Utility of neutralization test for laboratory diagnosis of suspected mumps

Mumps is an infectious disease caused by mumps virus (MuV), which belongs to the family Paramyxoviridae and genus Rubulavirus. Typical symptoms of mumps include fever and swelling of the parotid glands; however, mumps can be asymptomatic. Mumps is diagnosed by molecular and serological methods (i.e., PCR and Enzyme Immunoassay [EIA]); however, both methods have pros and cons. This study was performed to compare the diagnostic utility of a focus reduction neutralization test (FRNT) to that of MuV‐specific commercial IgM and IgG antibody EIA in patients suspected of having mumps. One hundred‐eighty six samples collected during mumps outbreak in 2012–16 were studied. Samples (n = 80) were tested by all the three serological assays and showed 70.4%, 83% and 92.5% positivity by IgM EIA, IgG and FRNT, respectively. In all, 58.8% samples (n = 47) tested positive in all three assays. Concordance between mumps RT‐PCR and IgM EIA was highest during the first 2–5 days and decreased with increasing time post‐onset. Mumps FRNT results agreed with those of RT‐PCR/IgM EIA from the second week onwards, whereas the results of mumps IgG EIA agreed with those of RT‐PCR/IgM EIA from post‐onset days 3–10. These findings suggest the utility of a FRNT for laboratory diagnosis of mumps in countries whose populations are not immunized against this infection.

     

Mumps Meningoencephalitis,Toronto, 1963

Between January and June 1963, 45 children were hospitalized with mumps meningoencephalitis. Of 39 patients with laboratory evidence of mumps infection, 24 had parotitis and 15 showed no salivary gland involvement. Cerebrospinal fluids from 18 of 40 patients yielded mumps virus by inoculation of rhesus monkey kidney cultures; 33 subjects, including 12 of the 18 virus excretors, showed rising or elevated levels of mumps antihemagglutinin during convalescence. Between May 1959 and June 1963, mumps virus was recovered from cerebrospinal fluids of 50 of 126 cases of mumps meningoencephalitis; virus isolation rates were highest during the peak incidence of mumps meningoencephalitis in winter and early spring.Mumps vaccine (inactivated) was administered to 34 parents with no history of mumps, shortly after their children developed mumps. Mumps occurred in three of 17 parents without prevaccination mumps antihemagglutinins, and in two others, but in none of 15 who had prevaccination antibodies.     

Seroprevalence of Mumps in The Netherlands: Dynamics over a Decade with High Vaccination Coverage and Recent Outbreaks

Here we present mumps virus specific antibody levels in a large cross-sectional population-based serosurveillance study performed in the Netherlands in 2006/2007 (n = 7900). Results were compared with a similar study (1995/1996) and discussed in the light of recent outbreaks. Mumps antibodies were tested using a fluorescent bead-based multiplex immunoassay. Overall seroprevalence was 90.9% with higher levels in the naturally infected cohorts compared with vaccinated cohorts. Mumps virus vaccinations at 14 months and 9 years resulted in an increased seroprevalence and antibody concentration. The second vaccination seemed to be important in acquiring stable mumps antibody levels in the long term. In conclusion, the Dutch population is well protected against mumps virus infection. However, we identified specific age- and population groups at increased risk of mumps infection. Indeed, in 2007/2008 an outbreak has occurred in the low vaccination coverage groups emphasizing the predictive value of serosurveillance studies.     

Enteroviral and Mumps Meningitis in Toronto, 1963

Virological investigations of 115 children with the aseptic meningitis syndrome during 1963 resulted in the isolation of enteroviruses from cerebrospinal fluid (CSF) and/or feces of 21 of 48 children who had no association with mumps. For the third successive year, Echo 9 was the dominant enterovirus in cases of aseptic meningitis in Toronto children, but no rashes were associated with Echo 9 meningitis during 1963, in contradistinction to previous years. Mumps virus was isolated from CSF of 25 patients by inoculation of rhesus monkey kidney cultures, and rising or elevated mumps antihemagglutinin titres in paired sera from a further 33 cases provided laboratory evidence of infection with mumps virus in 58 of 67 patients with mumps meningoencephalitis. No enlargement of salivary glands was noted in 20 laboratory-proved cases of mumps meningoencephalitis. Enteroviral meningitis occurred principally during summer, but the peak of mumps meningoencephalitis occurred during late winter.     

