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1.
J Med Virol ; 88(5): 746-53, 2016 May.
Artigo em Inglês | MEDLINE | ID: mdl-26400063

RESUMO

In Taiwan, although the coverage rate of two doses of measles-containing vaccine has been maintained at over 95% since 2001, measles outbreaks occurred in 2002, 2009, and 2011. The present study reports that 43 cases were confirmed by laboratory testing in Taiwan in 2012-2014 and that adults have emerged as one of groups susceptible to measles virus (MV) infection, who may have discrepant humoral immune reactions--indicated by the level of IgM and IgG antibodies compared to a naïve, susceptible measles case. Thirty-seven of 43 cases confirmed by RT-PCR were further characterized by genotyping. In Taiwan, genotype H1 was the major strain in circulation prior to 2010, while D9 was the most frequently detected MV genotype between 2010 and 2011. The genotyping data collected between 2012 and 2014 revealed that H1 rebounded in 2012 after an absence in 2011 and was imported from China and Vietnam. In 2014, genotype B3 first appeared in Taiwan following import from the Philippines and became the most frequently detected strain. Genotype D8, linked to importation from various countries, including India, Indonesia, Thailand, and Vietnam, showed sequence divergence. D9 was imported from Malaysia in 2014. The MV genotypes detected in Taiwan reflected the genotypes of circulating endemic measles strains in neighboring countries. A significant rise in the number of measles cases and in measles with genotypes imported from surrounding countries indicated that measles resurged in Asia in 2014.


Assuntos
Genótipo , Sarampo/epidemiologia , Sarampo/imunologia , Morbillivirus/classificação , Morbillivirus/genética , Adulto , Anticorpos Antivirais/sangue , Pré-Escolar , Monitoramento Epidemiológico , Feminino , Variação Genética , Técnicas de Genotipagem , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Lactente , Masculino , Sarampo/virologia , Pessoa de Meia-Idade , Epidemiologia Molecular , Morbillivirus/isolamento & purificação , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Taiwan/epidemiologia , Adulto Jovem
2.
J Epidemiol ; 26(4): 216-23, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26639752

RESUMO

BACKGROUND: The causative pathogen is rarely identified in the emergency department (ED), since the results of cultures are usually unavailable. As a result, antimicrobial treatment may be overused. The aim of our study was to investigate the pathogens, risk factors of acute gastroenteritis, and predictors of acute bacterial gastroenteritis in the ED. METHODS: We conducted a matched case-control study of 627 stool samples and 612 matched pairs. RESULTS: Viruses (41.3%) were the leading cause of gastroenteritis, with noroviruses (32.2%) being the most prevalent, followed by bacteria (26.8%) and Giardia lamblia (12.4%). Taking antacids (adjusted odds ratio [aOR] 4.10; 95% confidence interval [CI], 2.57-6.53), household members/classmates with gastroenteritis (aOR 4.69; 95% CI, 2.76-7.96), attending a banquet (aOR 2.29; 95% CI, 1.64-3.20), dining out (aOR 1.70; 95% CI, 1.13-2.54), and eating raw oysters (aOR 3.10; 95% CI, 1.61-5.94) were highly associated with gastroenteritis. Elders (aOR 1.04; 05% CI, 1.02-1.05), those with CRP >10 mg/L (aOR 2.04; 95% CI, 1.15-3.62), or those who were positive for fecal leukocytes (aOR 2.04; 95% CI, 1.15-3.62) or fecal occult blood (aOR 1.97; 95% CI, 1.03-3.77) were more likely to be hospitalized in ED. In addition, presence of fecal leukocytes (time ratio [TR] 1.22; 95% CI, 1.06-1.41), abdominal pain (TR 1.20; 95% CI, 1.07-1.41), and frequency of vomiting (TR 0.79; 95% CI, 0.64-0.98) were significantly associated with the duration of acute gastroenteritis. Presence of fecal leukocytes (aOR 2.08; 95% CI, 1.42-3.05), winter season (aOR 0.45; 95% CI, 0.28-0.74), frequency of diarrhea (aOR 1.69; 95% CI, 1.01-2.83), and eating shrimp or crab (aOR 1.53; 95% CI, 1.05-2.23) were highly associated with bacterial gastroenteritis. The area under the receiver operating characteristic curve of the final model was 0.68 (95% CI, 0.55-0.63). CONCLUSIONS: Acute bacterial gastroenteritis was highly associated with season, frequency of diarrhea, frequency of vomiting, and eating shrimp or crab.


