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Abstract Background Saline lakes are home to various archaea that play special and crucial roles in the global biogeochemical cycle. The Qinghai-Tibet Plateau hosts a large number of lakes with diverse salinity ranging from 0.1 to over 400 g/L, harboring complex and diverse archaea. To the best of our knowledge, the formation mechanisms and potential ecological roles of archaea in Qinghai-Tibetan Plateau saline lakes remain largely unknown. Results Using High-throughput Illumina sequencing, we uncovered the vastly distinct archaea communities between two typical saline lakes with significant salinity differences on the Qinghai Tibet Plateau (Qinghai saline lake and Chaka hypersaline lake) and suggested archaea played different important roles in methanogenesis-related and nitrate reduction-related functions of these two lakes, respectively. Rather than the individual effect of salinity, the composite effect of salinity with diverse environmental parameters (e.g., temperature, chlorophyll a, total nitrogen, and total phosphorus) dominated the explanation of the variations in archaeal community structure in different habitats. Based on the network analysis, we further found the correlations between dominant archaeal OTUs were tight but significantly different between the two habitats, implying that archaeal interactions may also largely determine the shape of archaeal communities. Conclusion The present study improved our understanding of the structure and function of archaea in different saline lakes on the Qinghai-Tibet Plateau and provided a new perspective on the mechanisms underlying shaping their communities.

With the widespread use of tetracycline antibiotics (TCs) and the application of manure fertilizer in farmland, TCs and their metabolites especially 4-epimers have been heavily detected in agricultural soil. However, existing studies have focused on the residual and environmental behavior of maternal TCs, and few studies have looked at the ecotoxicity of their 4-epimers in soil. In this study, the degradation and interconversion of tetracycline (TC), oxytetracycline (OTC) and their 4-epimers (4-epitetracycline, ETC; 4-epioxytetracycline, OTC) were revealed. Their effects on antibiotic resistance genes (ARGs), mobile genetic elements (MGEs) and bacterial community in soil were also investigated in comparison. The results showed that the 4-epimers could be substantially transformed to their parents and degraded as a whole. The degradation rates of four selected pollutants are followed: TC > OTC > ETC > EOTC. This indicated that when TCs entered the soil, part of TCs transformed into slower-degraded 4-epimers, and these 4-epimers could also be converted back to their antibiotic parents, causing the long-term residue of TCs in soil. When added to the soil alone, TC and OTC significantly promoted the proliferation of most ARGs and MGEs, among them, trb-C, IS1247 and IS1111 were the top three genes in abundance. ETC and EOTC had little effect at the beginning. However, as the 4-epimers continuously converted into their parents after one month of cultivation, ETC and EOTC treatments showed similar promoting effect on ARGs and MGEs, indicating that the effect of ETC and EOTC on soil resistome was lagged and mainly caused by their transformed parents. Nocardioides, unclassified_Rhizobiaceae, norank_Sericytochromatia, Microlunatus, Solirubrobacter and norank_67-14 were the most frequent hosts of ARGs, Most of which belong to the phylum Actinobacteria. Due to their large transformation to TCs, slow degradation rate and potential effects on soil microbes and ARGs, the harm of TCs’ 4-epimers on soil ecosystem cannot be ignored.

Anthropogenic activities are driving significant changes in coastal ecological environments, increasingly spotlighting microorganisms associated with seagrass bed ecosystems. Labyrinthula is primarily recognized as a saprophytic protist associated with marine detritus, and it also acts as an opportunistic pathogen affecting marine algae, terrestrial plants and mollusks, especially in coastal environments. The genus plays a key role in the decomposition of marine detritus, facilitated by its interactions with diatoms and through the utilization of a diverse array of carbohydrate-active enzymes to decompose seagrass cell walls. However, human activities have significantly influenced the prevalence and severity of seagrass wasting disease (SWD) through factors such as climate warming, increased salinity and ocean acidification. The rise in temperature and salinity, exacerbated by human-induced climate change, has been shown to increase the susceptibility of seagrass to Labyrinthula, highlighting the adaptability of pathogen to environmental stressors. Moreover, the role of seagrass in regulating pathogen load and their immune response to Labyrinthula underscore the complex dynamics within these marine ecosystems. Importantly, the genotype diversity of seagrass hosts, environmental stress factors and the presence of marine organisms such as oysters, can influence the interaction mechanisms between seagrass and Labyrinthula. Besides, these organisms have the potential to both mitigate and facilitate pathogen transmission. The complexity of these interactions and their impacts driven by human activities calls for the development of comprehensive multi-factor models to better understand and manage the conservation and restoration of seagrass beds.

The biocurrent generated by soil extracellular electron transfer (EET) partly drives biogeochemical cycles and controls soil quality. However, it is unclear how the soil abiotic and biotic conditions affect the biocurrent conduction. In this study, the response relationship of soil microenvironment and in-situ biocurrent was studied. The results showed that red soil exhibited the optimal electron transfer efficiency, as evidenced by the maximum current density and accumulated charge output, with increments of 56–93 % and 80–2800 %, respectively, compared with the other five types of soils. Soil physicochemical properties were the most important factor on the biocurrent generation, and further the quantity and bioavailability of dissolved organic matter, NH4+-N content, and lower pH were predictive indicators for the exoelectrogenic processes of soils. In addition, the high soil biocurrent was likely determined by a complex synergistic network of the transformation of carbon and nitrogen, electroactive bacteria involving the functions of cell wall/membrane and cytochrome enzyme metabolism and transport related EET process. Overall, we provide an insight into the relationship among soil biocurrent conduction, physicochemical properties, bacteria community and metabolic function, and a support for bioelectrochemical technology application.

