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1.
J Infect Dis ; 2024 Apr 29.
Artículo en Inglés | MEDLINE | ID: mdl-38682164

RESUMEN

BACKGROUND: Nipah virus (NiV), a highly lethal virus in humans, circulates in Pteropus bats throughout South and Southeast Asia. Difficulty in obtaining viral genomes from bats means we have a poor understanding of NiV diversity. METHODS: We develop phylogenetic approaches applied to the most comprehensive collection of genomes to date (N=257, 175 from bats, 73 from humans) from six countries over 22 years (1999-2020). We divide the four major NiV sublineages into 15 genetic clusters. Using Approximate Bayesian Computation fit to a spatial signature of viral diversity, we estimate the presence and the average size of genetic clusters per area. RESULTS: We find that, within any bat roost, there are an average of 2.4 co-circulating genetic clusters, rising to 5.5 clusters at areas of 1500-2000km2. We estimate that each genetic cluster occupies an average area of 1.3million km2 (95%CI: 0.6-2.3 million), with 14 clusters in an area of 100,000km2 (95%CI: 6-24). In the few sites in Bangladesh and Cambodia where genomic surveillance has been concentrated, we estimate that most clusters have been identified, but only ∼15% of overall NiV diversity has been uncovered. CONCLUSION: Our findings are consistent with entrenched co-circulation of distinct lineages, even within roosts, coupled with slow migration over larger spatial scales.

2.
Hum Genomics ; 17(1): 58, 2023 Jul 07.
Artículo en Inglés | MEDLINE | ID: mdl-37420264

RESUMEN

BACKGROUND: Wastewater-based epidemiological surveillance has been considered a powerful tool for early detection and monitoring of the dynamics of SARS-CoV-2 and its lineages circulating in a community. This study is aimed to investigate the complexity of SARS-CoV-2 infection dynamics in Dhaka city by examining its genetic variants in wastewater. Also, the study seeks to determine a connection between the SARS-CoV-2 variations detected in clinical testing and those found in wastewater samples. RESULTS: Out of 504 samples tested in RT-qPCR, 185 (36.7%) tested positive for SARS-CoV-2 viral RNA. The median log10 concentration of SARS-CoV-2 N gene copies/Liter of wastewater (gc/L) was 5.2, and the median log10 concentration of ORF1ab was 4.9. To further reveal the genetic diversity of SARS-CoV-2, ten samples with ORF1ab real-time RT-PCR cycle threshold (Ct) values ranging from 28.78 to 32.13 were subjected to whole genome sequencing using nanopore technology. According to clade classification, sequences from wastewater samples were grouped into 4 clades: 20A, 20B, 21A, 21J, and the Pango lineage, B.1, B.1.1, B.1.1.25, and B.1.617.2, with coverage ranging from 94.2 to 99.8%. Of them, 70% belonged to clade 20B, followed by 10% to clade 20A, 21A, and 21J. Lineage B.1.1.25 was predominant in Bangladesh and phylogenetically related to the sequences from India, the USA, Canada, the UK, and Italy. The Delta variant (B.1.617.2) was first identified in clinical samples at the beginning of May 2021. In contrast, we found that it was circulating in the community and was detected in wastewater in September 2020. CONCLUSION: Environmental surveillance is useful for monitoring temporal and spatial trends of existing and emerging infectious diseases and supports evidence-based public health measures. The findings of this study supported the use of wastewater-based epidemiology and provided the baseline data for the dynamics of SARS-CoV-2 variants in the wastewater environment in Dhaka, Bangladesh.


Asunto(s)
COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/genética , Bangladesh/epidemiología , COVID-19/epidemiología , Vigilancia en Salud Pública , Aguas Residuales , Proteínas del Sistema Complemento , ARN
3.
Emerg Infect Dis ; 29(2): 393-396, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36692447

RESUMEN

Spillovers of Nipah virus (NiV) from Pteropus bats to humans occurs frequently in Bangladesh, but the risk for spillover into other animals is poorly understood. We detected NiV antibodies in cattle, dogs, and cats from 6 sites where spillover human NiV infection cases occurred during 2013-2015.


