RESUMO
Rotavirus A strains detected in diarrhoeal children commonly possess any one of the genotypes G1, G2, G3, G4, and G9, with a recent increase in G12 detection globally. G12P[6] strains possessing short RNA (DS-1-like) and long RNA (Wa-like) migration patterns accounted for 27 % of the strains circulating in Blantyre, Malawi, between 2007 and 2008. To understand how the G12P[6] strains with two distinct genetic backgrounds emerged in Malawi, we conducted whole-genome analysis of two long-RNA and two short-RNA strains. While the former had a typical Wa-like genotype constellation of G12-P[6]-I1-R1-C1-M1-A1-N1-T1-E1-H1, the latter was found to have G12-P[6]-I2-R2-C2-M1-A2-N2-T2-E2-H2: a VP3 gene mono-reassortant on the DS-1-like backbone. Phylogenetic and Bayesian Markov chain Monte Carlo analyses showed that the short-RNA G12P[6] strains were generated around 2006 by reassortment between an African Wa-like G12P[6] strain donating three genes (the VP7, VP4, and VP3 genes) and a G2P[4] strain similar to the one circulating in Thailand or the United States of America that donated the remaining eight genes. On the other hand, the long-RNA strains were generated as a result of reassortment events within Wa-like G12 and non-G12 strains commonly circulating in Africa; only the VP4 gene was from a Malawian G8P[6] strain. In conclusion, this study uncovered the evolutionary pathways through which two distinct G12P[6] strains emerged in Malawi.
Assuntos
Genoma Viral , Genótipo , RNA Viral/genética , Infecções por Rotavirus/virologia , Rotavirus/isolamento & purificação , Análise por Conglomerados , Evolução Molecular , Humanos , Malaui , Filogenia , Vírus Reordenados/genética , Rotavirus/classificação , Rotavirus/genética , Análise de Sequência de DNA , Homologia de SequênciaRESUMO
Rotavirus vaccines work better in developed countries than in developing countries, leading to the question of whether the circulating strains are different in these two settings. In 2008, a clinical trial of the pentavalent rotavirus vaccine was performed in Nha Trang, Vietnam, in which the efficacy was reported to be 64 %. Although samples were collected independently from the clinical trial, we examined faecal specimens from children hospitalised for rotavirus diarrhoea and found that G3P[8] and G1P[8] were co-dominant at the time of the clinical trial. The aim of this study was to explore whether they were divergent from the strains circulating in the developed countries where the vaccine efficacy is high. Two G3P[8] and two G1P[8] strains that were regarded as representatives based on their electropherotypes were selected for full-genome sequencing. The genotype constellation was G1/G3-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1. All but the VP4 genes, one of which belonged to the emerging P[8]b genotype (OP354-like VP4), clustered into one or more lineages/alleles with the strains circulating in developed countries, with ≥97.5 % nucleotide sequence identity. Additionally, 10 G1 and 12 G3 VP7 sequences as well as 31 VP4 sequences were determined. No amino acid differences were observed between the Vietnamese strains and strains in the developed countries that were likely to have affected the neutralisation specificity of their VP7 and VP4. In conclusion, apart from prevalent P[8]b VP4, virtually no differences were observed between the predominant strains circulating in Vietnam at the time of the clinical trial and the strains in the developed countries; hence, the lower vaccine efficacy was more likely to be due to factors other than strain divergence.
Assuntos
Infecções por Rotavirus/prevenção & controle , Vacinas contra Rotavirus/imunologia , Rotavirus/isolamento & purificação , Antígenos Virais/genética , Antígenos Virais/metabolismo , Proteínas do Capsídeo/genética , Proteínas do Capsídeo/metabolismo , Genótipo , Humanos , Modelos Moleculares , Filogenia , Conformação Proteica , Rotavirus/classificação , Rotavirus/genética , Infecções por Rotavirus/epidemiologia , Infecções por Rotavirus/virologia , Vietnã/epidemiologiaRESUMO
An apparently single rotavirus A strain possessing a genotype constellation of G8-P[8]-I2-R2-C2-M2-A2-N2-T2-E2-H2 abruptly emerged, caused diarrhoea in children requiring hospitalisation, and increased to reach 27 % of strains detected during the first half of 2015 in Vietnam.
Assuntos
Surtos de Doenças , Genótipo , Recombinação Genética , Infecções por Rotavirus/epidemiologia , Infecções por Rotavirus/virologia , Rotavirus/classificação , Rotavirus/isolamento & purificação , Análise por Conglomerados , Gastroenterite/epidemiologia , Gastroenterite/virologia , Humanos , Dados de Sequência Molecular , Filogenia , RNA Viral/genética , Rotavirus/genética , Análise de Sequência de DNA , Homologia de Sequência , Vietnã/epidemiologiaRESUMO
BACKGROUND: The diagnosis of TB requires multiple visits. Reducing the number of visits for diagnosis could make the process more accessible, with significant savings to the patients. OBJECTIVE: To describe direct costs incurred by patients consulting TB diagnostic centres. METHOD: Adults with cough >3 weeks' duration were interviewed using structured questionnaires in Yemen and Nepal to quantify their expenses. RESULTS: A total of 456 adults were interviewed. Most patients were accompanied, and 20% were smear-positive. Patients in Nepal were more likely to be male, to live in urban areas and were older (123/206 [60%], 152 [74%] and mean age 41 years) than in Yemen (120/250 [48%], 114 [36%] and mean age 35 years). Although most patients from rural areas stayed with relatives, their overall expenses were higher than for patients from urban areas. Clinic fees represented the highest expenditure in both countries, and rural patients paid more than urban patients in both settings. The expenses for diagnosis were equivalent to 1 week of the national income per capita. CONCLUSION: Patients incur considerable costs for diagnosis, and clinic fees represent a substantial component of these costs. Patients requiring investigations for TB should be able to access diagnostic services free of charge.