Bioelectric field is a stimulated force to degrade xenobiotic pollutants in soils. However, the effect of bioelectric field on microplastics (MPs) aging is unclear. The degradation behavior of polyvinyl chloride (PVC), polyethylene (PE) and polylactic acid (PLA) was investigated in an agricultural soil microbial electrochemical system in which bioelectric field was generated in-situ by native microbes. Based on the density function theory, the energy gaps between the highest and the lowest occupied molecular orbitals of the three polymers with periodic structure were 4.20, 7.24 and 10.09 eV respectively, and further decreased under the electric field, indicating the higher hydrolysis potential of PLA. Meanwhile, the mass loss of PLA in the closed-circuit group (CC) was the highest on day 120, reaching 8.94%, which was 3.01–3.54 times of that without bioelectric field stimulation. This was mainly due to the enrichment of plastic-degrading bacteria and a robust co-occurrence network as the deterministic assembly process, e.g., the abundance of potential plastic-degrading bacteria on the surface of PLA and PVC in the CC increased by 1.92 and 1.30 times, respectively, compared to the open-circuit group. In terms of functional genes, the xenobiotic biodegradation and metabolism capacity of plasticsphere in the CC were stronger than that in soil, and determined by the bioaccessibility of soil nitrogen and carbon. Overall, this study explored the promoting effect of bioelectric field on the degradation of MPs and reveled the mechanism from quantum chemical calculations and microbial community analysis, which provides a novel perception to the in-situ degradation of MPs.

Fungi have long been known to be dynamic in coastal water columns with multiple trophic modes. However, little is known about their interactions with abiotic and biotic components, contribution to the biological carbon pump (BCP), and organic matter remineralization in the oceanic water column. In this study, we investigated how fungi vary spatially and how their variations relate to that of bacteria in the water column of the South China Sea (SCS). Fungi were about three orders less prevalent than bacteria, and the main factors influencing their distribution were depth, temperature, and distance from the sites of riverine inputs. The decline in the abundance of fungi with depth was less steep than that of bacteria. Correlation tests revealed a strong positive association between the abundance of fungi and bacteria, especially in the twilight (r = 0.62) and aphotic (r = 0.70) zones. However, the co-occurrence network revealed mutual exclusion between certain members of fungi and bacteria. The majority of fungi in the water column were saprotrophs, which indicated that they were generally involved in the degradation of organic matter, particularly in twilight and aphotic zones. Similar to bacteria, the involvement of fungi in the metabolism of carbohydrates, proteins, and lipids was predicted, pointing to their participation in the turnover of organic carbon and the biogeochemical cycling of carbon, nitrogen, and sulfur. These findings suggest that fungi play a role in BCP and support their inclusion in marine microbial ecosystem models.

ABSTRACT Labyrinthulomycetes protists are an important heterotrophic component of microeukaryotes in the world’s oceans, but their distribution patterns and ecological roles are poorly understood in pelagic waters. This study employed flow cytometry and high-throughput sequencing to characterize the abundance, diversity, and community structure of Labyrinthulomycetes in the pelagic Eastern Indian Ocean. The total Labyrinthulomycetes abundance varied much more among stations than did the abundance of prokaryotic plankton, reaching over 1,000 cells mL−1 at a few “bloom” stations. The total Labyrinthulomycetes abundance did not decline with depth throughout the whole water column (5 to 2,000 m) like the abundance of prokaryotic plankton did, and the Labyrinthulomycetes average projected biomass over all samples was higher than that of the prokaryotic plankton. However, Labyrinthulomycetes diversity showed obvious vertical variations, with richness, Shannon diversity, and evenness greatest in the upper epipelagic, lower epipelagic, and deep waters, respectively. Many abundant phylotypes were detected across multiple water layers, which aligned with the constant vertical Labyrinthulomycetes biomass, suggesting potential sinking and contribution to the biological pump. Hierarchical clustering revealed distinct ecotypes partitioning by vertical distribution patterns, suggesting their differential roles in the carbon cycle and storage processes. Particularly, most phylotypes showed patchy distributions (occurring in only few samples) as previously found in the coastal waters, but they were less associated with the Labyrinthulomycetes blooms than the prevalent phylotypes. Overall, this study revealed distinct patterns of Labyrinthulomycetes ecotypes and shed light on their importance in the pelagic ocean carbon cycling and sequestration relative to that of the prokaryotic plankton. IMPORTANCE While prokaryotic heterotrophic plankton are well accepted as major players in oceanic carbon cycling, the ecological distributions and functions of their microeukaryotic counterparts in the pelagic ocean remain largely unknown. This study focused on an important group of heterotrophic (mainly osmotrophic) protistan microbes, the Labyrinthulomycetes, whose biomass can surpass that of the prokaryotic plankton in many marine ecosystems, including the bathypelagic ocean. We found patchy horizontal but persistent vertical abundance profiles of the Labyrinthulomycetes protists in the pelagic waters of the Eastern Indian Ocean, which were distinct from the spatial patterns of the prokaryotic plankton. Moreover, multiple Labyrinthulomycetes ecotypes with distinct vertical patterns were detected and, based on the physiologic, metabolic, and genomic understanding of their cultivated relatives, were inferred to play multifaceted key roles in the carbon cycle and sequestration, particularly as contributors to the vertical carbon export from the surface to the dark ocean, i.e., the biological pump.