Asunto(s)
Quirópteros , Infecciones por Henipavirus , Virus Nipah , Humanos , Animales , Perros , Bovinos , Bangladesh/epidemiología , Infecciones por Henipavirus/epidemiología , Infecciones por Henipavirus/veterinaria , Brotes de Enfermedades
4.
Emerg Infect Dis ; 28(7): 1384-1392, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35731130

RESUMEN

Knowledge of the dynamics and genetic diversity of Nipah virus circulating in bats and at the human-animal interface is limited by current sampling efforts, which produce few detections of viral RNA. We report a series of investigations at Pteropus medius bat roosts identified near the locations of human Nipah cases in Bangladesh during 2012-2019. Pooled bat urine was collected from 23 roosts; 7 roosts (30%) had >1 sample in which Nipah RNA was detected from the first visit. In subsequent visits to these 7 roosts, RNA was detected in bat urine up to 52 days after the presumed exposure of the human case-patient, although the probability of detection declined rapidly with time. These results suggest that rapidly deployed investigations of Nipah virus shedding from bat roosts near human cases could increase the success of viral sequencing compared with background surveillance and could enhance understanding of Nipah virus ecology and evolution.


Asunto(s)
Quirópteros , Infecciones por Henipavirus , Virus Nipah , Animales , Bangladesh/epidemiología , Infecciones por Henipavirus/epidemiología , Infecciones por Henipavirus/veterinaria , Humanos , Virus Nipah/genética , ARN Viral/genética
5.
J Clin Lab Anal ; 36(2): e24203, 2022 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-34942043

RESUMEN

BACKGROUND: Globally, real-time reverse transcription-polymerase chain reaction (rRT-PCR) is the reference detection technique for SARS-CoV-2, which is expensive, time consuming, and requires trained laboratory personnel. Thus, a cost-effective, rapid antigen test is urgently needed. This study evaluated the performance of the rapid antigen tests (RATs) for SARS-CoV-2 compared with rRT-PCR, considering different influencing factors. METHODS: We enrolled a total of 214 symptomatic individuals with known COVID-19 status using rRT-PCR. We collected and tested paired nasopharyngeal (NP) and nasal swab (NS) specimens (collected from same individual) using rRT-PCR and RATs (InTec and SD Biosensor). We assessed the performance of RATs considering specimen types, viral load, the onset of symptoms, and presenting symptoms. RESULTS: We included 214 paired specimens (112 NP and 100 NS SARS-CoV-2 rRT-PCR positive) to the analysis. For NP specimens, the average sensitivity, specificity, and accuracy of the RATs were 87.5%, 98.6%, and 92.8%, respectively, when compared with rRT-PCR. While for NS, the overall kit performance was slightly lower than that of NP (sensitivity 79.0%, specificity 96.1%, and accuracy 88.3%). We observed a progressive decline in the performance of RATs with increased Ct values (decreased viral load). Moreover, the RAT sensitivity using NP specimens decreased over the time of the onset of symptoms. CONCLUSION: The RATs showed strong performance under field conditions and fulfilled the minimum performance limit for rapid antigen detection kits recommended by World Health Organization. The best performance of the RATs can be achieved within the first week of the onset of symptoms with high viral load.


Asunto(s)
Antígenos Virales/análisis , Prueba Serológica para COVID-19 , COVID-19/diagnóstico , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Prueba Serológica para COVID-19/métodos , Prueba Serológica para COVID-19/normas , Prueba Serológica para COVID-19/estadística & datos numéricos , Niño , Preescolar , Femenino , Humanos , Lactante , Masculino , Persona de Mediana Edad , Nasofaringe/virología , Juego de Reactivos para Diagnóstico/virología , SARS-CoV-2/aislamiento & purificación , Sensibilidad y Especificidad , Factores de Tiempo , Carga Viral , Adulto Joven
6.
J Infect Dis ; 224(12 Suppl 2): S864-S872, 2021 12 20.
Artículo en Inglés | MEDLINE | ID: mdl-34586390

RESUMEN

BACKGROUND: Since August 2017, Myanmar nationals from Rakhine state have crossed the border into Bangladesh and settled in Cox's Bazar, the World's largest refugee camp. Due to overcrowding, poor sanitation, and hygienic practices they have been under significant health risks including diarrheal diseases. The objective of this study is to determine the viral etiology of acute gastroenteritis (AGE) among forcibly displaced Myanmar nationals (FDMN) and adjacent Bangladeshi local host population (AHP). METHODS: From April 2018 to April 2019, we collected stool specimens from 764 FDMN and 1159 AHP of all ages. We tested 100 randomly selected specimens from each group for the most common AGE viruses. RESULTS: Among 200 diarrhea patients, 55% and 64% of FDMN and AHP patients, respectively, had viral infections; the most common viruses were rotavirus (29% vs 44%), adenovirus (24% vs 31%), and norovirus (14% vs 10%). In both populations, viral infections were significantly higher in children less than 5 years of age, compared with bacterial infections that were higher in patients older than 5 years of age (P ≤ .05). CONCLUSIONS: Disparities in viral and bacterial prevalence among various age groups warrant careful antibiotic usage, especially in children less than 5 years of age.