Assuntos
Serviço Hospitalar de Emergência , Gastroenterite/epidemiologia , Gastroenterite/etiologia , Doença Aguda , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Infecções Bacterianas/diagnóstico , Infecções Bacterianas/epidemiologia , Estudos de Casos e Controles , Testes Diagnósticos de Rotina , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Admissão do Paciente , Fatores de Risco , Taiwan/epidemiologia , Adulto Jovem
3.
J Infect Dis ; 211(2): 249-57, 2015 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-25124927

RESUMO

BACKGROUND: Patients contracting influenza A(H7N9) infection often developed severe disease causing respiratory failure. Neuraminidase (NA) inhibitors (NAIs) are the primary option for treatment, but information on drug-resistance markers for influenza A(H7N9) is limited. METHODS: Four NA variants of A/Taiwan/1/2013(H7N9) virus containing a single substitution (NA-E119V, NA-I222K, NA-I222R, or NA-R292K) recovered from an oseltamivir-treated patient were tested for NAI susceptibility in vitro; their replicative fitness was evaluated in cell culture, mice, and ferrets. RESULTS: NA-R292K led to highly reduced inhibition by oseltamivir and peramivir, while NA-E119V, NA-I222K, and NA-I222R caused reduced inhibition by oseltamivir. Mice infected with any virus showed severe clinical signs with high mortality rates. NA-I222K virus was the most virulent in mice, whereas virus lacking NA change (NA-WT) and NA-R292K virus seemed the least virulent. Sequence analysis suggests that PB2-S714N increased virulence of NA-I222K virus in mice; NS1-K126R, alone or in combination with PB2-V227M, produced contrasting effects in NA-WT and NA-R292K viruses. In ferrets, all viruses replicated to high titers in the upper respiratory tract but produced only mild illness. NA-R292K virus, showed reduced replicative fitness in this animal model. CONCLUSIONS: Our data highlight challenges in assessment of the replicative fitness of H7N9 NA variants that emerged in NAI-treated patients.


Assuntos
Antivirais/uso terapêutico , Farmacorresistência Viral , Subtipo H7N9 do Vírus da Influenza A/efeitos dos fármacos , Influenza Humana/tratamento farmacológico , Influenza Humana/virologia , Oseltamivir/uso terapêutico , Animais , Modelos Animais de Doenças , Furões , Humanos , Subtipo H7N9 do Vírus da Influenza A/enzimologia , Subtipo H7N9 do Vírus da Influenza A/genética , Subtipo H7N9 do Vírus da Influenza A/isolamento & purificação , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Proteínas Mutantes/genética , Mutação de Sentido Incorreto , Neuraminidase/genética , Infecções por Orthomyxoviridae/patologia , Infecções por Orthomyxoviridae/virologia , Proteínas Virais/genética , Cultura de Vírus , Replicação Viral
4.
J Med Virol ; 87(9): 1462-70, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25946552

RESUMO

In 2012, a new norovirus GII.4 variant (GII.4 Sydney) emerged and caused the majority of the acute gastroenteritis outbreaks in Australia, Asia, Europe, and North America. We examined the epidemiologic and molecular virologic characteristics of reported acute gastroenteritis outbreaks determined to be caused by norovirus in Taiwan from January 2012 to December 2013. A total of 253 (45.7%) of 552 reported acute gastroenteritis outbreaks tested positive for norovirus, of which 165 (65.5%) were typed as GII.4 Sydney. GII.4 Sydney outbreaks were reported from all geographic areas of Taiwan and occurred most frequently in schools (35.8%) and long-term care facilities (24.2%). Person-to-person transmission was identified in 116 (70.3%) of the outbreaks. Phylogenetic analyses of full-length ORF2 of eight specimens indicated that GII.4 Sydney strains detected in Taiwan were closely related to strains detected globally. Continued outbreak surveillance and strain typing are needed to provide information on epidemiologic and virologic trends of novel norovirus strains.


