Asymptomatic Mumps Research Articles

Outbreak of mumps virus genotype G infection in tribal individuals during 2016-17 in India.

Tribal individuals presented with fever and uni- or bi-lateral parotitis in Galonda and Silli villages (Dadra and Nagar Haveli, India) between 2 October 2016 and 19 March 2017. Consequently, the magnitude and epidemiological characteristics of the outbreak were investigated. Overall, 139 cases of suspected mumps were identified in both the above villages. Most of the suspected cases were 5-15 years old, the exceptions being three adults who had no noticeable complications. Specimens were collected from 42 of the suspected cases and their close contacts (n = 39) for laboratory investigation. Mumps infection was laboratory-confirmed in 73.8% and 20.5% of the suspected cases and contacts, respectively. Mumps was confirmed in seven adults aged 17-42 years, including three suspected cases and four contacts. To the best of our knowledge, this is the first report of a complete virus genome circulating among tribal individuals. Sequencing and phylogenetic studies revealed circulation of mumps virus genotype G in these tribal villages with 99% identity to a mumps virus detected in the UK (1996) and Canada (2009). Comparison with Indian mumps viruses revealed 99% and 98% identity to previously reported isolates from Pune during 2012 and 1986, respectively. Although the outbreak was large, no major complications were reported in the tribal villages. Detection of asymptomatic mumps in numerous close contacts indicates the importance of laboratory investigations in an outbreak setting.

Anti-mumps IgM antibody positive rate with sudden sensorineural hearing loss using second-generation enzyme immunoassay: A retrospective, multi-institutional investigation in Hokkaido, Japan

ObjectiveAlthough elevated anti-mumps IgM antibody levels were reported in 5.7%–7.2% of Japanese patients with sudden sensorineural hearing loss (SSNHL), there were several reports of false-positive cases, such as the continually IgM positive case and the IgM positive case in normal adults. To improve specificity, the new enzyme immuno assay (EIA) anti-mumps IgM antibody measurement kit was introduced in December 2009. This study re-examined the frequency of anti-mumps IgM antibody test positivity with SSNHL using the new measurement kit and compared the results with those from a previous report that used old kit. MethodsThis is a retrospective multi-institutional study involving patients diagnosed with SSNHL who exhibited the anti-mumps IgM antibody. We compared the positive rate of anti-mumps IgM antibody and the annual average number of mumps cases per sentinel in Hokkaido between the patients in the present study and patients previously evaluated. ResultsOverall, 100 patients with SSNHL were enrolled. One case (1.0%) was positive for anti-mumps IgM antibody. Of the 69 patients evaluated in the previous study, 5 cases (7.2%) were positive for anti-mumps IgM antibody. The positive rate of the anti-mumps IgM antibody in the present cases was significantly lower than that previously reported (p=0.042). The annual average number of mumps cases per sentinel in Hokkaido of the present and previous surveillance period was 34.47 and 42.77, respectively; no significant difference was seen in these data (p=0.4519). ConclusionThe present study revealed that 1.0% of SSNHL was positive for the anti-mumps IgM antibody using the new EIA-IgM measurement kit. After the introduction of the new EIA-IgM measurement kit, anti-mumps IgM antibody positive rate with SSNHL significantly decreased, indicating that the proportion of asymptomatic mumps among etiology of SSNHL may be lower than those previously reported.

Notes from the Field: Absence of Asymptomatic Mumps Virus Shedding Among Vaccinated College Students During a Mumps Outbreak - Washington, February-June 2017.

Notes from the Field: Absence of Asymptomatic Mumps Virus Shedding Among Vaccinated College Students During a Mumps Outbreak - Washington, February-June 2017.

