Rotavirus trends and distribution of genotypes before and during COVID-19 pandemic era: Bangladesh, 2017-2021.

Rotavirus gastroenteritis is accountable for an estimated 128 500 deaths among children younger than 5 years worldwide, and the majority occur in low-income countries. Although the clinical trials of rotavirus vaccines in Bangladesh revealed a significant reduction of severe rotavirus disease by around 50%, the vaccines are not yet included in the routine immunization program. The present study was designed to provide data on rotavirus diarrhea with clinical profiles and genotypes before (2017-2019) and during the COVID-19 pandemic period (2020-2021). Fecal samples were collected from 2% of the diarrheal patients at icddr,b Dhaka hospital of all ages between January 2017 and December 2021 and were tested for VP6 rotavirus antigen using ELISA. The clinical manifestations such as fever, duration of diarrhea and hospitalization, number of stools, and dehydration and so on were collected from the surveillance database (n = 3127). Of the positive samples, 10% were randomly selected for genotyping using Sanger sequencing method. A total of 12 705 fecal samples were screened for rotavirus A antigen by enzyme immunoassay. Overall, 3369 (27%) were rotavirus antigen-positive, of whom children <2 years had the highest prevalence (88.6%). The risk of rotavirus A infection was 4.2 times higher in winter than in summer. Overall, G3P[8] was the most prominent genotype (45.3%), followed by G1P[8] (32.1%), G9P[8] (6.8%), and G2P[4] (6.1%). The other unusual combinations, such as G1P[4], G1P[6], G2P[6], G3P[4], G3P[6], and G9P[6], were also present. Genetic analysis on Bangladeshi strains revealed that the selection pressure (dN/dS) was estimated as <1. The number of hospital visits showed a 37% drop during the COVID-19 pandemic relative to the years before the pandemic. Conversely, there was a notable increase in the rate of rotavirus positivity during the pandemic (34%, p < 0.00) compared to the period before COVID-19 (23%). Among the various clinical symptoms, only the occurrence of watery stool significantly increased during the pandemic. The G2P[4] strain showed a sudden rise (19%) in 2020, which then declined in 2021. In the same year, G1P[8] was more prevalent than G3P[8] (40% vs. 38%, respectively). The remaining genotypes were negligible and did not exhibit much fluctuation. This study reveals that the rotavirus burden remained high during the COVID-19 prepandemic and pandemic in Bangladesh. Considering the lack of antigenic variations between the circulating and vaccine-targeted strains, integrating the vaccine into the national immunization program could reduce the prevalence of the disease, the number of hospitalizations, and the severity of cases.

Drug resistance pattern among ART-naive clients attending an HIV testing and counseling center in Dhaka, Bangladesh.

In Bangladesh, antiretroviral therapy (ART) is provided without screening drug resistance-associated mutations (DRM) among people living with HIV, while DRM might emerge and transmit to the newly infected individual. The present study was aimed to identify DRM among ART-naive clients from an HIV testing and counseling (HTC) center in the initial stages of ART programs. Randomly selected (n = 64) archived plasma samples were used for the pol gene amplification and sequencing by sanger technology. Recovered sequences (n = 10) were genotyped using HIV genotyping tools of NCBI and analyzed using the Stanford University HIV drug resistance database (hivdb.stanford.edu). Various genotypes with a number of DRM were identified in HTC clients, who belonged to different risk groups based on behavioral data. The drug resistance algorithm showed that all samples were fully resistant to tipranavir/ritonavir drugs except for one intermediate resistance. Despite the small sample size, our understanding from this study warrants an ART policy with a DRM monitoring system for the country.

Factors influencing the performance of rapid SARS-CoV-2 antigen tests under field condition.

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.

Epidemiology and genetic characterization of human sapovirus among hospitalized acute diarrhea patients in Bangladesh, 2012-2015.