Assuntos
Infecções por Caliciviridae/epidemiologia , Infecções por Caliciviridae/virologia , Surtos de Doenças , Norovirus/classificação , Norovirus/genética , Infecções por Caliciviridae/transmissão , Fezes/virologia , Gastroenterite/virologia , Genótipo , Humanos , Norovirus/isolamento & purificação , Norovirus/patogenicidade , Filogenia , Análise de Sequência de DNA , Taiwan/epidemiologia , Fatores de Tempo
5.
J Formos Med Assoc ; 114(6): 546-52, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25715998

RESUMO

BACKGROUND/PURPOSE: An E1/226V variant Chikungunya virus (CHIKV) efficiently transmitted by Aedes albopictus to humans poses a significant threat to public health for those areas with the presence of Aedes albopictus, including Taiwan. METHODS: We infected three imported CHIKV isolates including the E1/226V variant with Ae. albopictus and Aedes aegypti in the laboratory to understand the disease risk. Viral RNA was measured by real time reverse transcription polymerase chain reaction. RESULTS: The viral susceptibility varied by virus strain and mosquito species and strain. The Asian virus strain started to replicate at 5-6 days post infection (dpi) with the maximum virus yield, ranging from 10(3.63) to 10(3.87) at 5-10 dpi in both species. The variant CHIKV Central/East/South African (CESA) virus genotype replicated earlier at 1 dpi with the maximum virus yield ranging from 10(5.63) to 10(6.52) at 3-6 dpi in Ae. albopictus females while the nonvariant virus strain replicated at 1-2 dpi with the maximum virus yield ranging from 10(5.51) to 10(6.27) at 6-12 dpi. In Ae. aegypti, these viruses replicated at 1-2 dpi, with maximum yields at 4-5 dpi (range from 10(5.38) to 10(5.62)). CONCLUSION: We concluded that the risk of CHIKV in Taiwan is high in all distribution areas of Ae. aegypti and Ae. albopictus for the CESA genotype and that the E1/226V variant virus strain presents an even higher risk.


Assuntos
Aedes/virologia , Vírus Chikungunya/genética , Animais , Feminino , RNA Viral/isolamento & purificação , Taiwan
6.
Emerg Infect Dis ; 20(5): 857-60, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24750594

RESUMO

Six persons in Taiwan who had contact with poultry infected with influenza A(H5N2) showed seroconversion for the virus by hemagglutinin inhibition or microneutralization testing. We developed an ELISA based on nonstructural protein 1 of the virus to differentiate natural infection from cross-reactivity after vaccination; 2 persons also showed seroconversion by this test.


Assuntos
Anticorpos Antivirais/imunologia , Vírus da Influenza A Subtipo H5N2/imunologia , Influenza Humana/imunologia , Animais , Anticorpos Antivirais/sangue , Galinhas , Reações Cruzadas , Ensaio de Imunoadsorção Enzimática , Humanos , Influenza Aviária/virologia , Influenza Humana/transmissão , Aves Domésticas , Doenças das Aves Domésticas/virologia , Taiwan , Proteínas não Estruturais Virais/imunologia
7.
J Clin Microbiol ; 52(1): 76-82, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24153120

RESUMO

New variants of the influenza A(H1N1)pdm09 and A(H3N2) viruses were detected in Taiwan between 2012 and 2013. Some of these variants were not detected in clinical specimens using a common real-time reverse transcription-PCR (RT-PCR) assay that targeted the conserved regions of the viral matrix (M) genes. An analysis of the M gene sequences of the new variants revealed that several newly emerging mutations were located in the regions where the primers or probes of the real-time RT-PCR assay bind; these included three mutations (G225A, T228C, and G238A) in the A(H1N1)pdm09 virus, as well as one mutation (C163T) in the A(H3N2) virus. These accumulated mismatch mutations, together with the previously identified C154T mutation of the A(H1N1)pdm09 virus and the C153T and G189T mutations of the A(H3N2) virus, result in a reduced detection sensitivity for the real-time RT-PCR assay. To overcome the loss of assay sensitivity due to mismatch mutations, we established a real-time RT-PCR assay using degenerate nucleotide bases in both the primers and probe and successfully increased the sensitivity of the assay to detect circulating variants of the human influenza A viruses. Our observations highlight the importance of the simultaneous use of different gene-targeting real-time RT-PCR assays for the clinical diagnosis of influenza.


