Sarampión / Measles

En abril de 2019, UNICEF denunció que más de 20 millones de niños en todo el mundo no habían sido vacunados y alertó sobre posibles brotes de sarampión que, por su alta contagiosidad, es la primera enfermedad en emerger entre las prevenibles mediante vacunación. De continuar el descenso en las vacunaciones, podrían reaparecer también pertussis, tétanos y otras enfermedades con menor requerimiento de cobertura para alcanzar protección poblacional. A fin de agosto de 2019 se inició en la Argentina el actual brote de sarampión. Este virus se transmite por vía respiratoria, infecta múltiples órganos e induce inmunosupresión. Su genoma consiste en ARN de cadena simple. La genotipificación se efectúa por secuenciación de un fragmento de 450 nucleótidos de la proteína N que contiene la mayor densidad de variación de nucleótidos del genoma. En Sudamérica circula el genotipo D8, y en Norteamérica hay, además, un 8% de genotipo B3. Cada persona con sarampión infecta, en promedio, otras 12-18 en una población susceptible. La vacunación confiere protección directa e indirecta, e induce tanto anticuerpos como inmunidad celular. Los recién nacidos tienen protección hasta los 6 meses por anticuerpos maternos transmitidos vía placentaria. En la Argentina, el Calendario de Vacunación incluye dos dosis de triple viral, a los 12 meses y a los 5 años, y una dosis cero (6- 11 meses de edad) en distritos con casos de enfermedad. Una dosis protege al 93% de los vacunados a los 12 meses y dos dosis al 97%, de por vida.

In April 2019, UNICEF denounced that more than 20 million children worldwide had not been vaccinated and alerted on possible outbreaks of measles which, due to the high transmissibility of this virus, is the first disease preventable by vaccination to emerge. If the decline in vaccinations continues, pertussis, tetanus and other diseases, which require less coverage to achieve population protection, may also reappear. In Argentina, the current outbreak began in late August 2019. Measles virus is transmitted by air, infects multiple organs, and is associated with immunosuppression. Its genome consists of single stranded RNA. Genotyping is carried out by sequencing a 450-nucleotide fragment of the N protein, which contains the highest density of nucleotide variation. In South America, D8 is the circulating genotype and in North America, B3 accounts for 8% of the cases. Each person with measles infects, on average, another 12-18 people in a susceptible population. Vaccination confers direct and indirect protection, and induces both antibodies and cellular immunity. Newborns are protected by maternal antibodies transmitted via the placenta, up to 6 months. In Argentina, the Vaccination Calendar includes two doses of triple viral vaccine, at 12 months and 5 years, and a zero dose (6- 11 months of age) in districts with disease cases. The protection conferred by the vaccine is 93% at 12 months with a dose, and with 2 doses 97% for life.

The first outbreak of measles virus caused by imported genotype D8 in Jiangsu province of China

ABSTRACT Here we reported the outbreak of measles cases caused by the genotype D8 measles virus for the first time in Jiangsu province in China, which was possibly imported by a foreign student from Laos. Throat swab specimens were collected, and used to isolate virus. 634-bp fragment of the N gene and 1854-bp fragment of H gene were amplified by reverse transcription-PCR and sequenced, respectively. Phylogenetic results indicated that they belonged to genotype D8 measles virus. Further epidemiology investigation showed that the adults with D8 measles virus infection did not receive measles vaccine before having measles. In China, almost all D8 genotype MeV only infected those population without receiving measles vaccine immunization. Therefore, it is still necessary to implement the supplement activity of measles immunization target adult with immunity gap.

Vigilancia de enfermedades febriles exantemáticas y casos de sarampión de la CABA / Surveillance of febrile diseases and measles cases at Buenos Aires City

En esta edición, se expondrán fundamentalmente los casos de sarampión confirmados de la Ciudad. Ante la circulación del virus de sarampión en países de América y el resto del mundo, la importación de casos es actualmente la forma de entrada del mismo al país y la Ciudad. Se deberá tener en cuenta que la Ciudad de Buenos Aires no presenta casos autóctonos desde 1999 y que confluyen en el momento actual varios factores que pueden desencadenar un brote ante la introducción de un caso: el incremento de susceptibles; la vigilancia cuya tasa de detección, durante varios años, no llegó a la establecida internacionalmente; bajas coberturas de vacunación y que la Ciudad representa el punto más importante del país para la entrada y salida de turistas hacia y desde otros países del mundo. La principal medida para evitar la reintroducción y diseminación del virus del sarampión y la rubéola es sin duda la vacunación de la población susceptible; ésta, junto a un sistema de vigilancia (clínica y de laboratorio) de alta calidad y suficientemente sensible son los pilares para impedir la producción de brotes relacionados con la importación y mantener eliminada esta enfermedad. El sistema de Vigilancia cumple el rol fundamental: detectar oportunamente los casos sospechosos a fin de accionar de manera rápida y efectiva.

Investigation of a measles outbreak caused by genotype D8 virus in Pinghu city of Zhejiang province, 2017 / 中华流行病学杂志

Objective: To investigate the epidemiological characteristics of measles outbreak caused by genotype D8 virus in Pinghu city of Zhejiang province, and provide evidence for the control of the outbreak. Methods: The measles outbreak data were collected through National Measles Surveillance System. The outpatient records and admission records were checked, field investigation and outbreak response were conducted. Blood samples in acute phase and swab specimens were collected from the patients for laboratory testing, including serology test, RNA extraction and amplification, measles virus isolation and genotype identification. Software SPSS 17.0 and Excel 2016 were used for data analysis. Results: A total of 10 confirmed measles cases were reported in Pinghu city, and 8 cases were aged >40 years. Six blood samples were collected, in which 5 were measles D8 virus positive and 1 was negative in measles virus detection. There were epidemiological links among 10 cases which occurred in a factory, a hospital and a family at the same time. There was no statistical difference in symptoms among cases caused by D8 virus and H1a virus. After the emergent measles vaccination, the measles outbreak was effectively controlled. Conclusion: Untimely response due to the uneasy detection of measles cases in the early stage, nosocomial infection and weak barrier of measles immunity in adults might be the main reasons for this outbreak. Measles vaccination is effective in the prevention of measles D8 virus infection. It is necessary to strengthen measles genotype monitoring for the tracing of infection source and control of outbreaks.

