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1.
PLoS One ; 19(5): e0297452, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38696397

RESUMO

BACKGROUND: Limited data exists regarding risk factors for adverse outcomes in older adults hospitalized with Community-Acquired Pneumonia (CAP) in low- and middle-income countries such as India. This multisite study aimed to assess outcomes and associated risk factors among adults aged ≥60 years hospitalized with pneumonia. METHODS: Between December 2018 and March 2020, we enrolled ≥60-year-old adults admitted within 48 hours for CAP treatment across 16 public and private facilities in four sites. Clinical data and nasal/oropharyngeal specimens were collected by trained nurses and tested for influenza, respiratory syncytial virus (RSV), and other respiratory viruses (ORV) using the qPCR. Participants were evaluated regularly until discharge, as well as on the 7th and 30th days post-discharge. Outcomes included ICU admission and in-hospital or 30-day post-discharge mortality. A hierarchical framework for multivariable logistic regression and Cox proportional hazard models identified risk factors (e.g., demographics, clinical features, etiologic agents) associated with critical care or death. FINDINGS: Of 1,090 CAP patients, the median age was 69 years; 38.4% were female. Influenza viruses were detected in 12.3%, RSV in 2.2%, and ORV in 6.3% of participants. Critical care was required for 39.4%, with 9.9% in-hospital mortality and 5% 30-day post-discharge mortality. Only 41% of influenza CAP patients received antiviral treatment. Admission factors independently associated with ICU admission included respiratory rate >30/min, blood urea nitrogen>19mg/dl, altered sensorium, anemia, oxygen saturation <90%, prior cardiovascular diseases, chronic respiratory diseases, and private hospital admission. Diabetes, anemia, low oxygen saturation at admission, ICU admission, and mechanical ventilation were associated with 30-day mortality. CONCLUSION: High ICU admission and 30-day mortality rates were observed among older adults with pneumonia, with a significant proportion linked to influenza and RSV infections. Comprehensive guidelines for CAP prevention and management in older adults are needed, especially with the co-circulation of SARS-CoV-2.


Assuntos
Hospitalização , Pneumonia , Humanos , Feminino , Masculino , Idoso , Índia/epidemiologia , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de Risco , Pneumonia/epidemiologia , Pneumonia/mortalidade , Pneumonia/virologia , Infecções Comunitárias Adquiridas/epidemiologia , Infecções Comunitárias Adquiridas/mortalidade , Infecções Comunitárias Adquiridas/virologia , Idoso de 80 Anos ou mais , Mortalidade Hospitalar , Unidades de Terapia Intensiva
2.
Viruses ; 16(1)2024 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-38275969

RESUMO

Understanding the genetic dynamics of circulating Human Adenovirus (HAdV) types is pivotal for effectively managing outbreaks and devising targeted interventions. During the West Bengal outbreak of 2022-2023, an investigation into the genetic characteristics and outbreak potential of circulating HAdV types was conducted. Twenty-four randomly selected samples underwent whole-genome sequencing. Analysis revealed a prevalent recombinant strain, merging type 3 and type 7 of human mastadenovirus B1 (HAd-B1) species, indicating the emergence of recent strains of species B in India. Furthermore, distinctions in VA-RNAs and the E3 region suggested that current circulating strains of human mastadenovirus B1 (HAd-B1) possess the capacity to evade host immunity, endure longer within hosts, and cause severe respiratory infections. This study underscores the significance of evaluating the complete genome sequence of HAdV isolates to glean insights into their outbreak potential and the severity of associated illnesses.