Assuntos
Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Vírus da Influenza A Subtipo H3N2/isolamento & purificação , Influenza Humana/diagnóstico , Mutação , Reação em Cadeia da Polimerase em Tempo Real/métodos , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Proteínas da Matriz Viral/genética , Pareamento Incorreto de Bases , Primers do DNA/genética , Humanos , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H3N2/genética , Influenza Humana/virologia , Técnicas de Diagnóstico Molecular/métodos , Dados de Sequência Molecular , Proteínas Mutantes/genética , Sondas de Oligonucleotídeos/genética , RNA Viral/genética , Sensibilidade e Especificidade , Análise de Sequência de DNA , Taiwan
8.
Open Forum Infect Dis ; 11(1): ofad614, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38192381

RESUMO

Background: The Taiwanese government made a concerted effort to contain a coronavirus disease 2019 (COVID-19) nosocomial outbreak of variant B.1.429, shortly before universal vaccination program implementation. This study aimed to investigate seroprevalence in the highest-risk regions. Methods: Between January and February 2021, we retrieved 10 000 repository serum samples from blood donors to examine for antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid (N) and spike (S) antigens. A positive result was confirmed if anti-N and anti-S antibodies were positive. Overall, 2000 donors residing in the highest-risk district and donating blood in January 2021 were further examined for SARS-CoV-2 RNA. We estimated seroprevalence and compared the epidemic curve between confirmed COVID-19 cases and blood donors with positive antibodies or viral RNA. Results: Twenty-one cases with COVID-19 were confirmed in the nosocomial cluster, with an incidence of 1.27/100 000 in the COVID-affected districts. Among 4888 close contacts of the nosocomial cases, 20 (0.4%) became confirmed cases during isolation. Anti-SARS-CoV-2 was detected in 2 of the 10000 blood donors, showing a seroprevalence of 2/10000 (95% CI, 0.55-7.29). None of the 2000 donors who underwent tests for SARS-CoV-2 RNA were positive. The SARS-CoV-2 infection epidemic curve was observed sporadically in blood donors compared with the nosocomial cluster. Conclusions: In early 2021, an extremely low anti-SARS-CoV-2 seroprevalence among blood donors was observed. Epidemic control measures through precise close contact tracing, testing, and isolation effectively contained SARS-CoV-2 transmission before universal vaccination program implementation.

9.
J Med Virol ; 85(4): 745-53, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23417619

RESUMO

Rubella has been listed as a mandatory notifiable disease in Taiwan since 1988. Because of high coverage rates with an effective vaccine, rubella cases have decreased dramatically in Taiwan since 1994. However, rubella outbreaks still occur due to imported transmission. Five large clusters were detected in Taiwan from 2007 to 2011. In 2007, one cluster was caused by rubella genotype 1E viruses that were imported from Vietnam, whereas another cluster was caused by genotype 2B viruses and was untraceable. In 2008, two clusters were caused by different lineages of genotype 1E viruses that were imported from Malaysia. In 2009, a cluster that was caused by genotype 2B viruses was associated with imported cases from Vietnam. The rubella viruses from 124 confirmed cases from 2005 to 2011 were characterized, and the data revealed that these viruses were distributed in the following four genotypes: 1E (n = 56), 1h (n = 1), 1j (n = 4), and 2B (n = 63). Of these viruses, 93 (75%) were associated with imported cases, and 43 of 56 genotype 1E viruses were associated with imported cases from China, Vietnam, Malaysia, and Indonesia. One genotype 1h virus was imported from Belarus, and three of four genotype 1j viruses were imported from the Philippines. Of 63 rubella genotype 2B viruses, 46 were imported from Vietnam, Thailand, Malaysia, China, Germany, and South Africa. Molecular surveillance allows for the differentiation of circulating rubella viruses and can be used to investigate transmission pathways, which are important to identify the interruption of endemic virus transmission.


Assuntos
Surtos de Doenças , Vírus da Rubéola/genética , Vírus da Rubéola/isolamento & purificação , Rubéola (Sarampo Alemão)/epidemiologia , Rubéola (Sarampo Alemão)/virologia , Adolescente , Adulto , Análise por Conglomerados , Feminino , Variação Genética , Genótipo , Humanos , Masculino , Epidemiologia Molecular , Dados de Sequência Molecular , Filogenia , Vírus da Rubéola/classificação , Análise de Sequência de DNA , Taiwan/epidemiologia , Adulto Jovem
10.
J Med Virol ; 85(6): 1095-9, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23588738