Molecular epidemiology of measles virus infection in Shanghai in 2000–2012: the first appearance of genotype D8

Purpose: The purpose of this study was to identify measles virus in Shanghai in 2012 and study the genotype trend of measles virus epidemic strains during 2000–2012. Methods: Nose and throat swab specimens were collected from 34 suspected measles cases in Shanghai. Measles virus was isolated using Vero-SLAM cells (African green monkey kidney cells/lymphoid signal activating factor-transfected African green monkey kidney cells). The 450 bp of C terminus of the N gene and the entire hemagglutinin gene sequence was amplified using RT-PCR. Phylogenetic analysis was performed by comparing the seven measles strains in Shanghai with the reference strains for H1a, H1b and D8 genotypes, as well as the Chinese measles virus vaccine strain. Results: Seven measles viruses strains were isolated from the 34 throat swap specimens. Six strains were genotype H1a, which is the predominant strain in China and one strain was genotype D8, which is the first imported strain since 2000. All these seven strains maintained most of the glycosylation sites except subtype H1a, which lost one glycosylation site. Conclusion: Since 2000, measles virus strains in Shanghai are consistent with measles virus from other provinces in China with H1a being the predominant genotype. This study is also the first report of genotype D8 strain in Shanghai. All strains maintained their glycosylation sites except H1a that lost one glycosylation site. These strains could still be neutralized by the Chinese measles vaccine. We suggest that Shanghai Center for Disease Control laboratories should strengthen their approaches to monitor measles cases to prevent further spread of imported strains. .

Molecular analysis of rubella virus in travelers suspected of measles infection in São Paulo, Brazil / Análise molecular do vírus da rubéola em turistas suspeitos de infecção por sarampo em São Paulo, Brasil

OBJECTIVE: To identify measles virus genotypes in three cases of travelers suspected of measles infection. METHODS: Samples (blood and urine) were collected for serology, virus isolation, and genotyping. Sera were analyzed for IgM antibodies against measles virus and rubella virus by enzyme-linked immunosorbent assay (ELISA) (Siemens - Marburg, Germany). Clinical samples (lymphocytes and urine) were inoculated into Statens Serum Institute rabbit corneal epithelial cell line- ATCC CL 60 (SIRC) and Vero Slam cells. RNA was extracted from clinical samples and cell culture was inoculated and processed by polymerase chain reaction (PCR) with oligonucleotides specific for measles virus (MV) and rubella virus (RV). RESULTS: All patients showed IgM negative serology for MV and positive IgM for RV. RV belonging to genotypes 1B, 1C, and 1E were isolated from patients who came from Finland, Peru, and Germany, respectively. Genotype 1B has been found in Europe and on the East Coast of South America; 1C has been found in Peru and the West Coast of South America, and 1E, first identified in 1997, now appears to have worldwide distribution. CONCLUSION: Information about RV and MV genotypes circulating in São Paulo is essential for the control of measles, rubella, and congenital rubella syndrome (CRS) in Brazil.

OBJETIVO: Identificar o genótipo do vírus do sarampo em três viajantes suspeitos de infecção por sarampo. MÉTODOS: Amostras (sangue e urina) foram coletadas para sorologia, isolamento viral e genotipagem. As sorologias para pesquisa de IgM para o vírus do sarampo e da rubéola foi realizada utilizando-se o kit de ELISA (Siemens - Marburg, Alemanha). As amostras clínicas (linfócito e urina) foram inoculadas na SIRC (Statens Serum Institute rabbit corneal epithelial cell line-ATCC CL 60) e nas células Vero Slam. O RNA foi extraído das amostras clínicas e das células inoculadas e processadas por PCR, utilizando oligonucleotideos específicos para sarampo e rubéola. RESULTADOS: Todos os pacientes apresentaram sorologia IgM negativa para sarampo e positivo para rubéola. Os vírus da rubéola isolados dos pacientes que vieram da Finlândia, Peru e Alemanha pertencem aos genótipos 1B, 1C e 1E, respectivamente. O genótipo 1B foi encontrado na Europa e na costa oriental da América do Sul, o genótipo 1C foi encontrado no Peru e na costa oeste da América do Sul e o genótipo 1E, identificado pela primeira vez em 1997, agora aparenta ser um genótipo com distribuição mundial. CONCLUSÃO: O conhecimento dos genótipos de sarampo e rubéola que circulam em São Paulo é essencial para o controle do sarampo, rubéola e síndrome da rubéola congênita.

Contribución del sistema integrado de vigilancia Sarampión/Rubéola al diagnóstico de otras enfermedades febriles eruptivas en Paraguay 2003-2005 / Contribution of the system integrated of monitoring Measles/Rubéola to the etiológico diagnosis of other eruptive febrile diseases in Paraguay 2003-2005

Presenta resultados de análisis serológicos realizados con el fin de conocer causas de brotes de fiebre y erupción ocurridos en los años 2004 y 2005 en Paraguay en una población de pacientes de cuaqluier edad en ausencia de sarampión, rubéola y dengue de los pacientes que ingresaron al sistema de vigilancia sarampión/rubéola