Assuntos
Infecções por Adenovirus Humanos , Adenovírus Humanos , Expedições , Mastadenovirus , Humanos , Epidemiologia Molecular , Filogenia , Genômica , Surtos de Doenças , Índia/epidemiologia , Genoma Viral , Análise de Sequência de DNA
3.
BMJ Public Health ; 1(1): e000103, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38116390

RESUMO

Introduction: Advocacy for the provision of public health resources, including vaccine for the prevention of acute respiratory illnesses (ARIs) among older adults in India, needs evidence on costs and benefits. Using a cohort of community-dwelling adults aged 60 years and older in India, we estimated the cost of ARI episode and its determinants. Methods: We enrolled 6016 participants in Ballabgarh, Chennai, Kolkata and Pune from July 2018 to March 2020. They were followed up weekly to identify ARI and classified them as acute upper respiratory illness (AURI) or pneumonia based on clinical features based on British Thoracic Society guidelines. All pneumonia and 20% of AURI cases were asked about the cost incurred on medical consultation, investigation, medications, transportation, food and lodging. The cost of services at public facilities was supplemented by WHO-Choosing Interventions that are Cost-Effective(CHOICE) estimates for 2019. Indirect costs incurred by the affected participant and their caregivers were estimated using human capital approach. We used generalised linear model with log link and gamma family to identify the average marginal effect of key determinants of the total cost of ARI. Results: We included 2648 AURI and 1081 pneumonia episodes. Only 47% (range 36%-60%) of the participants with pneumonia sought care. The mean cost of AURI episode was US$13.9, while that of pneumonia episode was US$25.6, with indirect costs comprising three-fourths of the total. The cost was higher among older men by US$3.4 (95% CI: 1.4 to 5.3), those with comorbidities by US$4.3 (95% CI: 2.8 to 5.7) and those who sought care by US$17.2 (95% CI: 15.1 to 19.2) but not by influenza status. The mean per capita annual cost of respiratory illness was US$29.5. Conclusion: Given the high community disease and cost burden of ARI, intensifying public health interventions to prevent and mitigate ARI among this fast-growing older adult population in India is warranted.

4.
Virology ; 587: 109875, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37703797

RESUMO

Differential regulation of the 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR), which is considered the rate-limiting enzyme of the cholesterol biosynthesis pathway, has been reported in case of infection with many viruses. In our study, we have found that influenza virus infection decreases total cellular cholesterol level which is directly related to the downregulation of HMGCR protein. We found that HMGCR is degraded through ubiquitination and proteasomal-mediated pathway upon viral infection. Upregulation of Autocrine Motility Factor Receptor (AMFR), which is an E3-ubiquitin ligase of HMGCR, was also observed. Furthermore, knockdown of AMFR inhibits ubiquitination of HMGCR and also leads to inactivation of the innate immunity components TANK-binding kinase 1 (TBK1) and Interferon regulatory factor 3 (IRF3). Our study is the first to show the role of HMGCR and AMFR in influenza virus infection and reveals that AMFR plays a crucial role in the downregulation of HMGCR and the activation of innate immunity following influenza virus infection.

5.
J Med Virol ; 95(7): e28897, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37394792

RESUMO

Globally, different genotypes of human adenoviruses are associated with outbreaks of acute respiratory infection (ARI) though such evidence is lacking from India. In the present study, we report a sudden increase in the positivity of respiratory adenovirus among hospitalized children with ARI from Kolkata and the surrounding districts of West Bengal, India, from December 2022 to date. A sharp rise in the positivity rate of respiratory adenovirus was found which ranged from 22.1% in early December 2022 to 52.6% in mid-March 2023. The overall positivity was 40.4% during the period and children in the 2 to <5 years (51.0%) age group were mostly affected. Single infection with adenovirus was found in 72.4% of cases while co-infection with rhinovirus was the maximum (9.4%). Around 97.5% of positive cases required hospitalization. Cough, breathlessness, and wheeze were the most common clinical features among positive patients. Phylogenetic analysis of the hexon and fiber gene of all the sequenced strains revealed HAdV-B 7/3 recombination with more than 99% homology within themselves. This report of a respiratory adenovirus outbreak in West Bengal, India causing severe illness in the pediatric population underscores the need for regular monitoring of the circulating strains.