Mumps transmission in social networks: a cohort study

BackgroundMumps emerged among highly vaccinated populations in the Netherlands. This offered a unique opportunity to study mumps virus transmission. In particular the extent to which asymptomatic infections in vaccinated people contribute to ongoing mumps virus transmission is uncertain. Insight into this could help project the future burden of mumps in vaccinated populations. We therefore studied the relative infectiousness of symptomatic and asymptomatic cases.MethodsIn a cohort study we followed contacts of notified mumps cases (ring 1) and contacts’ contacts (ring 2) for 40 days to ascertain symptoms of mumps and social contacts by weekly diaries and questionnaires, and mumps virus infections by taking finger stick dried blood spot specimens (DBS) that were tested for mumps-specific IgG antibodies. Mumps IgG concentrations >1500 RU/ml in a single sample, a four-fold increase in IgG antibody concentration in paired samples, or a positive oral fluid PCR were defined as recent infection.ResultsWe recruited 99 contacts (40 in ring 1 and 59 in ring 2) of 10 mumps index cases. The median age of participants was 23 years (range 18–57 years), 31 (31%) were male. At study entry, DBS of 4 out of 78 (5%) participants with samples showed serological evidence of recent mumps virus infection. Three of these reported mumps symptoms. Among the 59 participants who provided DBS at the beginning and end of the follow-up period, none had serological evidence of infection during this period. Of 72 participants who provided at least one oral fluid sample, one participant (1%) who also reported mumps symptoms, was found PCR positive. Of all 99 participants, the attack rate of self-reported mumps was 4% (95% CI 1.1–10.0%). Of the 5 laboratory confirmed mumps cases, 1 reported no mumps symptoms (percentage asymptomatic 20% (95% CI 0–71%)). Compared to non-students, students had larger households and more household members who were born after 1980 (p < 0.01 and <0.01, respectively).ConclusionsWe demonstrated that this prospective cohort study design allows for inference of the proportion of asymptomatic mumps infections. Because we only detected one asymptomatic mumps virus infection, we could not assess the relative infectiousness of asymptomatic mumps. Household characteristics of students differed from non-students. This may partly explain recent mumps epidemiology in the Netherlands.

Mumps-specific cross-neutralization by MMR vaccine-induced antibodies predicts protection against mumps virus infection

BackgroundSimilar to other recent mumps genotype G outbreaks worldwide, most mumps patients during the recent mumps genotype G outbreaks in the Netherlands had received 2 doses of measles, mumps and rubella (MMR) vaccine during childhood. Here, we investigate the capacity of vaccine-induced antibodies to neutralize wild type mumps virus strains, including mumps virus genotype G. MethodsIn this study, we tested 105 pre-outbreak serum samples from students who had received 2 MMR vaccine doses and who had no mumps virus infection (n=76), symptomatic mumps virus infection (n=10) or asymptomatic mumps virus infection (n=19) during the mumps outbreaks. In all samples, mumps-specific IgG concentrations were measured by multiplex immunoassay and neutralization titers were measured against the Jeryl Lynn vaccine strain and against wild type genotype G and genotype D mumps virus strains. ResultsThe correlation between mumps-specific IgG concentrations and neutralization titers against Jeryl Lynn was poor, which suggests that IgG concentrations do not adequately represent immunological protection against mumps virus infection by antibody neutralization. Pre-outbreak neutralization titers in infected persons were significantly lower against genotype G than against the vaccine strain. Furthermore, antibody neutralization of wild type mumps virus genotype G and genotype D was significantly reduced in pre-outbreak samples from infected persons as compared with non-infected persons. No statistically significant difference was found for the vaccine strain. The sensitivity/specificity ratio was largest for neutralization of the genotype G strain as compared with the genotype D strain and the vaccine strain. ConclusionsThe reduced neutralization of wild type mumps virus strains in MMR vaccinated persons prior to infection indicates that pre-outbreak mumps virus neutralization is partly strain-specific and that neutralization differs between infected and non-infected persons. Therefore, we recommend the use of wild type mumps virus neutralization assays as preferred tool for surveillance of protection against mumps virus infection.

Mumps serum antibody levels before and after an outbreak to assess infection and immunity in vaccinated students.

