected and infected classes. Throughout we assume that the infection probability increases with the ratio of antibody concentrations of the second to first sample. The estimated infection attack rate in this study is higher than reported earlier (0.095 versus 0.042). The analyses yield probabilistic classifications of participants, which are mostly quite precise owing to the high intraclass correlation of samples in uninfected participants (0.85, 95%CrI: 0.82-0.87). The estimated probability of infection increases with decreasing antibody concentration in the pre-outbreak sample, such that the probability of infection is 0.12 (95%CrI: 0.10-0.13) for the lowest quartile of the pre-outbreak samples and 0.056 (95%CrI: 0.044-0.068) for the highest quartile. We discuss the implications of these insights for the design of booster vaccination strategies.

The power of mumps virus: Matrix protein activates apoptotic pathways in human colorectal cell lines.

New therapeutic approaches can significantly impact the control of colorectal cancer (CRC), which is increasing worldwide. In this study, we investigated the potential of targeting viral proteins to combat cancer cells. Specifically, we examined the anticancer potential of the matrix (M) protein of the mumps virus Hoshino strain in SW480 CRC cell lines. To begin, we individually transfected SW480 cells with pcDNA3 plasmids containing the mumps virus M gene. We then investigated the percentage of cell death, caspase activity, and the expression levels of genes involved in apoptosis pathways. Following this, we performed bioinformatics analysis on the M protein to identify any similarities with Bcl-2 family members and their viral homologs. Our diagnostic methods showed that treatment with the mumps M protein induced apoptosis and upregulated the expression and activity of pro-apoptotic proteins in SW480 CRC cells compared to the control and vector groups. Based on our bioinformatics studies, we proposed that the BH3 motif in the M protein may trigger apoptosis in CRC cells by interacting with cellular Bax. Overall, our study showed for the first time that the mumps virus M protein could be considered as a targeted treatment for CRC by inducing apoptotic pathways.

Investigating Local Patterns of Mumps Virus Circulation, Using a Combination of Molecular Tools.

Mumps is a vaccine-preventable disease caused by the mumps virus (MuV). However, MuV has re-emerged in many countries with high vaccine coverage. The World Health Organization (WHO) recommends molecular surveillance based on sequencing of the small hydrophobic (SH) gene. Additionally, the combined use of SH and non-coding regions (NCR) has been described in different studies, proving to be a useful complement marker to discriminate general patterns of circulation at national and international levels. The aim of this work is to test local-level usefulness of the combination of SH and MF-NCR sequencing in tracing hidden transmission clusters and chains during the last epidemic wave (2015-2020) in Spain. A database with 903 cases from the Autonomous Community of Madrid was generated by the integration of microbiological and epidemiological data. Of these, 453 representative cases were genotyped. Eight different SH variants and thirty-four SH haplotypes were detected. Local MuV circulation showed the same temporal pattern previously described at a national level. Only two of the thirteen previously identified outbreaks were caused by more than one variant/haplotype. Geographical representation of SH variants allowed the identification of several previously undetected clusters, which were analysed phylogenetically by the combination of SH and MF-NCR, in a total of 90 cases. MF-NCR was not able to improve the discrimination of geographical clusters based on SH sequencing, showing limited resolution for outbreak investigations.

Co-circulation of two Mumps virus genotypes in Assam, India.

Mumps is a vaccine-preventable disease, and research on the vaccine's efficacy has recently indicated declining efficacy that has failed to protect against primary infections or reinfections, leading to a global resurgence in nations that use mumps vaccine in their national immunization programmes (NIPs). Lack of reports on its infection, documentation and published studies prevents it from being recognized as a public health issue in India. The waning of immunity is ascribed to the changes between the circulating and vaccine strains. The goal of the current study was to describe the circulating MuV strains in the Dibrugarh district of Assam, India, from 2016 to 2019. Blood samples were examined for IgM antibodies, and throat swab samples were put through Taqman assay for molecular detection. The small hydrophobic (SH) gene was targeted for genotyping through sequencing, and its genetic variations and phylogenetic analysis were carried out. Mumps RNA was found in 42 cases, and Mumps IgM in 14, of which 60% (25/42) of the cases were male and 40% (17/42) were female mostly affecting children between the ages of 6 and 12. Sequence and phylogeny analyses of SH gene revealed Genotypes C (83%) and G (17%) were simultaneously circulating during the study period. The study offers crucial genetic baseline information for the creation of Mumps prevention and control measures. Therefore, based on the research, it is clear that developing an effective vaccination strategy should take into account all currently prevalent genotypes in order to provide better protection against the disease's comeback.