Assuntos
Infecções por Adenovirus Humanos , Adenovírus Humanos , Infecções Respiratórias , Índia/epidemiologia , Infecções Respiratórias/epidemiologia , Infecções Respiratórias/virologia , Humanos , Adenovírus Humanos/classificação , Adenovírus Humanos/genética , Adenovírus Humanos/fisiologia , Recém-Nascido , Lactente , Pré-Escolar , Criança , Adolescente , Adulto , Filogenia , Infecções por Adenovirus Humanos/epidemiologia , Infecções por Adenovirus Humanos/virologia , Surtos de Doenças
6.
Molecules ; 28(5)2023 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-36903484

RESUMO

Antimicrobial resistance (AMR) is a major problem and an immediate alternative to antibiotics is the need of the hour. Research on the possible alternative products to tackle bacterial infections is ongoing worldwide. One of the most promising alternatives to antibiotics is the use of bacteriophages (phage) or phage-driven antibacterial drugs to cure bacterial infections caused by AMR bacteria. Phage-driven proteins, including holins, endolysins, and exopolysaccharides, have shown great potential in the development of antibacterial drugs. Likewise, phage virion proteins (PVPs) might also play an important role in the development of antibacterial drugs. Here, we have developed a machine learning-based prediction method to predict PVPs using phage protein sequences. We have employed well-known basic and ensemble machine learning methods with protein sequence composition features for the prediction of PVPs. We found that the gradient boosting classifier (GBC) method achieved the best accuracy of 80% on the training dataset and an accuracy of 83% on the independent dataset. The performance on the independent dataset is better than other existing methods. A user-friendly web server developed by us is freely available to all users for the prediction of PVPs from phage protein sequences. The web server might facilitate the large-scale prediction of PVPs and hypothesis-driven experimental study design.


Assuntos
Infecções Bacterianas , Bacteriófagos , Humanos , Biologia Computacional/métodos , Proteínas/metabolismo , Infecções Bacterianas/microbiologia , Vírion/metabolismo , Aprendizado de Máquina , Antibacterianos/metabolismo
7.
Infect Genet Evol ; 110: 105424, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36913995

RESUMO

Influenza A viruses (IAV) are fast-evolving pathogens with a very high mutation rate (2.0 × 10-6 to 2.0 × 10-4) compared to the influenza B (IBV) and influenza C (ICV) viruses. Generally, the tropical regions are considered as the reservoir for the IAV's genetic and antigenic evolutionary modification to be reintroduced into the temperate region. Therefore, in connection to the above facts, the present study emphasized on the evolutionary dynamic of the pandemic-2009 H1N1 (pdmH1N1) influenza virus in India. A total of Ninety-two whole genome sequences of pdmH1N1 viruses circulating in India during the 2009 post-pandemic era were analysed. The temporal signal of the study, indicating strict molecular clock evolutionary process and the overall substitution rate is 2.21 × 10-3/site/year. We are using the nonparametric Bayesian Skygrid coalescent model to estimates the effective past population dynamic or size over time. The study exhibits a strong relation between the genetic distances and collection dates of the Indian pdmH1N1 strain. The skygrid plot represents the highest exponential growth of IAV in rainy and winter seasons. All the genes of Indian pdmH1N1 were under purifying selective pressure. The Bayesian time-imprinted phylogenetic tree represents the following clade distributions in the country within the last 10 years; I) clade 6, 6C, and 7 were co-circulating between the 2011 to 2012 flu season; II) the clade 6B was introduced into circulation in the late seasons of 2012; III) lastly, the clade 6B remain existing in the circulation and segregated into subclade 6B.1 with five different subgroup (6B.1A, 6B.1A.1, 6B.1A.5a, 6B.1A.5a.2, 6B.1A.7). The recent circulating strain of Indian H1N1 strain represent the insertion of basic-amino acid arginine (R) in the cleavage site (325/K-R) of HA protein and amino acid mutation (314/I-M) on the lateral head surface domain of NA protein. Moreover, the study indicates the sporadic presence of the oseltamivir-resistant (275/H-Y) H1N1 variant in circulation. The present study suggests the purifying selective pressure and stochastic ecological factors for the existence and adaptation of a certain clade 6B in the host populations and additional information on the emergence of mutated strains in the circulation.