Human sapovirus, which causes acute gastroenteritis, is not well studied and poorly understood. This study aims to investigate the contribution of sapovirus in diarrhea, their clinical association, and genotypic diversity. Fecal specimens (n = 871) were randomly selected from diarrheal patients who attended International Centre for Diarrhoeal Disease Research, Bangladesh hospital in Dhaka, Bangladesh during January 2012-December 2015 and tested for the presence of sapovirus RNA using real-time polymerase chain reaction. Sapovirus RNA was identified in 2.3% (n = 20) of the samples. Seventy-five percent of the sapovirus positive cases were coinfected with other pathogens, such as rotavirus, norovirus, enterotoxigenic Escherichia coli, adenovirus, Shigella spp., and Vibrio cholerae. A vast genetic diversity was observed among sapovirus with at least seven common genotypes (GI.1, GI.2, GI.7, GII.1, GII.4, GII.6, and GIV), and a new genotype GII.NA1. Some of the GI.1 strains detected were similar to GI.4 in the polymerase region sequence and were confirmed as recombinant strains. Our findings suggest that the overall contribution of sapovirus in hospitalized diarrheal illness is low but highlight enormous genetic diversity.

Complete genome sequence of Escherichia phage iGC_PHA_EC001.

Antimicrobial resistance (AMR) in bacteria poses a global health emergency due to limited treatment options. Here, we report a lytic bacteriophage belonging to Stephanstirmvirinae family against an AMR Escherichia coli (ST2089). Escherichia phage iGC_PHA_EC001 is of genus Phapecoctavirus and 148,445 bp in length, encoding 269 predicted protein-coding sequences and 10 tRNAs. The phage encodes two lytic proteins containing phage_lysozyme (PF00959.22) and cell wall hydrolase_2 (PF07486.15) as catalytic domains, respectively.

Identification of Lytic Phages Against Multidrug-Resistant Klebsiella pneumoniae: Illuminating Hope on Antimicrobial-Resistance.

Background: Lytic phages have been considered as a solution to mitigate the emergence of multidrug-resistant bacteria. Nevertheless, finding phages capable of targeting a broad host-range remains a significant challenge. Materials and Methods: Our study introduces two lytic phages isolated from hospital effluent, which are active against extended-spectrum cephalosporin-resistant Klebsiella pneumoniae. Results: Overnight coculture with host, two purified phage lysates yielded around 3.0 × 107 PFU/mL with an average 0.8 ± 0.2 mm diameter of clear, round, and non-halo plaques in both instances. The genomes of iPHaGe-KPN-11i (177,603 bp, 273 coding sequences [CDS]) and iPHaGe-KPN-12i (178,179 bp, 275 CDS) belong to the Pseudotevenvirus genus. Both phages have at least 120 genes with known functions, including 1 endolysin and 2 tRNAs, and are capable of lysing at least 12 distinct bacterial species in vitro. Conclusions: Most phages are host-specific, whereas our phages can kill multiple bacterial species, enabling their potential use for a broad range of hosts.

Comprehensive Analysis of SARS-CoV-2 Dynamics in Bangladesh: Infection Trends and Variants (2020-2023).

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.

SARS-CoV-2 antigen detection by saliva; an alternative to nasopharyngeal specimen: A cross-sectional study.

Background and Aims: Saliva samples are less invasive and more convenient for patients than naso- and/or oropharynx swabs (NOS). However, there is no US Food and Drug Administration-approved severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) rapid antigen test kit, which can be useful in a prolonged pandemic to reduce transmission by allowing suspected individuals to self-sampling. We evaluated the performances of High sensitive AQ+ Rapid SARS-CoV-2 Antigen Test (AQ+ kit) using nasopharyngeal swabs (NPs) and saliva specimens from the same patients in laboratory conditions. Methods: The real-time reverse transcription-polymerase chain reaction (rRT-PCR) test result was used for screening the inrolled individuals and compared as the gold standard. NP and saliva samples were collected from 100 rRT-PCR positives and 100 negative individuals and tested with an AQ+ kit. Results: The AQ+ kit showed good performances in both NP and saliva samples with an overall accuracy of 98.5% and 94.0%, and sensitivity of 97.0% and 88.0%, respectively. In both cases, specificity was 100%. AQ+ kit performance with saliva was in the range of the World Health Organization recommended value. Conclusion: xOur findings indicate that the saliva specimen can be used as an alternative and less invasive to NPs for quick and reliable SARS-CoV-2 antigen detection.