RESUMO

Measles has been controlled effectively in some countries because of high coverage rates with an effective vaccine. However, measles outbreaks still occasionally occur in areas with high vaccine coverage as a result of imported transmission. To identify the sources of measles infection and to determine whether measles cases are part of a single outbreak or due to multiple importations, measles virus (MV) genotyping is required and plays an important role in MV elimination. In Taiwan, genotype H1 of MV was detected most frequently before 2009. From 2006 to 2011, 47 of 48 genotype H1 cases were associated with the imported cases, indicating that genotype H1 was not an endemic genotype in Taiwan after 2006. The distribution of the other genotypes (D3, D4, D5, D8, D9, and G3) detected during 2006-2011 varied by year. Taiwan has a pattern of measles genotypes that is consistent with the elimination of MV and with the absence of endemic genotypes. In this study, the genotypes of 40 cases of MV detected during 2010-2011 were investigated and analyzed. In 2010, the most common genotype changed from H1 (3/40) to D9 (35/40). In 2011, genotype H1 was not detected, and genotype D4 first appeared and was imported from Europe. The dynamic change of detected genotypes of MV in Taiwan is influenced by the activity of a measles control program in WHO regions. This study emphasizes that global synchronous elimination is important for an individual country or area to maintain free from MV.


Assuntos
Surtos de Doenças , Vírus do Sarampo/genética , Sarampo/epidemiologia , Sarampo/prevenção & controle , Vacinação , Adolescente , Adulto , Criança , Pré-Escolar , Genótipo , Humanos , Lactente , Sarampo/genética , Sarampo/imunologia , Vacina contra Sarampo/administração & dosagem , Vírus do Sarampo/classificação , Vírus do Sarampo/isolamento & purificação , Epidemiologia Molecular , Tipagem Molecular , Filogenia , Análise de Sequência de DNA , Taiwan/epidemiologia
11.
J Med Virol ; 85(3): 379-87, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23280715

RESUMO

The early isolated swine-origin influenza A(H1N1)pdm09 viruses were susceptible to oseltamivir; however, there is a concern about whether oseltamivir-resistant influenza A(H1N1)pdm09 viruses will spread worldwide as did the oseltamivir-resistant seasonal influenza A(H1N1) viruses in 2007-2008. In this study, the frequency of oseltamivir resistance in influenza A(H1N1)pdm09 viruses was determined in Taiwan. From May 2009 to April 2011, 1,335 A(H1N1)pdm09-positive cases in Taiwan were tested for the H275Y mutation in the neuraminidase (NA) gene that confers resistance to oseltamivir. Among these, 15 patients (1.1%) were found to be infected with H275Y virus. All the resistant viruses were detected after the patients have received the oseltamivir. The overall monthly ratio of H275Y-harboring viruses ranged between 0% and 2.88%, and the peak was correlated with influenza epidemics. The genetic analysis revealed that the oseltamivir-resistant A(H1N1)pdm09 viruses can emerged from different variants with a great diversity under drug pressure. The ratio of NA/HA activities in different clades of oseltamivir-resistant viruses was reduced compared to those in the wild-type viruses, indicating that the balance of NA/HA in the current oseltamivir-resistant influenza A(H1N1)pdm09 viruses was interfered. It is possible that H275Y-bearing A(H1N1)pdm09 virus has not yet spread globally because it lacks the essential permissive mutations that can compensate for the negative impact on fitness by the H275Y amino acid substitution in NA. Continuous monitoring the evolution patterns of sensitive and resistant viruses is required to respond to possible emergence of resistant viruses with permissive genetic background which enable the wide spread of resistance.


Assuntos
Antivirais/farmacologia , Farmacorresistência Viral , Vírus da Influenza A Subtipo H1N1/efeitos dos fármacos , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Influenza Humana/virologia , Oseltamivir/farmacologia , Antivirais/uso terapêutico , Humanos , Vírus da Influenza A Subtipo H1N1/classificação , Vírus da Influenza A Subtipo H1N1/genética , Influenza Humana/tratamento farmacológico , Dados de Sequência Molecular , Mutação de Sentido Incorreto , Neuraminidase/genética , Oseltamivir/uso terapêutico , RNA Viral/genética , Seleção Genética , Análise de Sequência de DNA , Taiwan , Proteínas Virais/genética
12.
J Med Entomol ; 50(2): 261-9, 2013 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-23540112