Assuntos
Vírus da Influenza A Subtipo H1N1 , Vírus da Influenza A , Influenza Humana , Humanos , Vírus da Influenza A Subtipo H1N1/genética , Filogenia , Teorema de Bayes , Análise de Sequência de DNA , Glicoproteínas de Hemaglutininação de Vírus da Influenza/genética , Neuraminidase/genética , Vírus da Influenza A/genética , Índia/epidemiologia
8.
Curr Pharm Biotechnol ; 24(10): 1277-1290, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36503459

RESUMO

Bacterial infections continue to jeopardize human and animal health, impacting millions of lives by causing significant deaths every year. The use of antibiotics remains the primary choice of therapy and has only been partly successful in reducing the disease burden due to the evolving nature of resistant microbes. Widespread and inappropriate use of antibiotics resulted in the development of antibiotic-resistant microbial species provoking substantial economic burdens. The most promising way to resolve the issue of antibiotic resistance is the use of bacterial viruses called bacteriophages to treat microbial infections. Earlier reports on experimental bacteriophage therapy showed successful patient outcomes, and many clinical trials of such clinical bacteriophages have already been investigated in many western countries. In this review, we are focusing on the advantages as well as drawbacks of bacteriophage therapy to use it as an alternative to antibiotics for microbial infections, together with its current success status. There is also a need to extensively study the past, present, and future outlook of phage therapy in comparison to presently available antimicrobial agents and especially immunological response by the host after phage administration. Our aim is to highlight the fast-promoting field of bacteriophage therapy and provocations that lie ahead as the world is gradually moving aside from complete dependence on antimicrobial agents.


Assuntos
Infecções Bacterianas , Bacteriófagos , Terapia por Fagos , Animais , Humanos , Bactérias , Infecções Bacterianas/tratamento farmacológico , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico
9.
PLoS One ; 17(9): e0273006, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36084080

RESUMO

AIM: To develop an accurate lab score based on in-hospital patients' potent clinical and biological parameters for predicting COVID-19 patient severity during hospital admission. METHODS: To conduct this retrospective analysis, a derivation cohort was constructed by including all the available biological and clinical parameters of 355 COVID positive patients (recovered = 285, deceased = 70), collected in November 2020-September 2021. For identifying potent biomarkers and clinical parameters to determine hospital admitted patient severity or mortality, the receiver operating characteristics (ROC) curve and Fischer's test analysis was performed. Relative risk regression was estimated to develop laboratory scores for each clinical and routine biological parameter. Lab score was further validated by ROC curve analysis of the validation cohort which was built with 50 COVID positive hospital patients, admitted during October 2021-January 2022. RESULTS: Sensitivity vs. 1-specificity ROC curve (>0.7 Area Under the Curve, 95% CI) and univariate analysis (p<0.0001) of the derivation cohort identified five routine biomarkers (neutrophil, lymphocytes, neutrophil: lymphocytes, WBC count, ferritin) and three clinical parameters (patient age, pre-existing comorbidities, admitted with pneumonia) for the novel lab score development. Depending on the relative risk (p values and 95% CI) these clinical parameters were scored and attributed to both the derivation cohort (n = 355) and the validation cohort (n = 50). ROC curve analysis estimated the Area Under the Curve (AUC) of the derivation and validation cohort which was 0.914 (0.883-0.945, 95% CI) and 0.873 (0.778-0.969, 95% CI) respectively. CONCLUSION: The development of proper lab scores, based on patients' clinical parameters and routine biomarkers, would help physicians to predict patient risk at the time of their hospital admission and may improve hospital-admitted COVID-19 patients' survivability.