The consequences of climate change may directly or indirectly impact the marine biosphere. Although ocean stratification has been recognized as one of the crucial consequences of ocean warming, its impacts on several critical aspects of marine microbes remain largely unknown in the Indian Ocean. Here, we investigate the effects of water stratification, in both surface and subsurface layers, on hydrogeographic parameters and bacterioplankton diversity within the equatorial eastern Indian Ocean (EIO). Strong stratification in the upper 200 m of equatorial EIO was detected with evidential low primary productivity. The vertical bacterioplankton diversity of the whole water columns displayed noticeable variation, with lower diversity occurring in the surface layer than in the subsurface layers. Horizontal heterogeneity of bacterioplankton communities was also in the well-mixed layer among different stations. SAR11 and Prochlorococcus displayed uncharacteristic low abundance in the surface water. Some amplicon sequence variants (ASVs) were identified as potential biomarkers for their specific depths in strongly-stratified water columns. Thus, barriers resulting from stratification are proposed to function as an ‘ASV filter’ to regulate the vertical bacterioplankton community diversity along the water columns. Overall, our results suggest that the effects of stratification on the structure and diversity of bacterioplankton can extend up to the bathypelagic zone in the strongly-stratified waters of the equatorial EIO. This study provides the first insight into the effect of stratification on the subsurface microbial communities in the equatorial eastern Indian Ocean.

Media supplementation with exogenous chemicals is known to stimulate the accumulation of important lipids produced by microalgae and thraustochytrids. However, the roles of exogenous chemicals in promoting and preserving the terpenoids pool of thraustochytrids have been rarely investigated. Here, we realized the effects of two media supplements—mannitol and biotin—on the biomass and squalene production by a thraustochytrid strain (Thraustochytrium sp. ATCC 26185) and elucidated their mechanism of action. A significant change in the biomass was not evident with the exogenous addition of these supplements. However, with mannitol (1 g/L) supplementation, the ATCC 26185 culture achieved the best concentration (642 ± 13.6 mg/L) and yield (72.9 ± 9.6 mg/g) of squalene, which were 1.5-fold that of the control culture (non-supplemented). Similarly, with biotin supplementation (0.15 mg/L), the culture showed 459 ± 2.9 g/L and 55.7 ± 3.2 mg/g of squalene concentration and yield, respectively. The glucose uptake rate at 24 h of fermentation increased markedly with mannitol (0.31 g/Lh−1) or biotin (0.26 g/Lh−1) supplemented culture compared with non-supplemented culture (0.09 g/Lh−1). In addition, the reactive oxygen species (ROS) level of culture supplemented with mannitol remained alleviated during the entire period of fermentation while it alleviated after 24 h with biotin supplementation. The ∆ROS with mannitol was better compared with biotin supplementation. The total antioxidant capacity (T-AOC) of the supplemented culture was more than 50% during the late stage (72–96 h) of fermentation. Our study provides the potential of mannitol and biotin to enhance squalene yield and the first lines of experimental evidence for their protective role against oxidative stress during the culture of thraustochytrids.

Thraustochytrids have gained significant attention in recent years because of their considerable ecological and biotechnological importance. Yet, the influence of seasons and habitats on their culturable diversity and lipid profile remains poorly described. In this study, a total of 58 thraustochytrid strains were isolated from the coastal waters of Qingdao, China. These strains were phylogenetically close to five thraustochytrid genera, namely Botryochytrium, Oblongichytrium, Schizochytrium, Thraustochytrium, and Sicyoidochytrium. Most of the isolated strains were classified into the genera Thraustochytrium and Oblongichytrium. Further diversity analysis revealed that samples collected from nutrient-rich habitats and during summer/fall yielded significantly higher culturable diversity of thraustochytrids than those from low-nutrient habitats and winter/spring. Moreover, sampling habitats and seasons significantly impacted the fatty acid profiles of the strains. Particularly, the Oblongichytrium sp. OC931 strain produced a significant amount (153.99 mg/L) of eicosapentaenoic acid (EPA), accounting for 9.12% of the total fatty acids, which was significantly higher than that of the previously reported Aurantiochytrium strains. Overall, the results of this study fill the gap in our current understanding of the culturable diversity of thraustochytrids in the coastal waters and the impact of the sampling habitats and seasons on their capacity for lipid accumulation.

Thraustochytrids are well-known unicellular heterotrophic marine protists because of their promising ability to accumulate docosahexaenoic acid (DHA). However, the implications of their unique genomic and metabolic features on DHA production remain poorly understood. Here, the effects of chemical and physical culture conditions on the cell mass and DHA production were investigated for a unique thraustochytrid strain, PKU#SW8, isolated from the seawater of Pearl River Estuary. All the tested fermentation parameters showed a significant influence on the cell mass and concentration and yield of DHA. The addition of monosaccharides (fructose, mannose, glucose, or galactose) or glycerol to the culture medium yielded much higher cell mass and DHA concentrations than that of disaccharides and starch. Similarly, organic nitrogen sources (peptone, yeast extract, tryptone, and sodium glutamate) proved to be beneficial in achieving a higher cell mass and DHA concentration. PKU#SW8 was found to grow and accumulate a considerable amount of DHA over wide ranges of KH2PO4 (0.125–1.0 g/L), salinity (0–140% seawater), pH (3–9), temperature (16–36 °C), and agitation (140–230 rpm). With the optimal culture conditions (glycerol, 20 g/L; peptone, 2.5 g/L; 80% seawater; pH 4.0; 28 °C; and 200 rpm) determined based on the shake-flask experiments, the cell mass and concentration and yield of DHA were improved up to 7.5 ± 0.05 g/L, 2.14 ± 0.03 g/L, and 282.9 ± 3.0 mg/g, respectively, on a 5-L scale fermentation. This study provides valuable information about the fermentation conditions of the PKU#SW8 strain and its unique physiological features, which could be beneficial for strain development and large-scale DHA production.