RESUMO

Aedes aegypti L. is the primary dengue vector in southern Taiwan. This article is the first report on a large-scale surveillance program to study the spatial-temporal distribution of the local Ae. aegytpi population using ovitraps stratified according to the human population in high dengue-risk areas. The sampling program was conducted for 1 yr and was based on weekly collections of eggs and adults in Kaohsiung City. In total, 10,380 ovitraps were placed in 5,190 households. Paired ovitraps, one indoors and one outdoors were used per 400 people. Three treatments in these ovitraps (paddle-shaped wooden sticks, sticky plastic, or both) were assigned by stratified random sampling to two areas (i.e., metropolitan or rural, respectively). We found that the sticky plastic alone had a higher sensitivity for detecting the occurrence of indigenous dengue cases than other treatments with time lags of up to 14 wk. The wooden paddle alone detected the oviposition of Ae. aegypti throughout the year in this study area. Furthermore, significantly more Ae. aegypti females were collected indoors than outdoors. Therefore, our survey identified the whole year oviposition activity, spatial-temporal distribution of the local Ae. aegypti population and a 14 wk lag correlation with dengue incidence to plan an effectively proactive control.


Assuntos
Aedes/fisiologia , Insetos Vetores/fisiologia , Controle de Mosquitos/métodos , Oviposição , Aedes/parasitologia , Animais , Dengue/epidemiologia , Vírus da Dengue/fisiologia , Feminino , Humanos , Incidência , Insetos Vetores/parasitologia , Masculino , Densidade Demográfica , Estações do Ano , Taiwan/epidemiologia
13.
Angew Chem Int Ed Engl ; 52(1): 366-70, 2013 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-23150231

RESUMO

The wizard of OS (resistance): the binding difference of neuraminidase inhibitors (zanamivir versus oseltamivir (OS)) was used to establish an assay to identify the influenza subtypes that are resistant to OS but still sensitive to zanamivir. This assay used a zanamivir-biotin conjugate to determine the OS susceptibility of a wide range of influenza viruses and over 200 clinical isolates.


Assuntos
Antivirais/química , Antivirais/farmacologia , Oseltamivir/química , Oseltamivir/farmacologia , Ligação Competitiva , Farmacorresistência Viral , Humanos , Vírus da Influenza A Subtipo H1N2/efeitos dos fármacos
14.
Emerg Infect Dis ; 17(8): 1523-6, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21801641

RESUMO

During November 2008-May 2009, an outbreak of 53 measles cases occurred in Taiwan. Of these, 3 cases were sporadic, and the other 50 cases could be grouped into 8 clusters by genetic analysis. We determined 7 H1 genotypes linked to importation and 1 G3 genotype linked to an untraceable source.


Assuntos
Vírus do Sarampo/genética , Sarampo/epidemiologia , Sarampo/prevenção & controle , Viagem , Adulto , Pré-Escolar , Análise por Conglomerados , Surtos de Doenças , Feminino , Genótipo , Humanos , Lactente , Masculino , Sarampo/virologia , Vacina contra Sarampo/administração & dosagem , Vírus do Sarampo/classificação , Vírus do Sarampo/isolamento & purificação , Filogenia , Taiwan/epidemiologia , Vacinação/estatística & dados numéricos
15.
J Med Virol ; 83(7): 1279-87, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21567431

RESUMO

We previously reported the detection of genotype P[19] rotavirus strains from children hospitalized with acute dehydrating diarrhea during a 5-year surveillance period in Taiwan. The characterization of five P[19] strains (0.4% of all typed), including three G3P[19], a novel G5P[19], and a unique G9P[19] genotype is described in this study. Phylogenetic analysis of the VP4, VP7, VP6, and NSP4 genes was performed, which demonstrated novel lineages for respective genotypes of the VP4 and the VP7 genes. The sequence similarities of the P[19] VP4 gene among Taiwanese human strains was higher (nt, 91.5-96.2%; aa, 93.7-97.6%) than to other P[19] strains (nt, 83.5-86.6%; aa, 89.4-94.1%) from different regions of the world. The VP7 gene of the three G3P[19] Taiwanese strains shared up to 93.4% nt and 97.5% aa identity to each other but had lower similarity to reference strain sequences available in GenBank (nt, <90.1%; aa, <95.6%). Similarly, the VP7 gene of the novel G5P[19] strain was only moderately related to the VP7 gene of reference G5 strains (nt, 82.2-87.3%; aa, 87.0-93.1%), while the VP7 gene of the single G9P[19] strain was genetically distinct from other known human and animal G9 rotavirus strains (nt, ≤ 92.0%; aa, ≤ 95.7%). Together, these findings suggest that the Taiwanese P[19] strains originated by independent interspecies transmission events. Synchronized surveillance of human and animal rotaviruses in Taiwan should identify possible hosts of these uncommon human rotavirus strains.