Assuntos
COVID-19 , Pneumonia , COVID-19/diagnóstico , Humanos , Contagem de Leucócitos , Prognóstico , Curva ROC , Estudos Retrospectivos
10.
Microbiol Insights ; 15: 11786361221096651, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35591947

RESUMO

In addition to the ongoing global problem of healthcare-acquired infections, the COVID-19 pandemic continues to pose a serious threat to the health of the global population. This unprecedented pandemic situation has reinforced the need for the development of technologies that can curb the transmission of viruses among human beings and help to control the infection. Existing disinfection techniques using either ultraviolet light or harsh chemicals pose safety risks and are not suitable for use in the presence of humans. Thus, the need for a safe and effective disinfection technique that can be used in the presence of humans to control viral transmission is evident. A technique that can continuously disinfect air and surfaces in indoor environments, where the chances of viral transmission are high, can be an indispensable tool to fight such a pandemic. The Airlens Minus Corona (AMC) device provided by Persapien Innovations has been developed to achieve this goal. In this study, the antiviral functionality and biocompatibility of AMC were evaluated. Activated water mist (AWM) generated from this device was tested in vitro and in vivo for its toxicity to cell lines and in animal model. The AWM was found to be non-cytotoxic to L-929 cell lines and had no sign of clinical toxicity in an animal model (rabbit). This device was further used to inactivate animal viruses and bacteriophages. The AWM was found to be effective in the complete inactivation of influenza A H1N1 virus within 5 minutes of direct treatment. This device was also found to be effective in inactivating >90% of bacteriophage particles.

11.
Front Microbiol ; 13: 803933, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35422793

RESUMO

Cholera continues to be a major burden for developing nations, especially where sanitation, quality of water supply, and hospitalization have remained an issue. Recently, growing antimicrobial-resistant strains of Vibrio cholerae underscores alternative therapeutic strategies for cholera. Bacteriophage therapy is considered one of the best alternatives for antibiotic treatment. For the identification of potential therapeutic phages for cholera, we have introduced a comprehensive comparative analysis of whole-genome sequences of 86 Vibrio cholerae phages. We have witnessed extensive variation in genome size (ranging from 33 to 148 kbp), GC (G + C) content (varies from 34.5 to 50.8%), and the number of proteins (ranging from 15 to 232). We have identified nine clusters and three singletons using BLASTn, confirmed by nucleotide dot plot and sequence identity. A high degree of sequence and functional similarities in both the genomic and proteomic levels have been observed within the clusters. Evolutionary analysis confirms that phages are conserved within the clusters but diverse between the clusters. For each therapeutic phage, the top 2 closest phages have been identified using a system biology approach and proposed as potential therapeutic phages for cholera. This method can be applied for the classification of the newly isolated Vibrio cholerae phage. Furthermore, this systematic approach might be useful as a model for screening potential therapeutic phages for other bacterial diseases.

12.
BMJ Open ; 11(10): e052473, 2021 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-34620665

RESUMO

PURPOSE: We describe here a multicentric community-dwelling cohort of older adults (>60 years of age) established to estimate incidence, study risk factors, healthcare utilisation and economic burden associated with influenza and respiratory syncytial virus (RSV) in India. PARTICIPANTS: The four sites of this cohort are in northern (Ballabgarh), southern (Chennai), eastern (Kolkata) and western (Pune) parts of India. We enrolled 5336 participants across 4220 households and began surveillance in July 2018 for viral respiratory infections with additional participants enrolled annually. Trained field workers collected data about individual-level and household-level risk factors at enrolment and quarterly assessed frailty and grip strength. Trained nurses surveilled weekly to identify acute respiratory infections (ARI) and clinically assessed individuals to diagnose acute lower respiratory infection (ALRI) as per protocol. Nasal and oropharyngeal swabs are collected from all ALRI cases and one-fifth of the other ARI cases for laboratory testing. Cost data of the episode are collected using the WHO approach for estimating the economic burden of seasonal influenza. Handheld tablets with Open Data Kit platform were used for data collection. FINDINGS TO DATE: The attrition of 352 participants due to migration and deaths was offset by enrolling 680 new entrants in the second year. All four sites reported negligible influenza vaccination uptake (0.1%-0.4%), low health insurance coverage (0.4%-22%) and high tobacco use (19%-52%). Ballabgarh had the highest proportion (54.4%) of households in the richest wealth quintile, but reported high solid fuel use (92%). Frailty levels were highest in Kolkata (11.3%) and lowest in Pune (6.8%). The Chennai cohort had highest self-reported morbidity (90.1%). FUTURE PLANS: The findings of this cohort will be used to inform prioritisation of strategies for influenza and RSV control for older adults in India. We also plan to conduct epidemiological studies of SARS-CoV-2 using this platform.


