Acute norovirus gastroenteritis in children in a highly rotavirus-vaccinated population in Northeast Brazil.

Background: Gastroenteritis is one of the most important causes of morbidity and mortality in children and an important etiological agent is norovirus. Objective: We describe the occurrence and characteristics of norovirus diarrhoea in children from Sergipe, Northeast-Brazil, over two consecutive periods of three years following rotavirus vaccine introduction. Study design: A cross sectional hospital-based survey conducted from October-2006 to September-2009 and from July-2011 to January-2013. Acute diarrhoea cases had a stool sample collected and tested for norovirus by RT-PCR and positive samples were sequenced. Results: In total 280 (19.6%) of 1432 samples were norovirus positive, including 204 (18.3%) of 1,113 samples collected during the first period and 76 (23.9%) of 318 collected during the second period. The proportion of children with norovirus infection increased significantly through the second study period (χ2 for trend = 6.7; p = 0.009), was more frequent in rotavirus vaccinated and in younger children (p < 0.001). Of 280 norovirus-positive specimens, 188 (67.1%) were sequenced. Of these, 12 were genogroup I and 176 genogroup II. The main genotype was GII.4 (149/188, 79.3%), followed by GII.2 (6, 3.2%) and GII.6 (5, 2.6%). Conclusion: Norovirus annual detection rates increased over the study period. The detection of norovirus was higher among young children

Rotavirus A genotype G1P[8]: a novel method to distinguish wild-type strains from the Rotarix® vaccine strain

Rotaviruses are important enteric pathogens for humans and animals. Group A rotaviruses (RV-A) are the most common agents of severe gastroenteritis in infants and young children and vaccination is the most effective method to reduce RV-A-associated diseases. G1P[8], the most prevalent RV-A genotype worldwide, is included in the RV-A vaccine Rotarix®. The discrimination between wild-type G1P[8] and vaccine G1P[8] strains is an important topic in the study of RV-A epidemiology to manage outbreaks and to define control measures for vac- cinated children. In this study, we developed a novel method to segregate the wild-type and vaccine strains using restriction endonucleases. The dsRNA from the Rotarix® vaccine was sequenced and the NSP3 gene was selected as the target gene. The vaccine strain has a restriction pattern that is different than that of wild-type RV-A G1P[8] isolates after digestion with the restriction endonuclease BspHI. This pattern could be used as a marker for the differentiation of wild-type G1P[8] strains from the vaccine strain

Phylogenetic prediction of cis-acting elements: a <it>cre</it>-like sequence in Norovirus genome?

Abstract Background Discrete RNA structures such as cis-acting replication elements (cre) in the coding region of RNA virus genomes create characteristic suppression of synonymous site variability (SSSV). Different phylogenetic methods have been developed to predict secondary structures in RNA viruses, for high-resolution thermodynamic scanning and for detecting SSSV. These approaches have been successfully in predicting cis-acting signals in different members of the family Picornaviridae and Caliciviridae. In order to gain insight into the identification of cis-acting signals in viruses whose mechanisms of replication are currently unknown, we performed a phylogenetic analysis of complete genome sequences from 49 Human Norovirus (NoV) strains. Findings The complete coding sequences of NoV ORF1 were obtained from the DDBJ database and aligned. Shannon entropy calculations and RNAalifold consensus RNA structure prediction identified a discrete, conserved, invariant sequence region with a characteristic AAACG cre motif at positions 240 through 291 of the RNA dependant RNA polymerase (RdRp) sequence (relative to strain [EMBL:EU794713]). This sequence region has a high probability to conform a stem-loop. Conclusion A new predicted stem-loop has been identified near the 5' end of the RdRp of Human NoV genome. This is the same location recently reported for Hepatovirus cre stem-loop.</p

Etiologia de exantema em crianças em uma área endêmica de dengue Etiology of exanthema in children in a dengue endemic area