Mumps resurgence in a highly vaccinated population: Insights gained from surveillance in Canada, 2002-2020.

Although mumps vaccination has been routine in Canada for decades, mumps cases and outbreaks continue to occur periodically. Mumps surveillance, including monitoring of the mumps virus genotype associated with disease activity, is important to document baseline activity and to advance further research into vaccine effectiveness. Here we describe a detailed analysis of mumps cases that have been detected in Canada from 2002 to 2020, with a focus on the mumps molecular epidemiology. In total, 7395 cases of mumps were reported to the surveillance system, with outbreaks occurring in the years 2007, 2010 and 2016 to 2018. Adolescents and young adults aged 15 to 29 years had the highest risk of being a case (rate ratios ranging from 1.50 to 2.29), compared to adults aged 30 to 39. Genotypes of mumps viruses were determined in 3225 specimens. Genotype G was predominantly detected (96% of genotyped specimens) and was first reported in 2005. Other genotypes were more likely to be detected in cases that also reported travel (or were linked to imported cases) than the cases with genotype G detected (p < 0.0001). The genotype G viruses had little sequence diversity in the 316 nucleotide window used for genotyping (the small hydrophobic protein gene) and mainly belonged to a single phylogenetic lineage that included the MuVi/Sheffield.GBR/1.05 reference sequence. The analysis of over ten years of data has demonstrated that mumps genotype G, specifically belonging to a single lineage, the Sheffield lineage, is the endemically circulating virus in Canada. This lineage is seen also in other countries using the genotype A vaccine. Mumps remains endemic despite high MMR vaccination coverage which has been sufficient to eliminate circulation of measles and rubella in Canada, raising the hypothesis of the evolution towards a vaccine escape mumps virus.

Genomic Characterization of a Relative of Mumps Virus in Lesser Dawn Bats of Southeast Asia.

The importance of genomic surveillance on emerging diseases continues to be highlighted with the ongoing SARS-CoV-2 pandemic. Here, we present an analysis of a new bat-borne mumps virus (MuV) in a captive colony of lesser dawn bats (Eonycteris spelaea). This report describes an investigation of MuV-specific data originally collected as part of a longitudinal virome study of apparently healthy, captive lesser dawn bats in Southeast Asia (BioProject ID PRJNA561193) which was the first report of a MuV-like virus, named dawn bat paramyxovirus (DbPV), in bats outside of Africa. More in-depth analysis of these original RNA sequences in the current report reveals that the new DbPV genome shares only 86% amino acid identity with the RNA-dependent RNA polymerase of its closest relative, the African bat-borne mumps virus (AbMuV). While there is no obvious immediate cause for concern, it is important to continue investigating and monitoring bat-borne MuVs to determine the risk of human infection.

[Mumps virus (Paramyxoviridae: Orthorubulavirus: Mumps orthorubulavirus) genotyping as a component of laboratory confirmation of infection].

INTRODUCTION: Mumps is a viral infection of high social significance. National program Elimination of measles and rubella and achievement of a stable sporadic incidence of epidemic mumps in the Russian Federation (20212025) sets the aim of gradual integration of mumps surveillance into the existing measles and rubella surveillance system. One of the key components of surveillance system is a laboratory confirmation of mumps cases. There are two approaches for laboratory confirmation of mumps cases, based on serological or molecular genetic methods. The aim of the work is molecular genetic characteristic of the mumps viruses (MuVs) circulated in the Russian Federation in 2022. MATERIALS AND METHODS: Samples of swabs from the inner surface of the cheek of 11 patients with mumps were collected for the study. Viral RNA was isolated directly from the samples. The isolated RNA was used as a matrix for RT-PCR. PCR products were sequenced using the Sanger method, and phylogenetic analysis was performed using the MEGA-X software. RESULTS: The MuV genotype G was detected in all samples. Phylogenetic analysis showed the presence of two virus genetic groups G-1 and G-2 that were significantly different from the viruses circulating in other countries. CONCLUSION: The identification of two MuV genetic groups in a limited area suggests a high genetic diversity of the pathogen.

