Detection of a Multiple Circulation Event of Dengue Virus 2 Strains in the Northern Region of Brazil.

Dengue virus serotype 2 (DENV-2) is responsible for dengue epidemics on a global scale and is associated with severe cases of the disease. This study conducted a phylogenetic investigation of DENV-2 isolates from 2017 to 2021 originating from the northern states of Brazil. A total of 32 samples from DENV-2 isolates were analyzed, including 12 from Acre, 19 from Roraima, and one from Tocantins. Only one lineage of the Asian-American genotype and one lineage of the cosmopolitan genotype were observed: Lineage 1, Asian-American genotype (connection to Puerto Rico); Lineage 5, cosmopolitan genotype (connection to Peru). Our results provide important data regarding the study of DENV genotypes and lineage distribution and open up possibilities for probable introduction and dissemination routes.

Emergence of a New Strain of DENV-2 in South America: Introduction of the Cosmopolitan Genotype through the Brazilian-Peruvian Border.

Dengue virus 2 (DENV-2) seriously contributes to dengue-related mortality. It includes five nonsylvatic genotypes, with cosmopolitan being the most widespread with a significant contribution to the total number of DENV-2 cases globally. In South America, the cosmopolitan genotype was first recorded in 2019 in Madre de Dios, Peru, and then in Goiás (Midwest Brazil) in November 2021. In this study, we tested 163 human serum samples from Acre (Northern Brazil) collected during a DENV outbreak between 2020 and 2021 for all DENV genotypes by RT-qPCR. Of the 163 samples, 139 were positive for DENV-2, and 5 were positive for DENV-1. Five DENV-2-positive samples from early 2021 were sequenced, and the sequences clustered with the three other DENV-2 cosmopolitan genotype sequences already recorded on the continent. These results create a geographical link, suggesting the possible route of introduction of the DENV-2 cosmopolitan genotype into Brazil through the border with Peru, from which it may have dispersed to Midwest Brazil.

Isolation of Flaviviruses and Alphaviruses with Encephalitogenic Potential Diagnosed by Evandro Chagas Institute (Pará, Brazil) in the Period of 1954-2022: Six Decades of Discoveries.

Viruses with encephalitogenic potential can cause neurological conditions of clinical and epidemiological importance, such as Saint Louis encephalitis virus, Venezuelan equine encephalitis virus, Eastern equine encephalitis virus, Western equine encephalitis virus, Dengue virus, Zika virus, Chikungunya virus, Mayaro virus and West Nile virus. The objective of the present study was to determine the number of arboviruses with neuroinvasive potential isolated in Brazil that corresponds to the collection of viral samples belonging to the Department of Arbovirology and Hemorrhagic Fevers, Evandro Chagas Institute (SAARB/IEC) of the Laboratory Network of National Reference for Arbovirus Diagnosis from 1954 to 2022. In the analyzed period, a total of 1,347 arbovirus samples with encephalitogenic potential were isolated from mice; 5,065 human samples were isolated exclusively by cell culture; and 676 viruses were isolated from mosquitoes. The emergence of new arboviruses may be responsible for diseases still unknown to humans, making the Amazon region a hotspot for infectious diseases due to its fauna and flora species characteristics. The detection of circulating arboviruses with the potential to cause neuroinvasive diseases is constant, which justifies the continuation of active epidemiological surveillance work that offers adequate support to the public health system regarding the virological diagnosis of circulating arboviruses in Brazil.

Evaluation of third-generation RIDASCREEN enzyme immunoassay for the detection of norovirus antigens in stool samples of hospitalized children in Belém, Pará, Brazil.

Noroviruses (NoVs) are major agents of gastroenteritis outbreaks and hospitalization worldwide. This study evaluated the sensitivity and specificity of the commercially available third-generation RIDASCREEN® Norovirus Enzyme Immunoassay (EIA) kit in comparison to the reverse transcription-polymerase chain reaction (RT-PCR) to detect NoVs in hospitalized children with gastroenteritis. An agreement of 88% (81/92) was observed when comparing EIA with RT-PCR. A sensitivity of 92% and a specificity of 83.3% were demonstrated. Eleven samples were positive by 1 method only (4 RT-PCR/7 EIA). Fourteen samples were sequenced and all classified as NoV genogroup GII-4. The 7 positive only by EIA were also evaluated by electron microscopy, and in 3 (42.9%) samples viral particles with a suggestive morphology of NoVs were visualized. These same samples were tested by seminested-RT-PCR with a positivity of 85.7%. The results obtained in this study demonstrated a significant improvement in the sensitivity and specificity of this updated assay.

Detection of corona-like virus in a case of flaccid paraparesis in Belém, Pará State, Brazil / Detecção de virus corona-like em um caso de paraparesia flácida em Belém, Estado do Pará, Brasil

In this study, we analyzed a fecal sample of a female infant with paralysis and other clinical symptoms that resembled poliomyelitis. Negative staining electron microscopy showed viral particles with a diameter of approximately 120 nm and displaying a crown-like appearance with surface projections. Ultrathin sections showed particles budding from the membranes of the Golgi apparatus. Based on these results, we propose the association of this virus with the neurological disorder and tentatively assign it to the Coronaviridae family. Further studies are required on this proposed relationship.