The evolutionary footprint of influenza A subtype H3N2 strains in Bangladesh: implication of vaccine strain selection.

In February each year, World Health Organization (WHO) recommends candidate vaccine viruses for the forthcoming northern hemisphere (NH) season; however, the influenza season in the temperate zone of NH begins in October. During egg- or cell culture-propagation, the vaccine viruses become too old to confer the highest match with the latest strains, impacting vaccine effectiveness. Therefore, an alternative strategy like mRNA-based vaccine using the most recent strains should be considered. We analyzed influenza A subtype H3N2 strains circulating in NH during the last 10 years (2009-2020). Phylogenetic analysis revealed multiple clades of influenza strains circulating every season, which had substantial mismatches with WHO-recommended vaccine strains. The clustering pattern suggests that influenza A subtype H3N2 strains are not fixed to the specific geographical region but circulate globally in the same season. By analyzing 39 seasons from eight NH countries with the highest vaccine coverage, we also provide evidence that the influenza A, subtype H3N2 strains from South and Southeast Asia, including Bangladesh, had the highest genetic proximity to the NH strains. Furthermore, insilico analysis showed minimal effect on the Bangladeshi HA protein structure, indicating the stability of Bangladeshi strains. Therefore, we propose that Bangladeshi influenza strains represent genetic makeup that may better fit and serve as the most suitable candidate vaccine viruses for the forthcoming NH season.

COVID-19 reinfections among naturally infected and vaccinated individuals.

The protection against emerging SARS-CoV-2 variants by pre-existing antibodies elicited due to the current vaccination or natural infection is a global concern. We aimed to investigate the rate of SARS-CoV-2 infection and its clinical features among infection-naïve, infected, vaccinated, and post-infection-vaccinated individuals. A cohort was designed among icddr,b staff registered for COVID-19 testing by real-time reverse transcriptase-polymerase chain reaction (rRT-PCR). Reinfection cases were confirmed by whole-genome sequencing. From 19 March 2020 to 31 March 2021, 1644 (mean age, 38.4 years and 57% male) participants were enrolled; where 1080 (65.7%) were tested negative and added to the negative cohort. The positive cohort included 750 positive patients (564 from baseline and 186 from negative cohort follow-up), of whom 27.6% were hospitalized and 2.5% died. Among hospitalized patients, 45.9% had severe to critical disease and 42.5% required oxygen support. Hypertension and diabetes mellitus were found significantly higher among the hospitalised patients compared to out-patients; risk ratio 1.3 and 1.6 respectively. The risk of infection among positive cohort was 80.2% lower than negative cohort (95% CI 72.6-85.7%; p < 0.001). Genome sequences showed that genetically distinct SARS-CoV-2 strains were responsible for reinfections. Naturally infected populations were less likely to be reinfected by SARS-CoV-2 than the infection-naïve and vaccinated individuals. Although, reinfected individuals did not suffer severe disease, a remarkable proportion of naturally infected or vaccinated individuals were (re)-infected by the emerging variants.

HIV-1 drug resistance and genotypes circulating among HIV-positive key populations in Bangladesh: 2016 update.

OBJECTIVE: HIV-1 subtyping data of Bangladeshi strains are available in global HIV Sequence Database up to 2007, and there is no sequence of drug resistance profile based on the pol gene segment. This study aimed to update HIV genotyping data and describe the drug resistance mutations for the first time from Bangladesh using specimens from the latest HIV sero-surveillance conducted in 2016. STUDY DESIGN AND METHODS: During HIV sero-surveillance, a total of 1268 people who inject drugs (PWID) and 3765 female sex workers (FSW) were screened and among them, 230 (18.1%) PWID and 7 (0.2%) FSW were HIV positive. Among HIV positives, randomly selected 74 specimens (60 male-PWID, 7 female-PWID, and 7 FSW) were subjected to gag, pol, and env gene sequencing using gene-specific primers. Genotyping was decided based on the partial gag and env genes while transmission dynamics was based on the gag sequence (n = 237). Drug resistance profiles were obtained by using the algorithm of the established available drug resistance database. RESULTS: HIV subtype C and C-related recombinants have remained the major circulating genotypes in Bangladesh. Although the recurring transmission of subtype C occurred among PWID, we identified possible transmission to other key populations (KPs), which suggests spillover from PWID through the sexual route. The prevalence of drug-resistant mutation was low, and all strains were susceptible to NRTIs and NNRTIs drugs. Unique recombination forms (URF) with genotype C for gag-pol and A1 for env was also identified. CONCLUSIONS: The study findings warrant continuous monitoring of HIV-positive individuals and future investigation to identify social networks within and between KPs to halt the transmission and prevent new infections.