Asunto(s)
Diarrea/epidemiología , Heces/virología , Gastroenteritis/diagnóstico , Gastroenteritis/virología , Refugiados , Adenoviridae , Adolescente , Bangladesh/epidemiología , Niño , Preescolar , Femenino , Gastroenteritis/etnología , Humanos , Lactante , Masculino , Mianmar/etnología , Norovirus , Prevalencia , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Rotavirus
7.
Clin Infect Dis ; 69(3): 505-513, 2019 07 18.
Artículo en Inglés | MEDLINE | ID: mdl-30351379

RESUMEN

BACKGROUND: Noroviruses are the most common cause of epidemic and endemic acute gastroenteritis (AGE) worldwide. The burden of norovirus disease in low-income settings is poorly understood. METHODS: We tested stool samples from children less than 5 years of age with diarrhea who were admitted in a rural hospital in Bangladesh from 2010-2012 and from matched, healthy controls from the same catchment area. RESULTS: Norovirus was detected in 109 (18%) of 613 children with diarrhea and in 30 (15%) of 206 healthy controls. Most (n = 118; 85%) norovirus infections belonged to genogroup II (GII). Of these, GII.4 viruses were identified in 36 (33%) of the cases and in 6 (21%) of the controls. Other major genotypes included GII.3 (13%), GII.6 (11%), and GII.13 (11%) in the cases and GII.6 (17%) and GII.2 (14%) in the controls. The greatest risk of severe norovirus disease (Vesikari score ≥11) was associated with GII.4 infections. GII.4 viruses were the predominant genotype detected during the winter (55%) and rainy season (23%), while GII.3 (19%) and GII.13 (19%) viruses were the most prevalent genotypes during the summer. Vomiting was significantly associated with GII.4 infections, while longer durations of diarrhea were associated with GI.3 infections. CONCLUSIONS: Future studies are needed to understand the high rates of virus shedding in children without AGE symptoms.


Asunto(s)
Infecciones por Caliciviridae/epidemiología , Diarrea/epidemiología , Heces/virología , Norovirus/genética , Enfermedad Aguda , Bangladesh/epidemiología , Estudios de Casos y Controles , Preescolar , Costo de Enfermedad , Diarrea/virología , Femenino , Gastroenteritis/epidemiología , Gastroenteritis/virología , Genotipo , Voluntarios Sanos , Humanos , Lactante , Recién Nacido , Masculino , Pobreza/estadística & datos numéricos , Prevalencia , ARN Viral/genética , Población Rural/estadística & datos numéricos , Estaciones del Año , Esparcimiento de Virus
8.
J Med Virol ; 91(4): 549-554, 2019 04.
Artículo en Inglés | MEDLINE | ID: mdl-30372530

RESUMEN

BACKGROUND: Acute respiratory infection (ARI) is a leading cause of morbidity and mortality in children in low and middle-income countries. Human metapneumovirus (hMPV) is one of the most common viral etiological agents for ARIs in children. OBJECTIVES: In this study, we explored the genotypic diversity and the epidemiology of hMPV among infants in Dhaka, Bangladesh. STUDY DESIGN: Between December 2014 and August 2016, a total of 3810 mid-turbinate nasal swab samples were collected from infants (0 to 6 months of age) who met clinical ARI criteria, as a part of a prospective ARI cohort study. hMPV was detected using polymerase chain reaction, and genotyped by sequencing and phylogenetic analysis. RESULTS: hMPV was identified in 206 (5.4%) nasal swab specimens. One-tenth of the hMPV-positive swabs (n = 19) were also positive for other respiratory viruses. hMPV activity peaked in January and September in 2015; however, no seasonal pattern of hMPV infection was detected. Phylogenetic analyses of the N and F gene-fragments revealed that the hMPV strains circulating in Dhaka, Bangladesh, belonged to three genotypes: A2b, A2c, and B1. Genotype A (57%) was the predominant hMPV genotype circulating in Bangladesh during the study period. CONCLUSION: This study describes both the epidemiology of hMPV infection and its genotypic strain diversity in Dhaka, Bangladesh.