Schizochytrium species are one of the best oleaginous thraustochytrids for high-yield production of docosahexaenoic acid (DHA, 22:6). However, the DHA yields from most wild-type (WT) strains of Schizochytrium are unsatisfactory for large-scale production. In this study, we applied the atmospheric and room-temperature plasma (ARTP) tool to obtain the mutant library of a previously isolated strain of Schizochytrium (i.e., PKU#Mn4). Two rounds of ARTP mutagenesis coupled with the acetyl-CoA carboxylase (ACCase) inhibitor (clethodim)-based screening yielded the mutant A78 that not only displayed better growth, glucose uptake and ACCase activity, but also increased (54.1%) DHA content than that of the WT strain. Subsequent optimization of medium components and supplementation improved the DHA content by 75.5 and 37.2%, respectively, compared with that of mutant A78 cultivated in the unoptimized medium. Interestingly, the ACCase activity of mutant A78 in a medium supplemented with biotin, citric acid or sodium citrate was significantly greater than that in a medium without supplementation. This study provides an effective bioengineering approach for improving the DHA accumulation in oleaginous microbes.

Species of Schizochytrium are well known for their remarkable ability to produce lipids intracellularly. However, during their lipid accumulation, reactive oxygen species (ROS) are generated inevitably as byproducts, which if in excess results in lipid peroxidation. To alleviate such ROS-induced damage, seven different natural antioxidants (ascorbic acid, α-tocopherol, tea extract, melatonin, mannitol, sesamol, and butylated hydroxytoluene) were evaluated for their effects on the lipid accumulation in Schizochytrium sp. PKU#Mn4 using a fractional factorial design. Among the tested antioxidants, mannitol showed the best increment (44.98%) in total fatty acids concentration. However, the interaction effects of mannitol (1 g/L) and ascorbic acid (1 g/L) resulted in 2.26 ± 0.27 g/L and 1.45 ± 0.04 g/L of saturated and polyunsaturated fatty acids (SFA and PUFA), respectively, in batch fermentation. These concentrations were further increased to 7.68 ± 0.37 g/L (SFA) and 5.86 ± 0.03 g/L (PUFA) through fed-batch fermentation. Notably, the interaction effects yielded 103.7% and 49.6% increment in SFA and PUFA concentrations in batch fermentation. The possible mechanisms underlining those increments were an increased maximum growth rate of strain PKU#Mn4, alleviated ROS level, and the differential expression of lipid biosynthetic genes andupregulated catalase gene. This study provides an applicable strategy for improving the accumulation of SFA and PUFA in thraustochytrids by exogenous antioxidants and the underlying mechanisms.

The element stoichiometry of bacteria has received considerable attention because of their significant role in marine ecosystems. However, relatively little is known about the composition of major structural elements of the unicellular heterotrophic protists—thraustochytrids, despite their widely recognized contribution to marine nutrient cycling. Here, we analyze the cell volume and elemental C, N, H, and S cell content of seven cultured thraustochytrids, isolated from different marine habitats, in the exponential and stationary growth phases. We further derive the relationships between the cell volume and elemental C and N content of the cultured thraustochytrids. The cell volumes varied significantly (p < 0.001) among the isolates, with median values of 96.9 and 212.5 μm3 in the exponential and stationary phases, respectively. Our results showed a significantly higher percentage of C (64.0 to 67.5) and H (9.9 to 13.2) but a lower percentage of N (1.86 to 2.16) and S (0.34 to 0.91) in the stationary phase, along with marked variations of C and N fractions among isolates in the exponential phase. The cell C (5.7 to 203.7 pg) and N (0.65 to 6.1 pg) content exhibited a significant (p < 0.001) linear relationship with the cell volume (27.7 to 510 μm3). On further analysis of the relationship across the two growth phases, we found the equation (cell C (pg) = 0.356 × cell volume (μm3) + 20.922) for stationary phase cells more appropriate for C estimation of natural thraustochytrids. This study provides the first experimental evidence of higher cell C density than the current estimate and relatively larger C contribution of thraustochytrids than bacteria to the marine organic pool.

Although composting is effective in deactivating antibiotic substances in manure, the influence of compost fertilization on the occurrence and dissemination of antibiotic resistance in arable soils remains to be controversial. Herein, the abundance and diversity of two sulfonamide resistance genes (sul1 and sul2) in soil fertilized by compost spiked with two concentrations of sulfadiazine (1 and 10 mg kg−1) were studied intensively by qPCR and high throughput sequencing based on a two-month microcosm experiment. The concentration of sulfadiazine decreased rapidly after spiking from 25% at Day 1 to less than 2.7% at Day 60. Relative abundance of both sul1 and sul2 were significantly higher in soil amended with compost than the non-amended control at Day 1 and slightly decreased with incubation time except for sul2 in the S10 treatment. Soil bacterial communities were transiently shifted by compost fertilization regardless of the presence of sulfadiazine. Relative abundance of genera in three hubs positively interlinked with sul1 and sul2 were significantly higher in compost treated soil than the control at Day 1, 7 and 21, but not at Day 60. High throughput sequencing analyses revealed that most detected (>67% in relative abundance) sul1 and sul2 genotypes sharing >99% similarity with those found in gammaproteobacterial pathogens frequently were commonly present in compost and soil. These results indicated that compost fertilization might increase the abundance rather than diversity of sulfadiazine-resistant populations in soil, which may be facilitated by the presence of sulfadiazine.

Introduction: Unsafe abortions account for about 5% maternal deaths in India. A very small proportion of induced abortions takes place at registered facilities, and many women prefer taking abortion pills as a method of contraception. The current study was planned to explore the factors related to use of abortion pills and knowledge about various contraceptives among slum-dwelling women. Materials and Methods: A community-based cross-sectional study was carried out in the urban slum area catered by a public health dispensary for 2 months among 22 females. Data collection was performed using a semistructured interview schedule for quantitative data, and focused group discussion (FGD) was performed for qualitative data collection. Thematic data analysis was performed for FGD. Themes pertaining to knowledge, ease of use, and source and side effects of abortion pills, knowledge, use, and fears/myths for modern contraceptive methods were identified. Results: A total of 35 unwanted pregnancies were reported by 22 women study participants, out of which only three were continued. Most study participants came to know about abortion pills from their neighborhood friends or maternal relatives such as sisters, and 90% of them preferred either chemists or local private practitioners for getting abortion pills. Fears and myths for modern contraceptive methods, their non-regular supply, and easy availability of abortion pills were the main reason for their use. Conclusion: The study highlights women’s perspective of using abortion pills over modern contraceptive methods as a method to limit their family size or for spacing and highlights the lack of family planning counseling. Such a situation calls for enhanced counseling services for modern contraceptive methods and health promotion programs to alleviate fears about contraceptive methods.