Assuntos
COVID-19 , Influenza Humana , Infecções por Vírus Respiratório Sincicial , Vírus Sincicial Respiratório Humano , Infecções Respiratórias , Vírus , Idoso , Humanos , Índia/epidemiologia , Lactente , Influenza Humana/epidemiologia , Infecções Respiratórias/epidemiologia , SARS-CoV-2
13.
Pathogens ; 10(9)2021 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-34578254

RESUMO

Coronavirus disease 2019 (COVID-19) is considered as the most dreaded disease that has spread all over the world in the recent past. Despite its outbreak in December 2019-January 2020, a few continents and countries such as India started to experience a significant number of COVID-19-positive cases from March 2020. GISAID clade variation analysis in the period March 2020-February 2021 (period I) and March 2021-first week of April 2021 (period II) showed a rapid variation of SARS-CoV-2 in all continents and India over time. Studying the relationship of patient age or gender with viral clades in these two periods revealed that the population under 10 years of age was the least affected, whereas the 11-60-year-old population was the most affected, irrespective of patient gender and ethnicity. In the first wave, India registered quite a low number of COVID-19-positive cases/million people, but the scenario unexpectedly changed in the second wave, when even over 400,000 confirmed cases/day were reported. Lineage analysis in India showed the emergence of new SARS-CoV-2 variants, i.e., B.1.617.1 and B.1.617.2, during April-May 2021, which might be one of the key reasons for the sudden upsurge of confirmed cases/day. Furthermore, the emergence of the new variants contributed to the shift in infection spread by the G clade of SARS-CoV-2 from 46% in period II to 82.34% by the end of May 2021. Along with the management of the emergence of new variants, few factors viz., lockdown and vaccination were also accountable for controlling the upsurge of new COVID-19 cases throughout the country. Collectively, a comparative analysis of the scenario of the first wave with that of the second wave would suggest policymakers the way to prepare for better management of COVID-19 recurrence or its severity in India and other countries.

14.
J Glob Infect Dis ; 12(2): 94-100, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32773997

RESUMO

BACKGROUND: Cholera is a primordial disease caused by Vibrio cholerae which existed from centuries in different parts of the world and still shows its periodic, endemic and epidemic presence. Thousands of cholera cases are reported from different parts of India and the disease remains endemic throughout the year. At present, we do not have enough knowledge about the phenotypic nature of the circulating V. cholerae strains in this part of the world. OBJECTIVES: This study was carried out over a period of 6 years with the aim defer with the changes in the prevalence and distribution of biotypes, serotypes and phage types of V. cholerae clinical isolates from various endemic regions of the country to determine phenotypic characteristics of the circulating strains and also to predict the attributes of cholera strains responsible for causing significant outbreaks in future. MATERIALS AND METHODS: A total of 1882 V.cholerae O1 isolates from different cholera endemic areas of India were included in this study. V.cholerae strains which were identified as O1 biotype ElTor further analyzed for serotype and phage types using the standard methodologies. Polyvalent O1 and monospecific Inaba and Ogawa antisera were used for serotyping. A panel of five phages of Basu and Mukherjee phage typing scheme and five phages from the new phage typing scheme were used for phage typing analysis following standard methodology. RESULTS: Maximum numbers of strains were isolated from cholera-endemic states like Gujarat and Maharashtra. All the isolates were confirmed as V. cholerae O1 biotype ElTor and majority of them were serotype Ogawa (93.2%). New phage typing scheme resulted in almost 100% typeable V. cholerae O1 strains included in this study and phage type 27 was the predominant type. Although 80% of the strains used in this study were sensitive to all the vibrio phages, S5 phage was found most efficient in lysing cholera strains indicating its broader host range. CONCLUSION: The current study identified phage type 27 as the most dominant type and serotype Ogawa was found continuous in circulation throughout the year which has caused recent cholera outbreaks in India during the past years. Phage sensitivity data propose an alternative cost-effective approach to prevent cholera outbreak by therapeutic uses of typing phages irrespective of origin or clonality of the strains.