Asunto(s)
Genotipo , Metapneumovirus/clasificación , Metapneumovirus/genética , Infecciones por Paramyxoviridae/epidemiología , Infecciones por Paramyxoviridae/virología , Bangladesh/epidemiología , Infecciones Comunitarias Adquiridas/epidemiología , Infecciones Comunitarias Adquiridas/virología , Infección Hospitalaria/epidemiología , Infección Hospitalaria/virología , Monitoreo Epidemiológico , Variación Genética , Técnicas de Genotipaje , Humanos , Lactante , Recién Nacido , Metapneumovirus/aislamiento & purificación , Epidemiología Molecular , Mucosa Nasal/virología , Reacción en Cadena de la Polimerasa , Estudios Prospectivos , Análisis de Secuencia de ADN
9.
Emerg Infect Dis ; 24(5): 926-928, 2018 05.
Artículo en Inglés | MEDLINE | ID: mdl-29664373

RESUMEN

Dromedary camels are bred domestically and imported into Bangladesh. In 2015, of 55 camels tested for Middle East respiratory syndrome coronavirus in Dhaka, 17 (31%) were seropositive, including 1 bred locally. None were PCR positive. The potential for infected camels in urban markets could have public health implications and warrants further investigation.


Asunto(s)
Camelus , Infecciones por Coronavirus/veterinaria , Coronavirus del Síndrome Respiratorio de Oriente Medio/aislamiento & purificación , Animales , Bangladesh/epidemiología , Infecciones por Coronavirus/epidemiología , Infecciones por Coronavirus/virología , Femenino , Masculino
10.
Emerg Infect Dis ; 24(1): 15-21, 2018 01.
Artículo en Inglés | MEDLINE | ID: mdl-29260663

RESUMEN

Nipah virus (NiV) has been transmitted from patient to caregivers in Bangladesh presumably through oral secretions. We aimed to detect whether NiV-infected patients contaminate hospital surfaces with the virus. During December 2013-April 2014, we collected 1 swab sample from 5 surfaces near NiV-infected patients and tested surface and oral swab samples by real-time reverse transcription PCR for NiV RNA. We identified 16 Nipah patients; 12 cases were laboratory-confirmed and 4 probable. Of the 12 laboratory-confirmed cases, 10 showed NiV RNA in oral swab specimens. We obtained surface swab samples for 6 Nipah patients; 5 had evidence of NiV RNA on >1 surface: 4 patients contaminated towels, 3 bed sheets, and 1 the bed rail. Patients with NiV RNA in oral swab samples were significantly more likely than other Nipah patients to die. To reduce the risk for fomite transmission of NiV, infection control should target hospital surfaces.


Asunto(s)
Contaminación de Equipos , Infecciones por Henipavirus/epidemiología , Infecciones por Henipavirus/virología , Hospitales , Virus Nipah/aislamiento & purificación , Bangladesh/epidemiología , Ropa de Cama y Ropa Blanca/virología , Lechos/virología , Brotes de Enfermedades , Fómites , Infecciones por Henipavirus/mortalidad , Humanos , Control de Infecciones/métodos , Boca/virología , ARN Viral/aislamiento & purificación
11.
J Med Virol ; 90(4): 677-684, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29244212

RESUMEN

Human adenoviruses (HAdVs) are common cause of nonbacterial acute gastroenteritis worldwide. Limited data exist on HAdVs molecular epidemiology associated with acute gastroenteritis in Bangladesh. We describe the genetic diversity and epidemiology of HAdVs among hospitalized diarrhea patients, including HAdV genotypes, clinical symptoms, and co-infecting enteric pathogens. Stool samples were collected from ongoing diarrhea surveillance during 2012-2015. HAdV was detected using PCR and genotyped by sequencing and phylogenetic analysis. Detailed socio-demographic and clinical information regarding each individual was recorded such as duration of diarrhea, dehydration status, vomiting, abdominal pain, fever, and severity. Of 871 fecal specimens, HAdV DNA was detected in 93 (10.7%). Among them 56% were co-infected with other known enteric viral and bacterial pathogens and 31.6% had severe gastroenteritis. The majority (55%) of HAdV positives were children <5 years of age. Two main clinical symptoms in HAdV infected patients were diarrhea and vomiting. HAdVs were detected throughout the year with low prevalence in winter (November-January). Five HAdV species (A, B, C, D, and F) including 17 different genotypes were identified during the study period, with enteric HAdV species F (HAdV-40/41) being the most dominant. However, non-enteric HAdV were also detected in substantial proportion of specimens (15% species C, 15% species D, 10.8% species A, and 4.3% species B). Our study demonstrates high genetic diversity of HAdVs including enteric and non-enteric HAdVs among diarrhea patients and provides a foundation for further clarification of the role of non-enteric HAdVs in diarrheal diseases.


