RESUMO
Human immunodeficiency virus type 1 (HIV-1) variants show considerable geographical separation across the world, but there is limited information from Central America. We provide the first detailed investigation of the genetic diversity and molecular epidemiology of HIV-1 in six Central American countries. Phylogenetic analysis was performed on 625 HIV-1 pol gene sequences collected between 2002 and 2010 in Honduras, El Salvador, Nicaragua, Costa Rica, Panama, and Belize. Published sequences from neighboring countries (n = 57) and the rest of the world (n = 740) were included as controls. Maximum likelihood methods were used to explore phylogenetic relationships. Bayesian coalescence-based methods were used to time HIV-1 introductions. Nearly all (98.9%) Central American sequences were of subtype B. Phylogenetic analysis revealed that 437 (70%) sequences clustered within five significantly supported monophyletic clades formed essentially by Central American sequences. One clade contained 386 (62%) sequences from all six countries; the other four clades were smaller and more country specific, suggesting discrete subepidemics. The existence of one large well-supported Central American clade provides evidence that a single introduction of HIV-1 subtype B in Central America accounts for most current cases. An introduction during the early phase of the HIV-1 pandemic may explain its epidemiological success. Moreover, the smaller clades suggest a subsequent regional spread related to specific transmission networks within each country.
Assuntos
Evolução Molecular , Variação Genética , Infecções por HIV/epidemiologia , Infecções por HIV/virologia , HIV-1/genética , Filogenia , Sequência de Bases , Teorema de Bayes , América Central/epidemiologia , Infecções por HIV/transmissão , HIV-1/classificação , Humanos , Funções Verossimilhança , Modelos Genéticos , Epidemiologia Molecular , Dados de Sequência Molecular , Prevalência , Alinhamento de Sequência , Análise de Sequência de DNA , Produtos do Gene pol do Vírus da Imunodeficiência Humana/genéticaRESUMO
The World Health Organization currently does not recommend the use of dried blood spot specimens for drug resistance testing in patients undergoing antiretroviral therapy (ART). Therefore, HIV-1 resistance testing using peripheral blood mononuclear cells (PBMCs) may be of value in resource-limited settings. We compared genotypic resistance profiles in plasma and PBMCs from patients failing ART in two cities of Honduras (Tegucigalpa and San Pedro Sula), a resource-limited country. One hundred patients failing ART were randomly selected from a longitudinal patient monitoring cohort. Plasma and PBMC samples without patient identifier were used for genotypic resistance testing. Sequence data were analyzed, resistance profiles were determined and compared using Stanford HIV Drug Resistance Database algorithm. Specimens with concordant resistance profiles between the two compartments were 88% (95% CI: 80.3% - 94.5 %). Nine specimens (12%, 95% CI: 6.5% - 21.3%) had discordant resistance profiles of clinical significance. Logistic regression analyses indicated that patients on triple therapy were 17.24 times more likely to have concordant drug resistance profile than those on non-triple therapies (OR=17.24, 95% CI: 3.48, 83.33), while patients with increasing number of regimens and years on ART have a decreased rate of concordance (OR = 0.59, 95% CI: 0.32, 1.09 and OR = 0.62, 95% CI: 0.43, 0.88), respectively, than those with less number of regimens and years on ART. Our results show high level of concordance between plasma and PBMC resistance profiles, indicating the possibility of using PBMCs for drug resistance testing in resources-limited settings.
RESUMO
Human respiratory syncytial virus (HRSV) is a major cause of viral lower respiratory tract infections among infants and young children. HRSV strains vary genetically and antigenically and have been classified into two broad subgroups, A and B (HRSV-A and HRSV-B, respectively). To date, little is known about the circulating strains of HRSV in Latin America. We have evaluated the genetic diversity of 96 HRSV strains by sequencing a variable region of the G protein gene of isolates collected from 2007 to 2009 in Central and South America. Our results show the presence of the two antigenic subgroups of HRSV during this period with the majority belonging to the genotype HRSV-A2.