Neste estudo, analisamos uma amostra fecal de criança do sexo feminino com paralisia e outros sintomas clínicos que se assemelharam à poliomielite. A microscopia eletrônica (contrastação negativa) mostrou partículas com 120 nm de diâmetro, exibindo projeções na superfície semelhantes a uma coroa. Cortes ultrafinos mostraram partículas brotando do complexo de Golgi. Com base nesses resultados, propomos a associação deste vírus com o distúrbio neurológico e o associamos provisoriamente à família Coronaviridae. Estudos adicionais são necessários para esclarecer a relação proposta.

Echovirus 30 associated with cases of aseptic meningitis in state of Pará, Northern Brazil.

Investigation of the aetiology of viral meningitis in Brazil is most often restricted to cases that occur in the Southern and Southeastern Regions; therefore, the purpose of this study is to describe the viral meningitis cases that occurred in state of Pará, Northern Brazil, from January 2005-December 2006. The detection of enterovirus (EV) in cerebrospinal fluid was performed using cell culture techniques, RT-PCR, nested PCR and nucleotide sequencing. The ages of the 91 patients ranged from < one year old to > 60 years old (median age 15.90 years). Fever (87.1%), headache (77.0%), vomiting (61.5%) and stiffness (61.5%) were the most frequent symptoms. Of 91 samples analyzed, 18 (19.8%) were positive for EV. Twelve were detected only by RT- PCR followed by nested PCR, whereas six were found by both cell culture and RT-PCR. From the last group, five were sequenced and classified as echovirus 30 (Echo 30). Phylogenetic analyses revealed that Echo 30 detected in Northern Brazil clustered within a unique group with a bootstrap value of 100% and could constitute a new subgroup (4c) according to the phylogenetic tree described by Oberste et al. (1999). This study described the first molecular characterization of Echo 30 in Brazil and this will certainly contribute to future molecular analyses involving strains detected in other regions of Brazil.

Echovirus 30 associated with cases of aseptic meningitis in state of Pará, Northern Brazil

Investigation of the aetiology of viral meningitis in Brazil is most often restricted to cases that occur in the Southern and Southeastern Regions; therefore, the purpose of this study is to describe the viral meningitis cases that occurred in state of Pará, Northern Brazil, from January 2005-December 2006. The detection of enterovirus (EV) in cerebrospinal fluid was performed using cell culture techniques, RT-PCR, nested PCR and nucleotide sequencing. The ages of the 91 patients ranged from < one year old to > 60 years old (median age 15.90 years). Fever (87.1 percent), headache (77.0 percent), vomiting (61.5 percent) and stiffness (61.5 percent) were the most frequent symptoms. Of 91 samples analyzed, 18 (19.8 percent) were positive for EV. Twelve were detected only by RT- PCR followed by nested PCR, whereas six were found by both cell culture and RT-PCR. From the last group, five were sequenced and classified as echovirus 30 (Echo 30). Phylogenetic analyses revealed that Echo 30 detected in Northern Brazil clustered within a unique group with a bootstrap value of 100 percent and could constitute a new subgroup (4c) according to the phylogenetic tree described by Oberste et al. (1999). This study described the first molecular characterization of Echo 30 in Brazil and this will certainly contribute to future molecular analyses involving strains detected in other regions of Brazil.

Prevalence and genetic diversity of astroviruses in children with and without diarrhea in São Luís, Maranhão, Brazil

Human astroviruses (HAstV) have been increasingly identified as important etiological agents of acute gastroenteritis in children up to five years old. The aim of this study was to determine the prevalence and genotype diversity of HAstV in children with symptomatic and asymptomatic infections in São Luís, Maranhão, Brazil. From June 1997 to July 1999 a total of 183 fecal samples 84 from symptomatic and 99 from asymptomatic children were tested by enzyme immunoassay for HAstV. Prevalence rates were found to be 11 and 3 percent for symptomatic and asymptomatic children, respectively. Reverse transcription-polymerase chain reaction (RT-PCR) was carried out in 46 specimens (26 symptomatic and 20 asymptomatic) including the 12 samples that were positive by enzyme immunoassay (EIA). The overall positivity yielded by both methods was 8 percent (15/184); of these, 11 percent (9/84) for symptomatic and 5 percent (5/99) for those without symptoms or signs. Sequence analysis of amplicons revealed that HAstV-1 genotype was the most prevalent, accounting for 60 percent of isolates. Genotypes 2, 3, 4, and 5 were also detected, as one single isolate (10 percent) for each type. Variations in the sequences were observed when Brazilian isolates were compared to prototype strains identified in the United Kingdom. No seasonal pattern of occurrence was observed during these two years of study, and peak detection rate was observed in children aged between 3 and 6 months in the symptomatic group, and between 18 and 24 months in the controls.

Prevalence and genetic diversity of astroviruses in children with and without diarrhea in São Luís, Maranhão, Brazil.

