Genetic diversity and evolutionary patterns of SARS-CoV-2 among the Bhutanese population during the pandemic.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic, caused by a dynamic virus, has had a profound global impact. Despite declining global COVID-19 cases and mortality rates, the emergence of new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants remains a major concern. This study provides a comprehensive analysis of the genomic sequences of SARS-CoV-2 within the Bhutanese population during the pandemic. The primary aim was to elucidate the molecular epidemiology and evolutionary patterns of SARS-CoV-2 in Bhutan, with a particular focus on genetic variations and lineage dynamics. METHODS: Whole-genome sequences of SARS-CoV-2 collected from Bhutan between May 2020 and February 2023 (n=135) were retrieved from the Global Initiative on Sharing All Influenza Database. RESULTS: The SARS-CoV-2 variants in Bhutan were predominantly classified within the Nextstrain clade 20A (31.1%), followed by clade 21L (20%) and clade 22D (15.6%). We identified 26 Pangolin lineages with variations in their spatial and temporal distribution. Bayesian time-scaled phylogenetic analysis estimated the time to the most recent common ancestor as February 15, 2020, with a substitution rate of 0.97×10-3 substitutions per site per year. Notably, the spike glycoprotein displayed the highest mutation frequency among major viral proteins, with 116 distinct mutations, including D614G. The Bhutanese isolates also featured mutations such as E484K, K417N, and S477N in the spike protein, which have implications for altered viral properties. CONCLUSION: This is the first study to describe the genetic diversity of SARS-CoV-2 circulating in Bhutan during the pandemic, and this data can inform public health policies and strategies for preventing future outbreaks in Bhutan.

Molecular epidemiology of dengue fever outbreaks in Bhutan, 2016-2017.

Dengue continues to pose a significant public health problem in tropical and subtropical countries. In Bhutan, first outbreak of dengue fever (DF) was reported in 2004 in a southern border town, followed by sporadic cases over the years. In this study, we analysed DF outbreaks that occurred in 3 different places during the years 2016 and 2017. A total of 533 cases in 2016 and 163 in 2017 were suspected of having of DF, where young adults were mostly affected. A total of 240 acute serum specimens collected and analyzed for serotype by nested RT-PCR revealed predominance of serotypes 1 and 2 (DENV-1 and 2). Phylogenetic analysis using envelope gene for both the serotypes demonstrated cosmopolitan genotype which were closely related to strains from India, indicating that they were probably imported from the neighboring country over the past few years.

Malaria elimination in Bhutan: asymptomatic malaria cases in the Bhutanese population living in malaria-risk areas and in migrant workers from India.

In 2018, Bhutan reported 54 cases of malaria, of which six were indigenous, 14 introduced and 34 imported. Considering the continuous reduction in the number of indigenous cases, Bhutan plans to eliminate malaria by 2025 under the Bhutan Malaria Elimination Strategy. The study was conducted to assess the presence of asymptomatic plasmodial infection in both, Bhutanese population living in malaria-risk areas and in migrant workers to guide the elimination strategies. A cross-sectional study was conducted from April to May 2016 in 750 Bhutanese people and 473 migrant workers. Plasmodium falciparum and Plasmodium vivax infections were investigated by using a rapid diagnostic test (RDT) and the polymerase chain reaction (PCR). Prevalence of asymptomatic plasmodial infection based on PCR was 0.27% (95% CI: 0.05-1.07%) among Bhutanese people with a mean age of 43 years old. The proportions of males and females were 45% and 55%, respectively. Among migrant workers, the prevalence of asymptomatic plasmodial infection was 0.42% (95% CI: 0.07-1.69%) with a mean age of 30 years old. The majority of migrant workers were from the neighboring Indian State of West Bengal (57.51%), followed by Assam (12.26%). RDT in both study groups did not detect any plasmodial infection. The presence of a low prevalence of asymptomatic plasmodial infection indicates that the current elimination strategies and interventions are effective.