靖西县2007—2011年流行性腮腺炎流行病学分析

目的为了解靖西县流行性腮腺炎的疫情动态,为制定预防控制措施提供依据。方法采用描述流行病学分析方法对靖西县2007—2011年流行性腮腺炎发病情况进行分析。结果 2007—2011年共报告流行性腮腺炎721例,占法定传染病报告数4.03%,占丙类传染病报告数17.82%,报告年均发病率为23.39/10万。2007—2011年发病率呈上升趋势,其中2011年发病率最高达49.32/10万。全年均有发病,以5—7月为发病高峰,占37.86%,5、6、7月发病数分别占13.73%、11.65%、12.48%。全县19个乡镇都有腮腺炎病例发生,以新靖镇发病率居首位达254.52/10万,其次化峒镇的发病率为183.65/10万。发病主要分布0～15岁年龄组,发病人数占89.65%,以4～8岁年龄组发病人数最多,占45.91%。结论靖西县流行性腮腺炎发病率较高,近年发病呈上升趋势,应采取以腮腺炎疫苗接种为重点的综合性预防控制措施,降低学生和托幼机构儿童的发病率。     

Infection of Mice,Ferrets, and Rhesus Macaques with a Clinical Mumps Virus Isolate

In recent years, many mumps outbreaks have occurred in vaccinated populations worldwide. The reasons for these outbreaks are not clear. Animal models are needed to investigate the causes of outbreaks and to understand the pathogenesis of mumps virus (MuV). In this study, we have examined the infection of three animal models with an isolate of mumps virus from a recent outbreak (MuV-IA). We have found that while both ferrets and mice generated humoral and cellular immune responses to MuV-IA infection, no obvious signs of illness were observed in these animals; rhesus macaques were the most susceptible to MuV-IA infection. Infection of rhesus macaques via both intranasal and intratracheal routes with MuV-IA led to the typical clinical signs of mumps 2 weeks to 4 weeks postinfection. However, none of the infected macaques showed any fever or neurologic signs during the experimental period. Mumps viral antigen was detected in parotid glands by immunohistochemistry (IHC). Rhesus macaques represent the best animal model for the study of mumps virus pathogenesis.     

Comparison of the Neurovirulence of a Vaccine and a Wild-Type Mumps Virus Strain in the Developing Rat Brain

Prior to the adoption of widespread vaccination programs, mumps virus was the leading cause of virus-induced central nervous system (CNS) disease. Mumps virus-associated CNS complications in vaccinees continue to be reported; outside the United States, some of these complications have been attributed to vaccination with insufficiently attenuated neurovirulent vaccine strains. The development of potentially neurovirulent, live, attenuated mumps virus vaccines stems largely from the lack of an animal model that can reliably predict the neurovirulence of mumps virus vaccine candidates in humans. The lack of an effective safety test with which to measure mumps virus neurovirulence has also hindered analysis of the neuropathogenesis of mumps virus infection and the identification of molecular determinants of neurovirulence. In this report we show, for the first time, that mumps virus infection of the neonatal rat leads to developmental abnormalities in the cerebellum due to cerebellar granule cell migration defects. The incidence of the cerebellar abnormalities and other neuropathological and clinical outcomes of mumps virus infection of the neonatal rat brain demonstrated the ability of this model to distinguish neurovirulent (Kilham) from nonneurovirulent (Jeryl Lynn) mumps virus strains. Thus, this neonatal rat model may prove useful in evaluating the neurovirulence potential of new live, attenuated vaccine strains and may also be of value in elucidating the molecular basis of mumps virus neurovirulence.     

The V protein of mumps virus plays a critical role in pathogenesis

Mumps virus (MuV) causes an acute infection in humans characterized by a wide array of symptoms ranging from relatively mild manifestations, such as parotitis, to more-severe complications, such as meningitis and encephalitis. Widespread mumps vaccination has reduced mumps incidence dramatically; however, outbreaks still occur in vaccinated populations. The V protein of MuV, when expressed in cell culture, blocks interferon (IFN) expression and signaling and interleukin-6 (IL-6) signaling. In this work, we generated a recombinant MuV incapable of expressing the V protein (rMuVΔV). The rescued MuV was derived from a clinical wild-type isolate from a recent outbreak in the United States (MuV(Iowa/US/06), G genotype). Analysis of the virus confirmed the roles of V protein in blocking IFN expression and signaling and IL-6 signaling. We also found that the rMuV(Iowa/US/06)ΔV virus induced high levels of IL-6 expression in vitro, suggesting that V plays a role in reducing IL-6 expression. In vivo, the rMuV(Iowa/US/06)ΔV virus was highly attenuated, indicating that the V protein plays an essential role in viral virulence.     