Abstract Background Several methodological tests are available to detect SARS-CoV-2 antibody. Tests are mostly used in the aid of diagnosis or for serological assessment. No tests are fully confirmatory and have variable level of diagnostic ability. We aimed at assessing agreement with three serological tests: quantitative anti receptor binding domain ELISA (Q-RBD), qualitative ELISA (WANTAI SARS-CoV-2 Ab) and qualitative chemiluminescence assay (CLIA). Methods This study was a part of a large population based sero-epidemiological cohort study. Participants aged 1 year or older were included from 25 randomly selected clusters each in Delhi urban (urban resettlement colony of South Delhi district) and Delhi rural (villages in Faridabad district, Haryana). Three type of tests were applied to all the baseline blood samples. Result of the three tests were evaluated by estimating the total agreement and kappa value. Results Total 3491 blood samples collected from March to September, 2021, out of which 1700 (48.7%) from urban and 1791 (51.3%) from rural. Overall 44.1% of participants were male. The proportion of sero-positivity were 78.1%, 75.2% and 31.8% by Wantai, QRBD and CLIA tests respectively. The total agreement between Wantai and QRBD was 94.5%, 53.1% between Wantai and CLIA, and 56.8% between QRBD and CLIA. The kappa value between these three tests were 0.84 (95% CI 0.80–0.87), 0.22 (95% CI 0.19–0.24) and 0.26 (95% CI 0.23–0.28). Conclusions There was strong concordance between Wantai and QRBD test. Agreement between CLIA with other two tests was low. Wantai and QRBD tests measuring the antibody to same S protein can be used with high agreement based on the relevant scenario.

Abstract Background Despite significant economic growth and development, undernutrition among children remains a major public health challenge for low- and middle-income countries in the twenty-first century. In Millennium Development Goals, India committed halving the prevalence of underweight children by 2015. This study aimed to explain the geographical variation in child malnutrition level and understand the socio-biomedical predictors of child nutrition in India. Methods We used the data from India’s National Family Health Survey 2015–2016. The survey provided estimates of stunting, wasting, and underweight at the national, state, and district level to measure nutritional status of under-five children. Level of stunting, wasting and underweight at the district level are considered as outcome variables. We have used variance inflation factor to check the multicollinearity between potential predictors of nutrition. In this study, we performed spatial analysis using ArcGIS and multiple linear regression analysis using Stata version 15. Results Five states (Uttar Pradesh, Bihar, Madhya Pradesh, Jharkhand and Meghalaya) had very high prevalence of stunting (40% and above). High prevalence of wasting was documented in Jharkhand, Madhya Pradesh, Chhattisgarh, and Karnataka (23 to 29%). Jharkhand, Madhya Pradesh, Maharashtra, and Chhattisgarh had the highest proportion of underweight children in the country. We found that electricity and clean fuel use in the household, use of iodized salt, and level of exclusive breastfeeding had significantly negative influence on the stunting level in the districts. The use of iodized salt has similar effect on the wasting status of under-five children in the districts (b: − 0.27, p

Background: Estimating seroepidemiolgical prevalence of SARS-CoV-2 antibody is an essential public health strategy. There is insufficient evidence of prevalence among those belonging to young age population in India. Objective: To compare the SARS-CoV-2 seropositivity rate between children and adults in selected sites from India. Materials and Methods: This was a multicentric population-based seroepidemiological study conducted in selected urban and rural areas of five sites selected from four states (Delhi, Odisha, Uttar Pradesh, Tripura) of India. Participants aged ≥1 year were included from different clusters of each area. Total serum antibody against SARS-CoV-2 virus was assessed qualitatively by using a standard enzyme-linked immunosorbent assay (ELISA) kit.Results: Data collection period was from 15 March 2021 to 10 June 2021. Total available data was of 4509 participants, of whom 700 were

Repeated serological testing tells about the change in the overall infection in a community. This study aimed to evaluate changes in antibody prevalence and kinetics in a closed cohort over six months in different sub-populations in India. The study included 10,000 participants from rural and urban areas in five states and measured SARS-CoV-2 antibodies in serum in three follow-up rounds. The overall seroprevalence increased from 73.9% in round one to 90.7% in round two and 92.9% in round three. Among seropositive rural participants in round one, 98.2% remained positive in round two, and this percentage remained stable in urban and tribal areas in round three. The results showed high antibody prevalence that increased over time and was not different based on area, age group, or sex. Vaccinated individuals had higher antibody prevalence, and nearly all participants had antibody positivity for up to six months.