Asunto(s)
Infecciones por Adenovirus Humanos/epidemiología , Infecciones por Adenovirus Humanos/virología , Adenovirus Humanos/clasificación , Adenovirus Humanos/aislamiento & purificación , Gastroenteritis/epidemiología , Gastroenteritis/virología , Genotipo , Infecciones por Adenovirus Humanos/patología , Adenovirus Humanos/genética , Adolescente , Adulto , Anciano , Bangladesh/epidemiología , Niño , Preescolar , Coinfección/epidemiología , Coinfección/patología , Coinfección/virología , Heces/virología , Femenino , Gastroenteritis/patología , Variación Genética , Humanos , Lactante , Masculino , Persona de Mediana Edad , Epidemiología Molecular , Filogenia , Reacción en Cadena de la Polimerasa , Prevalencia , Análisis de Secuencia de ADN , Adulto Joven
13.
Clin Infect Dis ; 64(suppl_3): S378-S386, 2017 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-28575375

RESUMEN

BACKGROUND.: Lack of a gold standard for identifying bacterial and viral etiologies of pneumonia has limited evaluation of C-reactive protein (CRP) for identifying bacterial pneumonia. We evaluated the sensitivity and specificity of CRP for identifying bacterial vs respiratory syncytial virus (RSV) pneumonia in the Pneumonia Etiology Research for Child Health (PERCH) multicenter case-control study. METHODS.: We measured serum CRP levels in cases with World Health Organization-defined severe or very severe pneumonia and a subset of community controls. We evaluated the sensitivity and specificity of elevated CRP for "confirmed" bacterial pneumonia (positive blood culture or positive lung aspirate or pleural fluid culture or polymerase chain reaction [PCR]) compared to "RSV pneumonia" (nasopharyngeal/oropharyngeal or induced sputum PCR-positive without confirmed/suspected bacterial pneumonia). Receiver operating characteristic (ROC) curves were constructed to assess the performance of elevated CRP in distinguishing these cases. RESULTS.: Among 601 human immunodeficiency virus (HIV)-negative tested controls, 3% had CRP ≥40 mg/L. Among 119 HIV-negative cases with confirmed bacterial pneumonia, 77% had CRP ≥40 mg/L compared with 17% of 556 RSV pneumonia cases. The ROC analysis produced an area under the curve of 0.87, indicating very good discrimination; a cut-point of 37.1 mg/L best discriminated confirmed bacterial pneumonia (sensitivity 77%) from RSV pneumonia (specificity 82%). CRP ≥100 mg/L substantially improved specificity over CRP ≥40 mg/L, though at a loss to sensitivity. CONCLUSIONS.: Elevated CRP was positively associated with confirmed bacterial pneumonia and negatively associated with RSV pneumonia in PERCH. CRP may be useful for distinguishing bacterial from RSV-associated pneumonia, although its role in discriminating against other respiratory viral-associated pneumonia needs further study.


Asunto(s)
Proteína C-Reactiva/análisis , Neumonía Bacteriana/diagnóstico , Neumonía Viral/diagnóstico , Bacterias/genética , Bacterias/aislamiento & purificación , Biomarcadores/sangre , Estudios de Casos y Controles , Preescolar , Infecciones Comunitarias Adquiridas/diagnóstico , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Nasofaringe/virología , Orofaringe/virología , Neumonía Bacteriana/microbiología , Neumonía Viral/virología , Reacción en Cadena de la Polimerasa , Curva ROC , Infecciones por Virus Sincitial Respiratorio/sangre , Virus Sincitial Respiratorio Humano/genética , Virus Sincitial Respiratorio Humano/aislamiento & purificación , Sensibilidad y Especificidad
14.
BMC Pregnancy Childbirth ; 16(1): 309, 2016 10 13.
Artículo en Inglés | MEDLINE | ID: mdl-27737646