Assuntos
Proteínas do Capsídeo/genética , Diarreia/genética , Genes Virais , Infecções por Rotavirus/genética , Rotavirus , Proteínas não Estruturais Virais/genética , Doença Aguda , Antígenos Virais/genética , Sequência de Bases , Proteínas do Capsídeo/classificação , Criança , Diarreia/epidemiologia , Diarreia/virologia , Fezes/virologia , Genótipo , Humanos , Dados de Sequência Molecular , Filogenia , Polimorfismo Genético , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Rotavirus/classificação , Rotavirus/genética , Rotavirus/isolamento & purificação , Infecções por Rotavirus/epidemiologia , Infecções por Rotavirus/virologia , Análise de Sequência de DNA , Taiwan , Proteínas não Estruturais Virais/classificação
16.
Virol J ; 7: 277, 2010 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-20959020

RESUMO

BACKGROUND: Human enterovirus 71 (EV-71) is known of having caused numerous outbreaks of hand-foot-mouth disease, and other clinical manifestations globally. In 2008, 989 EV-71 strains were isolated in Taiwan. RESULTS: In this study, the genetic and antigenic properties of these strains were analyzed and the genetic diversity of EV-71 subgenogroups surfacing in Taiwan was depicted, which includes 3 previously reported subgenogroups of C5, B5, and C4, and one C2-like subgenogroup. Based on the phylogenetic analyses using their complete genome nucleotide sequences and neutralization tests, the C2-like subgenogroup forms a genetically distinct cluster from other subgenogroups, and the antisera show a maximum of 128-fold decrease of neutralization titer against this subgenogroup. In addition, the subgenogroup C4 isolates of 2008 were found quite similar genetically to the Chinese strains that caused outbreaks in recent years and thus they should be carefully watched. CONCLUSIONS: Other than to be the first report describing the existence of C2-like subgenogroup of EV-71 in Taiwan, this article also foresees a potential of subgenogroup C4 outbreaks in Taiwan in the near future.


Assuntos
Enterovirus Humano A/classificação , Enterovirus Humano A/genética , Infecções por Enterovirus/virologia , Variação Genética , Adolescente , Adulto , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Criança , Pré-Escolar , Análise por Conglomerados , Enterovirus Humano A/imunologia , Enterovirus Humano A/isolamento & purificação , Feminino , Genoma Viral , Humanos , Lactente , Recém-Nascido , Masculino , Dados de Sequência Molecular , Testes de Neutralização , Filogenia , RNA Viral/genética , Análise de Sequência de DNA , Taiwan , Adulto Jovem
17.
J Clin Microbiol ; 47(11): 3714-6, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19741076

RESUMO

A rapid SYBR green I real-time reverse transcription-PCR (RT-PCR) assay was developed to identify pandemic influenza H1N1 virus from clinical specimens in less than 1 h. Probe real-time RT-PCR influenza A/B, H1/H3, and swNP/swHA assays were modified into the same PCR program, which allows for rapid and simultaneous typing and subtyping of influenza viruses.


Assuntos
Vírus da Influenza A Subtipo H1N1/classificação , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Influenza Humana/virologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Benzotiazóis , Diaminas , Humanos , Vírus da Influenza A Subtipo H1N1/genética , Sondas de Oligonucleotídeos/genética , Compostos Orgânicos/metabolismo , Quinolinas , Sensibilidade e Especificidade , Coloração e Rotulagem/métodos , Fatores de Tempo , Proteínas Virais/genética
18.
J Clin Microbiol ; 46(3): 1090-7, 2008 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18174299