Disentangling the causes of mumps reemergence in the United States.

Over the past two decades, multiple countries with high vaccine coverage have experienced resurgent outbreaks of mumps. Worryingly, in these countries, a high proportion of cases have been among those who have completed the recommended vaccination schedule, raising alarm about the effectiveness of existing vaccines. Two putative mechanisms of vaccine failure have been proposed as driving observed trends: 1) gradual waning of vaccine-derived immunity (necessitating additional booster doses) and 2) the introduction of novel viral genotypes capable of evading vaccinal immunity. Focusing on the United States, we conduct statistical likelihood-based hypothesis testing using a mechanistic transmission model on age-structured epidemiological, demographic, and vaccine uptake time series data. We find that the data are most consistent with the waning hypothesis and estimate that 32.8% (32%, 33.5%) of individuals lose vaccine-derived immunity by age 18 y. Furthermore, we show using our transmission model how waning vaccine immunity reproduces qualitative and quantitatively consistent features of epidemiological data, namely 1) the shift in mumps incidence toward older individuals, 2) the recent recurrence of mumps outbreaks, and 3) the high proportion of mumps cases among previously vaccinated individuals.

Demonstration of bacterium-free very rapid reverse genetics system using mumps virus.

The reverse genetics system is a very powerful tool for analyzing the molecular mechanisms of viral propagation and pathogenesis. However, full-length genome plasmid construction is highly time-consuming and laborious, and undesired mutations may be introduced by Escherichia coli. This study shows a very rapid E. coli-free method of full-genome construction using the mumps virus as an example. This method was able to reduce dramatically the time for full-genome construction, which was used very efficiently for virus rescue, from several days or more to ~2 days, with a similar accuracy and yield to the conventional method using E. coli/plasmid.

Mumps-specific IgG, IgG subclasses and neutralization titres to the vaccine and outbreak mumps strains differ in vaccinated healthy controls, breakthrough mumps infection cases and naturally infected individuals.

BACKGROUND: Despite widespread use of the mumps vaccine resulting in significant reduction in the incidence of symptomatic mumps infection, large outbreaks continue to occur in highly vaccinated populations. OBJECTIVES: We examined the mumps-specific IgG, IgG subclasses and neutralization titres to the outbreak Genotype G5 and Jeryl Lynn vaccine (Genotype A) mumps strains. STUDY DESIGN: Sera from 207 individuals were classified into five distinct cohorts: healthy controls and mumps cases of 5-17 years and 18-25 years, and naturally infected individuals of 50+ years. Mumps specific IgG and IgG subclass levels were measured using modified ELISA assays with lysates and nucleoprotein antigens from both the mumps vaccine and circulating Genotype G5 strains. All sera were investigated for in vitro neutralizing antibody titres (GMT) using focus reduction neutralization assays. Data was analysed using the Kruskal-Wallis test and pairwise Wilcoxon tests. RESULTS: Mumps cases had higher mumps IgG levels compared to controls, to both the vaccine and outbreak strains, however levels decreased with age. Mumps IgG3 levels were significantly raised in mumps cases (p < 0.001). Neutralization titres were lower to the outbreak strain in all cohorts with titres markedly lower in the mumps cohorts compared to healthy controls. Mean GMT to the vaccine strain increased with age. The naturally infected group displayed the highest GMT to the JL vaccine and the lowest GMT to the outbreak strain. CONCLUSIONS: Antigenic differences between mumps vaccine strain and circulating mumps viruses decrease the cross-neutralization capacity of vaccine-induced antibodies which may play a role in breakthrough infection.