BackgroundTransmissibility within closed settings, such as households, can provide a strategic way to characterize the virus transmission patterns because the denominator can be well defined. We aimed to characterize the household transmission of Severe Acute Respiratory Syndrome Coronavirus (SARS CoV-2) and its associated risk factors.MethodsThis prospective case-ascertained study was conducted among the household contacts of laboratory-confirmed SARS CoV-2 cases residing in Ballabgarh, Haryana. We enrolled 148 index cases and their 645 household contacts between December 16, 2020 and June 24, 2021. We defined household contact as any person who had resided in the same household as a confirmed COVID-19 case. Baseline data collection and sample collection for real time- reverse transcriptase polymerase chain reaction (RT-PCR) and IgM/IgG against SARS CoV-2 were done on day 1 visit, and followed for a period of 28 days. RT-PCR was repeated on day 14 or whenever the contact is symptomatic and blood sample for serology was repeated on day 28. We estimated household secondary infection rate (SIR) and other epidemiological indicators-median incubation period and serial interval. We employed binomial logistic regression to quantify risk factors associated with infection.ResultsThe household SIR was 30.5% (95% CI: 27.1-34.1%). The secondary clinical attack rate was 9.3% (95% CI: 7.2-11.8). The risk factors that showed higher susceptibility to infection were household contacts who were the primary care giver of the case, whose index cases were symptomatic, those with underlying medical conditions, those living in overcrowded households, who were sharing toilet with the index cases and also who were not wearing a mask when coming in contact with the case. The median (IQR) incubation period was 4 days (4, 5), mean (SD) serial interval 6.4 (±2.2) days, and median (IQR) serial interval 5 days (5, 7).ConclusionHouseholds favour secondary transmission of SARS CoV- 2, hence, index cases are recommended to self-isolate and wear masks; and household contacts to follow strict COVID infection control measures within households when a family member is infected.

Background: Predictors of survival for interstitial lung disease (ILD) in the Indian population have not been studied. The primary objective of the study was to assess the Modified-Gender Age and Physiology (M-GAP) score to predict survival in patients with ILD seen in clinical practice. We also analyzed the role of demographic and radiological characteristics in predicting the survival of patients with ILD. Materials and Methods: In the ILD India registry, data were collected from 27 centers across 19 cities in India between March 2012 and June 2015. A single follow-up was conducted at 18 centers who agreed to participate in the follow-up in 2017. M-GAP score (range 0–5) was calculated with the following variables: age (≤60 years 0, 61–65 years 1, and >65 years 2), gender (female 0, male 1), and forced vital capacity% (>75% 0, 50%–75% 1, and >75% 2). A score of 0–3 and score of 4 and 5 were classified into Stage 1 and 2, respectively. Other predictors of survival, such as the history of tuberculosis, smoking, and the presence of honeycombing on computed tomography scan, were also evaluated. Results: Nine hundred and seven patients were contacted in 2017. Among them, 309 patients were lost to follow-up; 399 were alive and 199 had died. M-GAP was significantly associated with survival. Similarly, other predictors of survival were ability to perform spirometry (hazard ratio [HR]: 0.49, 95% confidence interval [CI]: 0.34–0.72), past history of tuberculosis (HR: 1.57, 95% CI: 1.07–2.29), current or past history of smoking (HR: 1.51, 95% CI: 1.06–2.16), honeycombing (HR: 1.81, 95% CI: 1.29–2.55), a diagnosis of connective tissue disease -ILD (HR: 0.41, 95% CI: 0.22–0.76), and sarcoidosis (HR: 0.24, 95% CI: 0.08–0.77). Conclusion: In a subgroup of patients with newly diagnosed ILD enrolled in ILD India registry and who were available for follow-up, M-GAP score predicted survival. Honeycombing at the time of diagnosis, along with accurate history of smoking, and previous history of tuberculosis were useful indices for predicting survival.

Background: Interstitial lung disease (ILD) is a complex and heterogeneous group of acute and chronic lung diseases of several known and unknown causes. While clinical practice guidelines (CPG) for idiopathic pulmonary fibrosis (IPF) have been recently updated, CPG for ILD other than IPF are needed. Methods: A working group of multidisciplinary clinicians familiar with clinical management of ILD (pulmonologists, radiologist, pathologist, and rheumatologist) and three epidemiologists selected by the leaderships of Indian Chest Society and National College of Chest Physicians, India, posed questions to address the clinically relevant situation. A systematic search was performed on PubMed, Embase, and Cochrane databases. A modified GRADE approach was used to grade the evidence. The working group discussed the evidence and reached a consensus of opinions for each question following face-to-face discussions. Results: Statements have been made for each specific question and the grade of evidence has been provided after performing a systematic review of literature. For most of the questions addressed, the available evidence was insufficient and of low to very low quality. The consensus of the opinions of the working group has been presented as statements for the questions and not as an evidence-based CPG for the management of ILD. Conclusion: This document provides the guidelines made by consensus of opinions among experts following discussion of systematic review of evidence pertaining to the specific questions for management of ILD other than IPF. It is hoped that this document will help the clinician understand the accumulated evidence and help better management of idiopathic and nonidiopathic interstitial pneumonias.

Digital hemoglobinometers have been used as point-of-care tests (POCT) to estimate the burden of anemia in community-based studies and national-level surveys in India. As the accuracy of hemoglobin estimated in POCT varies, there is a need for adjustments to the POCT-hemoglobin to ensure they are closer to reality and are comparable. We used data (collected between 2016 and 2020) (N = 1145) from four studies from India: three among pregnant women and 6–59-month-old children from Haryana and the fourth from a national nutritional survey among 1–19-year-old children. We compared the same individuals’ POCT-hemoglobin (capillary blood) and automated hematology analyzers (AHA) hemoglobin (venous blood) and developed a predictive linear regression model to obtain the correction equation for POCT-hemoglobin. We analyzed paired data from 1145 participants. The correction equation for obtaining the true hemoglobin value = 3.35 + 0.71 × POCT-hemoglobin using capillary blood (adjusted R2—64.4% and mean squared error −0.841 g/dL). In comparison with the AHA-hemoglobin, the mean difference of POCT-hemoglobin was 0.2 g/dL, while with the predicted Hb obtained from the correction equation it was 0.01 g/dL. The correction equation was the first attempt at deriving the true hemoglobin values from the POCTs. There is a need for multi-country collaborative studies to improve the correction equation by adjusting for factors affecting hemoglobin estimation.