15.
Crit Rev Microbiol ; 46(2): 182-193, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-32282268

RESUMO

The last century has witnessed several assaults from RNA viruses, resulting in millions of death throughout the world. The 21st century appears no longer an exception, with the trend continued with escalated fear of SARS coronavirus in 2002 and further concern of influenza H5N1 in 2003. A novel influenza virus created the first pandemic of the 21st century, the pandemic flu in 2009 preceded with the emergence of another deadly virus, MERS-CoV in 2012. A novel coronavirus "SARS-CoV-2" (and the disease COVID-19) emerged suddenly, causing a rapid outbreak with a moderate case fatality rate. This virus is continuing to cause health care providers grave concern due to the lack of any existing immunity in the human population, indicating their novelty and lack of previous exposure. The big question is whether this novel virus will be establishing itself in an endemic form or will it eventually die out? Endemic viruses during circulation may acquire mutations to infect naïve, as well as individual with pre-existing immunity. Continuous monitoring is strongly advisable, not only to the newly infected individuals, but also to those recovered individuals who were infected by SARS-CoV-2 as re-infection may lead to the selection of escape mutants and subsequent dissemination to the population.


Assuntos
Betacoronavirus/patogenicidade , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/virologia , Pneumonia Viral/epidemiologia , Pneumonia Viral/virologia , Betacoronavirus/genética , COVID-19 , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/mortalidade , Surtos de Doenças , Doenças Endêmicas , Humanos , Mutação , Pandemias , Pneumonia Viral/imunologia , Pneumonia Viral/mortalidade , SARS-CoV-2 , Virulência/genética
16.
Appl Opt ; 59(3): 735-741, 2020 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-32225202

RESUMO

In this experimental work we report our findings about a cascade (Ξ) transition 5S1/2→5P3/2→5D3/2 of both 85,87Rb atoms under different laser detuning combinations. The relative power levels of two individual lasers are adjusted under a counter-propagating configuration so that the system exhibits Autler-Townes splitting (ATS). However, the ATS, which is otherwise difficult to detect in a room-temperature alkali vapor cell offering large Doppler background, is well resolved here by using a combination of modulation transfer and phase-sensitive detection techniques. The results show that the AT components clearly indicate the hyperfine structure of 5D3/2 level for 87Rb isotope. For 85Rb, the resolution of ATS is limited by the relatively closer proximity of 5D3/2 hyperfine components. The results are also verified through blue fluorescence detection by monitoring the 5D3/2→6P3/2→5S1/2 non-degenerate decay arm. The technique is easy to implement and is able to reveal the hyperfine structure of the excited levels. However, the technique is not a good choice when an excited level with dense hyperfine structure is targeted.

17.
Rev Sci Instrum ; 91(3): 033306, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-32260021

RESUMO

An analytical and cold model study of a prototype extended vane rod-type RFQ (radio frequency quadrupole linac) is presented. The bead-pull measurement allowed us to experimentally determine the effect of shaping of the vane-supporting posts and, most interestingly, the size of the vacuum enclosure in the dipolar and quadrupolar field asymmetry. Disk shaped beads of BaTiO3 have been tailor made for this purpose. The special shape of the beads has allowed precise measurements of frequency shifts all along the length of the RFQ. The measured quadrupolar asymmetry and dipole component at a radial distance of 7 mm from the beam axis are within ±1% for the optimized structure. Particle tracking of a 10 mA proton beam with a simulated 3D field for the optimized full scale RFQ with modulated vanes has been carried out. Simulation shows vertical and horizontal shifts of only 0.01 mm and 0.03 mm, respectively, for the accelerated beam at the exit of RFQ. The percentage of accelerated particles lying within an energy width of ±40 keV about 800 keV is increased from 86% for the original enclosure to 88% for the reduced enclosure, whereas the transmission efficiency is 100% for both the cases.