Significance of Autophagy in Dengue Virus Infection: A Brief Review.

Dengue virus (DENV) causes asymptomatic to severe life-threatening infections and affects millions of people worldwide. Autophagy, a cellular degradative pathway, has both proviral and antiviral functions. Dengue virus triggers the autophagy pathway for the successful replication of its genome. However, the exact mechanism and the viral factors involved in activating this pathway remain unclear. This review summarizes the existing knowledge on the mechanism of autophagy induction and its significance during DENV infection.

Distribution of influenza virus types by age using case-based global surveillance data from twenty-nine countries, 1999-2014.

BACKGROUND: Influenza disease burden varies by age and this has important public health implications. We compared the proportional distribution of different influenza virus types within age strata using surveillance data from twenty-nine countries during 1999-2014 (N=358,796 influenza cases). METHODS: For each virus, we calculated a Relative Illness Ratio (defined as the ratio of the percentage of cases in an age group to the percentage of the country population in the same age group) for young children (0-4 years), older children (5-17 years), young adults (18-39 years), older adults (40-64 years), and the elderly (65+ years). We used random-effects meta-analysis models to obtain summary relative illness ratios (sRIRs), and conducted meta-regression and sub-group analyses to explore causes of between-estimates heterogeneity. RESULTS: The influenza virus with highest sRIR was A(H1N1) for young children, B for older children, A(H1N1)pdm2009 for adults, and (A(H3N2) for the elderly. As expected, considering the diverse nature of the national surveillance datasets included in our analysis, between-estimates heterogeneity was high (I2>90%) for most sRIRs. The variations of countries' geographic, demographic and economic characteristics and the proportion of outpatients among reported influenza cases explained only part of the heterogeneity, suggesting that multiple factors were at play. CONCLUSIONS: These results highlight the importance of presenting burden of disease estimates by age group and virus (sub)type.

An Evaluation of the National Malaria Surveillance System of Bhutan, 2006-2012 as It Approaches the Goal of Malaria Elimination.

INTRODUCTION: Bhutan is progressing toward malaria elimination. The purpose of this evaluation was to assess the ability of the surveillance system from 2006 to 2012 to meet the objectives of the Bhutan Vector-borne Disease Control Program (VDCP) and to highlight priorities requiring attention as the nation transitions to elimination. METHODS: The evaluation was conducted using the Center for Disease Control guidelines for evaluating public health surveillance systems. Data sources included a search of publically available literature, VDCP program data, and interviews with malaria surveillance personnel. Blood slide quality assurance and control through formal assessment of slide preparation and measures of between-reader correlation were performed. RESULTS: Total malaria cases declined from 2006 to 2012. The average slide positivity rate decreased from 3.4% in 2006 to 0.2% in 2012. The proportion of non-residents in all cases increased to its highest value of 22.6% in 2012, and significant clustering in the border regions of India was noted, with Sarpang accounting for more cases than any other district from 2009 onward. Case detection was almost exclusively passive, but flexibility and sensitivity was demonstrated by the later addition of active case detection and specification of imported and locally acquired cases. Spatial data were limited to the village level, not allowing identification of transmission hotspots. For blood smears, statistical measures of between-reader agreement and predictive value were not computed. Blood smear quality was suboptimal by at least one criterion in over half of evaluated smears. Timeliness in reporting of cases was on a weekly to monthly basis, and did not meet the WHO goal of immediate notification. CONCLUSION: As of 2012, the national malaria surveillance system demonstrated flexibility, representativeness, simplicity, and stability. The full potential for data analysis was not yet realized. Attaining the goal of malaria elimination will require system function enhancement through increased and more accurate case detection and rapid investigation, improved health worker training and accountability, focally targeted response measures, and, in particular, the challenge of finding re-introductions of infections from India. Many such measure have been undertaken or planned as part of the next phase of the Bhutan's National Strategic Plan.