A highly efficacious live attenuated mumps virus-based SARS-CoV-2 vaccine candidate expressing a six-proline stabilized prefusion spike.

With the rapid increase in SARS-CoV-2 cases in children, a safe and effective vaccine for this population is urgently needed. The MMR (measles/mumps/rubella) vaccine has been one of the safest and most effective human vaccines used in infants and children since the 1960s. Here, we developed live attenuated recombinant mumps virus (rMuV)-based SARS-CoV-2 vaccine candidates using the MuV Jeryl Lynn (JL2) vaccine strain backbone. The soluble prefusion SARS-CoV-2 spike protein (preS) gene, stablized by two prolines (preS-2P) or six prolines (preS-6P), was inserted into the MuV genome at the P-M or F-SH gene junctions in the MuV genome. preS-6P was more efficiently expressed than preS-2P, and preS-6P expression from the P-M gene junction was more efficient than from the F-SH gene junction. In mice, the rMuV-preS-6P vaccine was more immunogenic than the rMuV-preS-2P vaccine, eliciting stronger neutralizing antibodies and mucosal immunity. Sera raised in response to the rMuV-preS-6P vaccine neutralized SARS-CoV-2 variants of concern, including the Delta variant equivalently. Intranasal and/or subcutaneous immunization of IFNAR1-/- mice and golden Syrian hamsters with the rMuV-preS-6P vaccine induced high levels of neutralizing antibodies, mucosal immunoglobulin A antibody, and T cell immune responses, and were completely protected from challenge by both SARS-CoV-2 USA-WA1/2020 and Delta variants. Therefore, rMuV-preS-6P is a highly promising COVID-19 vaccine candidate, warranting further development as a tetravalent MMR vaccine, which may include protection against SARS-CoV-2.

Exploring the Mumps Virus Glycoproteins: A Review.

The resurgence of mumps in vaccinated adult populations has raised concerns about possible waning vaccine immunity or a potential lack of protection to the circulating strain. A number of individual studies have investigated if there are amino acid variations between the circulating wild-type strains and vaccine strains. In these studies, the HN and F mumps surface glycoproteins have been of interest, because of their role in viral infection, and because the HN protein is the target of neutralizing antibodies. Here, we summarize the single nucleotide variants and their potential effect that have been identified between mumps genotypes in the HN and F proteins.

[Genetic diversity of the mumps viruses (Paramyxoviridae: Orthorubulavirus: Mumps orthorubulavirus): an overview].

Mumps is an infectious disease controlled by specific vaccine prophylaxis. To date, its social and epidemiological significance remains high. This is evidenced by the process of developing and implementing into the health care practices of many countries a set of measures for surveillance of mumps. In the Russian Federation, the National Program «Elimination of measles and rubella and achievement of sporadic morbidity with epidemic mumps in the Russian Federation (2021-2025)¼ and the national plan for its implementation were adopted in 2021. The basis for the adoption of these documents was the development of the domestic trivalent vaccine for the prevention of measles, rubella and mumps, Vaktrivir, and the start of its clinical application. The availability of this vaccine will make the epidemiological surveillance of mumps to be a part of the existing system of appropriate measures for measles and rubella. The fulfillment of this set of tasks involves the study of the molecular epidemiology of the mumps virus (MuV) with possible subsequent implementation of its methodology into the surveillance actions. In this connection, this work was aimed at presenting the data on global genetic diversity of MuV as well as its genotyping methods in a systematized form. The analysis of MuV global genetic diversity in different years will be the starting point in the subsequent development of approach to monitoring virus strains circulating in the Russian Federation.

Increase of Diversity of Mumps Virus Genotype G SH Variants Circulating Among a Highly Immunized Population: Spain, 2007-2019.