Assuntos
Vírus Sinciciais Respiratórios/isolamento & purificação , Animais , Sequência de Bases , Linhagem Celular , América Central , Primers do DNA , Humanos , Filogenia , Vírus Sinciciais Respiratórios/química , Reação em Cadeia da Polimerase Via Transcriptase Reversa , América do SulRESUMO
Antiretroviral therapy has had a great impact on the prevention of mother-to-child transmission (MTCT) of HIV-1. However, development of drug resistance, which could be subsequently transmitted to the child, is a major concern. In Honduras and Belize the prevalence of drug resistance among HIV-1-infected children remains unknown. A total of 95 dried blood spot samples was obtained from HIV-1-infected, untreated children in Honduras and Belize born during 2001 to 2004, when preventive antiretroviral therapy was often suboptimal and consisted of monotherapy with nevirapine or zidovudine. Partial HIV-1 pol gene sequences were successfully obtained from 66 children (Honduras n=55; Belize n=11). Mutations associated with drug resistance were detected in 13% of the Honduran and 27% of the Belizean children. Most of the mutations detected in Honduras (43%) and all mutations detected in Belize were associated with resistance to nonnucleoside reverse transcriptase inhibitors, which was expected from the wide use of nevirapine to prevent MTCT during the study period. In addition, although several mothers reported that they had not received antiretroviral therapy, mutations associated with resistance to nucleoside reverse transcriptase inhibitors and protease inhibitors were found in Honduras. This suggests prior and unreported use of these drugs, or that these women had been infected with resistant virus. The present study demonstrates, for the first time, the presence of drug resistance-associated mutations in HIV-1-infected Honduran and Belizean children.
Assuntos
Farmacorresistência Viral Múltipla , Infecções por HIV/tratamento farmacológico , HIV-1/efeitos dos fármacos , Mutação , RNA Viral/sangue , Fármacos Anti-HIV/farmacologia , Sequência de Bases , Belize/epidemiologia , Estudos de Coortes , Feminino , Infecções por HIV/sangue , Infecções por HIV/epidemiologia , Infecções por HIV/transmissão , Infecções por HIV/virologia , HIV-1/classificação , HIV-1/genética , HIV-1/patogenicidade , Honduras/epidemiologia , Humanos , Lactente , Recém-Nascido , Masculino , Dados de Sequência Molecular , Nevirapina/farmacologia , Filogenia , Gravidez , Prevalência , RNA Viral/genética , Inibidores da Transcriptase Reversa/farmacologia , Zidovudina/farmacologia , Produtos do Gene pol do Vírus da Imunodeficiência Humana/genéticaRESUMO
Since the first detection of swine origin virus (SOIV) on March 28, 2009, the virus has spread worldwide and oseltamivir-resistant strains have already been identified in the past months. Here, we show the phylogenetic analysis of 63 SOIV isolates from eight countries in Central and South America, and their sensitivity to oseltamivir.
Assuntos
Vírus da Influenza A Subtipo H1N1/genética , Animais , América Central , Humanos , América do Sul , SuínosRESUMO
The humoral immune response in Honduran dengue hemorrhagic fever (DHF) hospitalized pediatric cases from the epidemics of 2004 and 2005 was studied in sera collected from 5 to 7 days of fever onset. A total of 145 cases were included in the study: 40 classified as primary with DHF Grade I or II and 86 classified as secondary; from them, 73 were DHF Grade I or II and 13 were dengue shock syndrome (DSS) Grade III or IV. The highest number of primary cases was found in children < 1 year of age. The highest number of secondary cases was observed in children between 5 and 10 years of age. The IgA values showed a statistically significant difference between primary and secondary groups. The relationship between antibody responses and severity grade is discussed. This is the first study related to the humoral immune response and severity grade in DHF cases in Honduran children.
Assuntos
Anticorpos Antivirais/biossíntese , Vírus da Dengue/imunologia , Dengue Grave/epidemiologia , Dengue Grave/imunologia , Adolescente , Anticorpos Antivirais/sangue , Criança , Pré-Escolar , Surtos de Doenças , Feminino , Honduras/epidemiologia , Humanos , Imunoglobulina A/sangue , Imunoglobulina M/sangue , Lactente , Masculino , Dengue Grave/sangueRESUMO
Proper sampling is essential to characterize the molecular epidemiology of human immunodeficiency virus (HIV). HIV sampling frames are difficult to identify, so most studies use convenience samples. We discuss statistically valid and feasible sampling techniques that overcome some of the potential for bias due to convenience sampling and ensure better representation of the study population. We employ a sampling design called stratified cluster sampling. This first divides the population into geographical and/or social strata. Within each stratum, a population of clusters is chosen from groups, locations, or facilities where HIV-positive individuals might be found. Some clusters are randomly selected within strata and individuals are randomly selected within clusters. Variation and cost help determine the number of clusters and the number of individuals within clusters that are to be sampled. We illustrate the approach through a study designed to survey the heterogeneity of subtype B strains in Honduras.