Background Since 2009, various mumps outbreaks have occurred in the Netherlands, affecting mostly young adults vaccinated against mumps. In this retrospective study, we estimated attack rates for symptomatic and asymptomatic mumps virus infection based on mumps-specific immunoglobulin (Ig)G concentrations in paired blood samples obtained before and after the mumps outbreaks, collected in 2 university cities. We aimed to identify a serological correlate of immune protection and risk factors for mumps virus infection.Methods Mumps-specific IgG levels were measured by Luminex technology in paired pre- and post-outbreak samples from students from Leiden (n = 135) and Utrecht (n = 619). Persons with a 4-fold increase in mumps IgG concentrations or mumps IgG concentrations >1500 RU/mL were assumed to have had a mumps virus infection.Results Attack rates for symptomatic and asymptomatic mumps virus infection were 2.0% and 3.8%, respectively. Pre-outbreak mumps-specific IgG concentrations were lower among cases than among noncases (P = .005) despite vaccination history, but no serological cutoff for immune protection could be established. Mumps among housemates was significantly associated with serological evidence for mumps virus infection (odds ratio, 7.25 [95% confidence interval, 3.20–16.40]; P < .001).Conclusions Symptomatic and asymptomatic mumps virus infections in vaccinated persons can be identified by retrospective assessment of mumps-specific IgG antibodies in blood samples.

小児突発難聴の臨床像についての検討

Sudden sensorineural hearing loss is usually unilateral, and the cause is not identified in most adult cases. However, a specific cause has frequently been found in the case of children, in whom idiopathic sudden sensorineural hearing loss (ISHL) is comparatively rare. We investigated 20 cases of acute unilateral sensorineural hearing loss in children associated with a certain disease, but which was first diagnosed as ISHL. Thirteen patients aged 6 to 16 years old were diagnosed as having psychogenic (functional) hearing loss. Discrepancies in behavioral and objective tests are most valuable when functional hearing loss is suspected. Elevated pure-tone thresholds associated with normal distortion product otoacoustic emissions (DPOAEs) enable prompt further investigation. There are several conditions that may mimic functional hearing loss, so auditory brainstem response (ABR) testing is necessary to verify the actual cause. The unilateral profound hearing loss in 2 patients aged 7 and 11 years old was due to asymptomatic mumps proven by detecting the mumps IgM antibody. Total hearing recovery in the 125-1000 Hz frequencies occurred in one case. In 5 patients aged 6 to 12 years old with acute hearing loss and vertigo, high resolution CT imaging showed an abnormally enlarged vestibular aqueduct on the affected side. Large vestibular aqueduct syndrome should be considered in acute high-frequency sloping hearing loss with an A-B gap at low frequencies.

Assessment of serological evidence for mumps virus infection in vaccinated children

It is estimated that at least one-third of mumps virus infections in non-vaccinated individuals are asymptomatic. Little information is available whether this proportion is the same among those vaccinated. We validated a commercial oral fluid mumps IgG-specific Enzyme Immunoassays (EIA) with vaccinated control groups to identify symptomatic and asymptomatic mumps virus infections in vaccinated individuals during a mumps outbreak in The Netherlands. A vaccinated control group was required to define a new cutoff value for the assay, because of the presence of low but significant levels of IgG antibodies in oral fluid as a result of mumps vaccination in the past. With a new cutoff, calculated using receiver operator characteristic analysis, we identified an attack rate of 7-10% compared to 2.7% based on clinical symptoms among vaccinated children. This finding has important implications when studying transmission patterns, strain virulence, as well as mumps vaccine effectiveness to protect from infection rather than disease.

