ABSTRACT
Resumen Comunicamos el caso de un lactante mayor previamente sano, que luego de tres semanas de recibir la vacuna SPR (sarampión, parotiditis, rubeola) presentó fiebre, aumento de volumen parotídeo y compromiso de conciencia. Se diagnosticó una meningitis aséptica, con pleocitosis en el LCR de predominio mononuclear, detectándose virus parotídeo en LCR por biología molecular. En el Instituto de Salud Pública de Chile se realizó serología (IgM e IgG) que resultó positiva. La muestra de saliva confirmó la etiología por virus parotídeo con genotipo N. La evolución fue favorable, sin secuelas al seguimiento a seis meses. Ante esta situación clínica, se revisó la información respecto a la asociación y causalidad de esta entidad clínica y vacuna SPR, focalizado en diferentes cepas del virus parotiditis.
Abstract We report the case of an older infant with no prior morbidity that approximately 3 weeks after receiving MMR vaccination (measles, mumps, rubella) was hospitalized for feverish symptoms, increased parotid volume and compromised consciousness. Aseptic meningitis was diagnosed, detecting pleocytosis in the CSF, predominantly mononuclear, and confirming by molecular biology, presence of parotid virus in CSF. A study was carried out by the Institute of Public Health of Chile, where serology (IgM and IgG) was positive. Saliva sample confirmed the etiology of parotid virus with genotype N. The evolution was favorable and at 6-month follow-up, there were no sequelae. Given this clinical situation, information regarding the association and causality of this clinical entity and the MMR vaccine, focused on different strains of the mumps virus, was reviewed.
Subject(s)
Humans , Infant , Rubella , Measles , Meningitis, Aseptic , Mumps , Chile , Measles-Mumps-Rubella Vaccine/adverse effects , Mumps virus/geneticsABSTRACT
Resumen El virus de la parotiditis produce una infección benigna caracterizada por un aumento de volumen parotídeo que, antes de la introducción de la vacuna tres vírica, afectaba principalmente a niños y adolescentes. Luego de que esta vacuna se implementara en el Programa Nacional de Inmunizaciones, se produjo una notable disminución en su incidencia. Además, ocasionó un cambio en la edad y presentación clínica, siendo más frecuente en adultos jóvenes con mayor riesgo de complicaciones. Presentamos dos casos clínicos de parotiditis en adultos jóvenes confirmados por serología y en uno de ellos, por biología molecular. Se caracterizó el virus como del genotipo G, como el descrito en los brotes en E.U.A y Europa, diferente al virus contenido en la vacuna. El virus parotídeo sigue circulando en nuestro país y debemos mantenernos alerta ante eventuales brotes. Se hace relevante optimizar el diagnóstico etiológico por serología o técnicas de biología molecular con fines clínicos y epidemiológicos.
Mumps virus usually produces a benign infection characterized by increased parotid volume which, prior to vaccination, mainly affected children and adolescents. After the introduction of measles, mumps and rubella (MMR) vaccine, mumps incidence decreased dramatically. This intervention also produced a change in its clinical presentation, moving to young adult patients, with an increased risk of complications. We report two clinical mumps cases in young adults with different clinical presentations. In both cases, serologic assays were assessed and, in one case, a polymerase chain reaction (PCR) was performed in order to confirm the diagnosis. The isolated virus was characterized and identifed as G genotype, the same genotype observed during outbreaks in United States and Europe, and different to the vaccinal strain. Mumps virus is currently circulating in Chile and it is important to be aware of possible outbreaks. Viral diagnosis can be difficult, particularly in populations with high vaccination coverage. Therefore, the access to etiologic study through PCR and serology becomes more relevant in order to optimize clinical management and secondary prevention measures.
Subject(s)
Humans , Male , Female , Adult , Parotitis/diagnosis , Parotitis/genetics , Mumps virus/genetics , Parotitis/microbiology , Parotitis/drug therapy , Mumps Vaccine/administration & dosage , Chile , Polymerase Chain Reaction , Risk Factors , Vaccination , Genotype , Mumps virus/isolation & purificationABSTRACT
A point mutation from guanine (G) to adenine (A) at nucleotide position 1081 in the hemagglutinin-neuraminidase (HN) gene has been associated with neurovirulence of Urabe AM9 mumps virus vaccine. This mutation corresponds to a glutamic acid (E) to lysine (K) change at position 335 in the HN glycoprotein. We have experimentally demonstrated that two variants of Urabe AM9 strain (HN-A1081 and HN-G1081) differ in neurotropism, sialic acidbinding affinity and neuraminidase activity. In the present study, we performed a structure-function analysis of that amino acid substitution; the structures of HN protein of both Urabe AM9 strain variants were predicted. Based on our analysis, the E/K mutation changes the protein surface properties and to a lesser extent their conformations, which in turn reflects in activity changes. Our modeling results suggest that this E/K interchange does not affect the structure of the sialic acid binding motif; however, the electrostatic surface differs drastically due to an exposed short alpha helix. Consequently, this mutation may affect the accessibility of HN to substrates and membrane receptors of the host cells. Our findings appear to explain the observed differences in neurotropism of these vaccine strains.