Genome Sequence of a SARS-CoV-2 Strain from Bangladesh That Is Nearly Identical to United Kingdom SARS-CoV-2 Variant B.1.1.7.

The coding-complete genome sequence of a coronavirus strain, SARS-CoV-2/human/BGD/G039392/2021, obtained from a symptomatic male patient with coronavirus disease 2019 (COVID-19) in Dhaka, Bangladesh, is reported. The strain G039392 is 99.9% identical to the UK variant B.1.1.7.

Epidemiology and genotypes of group A rotaviruses in cattle and goats of Bangladesh, 2009-2010.

Group A rotavirus (RVA) is recognized as a major cause of severe gastroenteritis in newborn calves and goat kids. We estimated the proportion of ruminants infected with rotavirus and identified the circulating genotypes in cattle and goats in Bangladesh. Between May 2009 and August 2010, fecal samples were collected from 520 cattle and goats presenting with diarrhea at three government veterinary hospitals in three districts of Bangladesh. All samples were screened for RVA RNA using real-time, one-step, reverse transcription polymerase chain reaction (qRT-PCR). Of the 520 animals tested, 11.7% (61) were positive for RVA RNA, with 6.2% (15/241) and 16.5% (46/279) positivity in cattle and goats, respectively. RVA positive samples were further characterized by nucleotide sequence analysis of two structural protein gene fragments, VP7 (G genotype), and VP4 (P genotype). Among 17 successfully sequenced strains, G8 (17.9%) was the most prevalent G-genotype followed by G10 (8%) and G6 (1.6%). P[1] (11.3%) was the most frequently detected P-genotype followed by P[11] (3.2%) and P[15] (1.6%). The most common VP7/VP4 combinations for cattle were G10P[11], G10P[15], and G6P[11], and for goat, G8P[1], and G10P[1]. Phylogenetic analysis of the RVA strains showed clustering with bovine and caprine strains from neighboring India. The study adds to our understanding of the genetic diversity of bovine and caprine rotavirus strains in Bangladesh. Our findings highlight the importance of rotavirus surveillance in cattle and goat populations, which may serve as a potential source for genetic reassortment and zoonotic transmission.

Distribution of rotavirus genotypes in Dhaka, Bangladesh, 2012-2016: Re-emergence of G3P[8] after over a decade of interval.

Group A rotavirus causes a substantial proportion of diarrhoea related deaths worldwide among children under five years. We analyzed rotavirus prevalence and genotypes distribution among patients admitted with diarrhoea at icddr,b hospital in Dhaka during 2012-16. Stool specimens (n = 1110) were collected from diarrhoea patients and tested for RVA antigen using enzyme immunoassay. Rotavirus positive samples were G (VP7) and P (VP4) genotyped by RT-PCR and sanger sequencing. Data on clinical manifestations were collected from icddr,b hospital surveillance system. A total of 351 (32%) patients were positive for rotavirus antigen, about half of those were children under two years old. During the study period, G1P[8] (27%) was the most prevalent strain, followed by G12P[8] (15%) and G9[P4] (9%). Mixed G or P genotypes were identified in a substantial proportion (23%) with few strains of rare combinations such as G1P[4], G1P[6], G2P[6], G2P[8], G9P[6]. The genotypic fluctuation was noteworthy; G12P[8] was the major strain in 2012-14 but sharply decreased in 2015-16 when G1P[8] became the most common strain. G3P[8] re-emerged (17%) in 2016 after 11 years. Since the Government of Bangladesh has planned to include rotavirus vaccine in national immunization programme from 2018, our data will provide baseline information on rotavirus genotypes in the pre-vaccination era to observe the selection pressure on genotypes in the post vaccination epoch.