2007-2009年玉溪市流行性腮腺炎病毒的基因型分析

目的了解2007-2009年玉溪市流行性腮腺炎病毒流行株(MuV)的基因型分布及变异情况。方法采集玉溪市医疗机构部分临床诊断病例含漱液进行RT-PCR病毒核酸检测,对核酸检测阳性标本进行病毒培养病毒分离,将分离病毒株进行SH基因316 bp片段序列分析,并与其他基因型参考株进行同源性比较,构建亲缘进化树。结果采集流行性腮腺炎病例标本136份,RT-PCR病毒核酸阳性30份,阳性率为22.1%;vero细胞分离到6株,6株MuV属于F基因型,各流行株SH基因之间的核苷酸最大差异为2.6%;与其他各基因型代表株之间的核苷酸最大差异达到17.8%,与疫苗株的最大差异为17.4%,与国内F基因型代表株SP的基因差异为2.7%。结论玉溪市流行性腮腺炎病毒流行株为F基因型,针对基因型变异和疫苗效果评价的预防控制策略变得日益重要。     

Mumps vaccine L-Zagreb, prepared in chick fibroblasts. I. Production and field trials

Leningrad-L3 Mumps Vaccine virus has been further attenuated by adaptation and passage on SPF chick embryo fibroblast cell cultures. This new mumps strain has been designated L-Zagreb and has been used to prepare mumps vaccines which meet the WHO requirements. Observations during both the field trial period prior to registration and during the later use of the vaccine showed that the few reactions observed were mild and that seroconversion was obtained in 88-98% of vaccines. The morbidity of mumps in Croatia declined more than tenfold after the introduction of the new vaccine. During a mumps epidemic, vaccine efficiency was calculated to be 97-100%.     

Easy and Rapid Detection of Mumps Virus by Live Fluorescent Visualization of Virus-Infected Cells

Mumps viruses show diverse cytopathic effects (CPEs) of infected cells and viral plaque formation (no CPE or no plaque formation in some cases) depending on the viral strain, highlighting the difficulty in mumps laboratory studies. In our previous study, a new sialidase substrate, 2-(benzothiazol-2-yl)-4-bromophenyl 5-acetamido-3,5-dideoxy-α-D-glycero-D-galacto-2-nonulopyranosidonic acid (BTP3-Neu5Ac), was developed for visualization of sialidase activity. BTP3-Neu5Ac can easily and rapidly perform histochemical fluorescent visualization of influenza viruses and virus-infected cells without an antiviral antibody and cell fixation. In the present study, the potential utility of BTP3-Neu5Ac for rapid detection of mumps virus was demonstrated. BTP3-Neu5Ac could visualize dot-blotted mumps virus, virus-infected cells, and plaques (plaques should be called focuses due to staining of infected cells in this study), even if a CPE was not observed. Furthermore, virus cultivation was possible by direct pick-up from a fluorescent focus. In conventional methods, visible appearance of the CPE and focuses often requires more than 6 days after infection, but the new method with BTP3-Neu5Ac clearly visualized infected cells after 2 days and focuses after 4 days. The BTP3-Neu5Ac assay is a precise, easy, and rapid assay for confirmation and titration of mumps virus.     

Effects of influenza, mumps, and western equine encephalitis viruses on fetal rhesus monkeys (Macaca mulatta).

Pregnant Rhesus monkeys were infected via instillation of influenza, mumps and western equine encephalomyelitis viruses respectively into the amniotic sacs at approximately 90 days gestation to determine if fetal infections would occur. Virus was recovered from fetal tissues after seven days in 100% of the exposed animals. Thus, the viruses are capable of causing fetal infection. Rhesus monkey fetuses were inoculated with influenza, mumps and WEE viruses by the direct intracerebral route at approximately 90 days gestation to determine possible teratogenicity of the viruses. influenza virus caused no malformations or measurable fetal effects. Mumps virus resulted in significant fetal mortality. WEE virus resulted in a 100% incidence of encephalitis and hydrocephalus. Thus, mumps and WEE viruses are teratogens in primates and are potential teratogens of man.     