RESUMEN

BACKGROUND: Early infancy is a high-risk period for severe acute respiratory infection (ARI), particularly in low-income countries with resource-limited health systems. Lower respiratory tract infection (LRTI) is commonly preceded by upper respiratory infection (URTI), and often caused by respiratory syncytial virus (RSV), influenza and other common community-acquired viral pathogens. Vitamin D status is a candidate modifiable early-life determinant of the host antiviral immune response and thus may influence the risk of ARI-associated morbidity in high-risk populations. METHODS/DESIGN: In the Maternal Vitamin D for Infant Growth (MDIG) study in Dhaka, Bangladesh (NCT01924013), 1300 pregnant women are randomized to one of five groups: placebo, 4200 IU/week, 16,800 IU/week, or 28,000 IU/week from 2nd trimester to delivery plus placebo from 0-6 months postpartum; or, 28,000 IU/week prenatal and until 6-months postpartum. In the Maternal Vitamin D for ARI in Infancy (MDARI) sub-study nested within the MDIG trial, trained personnel conduct weekly postnatal home visits to inquire about ARI symptoms and conduct a standardized clinical assessment. Supplementary home visits between surveillance visits are conducted when caregivers make phone notifications of new infant symptoms. Mid-turbinate nasal swab samples are obtained from infants who meet standardized clinical ARI criteria. Specimens are tested by polymerase chain reaction (PCR) for 8 viruses (influenza A/B, parainfluenza 1/2/3, RSV, adenovirus, and human metapneumovirus), and nasal carriage density of Streptococcus pneumoniae. The primary outcome is the incidence rate of microbiologically-positive viral ARI, using incidence rate ratios to estimate between-group differences. We hypothesize that among infants 0-6 months of age, the incidence of microbiologically-confirmed viral ARI will be significantly lower in infants whose mothers received high-dose prenatal/postpartum vitamin D supplements versus placebo. Secondary outcomes include incidence of ARI associated with specific pathogens (influenza A or B, RSV), clinical ARI, and density of pneumococcal carriage. DISCUSSION: If shown to reduce the risk of viral ARI in infancy, integration of maternal prenatal/postpartum vitamin D supplementation into antenatal care programs in South Asia may be a feasible primary preventive strategy to reduce the burden of ARI-associated morbidity and mortality in young infants. TRIAL REGISTRATION: NCT02388516 , registered March 9, 2015.


Asunto(s)
Suplementos Dietéticos , Enfermedades del Recién Nacido/prevención & control , Lactancia , Atención Prenatal/métodos , Infecciones del Sistema Respiratorio/prevención & control , Vitamina D/administración & dosificación , Vitaminas/administración & dosificación , Enfermedad Aguda , Adulto , Bangladesh , Lactancia Materna , Protocolos Clínicos , Femenino , Humanos , Lactante , Recién Nacido , Enfermedades del Recién Nacido/virología , Masculino , Fenómenos Fisiologicos Nutricionales Maternos , Embarazo , Estudios Prospectivos , Infecciones por Virus Sincitial Respiratorio/prevención & control , Infecciones por Virus Sincitial Respiratorio/virología , Infecciones del Sistema Respiratorio/virología , Resultado del Tratamiento
15.
Curr Microbiol ; 68(5): 642-7, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24452425

RESUMEN

The environmental Escherichia albertii strain DM104, which cross-reacts serologically with Shigella dysenteriae was assessed for pathogenic properties, immunogenicity, and protective efficacy in different animal models to evaluate it as a vaccine candidate against S. dysenteriae, which causes the severe disease, shigellosis. The DM104 isolate was found to be non-invasive and did not produce any entero- or cyto-toxins. The strain also showed negative results in the mouse lethal activity assay. The non-pathogenic DM104 strain gave, however, a high protective efficacy as an ocularly administered vaccine in the guinea pig eye model against S. dysenteriae type 4 challenge. It also induced a high titer of serum IgG against S. dysenteriae type 4 whole cell lysate and lipopolysaccharide. Taken together, all these results indicate a good potential for the use of the DM104 as a live vaccine candidate against shigellosis.