18.
Int Rev Immunol ; 39(1): 21-36, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31707873

RESUMO

Annual flu led by influenza viruses is contemplated to be one of the foremost global health challenges due to its rapid spread leading to the life-threatening epidemic or pandemic. An enormous number of people die due to flu and its associated intricacies every year. Annual vaccination is considered to be the gold standard strategy to protect the individual from acquiring infection and further decimation, although recent estimates suggest that overall flu vaccine effectiveness was within 19% to 53% in last five years. A significant weakness of current vaccination is its inability to protect an individual from different or mutant flu strain. Host immune system performs a vital role during natural infection or after vaccination leading to influenza-specific immunities. Previous imprints of common flu or vaccination may alter the outcomes of the current vaccination. Current flu vaccine regime does not consider the host immune status before vaccination. Irrespective of the previous influenza exposure history or prior flu vaccination, individual get flu vaccination based on WHO recommendation with selected strains which may be the reason why induction of broad immunities does not transpire with their testimonial. Over the last few decades, scientific research had identified the role of preexisting immunities on vaccination or natural infection outcome. In this review, we are proposing the concept of personalized flu vaccines depending on individual immune status. We will also discuss why individual was unable to induce broader immunities to protect itself from diverse influenza viruses and how we can accomplish that goal with the current findings.


Assuntos
Variação Genética/imunologia , Vírus da Influenza A/imunologia , Vacinas contra Influenza/imunologia , Influenza Humana/imunologia , Vacinação/estatística & dados numéricos , Variação Genética/genética , Humanos , Sistema Imunitário/imunologia , Sistema Imunitário/virologia , Imunidade/imunologia , Vírus da Influenza A/genética , Vacinas contra Influenza/administração & dosagem , Influenza Humana/epidemiologia , Influenza Humana/prevenção & controle , Pandemias/prevenção & controle , Medicina de Precisão/métodos , Vacinação/métodos
19.
J Glob Infect Dis ; 10(2): 84-88, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29910569

RESUMO

OBJECTIVES: We have isolated a total of five newer cholera phages which are novel broad host range to incorporate with the existing phage typing schemes for an extended typing scheme. MATERIALS AND METHODS: These newly isolated phages were well characterized including the electron micrograph. A total of 300 Vibrio cholerae strains were isolated from the different endemic region in India were included in phage typing study. RESULTS: These phages were found different from the existing phages. Electron microscopic results showed that the phages belonged to myophage and podophage group. Characterization of the phages based on pH, temperature, and organic solvent sensitivity showed differences among the phages used in this study. All the strains of Vibrio O1 were typeable (100%) with the five set of cholera phages. Of these, 40% strains were clustered under Type-1. CONCLUSION: The newer Vibrio phages are novel and broad host range and will be useful to incorporate with the existing phage typing system for more precisely discriminate the strains of Vibrio cholerae.

20.
Appl Opt ; 57(13): 3612-3617, 2018 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-29726540

RESUMO

In this work, we address the issue of the suitability of blue fluorescent light as a frequency offset reference during the ladder-level excitation 5S1/2→5P3/2→5D3/2 of Rb85 atoms. A simple pump-probe spectroscopy experiment is performed to generate non-degenerate blue light emission produced by the spontaneous decay route 5D3/2→6P3/2→5S1/2. By varying the relative intensity of the pump-probe combination, we can hover between regimes dominated by mechanisms such as double resonance optical pumping (DROP) and Autler-Townes splitting. The efficacy of the blue fluorescence (420 nm) as a frequency offset reference is pronounced under the DROP regime due to its narrow (∼natural) linewidth. To provide further insight into the stability performance, the pump laser connecting the 5P3/2→5D3/2 transition is stabilized to the peak of the blue light with the help of a probe stabilized to the saturation absorption signal of the 5S1/2→5P3/2 transition. For this purpose, we used the coherence-induced modulation transfer technique. The error frequency noise power spectra and the subsequent Allan variance calculation clearly show that probe fluctuations are transferred to the pump laser because of an existing two-photon coherent coupling.

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