Human astroviruses (HAstV) have been increasingly identified as important etiological agents of acute gastroenteritis in children up to five years old. The aim of this study was to determine the prevalence and genotype diversity of HAstV in children with symptomatic and asymptomatic infections in São Luís, Maranhão, Brazil. From June 1997 to July 1999 a total of 183 fecal samples 84 from symptomatic and 99 from asymptomatic children were tested by enzyme immunoassay for HAstV. Prevalence rates were found to be 11 and 3% for symptomatic and asymptomatic children, respectively. Reverse transcription-polymerase chain reaction (RT-PCR) was carried out in 46 specimens (26 symptomatic and 20 asymptomatic) including the 12 samples that were positive by enzyme immunoassay (EIA). The overall positivity yielded by both methods was 8% (15/184); of these, 11% (9/84) for symptomatic and 5% (5/99) for those without symptoms or signs. Sequence analysis of amplicons revealed that HAstV-1 genotype was the most prevalent, accounting for 60% of isolates. Genotypes 2, 3, 4, and 5 were also detected, as one single isolate (10%) for each type. Variations in the sequences were observed when Brazilian isolates were compared to prototype strains identified in the United Kingdom. No seasonal pattern of occurrence was observed during these two years of study, and peak detection rate was observed in children aged between 3 and 6 months in the symptomatic group, and between 18 and 24 months in the controls.

Prevalência de anticorpos para HTLV-I/II em recém-nascidos, em Belém do Pará / Prevalence of HTLV-I/II antibodies among neonates in Belém, Pará

Introdução: De novembro de 1995 a março de 1996 foram analisados soros de 167 recém-nascidos, de ambos os sexos, com idades inferiores a três meses, provenientes de um estudo longitudinal realizado no Instituto Evandro Chagas (I. E. C.) de abril de 1990 a junho de 1992, para observação de crianças vacinadas contra o rotavírus. Objetivo: Detenninar a prevalência de anticorpos para HTLv-InI em recém-nascidos de Belém, Pará, Brasil. Método: Anticorpos para o vírus linfotrópico de células T humanastipos I ( HTLV -I) e II ( HTLV-II) foram detectados, inicialmente, pelo método imunoenzimático ( ELISA),obtendo-se 9 ( 5,39por cento ) crianças soropositivas. Subseqiientemente, se procedeu à tentativa de confirmaçãodos resultados pela pesquisa de anticorpospelo método de Western Blot (WB). Resultados e considerações finais: Das nove amostras positivas, 1 ( 11por cento) exibiu perfil compatível com resposta para o HTLV-I e 8 ( 89por cento ) resultaram negativas. Com base nesse último procedimento, a prevalência global declinou para 0,6por cento. Esse único recém-nascido reativo por WB era do sexo feminino, com idade de 58 dias, tendo feito uso de leite materno. Uma baixa taxa de prevalência entre os recém-nascidos -portanto, refletindo uma positividade baixa entre as mães -sugere que a infecção pelo HTLV não representa problema de saúde pública relevante em nossa região, pelo menos no segmento populacional estudado. Desta forma, as mães não devem ser estimuladas a se abster da amamentação na tentativa de, eventualmente, prevenir uma possível transmissão vertical do HTLV

Anticorpos para HTLV-I e HTLV-II entre doadores de sangue em Belém, Brasil / HTLV-I and HLTV-II antibodies among blood donors in Belém, Brazil

Amostras de soro obtidas de 379 doadores de sangue do Centro de hemoterapia do Pará (HEMOPA) no período de junho de 1996 a julho de 1998, positivas quanto á presença de anticorpos para o vírus linfotrópico de células T humanas do tipo I (HTLV-I), foram examinadas no Instituto Evandro Chagas (IEC) visando-se a confirmação dos resultados. O exame em duplicata de cada soro, pelo método imunoenzimático (ELISA), exibiu positividade em 112 (29,5 por cento) dos espécimes previamente caracterizados como reativos na triagem inicial. Tais amostras também se revelaram positivas à análise pelo procedimento de Western blot, compreendendo presença de anticorpos para HTLV-I, HTLV-II e reposta indeterminada em 66 (59 por cento), 15 (13,4 por cento) e 31 (27,7 por cento) indivíduos, respectivamente. Observou-se que a presença de anticorpos para HTLV foi nitidamente mais expressiva entre as mulheres (47,2 por cento), se comparadas aos homens (27,8 por cento) (c² = 7,65, p= 0,006). As infecções por HTLV-I e HTLV-II foram registradas em freqüências relativas comparáveis ao longo de todo o período de investigação (c² = 0,66; p=0,42). Os resultados sugerem que (i)o método de ELISA, então utilizado em Belém para triagem dos doadores de sangue em potencial era dotado de especificidade limitada; (ii) as taxas de reação positiva para HILV-II superiores a 10 por cento indicam possível transmissão viral via drogas injetáveis; e (iii) os dados de soroprevalência em relação ao sexo sustentam a maior suscetibilidade das mulheres à infecção