Primary paraesophageal hernia in children

Background Paraesophageal hernias are uncommon in children and are distinctively different from the more common sliding hiatus hernias and those occurring after antireflux surgery in anatomy, pathology, symptoms, complications, and management. We reviewed a single institution's experience with the pathology of paraesophageal hernias. Methods We conducted a retrospective analysis of patient records. Results Fifty-nine children with paraesophageal hernias were treated during a 42-year period. Their mean age at presentation was 23.4 months (range, 1 day to 11 years). Presenting complaints were recurrent chest infections (n = 32), vomiting (n = 24), symptomatic anemia (n = 20), failure to thrive (n = 18), and dysphagia (n = 6). Five children were asymptomatic, and their diagnosis was established when they were investigated for incidentally noted asymptomatic anemia (n = 3), scoliosis (n = 2), and mumps (n = 1). Radiology typically showed cystic masses in the posterior mediastinum in the right lower chest and occasionally had an air-fluid level in the cystic mass or a dilated esophagus. None presented with strangulation or hematemesis. All patients were operated on. Surgical findings included a peritoneal lined sac and herniation through a widened diaphragmatic hiatus, containing the stomach and at times the transverse colon, spleen, and small bowel. The hernial sac usually occurred on the right. Principles of surgery included reduction of the contents, partial excision of the sac, crural approximation, and a fundoplication in 39 patients. No fundoplication was done in the earlier years in 20 patients, of whom 12 had recurrent reflux symptoms. Postoperative complications were bowel obstruction (n = 6), intussusception (n = 3), dysphagia (n = 3), breakdown of the repair (n = 3), and pneumothorax (n = 1). There was one mortality caused by preoperative aspiration. Conclusion Paraesophageal hernias in children are uncommon and most likely caused by a congenital defect. They are associated with considerable morbidity. Strangulation is not a feature. Principles of repair are well established and should include an antireflux procedure.

Virology of infantile chronic recurrent parotitis in Santiago de Chile

Infantile chronic recurrent parotitis (ICRP) has been attributed to multiple causes, including viral infections, and therefore its treatment remains empirical. Our aim was to evaluate the involvement of respiratory and oropharyngeal viruses in acute episodes of ICRP. Seventy children were studied, 50 patients and 20 age‐matched controls, in a 2‐year follow‐up study. Saliva samples were taken from the parotid duct and analyzed by viral isolation and immunofluorescence for adenovirus (Ad), respiratory sincitial virus (RSV), parainfluenza virus (PI), influenza virus (Flu), Cytomegalovirus (CMV), and herpes simplex virus (HSV). Paired sera samples were tested by ELISA for anti‐Epstein‐Barr virus (EBV) IgG and anti‐mumps IgM and IgG. Viral infections were detected in 7/50 (14%) cases of the ICRP group: one CMV; 2 Enteroviruses isolated in human embryonic lung fibroblast cells; 1 Flu A; and 3 mumps virus. No EBV seroconversions were detected. In the control group, 2 out of the 20 children had an asymptomatic mumps positive IgM titer. Our data indicate that the main respiratory and oropharyngeal viruses are not the cause of acute episodes of ICRP in Chilean children. J. Med. Virol. 70:459–462, 2003. © 2003 Wiley‐Liss, Inc.

ムンプス不顕性感染によりめまい，難聴をきたした３歳児の症例

We report the case of a young child suffering from vertigo and hearing loss caused by asymptomatic mumps.A three-year-old boy showed loss of body balance and vomiting. There was no swelling of the parotid glands and he did not complain of hearing loss, but we found he had spontaneous nystagmus to the left. During the medical examination, he staggered to the right from the standing position. After ABR testing, we found abnormality of his right ear and the testing showed high indices of mumps IgM and IgG. CT findings suggested tympanitis in his left ear, but no such sign was seen in the right. As a result of these tests we diagnosed asymptomatic mumps causing dizziness and hearing loss. Four months after he became ill, we found his spontaneous nystagmus had disappeared, but after head shaking nystagmus testing, nystagmus to the left was still observed. Subsequently, we observed that the patient often ran in the opposite direction from which his name was called.It is very rare for young children to complain of dizziness and vertigo. We should be aware that some children with hearing loss may not complain of symptoms. Physi-cians must also keep in mind that inner ear disorders can be caused by asymptomatic mumps. The number of mumps infections is on the increase. This disease is very hard to cure, so vaccination against mumps needs to be encouraged.