Mumps virus decreases testosterone production and gamma interferon-induced protein 10 secretion by human leydig cells

Mumps virus is responsible for sterility. Here, we show that the mumps virus infects Leydig cells in vitro and totally inhibits testosterone secretion and that ribavirin in mumps virus-infected Leydig cell cultures completely restores testosterone production. Moreover, we show that gamma interferon-induced protein 10 (IP-10) is highly expressed by mumps virus-infected Leydig cells and that ribavirin does not block IP-10 production.     

2018-2019年中国流行性腮腺炎流行特征和病毒基因特征分析

阐明中国(未包括香港、澳门特别行政区和台湾地区,下同)2018-2019年流行性腮腺炎(流腮)流行特征和病毒基因特征。对2018-2019年中国流腮流行病学和病毒学监测数据进行描述流行病学和分子流行病学分析。2018-2019年中国流腮年报告发病率分别为18.65/10万和21.48/10万,15岁以下儿童和青少年是我国流腮的高发人群,分别占总病例数的85.30%和82.56%。流腮的流行具有明显的季节性特征。全国各省、自治区、直辖市份均有流腮病例报告,西部和中部地区发病率高于东部地区。2018-2019年共获得160条腮腺炎病毒(Mumps virus,MuV)SH基因序列,其中150条(93.75%)序列鉴定为F基因型MuV,在我国11个省份检测到;10条(6.25%)序列为G基因型MuV,2019年在广东、湖北和新疆3个省份检测到。和我国既往流行MuV代表株相比,2018-2019年流行的F基因型MuV代表株序列在基因亲缘性关系树上相对集中。现阶段我国流腮的流行病学特征未发生明显改变,仍呈现病毒自然流行模式;F基因型作为优势流行基因型,在我国大部分地区持续流行,但毒株的遗传多态性有所降低,这可能和我国实施1剂次腮腺炎疫苗常规免疫策略有关。G基因型MuV主要在我国局部地区流行,但流行范围在逐渐扩大。建议进一步加强两剂次腮腺炎疫苗接种工作,降低我国腮腺炎易感人群。同时持续性开展MuV流行学和病毒学监测工作,为鉴别病毒的来源,确定病毒传播途径和评估腮腺炎疫苗免疫策略奠定重要的基础。     

Mumps and Enteroviral Meningitis in Toronto, 1966

Of 52 children admitted to hospital for apparently typical mumps meningitis in 1966, 50 had their cerebrospinal fluid (CSF) examined. In only 17 was the mumps virus isolated from the CSF. Mumps antihemagglutinin conversions or increments were detected in 32 subjects including 10 whose CSF yielded virus. Antibody conversions were found in 16 patients and fourfold increments in another nine whose serum pairs were collected only one to four days apart. Initial sera from 20 patients were obtained three days or less after the onset of meningitis. Antibody increments were frequently noted about one day after defervescence and clinical improvement. Interferon was detected in CSF from two of eight patients, both of whom yielded virus. Enteroviruses were isolated from CSF and/or feces in seven of 15 cases of aseptic meningitis which occurred between July and October. Six patients including three virus excretors showed enteroviral neutralizing antibody increments during convalescence. The dominant enteroviral serotype was coxsackievirus A9.     

Clinical characteristics of 24 asymptomatic infections with COVID-19 screened among close contacts in Nanjing,China