Asunto(s)
Vacunas Bacterianas/inmunología , Disentería Bacilar/prevención & control , Escherichia/inmunología , Oftalmopatías/prevención & control , Shigella dysenteriae/inmunología , Vacunación/métodos , Administración Oftálmica , Animales , Anticuerpos Antibacterianos/sangre , Vacunas Bacterianas/administración & dosificación , Disentería Bacilar/inmunología , Microbiología Ambiental , Escherichia/aislamiento & purificación , Escherichia/patogenicidad , Oftalmopatías/inmunología , Cobayas , Inmunoglobulina G/sangre , Ratones
16.
One Health ; 18: 100681, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-39010948

RESUMEN

Avian influenza virus (AIV) is of major concern to livestock, wildlife, and human health. In many countries in the world, including Bangladesh, AIV is endemic in poultry, requiring improving biosecurity. In Bangladesh, we investigated how variation in biosecurity practices in commercial chicken farms affected their AIV infection status to help guide AIV mitigation strategies. We collected pooled fecal swabs from 225 farms and tested the samples for the AIV matrix gene followed by H5, H7, and H9 subtyping using rRT-PCR. We found that 39.6% of chicken farms were AIV positive, with 13% and 14% being positive for subtypes H5 and H9, respectively. Using a generalized linear mixed effects model, we identified as many as 12 significant AIV risk factors. Two major factors promoting AIV risk that cannot be easily addressed in the short term were farm size and the proximity of the farm to a live bird market. However, the other ten significant determinants of AIV risk can be more readily addressed, of which the most important ones were limiting access by visitors (reducing predicted AIV risk from 42 to 6%), isolation and treatment of sick birds (42 to 7%), prohibiting access of vehicles to poultry sheds (38 to 8%), improving hand hygiene (from 42 to 9%), not sharing farm workers across farms (37 to 8%), and limiting access by wild birds to poultry sheds (37 to 8%). Our findings can be applied to developing practical and cost-effective measures that significantly decrease the prevalence of AIV in chicken farms. Notably, in settings with limited resources, such as Bangladesh, these measures can help governments strengthen biosecurity practices in their poultry industry to limit and possibly prevent the spread of AIV.

17.
Emerg Microbes Infect ; : 2399268, 2024 Aug 29.
Artículo en Inglés | MEDLINE | ID: mdl-39207215

RESUMEN

AbstractHigh pathogenicity avian influenza (HPAI) virus H5N1 first emerged in Bangladesh in 2007. Despite the use of vaccines in chickens since 2012 to control HPAI, HPAI H5Nx viruses have continued to infect poultry, and wild birds, resulting in notable mass mortalities in house crows (Corvus splendens). The first HPAI H5Nx viruses in Bangladesh belonged to clade 2.2.2, followed by clade 2.3.4.2 and 2.3.2.1 viruses in 2011. After the implementation of chicken vaccination in 2012, these viruses were mostly replaced by clade 2.3.2.1a viruses and more recently clade 2.3.4.4b and h viruses. In this study, we reconstruct the phylogenetic history of HPAI H5Nx viruses in Bangladesh to evaluate the role of major host species in the maintenance and evolution of HPAI H5Nx virus in Bangladesh and reveal the role of heavily impacted crows in virus epidemiology. Epizootic waves caused by HPAI H5N1 and H5N6 viruses amongst house crows occurred annually in winter. Bayesian phylodynamic analysis of clade 2.3.2.1a revealed frequent bidirectional viral transitions between domestic ducks, chickens, and house crows that was markedly skewed towards ducks; domestic ducks might be the source, or reservoir, of HPAI H5Nx in Bangladesh, as the number of viral transitions from ducks to chickens and house crows was by far more numerous than the other transitions. Our results suggest viral circulation in domestic birds despite vaccination, with crow epizootics acting as a sentinel. The vaccination strategy needs to be updated to use more effective vaccinations, assess vaccine efficacy, and extension of vaccination to domestic ducks, the key reservoir.

18.
Microbiol Spectr ; 12(1): e0327223, 2024 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-38014980

RESUMEN

IMPORTANCE: Affordable and accessible tests for COVID-19 allow for timely disease treatment and pandemic management. SalivaDirect is a faster and easier method to implement than NPS sampling. Patients can self-collect saliva samples at home or in other non-clinical settings without the help of a healthcare professional. Sample processing in SalivaDirect is less complex and more adaptable than in conventional nucleic acid extraction methods. We found that SalivaDirect has good diagnostic performance and is ideal for large-scale testing in settings where supplies may be limited or trained healthcare professionals are unavailable.