Sudden total bilateral deafness due to asymptomatic mumps infection

Mumps is the most common cause of unilateral acquired sensorineural hearing loss in children. Although it usually affects the salivary glands, the inner ear may be involved. Deafness is usually unilateral, sudden in onset, profound and permanent. Bilateral total sensorineural hearing loss had been rarely reported in English literature. We present a case of total deafness due to asymptomatic mumps infection.

Magnetic resonance imaging in a case of mumps postinfectious encephalitis with asymptomatic optic neuritis

A 5-year-old male patient with asymptomatic optic neuritis and mumps postinfectious encephalitis or acute disseminated encephalomyelitis is reported. Magnetic resonance imaging (MRI) with a short inversion time inversion recovery sequence was valuable in detecting clinically silent lesions of the unilateral right optic nerve in addition to visual evoked potentials. Evidence of concurrent optic neuritis was useful for detecting more extensive neurological involvement, leading to the diagnosis of mumps postinfectious encephalitis. A systematic MRI study should be performed in children with mumps encephalitis, regardless of appreciable clinical deficits.

ムンプス難聴確実例の検討

The clinical features of 12 patients with deafness due to mumps, including one with asymptomatic mumps, are reviewed. The diagnosis was made according to the criteria for diagnosis of mumps deafness determined by the Acute Profound Deafness Committee set up by the Ministry of Health and Welfare, Japan.1) The 12 patients were 5 to 25 years old (mean, 9.5).2) All 12 had unilateral total or profound sensorineural hearing loss.3) Hearing did not improve after treatment.4) Six patients complained of dizziness or vertigo. Eight patients were examined with the ice water caloric test; four showed a normal response and four no response.The patient with deafness due to asymptomatic mumps was a 5-year-old girl, who complained of dizziness and hearing loss in her left ear. Three days after the onset of deafness, she visited our hospital. Total sensorineural hearing loss on the left and right-beating nystagmus were noted. Her left ear showed no response to the ice water caloric test. Treatment with steroid medication did not improve her hearing. No swelling of the salivary glands was noted during the entire clinical course. Paired sera taken 3 days and 18 days after the onset of deafness showed a significant increase in antibody titer to mumps virus, confirming the diagnosis of asymptomatic mumps. The importance of serological tests in such a case is discussed.

Sudden deafness and asymptomatic mumps.

Adult patients who had experienced sudden deafness were examined for possible presence of subclinical mumps infection, using a new method of detecting mumps IgM antibody. Three of 53 patients demonstrated a positive reaction, indicating a strong correlation of sudden deafness with recent mumps infection. Mumps vaccination is recommended for those who have one deaf ear, in order to protect the better ear from mumps infection.

Immunological Study on Association between Mumps and Infantile Unilateral Deafness

The incidence of unilateral deafness in primary school children has been reported to be about 0.1%, but the cause of most of these cases has not been clarified, because parents and children themselves cannot recognize the onset of hearing loss occurring in one ear alone. This study was performed to clarify the possibility that mumps causes infantile unilateral deafness. The results were: 1) on dividing a total of 78 cases of infantile unilateral deafness according to age from 3 to 6 years, mumps infection rate in the 4-year-old group was nearly twice that in a randomly selected group; 2) on checking the neutralizing or ELISA IgG test of 31 cases with no history of mumps only, the 4-year-old group demonstrated a positive reaction to mumps more than the randomly selected group did. The above results suggested that unilateral deafness may be caused by asymptomatic mumps infection. To confirm this, we studied 5 infantile cases of sudden hearing loss by means of ELISA IgM antibody test and found a bilateral sudden deafness in children aged 1.9 years, caused by asymptomatic mumps infection.