Abstract Background There is lack of information on the magnitude of depression among elderly population in India. This systematic review and meta-analysis aimed to estimate the prevalence of depression among elderly population in India. Methods PubMed, Scopus, Web of Science, Embase, PsycINFO, IndMed, and Google Scholar were searched to identify articles reported community-based prevalence of depression among elderly population using screening tools. This study included the articles published during the years 1997 to 2016. Studies conducted in the special population groups, hospitals, reported only a subcategory of depression, and not specified the screening tool were excluded. Data were extracted from published reports and any missing information was requested from authors. Estimates were pooled using random-effects meta-analyses. Subgroup and sensitivity analysis were performed. The publication bias was evaluated by using Egger’s test and visual inspection of the symmetry in funnel plots. Results Fifty-one studies from 16 States of India were included as 56 datasets, which estimated the prevalence of depression among Indian elderly population as 34.4% (95% CI: 29.3–39.7). In sub-group analysis, the pooled prevalence was higher among females, rural populations, and in the eastern part of the country. Studies using non-probability sampling, and GDS and CES-D screening tool showed higher prevalence. Exclusion of the studies with sample size less than 100 and low-quality studies (score

Background: The plaque reduction neutralization test (PRNT) is the gold standard to detect the neutralizing capacity of serum antibodies. Neutralizing antibodies confer protection against further infection. The present study measured the antibody level against SARS-CoV-2 among laboratory-confirmed COVID-19 cases and evaluated whether the presence of anti-SARS-CoV-2 antibodies indicates virus neutralizing capacity. Methods: One hundred COVID-19 confirmed cases were recruited. Their sociodemographic details and history of COVID-19 vaccination, contact with positive COVID-19 cases, and symptoms were ascertained using a self-developed semi-structured interview schedule. Serum samples of the participants were collected within three months from the date of the positive report of COVID-19. The presence of anti-SARS-CoV-2 antibodies (IgA, IgG and IgM antibodies), receptor binding domain antibodies (anti-RBD), and neutralizing antibodies were measured. Findings: Almost all the participants had anti-SARS-CoV-2 antibodies (IgA, IgG and IgM) (99%) and anti-RBD IgG antibodies (97%). However, only 69% had neutralizing antibodies against SARS-CoV-2. Anti-RBD antibody levels were significantly higher among participants having neutralizing antibodies compared with those who did not. Interpretation: The present study highlights that the presence of antibodies against SARS-CoV-2, or the presence of anti-RBD antibodies does not necessarily imply the presence of neutralizing antibodies.

Introduction. This meta-analysis was conducted to estimate the prevalence of hypothyroidism among pregnant women in India. Methods. We searched PubMed, Web of Science, Scopus, Google Scholar, and Shodhganga (Indian thesis repository) for observational studies, providing prevalence of hypothyroidism among pregnant women in India. Systematic study selection and data extraction procedures were followed. Quality assessment of each study was done using JBI critical appraisal checklist. The random effects model was used for pooling the effect sizes. Publication bias was assessed using the funnel plot and rank correlation test. I2 statistics was used to measure heterogeneity across the studies. Heterogeneity in the pooled estimates was further explored with subgroup analyses and meta-regression analysis. Results. Sixty-one studies were found eligible and included in this review. The pooled estimate of the prevalence of hypothyroidism in pregnant women was 11.07% (95% CI: 8.79–13.84, I2 = 99%). Pooled prevalence estimates of subclinical and overt hypothyroidism are 9.51% (95% CI: 7.48–12.04, I2 = 98%) and 2.74% (95% CI: 2.08–3.58, I2 = 94%). Conclusion. We documented 11.07% pooled prevalence of hypothyroidism in pregnant women in India.

The low-and-middle-income country (LMIC) context is volatile, uncertain and resource-constrained. India, an LMIC, has put up a complex response to the COVID-19 pandemic. Using an analytic approach, we have described India’s response to combat the pandemic during the initial months (from 17 January to 20 April 2020). India issued travel advisories and implemented graded international border controls between January and March 2020. By early March, cases started to surge. States scaled up movement restrictions. On 25 March, India went into a nationwide lockdown to ramp up preparedness. The lockdown uncovered contextual vulnerabilities and stimulated countermeasures. India leveraged existing legal frameworks, institutional mechanisms and administrative provisions to respond to the pandemic. Nevertheless, the cross-sectoral impact of the initial combat was intense and is potentially long-lasting. The country could have further benefited from evidence-based policy and planning attuned to local needs and vulnerabilities. Experience from India offers insights to nations, especially LMICs, on the need to have contextualised pandemic response plans.

Summary: Background: Oral rehydration solution (ORS) is a form of oral rehydration therapy (ORT) for diarrhoea that has the potential to drastically reduce child mortality; yet, according to UNICEF estimates, less than half of children younger than 5 years with diarrhoea in low-income and middle-income countries (LMICs) received ORS in 2016. A variety of recommended home fluids (RHF) exist as alternative forms of ORT; however, it is unclear whether RHF prevent child mortality. Previous studies have shown considerable variation between countries in ORS and RHF use, but subnational variation is unknown. This study aims to produce high-resolution geospatial estimates of relative and absolute coverage of ORS, RHF, and ORT (use of either ORS or RHF) in LMICs. Methods: We used a Bayesian geostatistical model including 15 spatial covariates and data from 385 household surveys across 94 LMICs to estimate annual proportions of children younger than 5 years of age with diarrhoea who received ORS or RHF (or both) on continuous continent-wide surfaces in 2000–17, and aggregated results to policy-relevant administrative units. Additionally, we analysed geographical inequality in coverage across administrative units and estimated the number of diarrhoeal deaths averted by increased coverage over the study period. Uncertainty in the mean coverage estimates was calculated by taking 250 draws from the posterior joint distribution of the model and creating uncertainty intervals (UIs) with the 2·5th and 97·5th percentiles of those 250 draws. Findings: While ORS use among children with diarrhoea increased in some countries from 2000 to 2017, coverage remained below 50% in the majority (62·6%; 12 417 of 19 823) of second administrative-level units and an estimated 6 519 000 children (95% UI 5 254 000–7 733 000) with diarrhoea were not treated with any form of ORT in 2017. Increases in ORS use corresponded with declines in RHF in many locations, resulting in relatively constant overall ORT coverage from 2000 to 2017. Although ORS was uniformly distributed subnationally in some countries, within-country geographical inequalities persisted in others; 11 countries had at least a 50% difference in one of their units compared with the country mean. Increases in ORS use over time were correlated with declines in RHF use and in diarrhoeal mortality in many locations, and an estimated 52 230 diarrhoeal deaths (36 910–68 860) were averted by scaling up of ORS coverage between 2000 and 2017. Finally, we identified key subnational areas in Colombia, Nigeria, and Sudan as examples of where diarrhoeal mortality remains higher than average, while ORS coverage remains lower than average. Interpretation: To our knowledge, this study is the first to produce and map subnational estimates of ORS, RHF, and ORT coverage and attributable child diarrhoeal deaths across LMICs from 2000 to 2017, allowing for tracking progress over time. Our novel results, combined with detailed subnational estimates of diarrhoeal morbidity and mortality, can support subnational needs assessments aimed at furthering policy makers' understanding of within-country disparities. Over 50 years after the discovery that led to this simple, cheap, and life-saving therapy, large gains in reducing mortality could still be made by reducing geographical inequalities in ORS coverage. Funding: Bill & Melinda Gates Foundation.