OBJETIVO: Estudar a etiologia dos casos de exantema com ou sem febre em crianças atendidas no pronto-socorro de um hospital de uma zona endêmica para dengue. MÉTODOS: No período de 21/09/2001 a 20/09/2002, foram inscritas no estudo 95,9% (71/74) das crianças atendidas no pronto-socorro do Hospital Universitário de Campo Grande (MS) que apresentassem exantema (percentual de recusa de 4,1%). Após preenchimento do protocolo com os dados das crianças, as mesmas foram submetidas a exame físico seguido da coleta de amostras de sangue para realizar hemograma com contagem de plaquetas e sorologias (IgM e IgG); inicialmente para dengue, rubéola e toxoplasmose e, posteriormente, naqueles casos com resultado negativo, realizou-se sorologia para parvovirose, herpes vírus tipo 6 e sarampo. RESULTADOS: O diagnóstico laboratorial foi confirmado através da pesquisa de anticorpo IgM em 88,7% dos casos investigados: dengue (77,5%), herpes vírus tipo 6 (8,4%), parvovirose (2,8%) e diagnóstico inconclusivo em oito pacientes (11,3%). Não foi evidenciada sorologia positiva (IgM) para sarampo, rubéola ou toxoplasmose naquela ocasião. As manifestações clínicas mais freqüentes nos pacientes com dengue foram: febre, prurido, prostração, mialgia e prova do laço positiva. Nos pacientes cujo diagnóstico foi dengue, a prova do laço foi positiva em 58,4% (32/55) dos casos, demonstrando diferença estatisticamente significativa quando comparada com o grupo cujo diagnóstico não foi dengue. CONCLUSÕES: Nas crianças com exantema, dengue pode ser a principal enfermidade causal, atentando-se para a epidemiologia do local. É necessário um controle constante da vigilância epidemiológica e sorológica das doenças exantemáticas.<br>OBJECTIVE: To study the etiology of exanthema cases, with or without fever, in children seen in the emergency room of a hospital located in a region where dengue is endemic. METHODS: Enrollment took place between 21/09/2001 and 20/09/2002 and included 95.9% (71/74) of children presenting with exanthema at the emergency room of the Hospital Universitário de Campo Grande, MS (4.1% refusals). After the children had had their details taken and entered on the study protocol, they were subjected to physical examination followed by collection of blood samples for blood testing with platelet counts and serology (IgM and IgG); initially for dengue, rubella and toxoplasmosis and then, in negative cases, serology was also run for parvovirus, herpes virus type 6 and measles. RESULTS: Laboratory diagnoses were confirmed by means of IgM antibody assay in 88.7% of the cases investigated: dengue (77.5%), herpes virus type 6 (8.4%), parvovirus (2.8%) and in eight patients diagnosis was inconclusive (11.3%). On this occasion no positive serology (IgM) was observed for measles, rubella or toxoplasmosis. The most common clinical manifestations among the dengue patients were: fever, itching, prostration, myalgia and positive tourniquet test results. In 58.4% (32/55) of those cases diagnosed with dengue, the tourniquet test was positive, which was a statistically significant difference when compared with the remainder of the sample. CONCLUSIONS: When children present with exanthema, it is possible that dengue is the primary causative disease, depending on the epidemiology of the location. Constant control of epidemiological and serological surveillance of exanthematous diseases is necessary

Rapid Subtyping of Dengue Virus Serotypes 1 and 4 by Restriction Site-Specific PCR

We previously reported a simple subtyping method, restriction site-specific PCR (RSS-PCR), for dengue virus serotypes 2 and 3; here we describe its application for subtyping dengue virus serotypes 1 and 4. Three major RSS-PCR types were observed for dengue virus serotype 1 and two types were observed for dengue virus serotype 4, in agreement with previous strain classifications based on sequence analysis. Because of its simplicity, this method is amenable to rapid subtyping and application to epidemiological studies of dengue in countries where dengue is endemic