Previous studies have showed clinical characteristics of patients with the 2019 novel coronavirus disease(COVID-19) and the evidence of person-to-person transmission. Limited data are available for asymptomatic infections. This study aims to present the clinical characteristics of 24 cases with asymptomatic infection screened from close contacts and to show the transmission potential of asymptomatic COVID-19 virus carriers. Epidemiological investigations were conducted among all close contacts of COVID-19 patients(or suspected patients) in Nanjing, Jiangsu Province, China, from Jan 28 to Feb 9, 2020, both in clinic and in community. Asymptomatic carriers were laboratory-confirmed positive for the COVID-19 virus by testing the nucleic acid of the pharyngeal swab samples. Their clinical records, laboratory assessments, and chest CT scans were reviewed. As a result, none of the 24 asymptomatic cases presented any obvious symptoms while nucleic acid screening. Five cases(20.8%) developed symptoms(fever, cough, fatigue, etc.) during hospitalization. Twelve(50.0%) cases showed typical CT images of ground-glass chest and 5(20.8%) presented stripe shadowing in the lungs. The remaining 7(29.2%) cases showed normal CT image and had no symptoms during hospitalization. These 7 cases were younger(median age: 14.0 years;P=0.012) than the rest. None of the 24 cases developed severe COVID-19 pneumonia or died. The median communicable period, defined as the interval from the first day of positive nucleic acid tests to the first day of continuous negative tests, was 9.5 days(up to 21 days among the 24 asymptomatic cases). Through epidemiological investigation, we observed a typical asymptomatic transmission to the cohabiting family members, which even caused severe COVID-19 pneumonia. Overall, the asymptomatic carriers identified from close contacts were prone to be mildly ill during hospitalization. However, the communicable period could be up to three weeks and the communicated patients could develop severe illness. These results highlighted the importance of close contact tracing and longitudinally surveillance via virus nucleic acid tests. Further isolation recommendation and continuous nucleic acid tests may also be recommended to the patients discharged.     

河南省2009—2013年流行性腮腺炎流行病学特征分析

了解河南省2009—2013年流行性腮腺炎的流行病学特征及规律,为制定流行性腮腺炎的预防控制措施提供参考依据。方法对河南省2009年1月1日至2013年12月31日通过"传染病报告信息管理系统"网络直报系统获得的流行性腮腺炎个案资料进行描述性流行病学分析。结果 2009—2013年河南省累计报告流行性腮腺炎病例91 822例,年均发病率为19.50/10万,男女发病比为1.95∶1(男性60 699例,女性31 123例),14岁以下年龄组发病率较高,年均发病率为88.99/10万,学生是主要的发病人群;流行性腮腺炎冬春季节多发,疾病流行呈现双峰分布;每年均有暴发疫情报告,多为学校内暴发。结论 2013年河南省年流行性腮腺炎发病率呈现下降趋势。暴发疫情起数和病例数波动较大,学校及托幼机构是流行性腮腺炎暴发流行的主要场所,应加强冬春季节学校及托幼机构流行性腮腺炎疫情的预防与控制,做好腮腺炎疫苗接种工作。     

Isolation and Characterization of Mumps Virus Strains in a Mumps Outbreak with a High Incidence of Aseptic Meningitis

In 1993, mumps with a high incidence of aseptic meningitis became prevalent in Akita prefecture, Japan. Three mumps virus isolates obtained from the nonvaccine-associated cases lacked the BamHI restriction cleavage site of the P gene, like the Urabe strain (Yamada, A. et al, Vaccine 8: 553-557). However, four additional nucleotide substitutions were found in the determined region of 157 bp. Fourteen of 19 cases from which mumps virus showing the Urabe-like RFLP profile was detected were complicated with symptomatic meningitis, whereas there were only four cases of meningitis among 23 individuals infected with the wild type showing no Urabe-like RFLP profile (non-“Urabe-like” wild-type). The incidence of meningitis was over 70% among patients infected with the “Urabe-like” wild-type virus. The “Urabe-like” wild-type disappeared after February 1994 in the epidemic area and was replaced by the non-“Urabe-like” wild-type. Patients infected with the “Urabe-like” wild-type lived in a closed colony, in which there were two instances of transmission between siblings. Thus this outbreak was transient and narrowly localized.     

Studies on live attenuated mumps vaccine. II. Follow-up study on the efficacy of Biken Vaccine.

Clinical and serological follow-ups were made on 18 children for 3 years and on another 18 children for 4 years, after immunization against mumps by attenuated mumps vaccine; Biken vaccine. To evaluate the protective efficacy of the vaccine, matched controls were studied during the same period. Serological examinations revealed that 77% of the vaccinees and 93% of the controls were infected with mumps after close contacts with mumps patients. Regular mumps was contracted by 88% of the controls, but none of the vaccinees. There was no substantial decrease in the antibody titers in unexposed vaccinees after vaccination.