RESUMO

We assessed the use of high-resolution melting (HRM) analysis for the rapid identification of influenza A virus subtypes and the detection of newly emerging virus variants. The viral matrix gene was amplified by LightCycler real-time reverse transcription-PCR (RT-PCR) in the presence of the LCGreen I fluorescent dye. Upon optimization of the assay conditions, all the major influenza A virus subtypes, including H1N1, H3N2, H5N1, H7N3, and H9N2, were amplifiable by this method and had a PCR product length of 179 bp. Real-time RT-PCR of in vitro-transcribed H3N2 RNA revealed a standard curve for quantification with a linear range (correlation coefficient = 0.9935) across at least 8 log units of RNA concentrations and a detection limit of 10(3) copies of viral RNA. We performed HRM analysis of the PCR products with the HR-1 instrument and used the melting profiles as molecular fingerprints for virus subtyping. The virus subtypes were identified from the high-resolution derivative plot obtained by heteroduplex formation between the PCR products of the viral isolates tested and those of the reference viral isolates. The melting profiles were consistent with minimal interassay variability. Hence, an HRM database and a working protocol were established for the identification of these five influenza A virus subtypes. When this protocol was used to test 21 clinical influenza A virus isolates, the results were comparable to those obtained by RT-PCR with hemagglutinin-specific primer sets. Sequence variants of the clinical isolates (n = 4) were also revealed by our HRM analytical scheme. This assay requires no multiplexing or hybridization probes and provides a new approach for influenza A virus subtyping and genetic screening of virus variants in a clinical virology laboratory.


Assuntos
Variação Genética , Vírus da Influenza A/classificação , Vírus da Influenza A/isolamento & purificação , Influenza Humana/diagnóstico , Influenza Humana/virologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Temperatura de Transição , Humanos , Vírus da Influenza A/genética , RNA Viral/análise , RNA Viral/isolamento & purificação , Especificidade da Espécie , Fatores de Tempo , Proteínas da Matriz Viral/genética
19.
J Clin Microbiol ; 46(4): 1426-34, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18256223

RESUMO

The genetic characterization of Taiwanese influenza A and B viruses on the basis of analyses of pairwise amino acid variations, genetic clustering, and phylogenetics was performed. A total of 548, 2,123, and 1,336 sequences of the HA1 genes of influenza A virus subtypes H1 and H3 and influenza B virus, respectively, collected during 2003 to 2006 from an island-wide surveillance network were determined. Influenza A virus H3 showed activity during all periods, although it was dominant only in the winters of 2002-2003 and 2003-2004. Instead, influenza B virus and influenza A virus H1 were dominant in the winters of 2004-2005 and 2005-2006, respectively. Additionally, two influenza A virus H3 peaks were found in the summers of 2004 and 2005. From clustering analysis, similar characteristics of high sequence diversity and short life spans for the influenza A virus H1 and H3 clusters were observed, despite their distinct seasonal patterns. In contrast, clusters with longer life spans and fewer but larger clusters were found among the influenza B viruses. We also noticed that more amino acid changes at antigenic sites, especially at sites B and D in the H3 viruses, were found in 2003 and 2004 than in the following 2 years. The only epidemic of the H1 viruses, which occurred in the winter of 2005-2006, was caused by two genetically distinct lineages, and neither of them showed apparent antigenic changes compared with the antigens of the vaccine strain. For the influenza B viruses, the multiple dominant lineages of Yamagata-like strains with large genetic variations observed reflected the evolutionary pressure caused by the Yamagata-like vaccine strain. On the other hand, only one dominant lineage of Victoria-like strains circulated from 2004 to 2006.


Assuntos
Surtos de Doenças , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H3N2/genética , Vírus da Influenza B/genética , Influenza Humana/epidemiologia , Filogenia , Variação Genética , Humanos , Vírus da Influenza A Subtipo H1N1/classificação , Vírus da Influenza A Subtipo H3N2/classificação , Vírus da Influenza B/classificação , Vírus da Influenza B/isolamento & purificação , Influenza Humana/virologia , Dados de Sequência Molecular , Estações do Ano , Análise de Sequência de DNA , Taiwan/epidemiologia
20.
J Clin Microbiol ; 46(2): 785-8, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18032614

RESUMO

We describe the development and evaluation of an indirect immunofluorescence assay (IFA) kit for rapid and sensitive detection of coxsackievirus A2, -4, -5, -6, and -10. This IFA kit was determined to have 95.9 to 100% sensitivity and 95.8 to 97.2% specificity. It also proved to be beneficial in reducing the number of enteroviruses that are untypeable in the clinical virology laboratory.


Assuntos
Infecções por Coxsackievirus/diagnóstico , Infecções por Coxsackievirus/virologia , Enterovirus/classificação , Técnica Indireta de Fluorescência para Anticorpo/métodos , Humanos , Sensibilidade e Especificidade
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