MuV caused three epidemic waves in Spain since genotype G emerged in 2005, despite high vaccination coverage. SH gene sequencing according to WHO protocols allowed the identification of seven relevant variants and 88 haplotypes. While the originally imported MuVi/Sheffield.GBR/1.05/-variant prevailed during the first two waves, it was subsequently replaced by other variants originated by either local evolution or importation, according to the additional analysis of hypervariable NCRs. The time of emergence of the MRCA of each MuV variant clade was concordant with the data of the earliest sequence. The analysis of Shannon entropy showed an accumulation of variability on six particular positions as the cause of the increase on the number of circulating SH variants. Consequently, SH gene sequencing needs to be complemented with other more variable markers for mumps surveillance immediately after the emergence of a new genotype, but the subsequent emergence of new SH variants turns it unnecessary.

Immunogenicity of Mumps Virus Genotype G Vaccine Candidates in Jeryl Lynn-Immunized Mice.

Mumps virus (MuV) causes a highly contagious human disease characterized by the enlargement of the parotid glands. In severe cases, mumps can lead to neurological complications such as aseptic meningitis and encephalitis. Vaccination with the attenuated Jeryl Lynn (JL) MuV vaccine has dramatically reduced the incidence of MuV infection. Recently, large outbreaks have occurred in vaccinated populations. The vaccine strain JL was generated from genotype A, while most current circulating strains belong to genotype G. In this study, we examined the immunogenicity and longevity of genotype G-based vaccines. We found that our recombinant genotype G-based vaccines provide robust neutralizing titers toward genotype G for up to 1 year in mice. In addition, we demonstrated that a third dose of a genotype G-based vaccine following two doses of JL immunization significantly increases neutralizing titers toward the genotype G strain. Our data suggest that after two doses of JL vaccination, which most people have received, a third dose of a genotype G-based vaccine can generate immunity against a genotype G strain. IMPORTANCE At present, most individuals have received two doses of the measles, mumps, and rubella (MMR) vaccine, which contains genotype A mumps vaccine. One hurdle in developing a new mumps vaccine against circulating genotype G virus is whether the new genotype G vaccine can generate immunity in humans that are immunized against genotype A virus. This work demonstrates that a novel genotype G-based vaccine can be effective in animals which received two doses of genotype A-based vaccine, suggesting that the lead genotype G vaccine may induce anti-G immunity in humans who have received two doses of the current vaccine, providing support for testing this vaccine in humans.

Influence of Ribavirin on Mumps Virus Population Diversity.

Frequent mumps outbreaks in vaccinated populations and the occurrence of neurological complications (e.g., aseptic meningitis or encephalitis) in patients with mumps indicate the need for the development of more efficient vaccines as well as specific antiviral therapies. RNA viruses are genetically highly heterogeneous populations that exist on the edge of an error threshold, such that additional increases in mutational burden can lead to extinction of the virus population. Deliberate modulation of their natural mutation rate is being exploited as an antiviral strategy and a possibility for rational vaccine design. The aim of this study was to examine the ability of ribavirin, a broad-spectrum antiviral agent, to introduce mutations in the mumps virus (MuV) genome and to investigate if resistance develops during long-term in vitro exposure to ribavirin. An increase in MuV population heterogeneity in the presence of ribavirin has been observed after one passage in cell culture, as well as a bias toward C-to-U and G-to-A transitions, which have previously been defined as ribavirin-related. At higher ribavirin concentration, MuV loses its infectivity during serial passaging and does not recover. At low ribavirin concentration, serial passaging leads to a more significant increase in population diversity and a stronger bias towards ribavirin-related transitions, independently of viral strain or cell culture. In these conditions, the virus retains its initial growth capacity, without development of resistance at a whole-virus population level.

Population Variability Generated during Rescue Process and Passaging of Recombinant Mumps Viruses.

Recombinant mumps viruses (MuVs) based on established vaccine strains represent attractive vector candidates as they have known track records for high efficacy and the viral genome does not integrate in the host cells. We developed a rescue system based on the consensus sequence of the L-Zagreb vaccine and generated seven different recombinant MuVs by (a) insertion of one or two additional transcription units (ATUs), (b) lengthening of a noncoding region to the extent that the longest noncoding region in MuV genome is created, or (c) replacement of original L-Zagreb sequences with sequences rich in CG and AT dinucleotides. All viruses were successfully rescued and faithfully matched sequences of input plasmids. In primary rescued stocks, low percentages of heterogeneous positions were found (maximum 0.12%) and substitutions were predominantly obtained in minor variants, with maximally four substitutions seen in consensus. ATUs did not accumulate more mutations than the natural MuV genes. Six substitutions characteristic for recombinant viruses generated in our system were defined, as they repetitively occurred during rescue processes. In subsequent passaging of primary rescue stocks in Vero cells, different inconsistencies within quasispecies structures were observed. In order to assure that unwanted mutations did not emerge and accumulate, sub-consensus variability should be closely monitored. As we show for Pro408Leu mutation in L gene and a stop codon in one of ATUs, positively selected variants can rise to frequencies over 85% in only few passages.