Asunto(s)
COVID-19 , SARS-CoV-2 , Humanos , SARS-CoV-2/genética , COVID-19/diagnóstico , Personal de Salud , Pandemias , ARN , Saliva , Manejo de Especímenes
19.
Viruses ; 16(8)2024 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-39205237

RESUMEN

The first case of COVID-19 was detected in Bangladesh on 8 March 2020. Since then, the Government of Bangladesh (GoB) has implemented various measures to limit the transmission of COVID-19, including widespread testing facilities across the nation through a laboratory network for COVID-19 molecular testing. This study aimed to analyze the dynamics of SARS-CoV-2 in Bangladesh by conducting COVID-19 testing and genomic surveillance of the virus variants throughout the pandemic. Nasopharyngeal swabs were collected from authorized GoB collection centers between April 2020 and June 2023. The viral RNA was extracted and subjected to real-time PCR analysis in icddr,b's Virology laboratory. A subset of positive samples underwent whole-genome sequencing to track the evolutionary footprint of SARS-CoV-2 variants. We tested 149,270 suspected COVID-19 cases from Dhaka (n = 81,782) and other districts (n = 67,488). Of these, 63% were male. The highest positivity rate, 27%, was found in the >60 years age group, followed by 26%, 51-60 years, 25% in 41-50 years, and the lowest, 9% in under five children. Notably, the sequencing of 2742 SARS-CoV-2 genomes displayed a pattern of globally circulating variants, Alpha, Beta, Delta, and Omicron, successively replacing each other over time and causing peaks of COVID-19 infection. Regarding the risk of SARS-CoV-2 infection, it was observed that the positivity rate increased with age compared to the under-5 age group in 2020 and 2021. However, these trends did not remain consistent in 2022, where older age groups, particularly those over 60, had a lower positivity rate compared to other age groups due to vaccination. The study findings generated data on the real-time circulation of different SARS-CoV-2 variants and the upsurge of COVID-19 cases in Bangladesh, which impacted identifying hotspots and restricting the virus from further transmission. Even though there is currently a low circulation of SARS-CoV-2 in Bangladesh, similar approaches of genomic surveillance remain essential for monitoring the emergence of new SARS-CoV-2 variants or other potential pathogens that could lead to future pandemics.


Asunto(s)
COVID-19 , Genoma Viral , SARS-CoV-2 , Bangladesh/epidemiología , Humanos , COVID-19/epidemiología , COVID-19/virología , COVID-19/transmisión , SARS-CoV-2/genética , SARS-CoV-2/clasificación , SARS-CoV-2/aislamiento & purificación , Masculino , Adulto , Persona de Mediana Edad , Femenino , Adolescente , Niño , Preescolar , Adulto Joven , Lactante , Secuenciación Completa del Genoma , Anciano , Recién Nacido , Filogenia , ARN Viral/genética
20.
Emerg Microbes Infect ; : 2398640, 2024 Aug 28.
Artículo en Inglés | MEDLINE | ID: mdl-39194145

RESUMEN

ABSTRACTNipah virus (NiV) is an emerging zoonotic RNA virus that can cause fatal respiratory and neurological disease in animals and humans. Accurate NiV diagnostics and surveillance tools are crucial for the identification of acute and resolved infections and to improve our understanding of NiV transmission and circulation. Here, we have developed and validated a split NanoLuc luciferase NiV glycoprotein (G) biosensor for detecting antibodies in clinical and animal samples. This assay is performed by simply mixing reagents and measuring luminescence, which depends on the complementation of the split NanoLuc luciferase G biosensor following its binding to antibodies. This anti-NiV-G "mix-and-read" assay was validated using the WHO's first international standard for anti-NiV antibodies and more than 700 serum samples from the NiV-endemic country of Bangladesh. Anti-NiV antibodies from survivors persisted for at least 8 years according to both ⍺NiV-G mix-and-read and NiV neutralization assays. The ⍺NiV-G mix-and-read assay sensitivity (98.6%) and specificity (100%) were comparable to anti-NiV IgG ELISA performance but failed to detect anti-NiV antibodies in samples collected less than a week following the appearance of symptoms. Overall, the anti-NiV-G biosensor represents a simple, fast, and reliable tool that could support the expansion of NiV surveillance and retrospective outbreak investigations.

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