Outbreaks of mumps genotype G viruses in the Netherlands between October 2019 and March 2020: clusters associated with multiple introductions.

BACKGROUND: From October 2019-March 2020, several clusters of mumps cases were identified in the Netherlands. Our objective was to describe cluster-associated mumps virus transmission using epidemiological and molecular information in order to help future mumps outbreak investigation and control efforts. METHODS: An epidemiological cluster includes ≥ 2 mumps cases with at least an epidemiological-link to a laboratory-confirmed mumps case. A molecular group includes ≥ 2 mumps cases with identical mumps virus sequences. Cases with symptom onset date between 1 October 2019 and 31 March 2020 reported through the National Notifiable Diseases Surveillance System were included. We described epidemiological and clinical characteristics of mumps cases. Sequence data was obtained from selected regions of mumps virus genomes (2270 nucleotides). Associations between epidemiological and molecular information were investigated. RESULTS: In total, 102 mumps cases were notified (90% laboratory-confirmed, 10% epidemiologically-linked). 71 out of 102 cases were identified as part of an epidemiological cluster and/or molecular group. Twenty-one (30%) of 71 cases were identified solely from epidemiological information, 25 (35%) solely from molecular surveillance, and 25 (35%) using both. Fourteen epidemiological clusters were identified containing a total of 46 (range: 2-12, median: 3) cases. Complete sequence data was obtained from 50 mumps genotype G viruses. Twelve molecular groups were identified containing 43 (range: 2-13) cases, dispersed geographically and timewise. Combined information grouped seven epidemiological clusters into two distinct molecular groups. The first lasting for 14 weeks, the other for 6. Additionally, one molecular group was detected, linked by geography and time but without an epidemiological-link. CONCLUSIONS: Combined epidemiological and molecular information indicated ongoing mumps virus transmission from multiple introductions for extended time periods. Sequence analysis provided valuable insights into epidemiological clustering. If combined information is available in a timely manner, this would improve outbreak detection, generate further insight into mumps transmission, and guide necessary control measures.

Mumps virus outbreak related to a water pipe (narghile) shared smoking.

INTRODUCTION: This study describes a mumps outbreak among a group of young people who shared a same narghile to smoking. Saliva and blood samples were obtained from 3 cases for RT-PCR and serology respectively. METHODS: The notification of a mumps case started an epidemiological investigation. Information of other 6 additional symptomatic persons who had gathered with the case in a discotheque where they smoking in a same narghile was achieved. RT-PCR positive samples were genotyped by sequencing. RESULTS: The 7 patients resided in 3 different municipalities, and they do not have get together for more than a month until the meeting in the discotheque. Four cases were confirmed by RT-PCR and/or IgM determinations. The genomic investigation showed identical nucleic sequences. CONCLUSIONS: This outbreak is consequence of the common use of a narghile to smoking. The public usage of these water pipes should be regulated.

Mumps outbreak among fully vaccinated school-age children and young adults, Portugal 2019/2020.

On 16-17 January 2020, four suspected mumps cases were reported to the local Public Health Authorities with an epidemiological link to a local school and football club. Of 18 suspected cases identified, 14 were included in this study. Laboratory results confirmed mumps virus as the cause and further sequencing identified genotype G. Our findings highlight that even with a high MMR vaccine coverage, mumps outbreaks in children and young adults can occur. Since most of the cases had documented immunity for mumps, we hypothesise that waning immunity or discordant mumps virus strains are likely explanations for this outbreak.