Abstract Background Globally, road traffic injuries are the leading cause of death among those aged 15–29 years. However, road traffic injury research has not received adequate attention from the scientific community in low- and middle-income countries, including India. The present study aims to provide a bibliometric overview of research assessing road traffic injuries in India. Methods We used Scopus to extract relevant research in road traffic injuries published from 1991 to 2017. This study presented the key bibliometric indicators such as trends of annual publications and citations, top 10 authors, journals, institutions and highly cited articles, citation analysis of articles, co-occurrence of keywords, etc. Analysis was performed using Scopus, Microsoft Excel, and VOS-viewer. Results A total of 242 articles were retrieved with an h-index of 18, excluding self-citations. A steadfast growth of publications was documented in last decade, especially after the year 2010. The h-index of the top 10 authors, institutions, journals and highly cited articles did not surpass single digits. A network visualisation map showed that ‘traffic accident’, ‘male’, ‘adolescent’ and ‘child’ were the most commonly encountered key terms. The prominent authors were Gururaj G, Dandona R, and Hyder AA, whereas the top journals were the Indian Journal of Forensic Medicine and Toxicology, Medico Legal Update, and the International Journal of Applied Engineering Research and top institutions were the All India Institute of Medical Sciences, New Delhi, the Indian Institute of Technology, Delhi, and the Administrative Staff College of India. Conclusion In India, road traffic injuries research is inadequate in quantity and quality, warranting greater attention from researchers and policy planners to address the burden of road traffic injuries.

Recent National Mental Health Survey (2015-16) reported a prevalence of 13.7% for any mental disorders excluding tobacco use disorders in India. Translating it into real numbers, nearly 150 million people need active mental health interventions, disproportionately more in rural areas. Major challenges in delivering comprehensive mental health services in rural India are: a) lack of a well-defined strategy; and b) lack of trained mental health manpower. To fill this gap, the global mental health community has increasingly realized the importance of Community Health Workers (CHWs) and role of stepped care approach in mental health service delivery. We propose a model of stepped care approach to fulfil the need of rural India, utilizing the existing health system components for improving mental health knowledge, reducing social stigma for mental disorders, screening for priority mental disorders at community level, ensuring compliance to treatment, timely follow-up, and community-based rehabilitation by mobilising community support for diagnosed cases. This stepped care approach will integrate mental health into Ayushman Bharat’s Health and Wellness Centres (HWCs) for the provision of comprehensive primary health care. Integration of new age technologies such as telepsychiatry, e-health, and mHealth into the proposed model will make it feasible and cost-efficient for inaccessible parts of the country.

Background: In India, more than half of the pregnant women suffer from anemia. Low compliance to iron supplementation is one of the important reasons. Objectives: The objective of the study is to estimate the reduction in the prevalence of anemia, improvement in iron status, and to compare the compliance to oral iron supplementation during pregnancy between directly observed iron-folic acid (IFA) supplementation group and control group. Methods: This was a community-based open labeled parallel block-randomized controlled trial including 400 pregnant women in a rural setting of north India. In the intervention group, the first dose of IFA every week was supervised by ASHA and women were instructed to take the remaining tablets during the week as per the prescription. In control group, IFA tablets were supplemented without direct supervision. Results: After 100 days of IFA supplementation, the reduction in anemia in the intervention group was 6% higher as compared to control group (P = 0.219). The increase in the mean hemoglobin level over and above control group was 0.52 g/dl in intervention group (P < 0.001). However, the mean increase in serum ferritin level in the intervention group was similar to the control group. The mean percentage compliance in the intervention group was almost 9% higher than that of control group (P = 0.001). Conclusion: Directly supervised oral iron (IFA) supplementation improves compliance to oral iron (IFA) supplementation and also improves hemoglobin status among pregnant women. However, the mean increase in serum ferritin and reduction in the prevalence of anemia in the intervention group were not higher than the control group.

Background: Depression in the elderly has been emerged as a serious public health challenge in the developing countries. Elderly population with depression is on rise in India, but is not adequately addressed. This study was planned to ascertain the prevalence of depression among elderly in a rural population of Haryana and assess its socio-demographic correlates. Methods: This study was a community based, cross sectional study, which was conducted in Community Health Centre (CHC), Chiri of Rohtak district (Haryana, India). Of total 124 Anganwadi centres in study area, 10 were randomly selected. A total 500 elderly persons aged 60 years and above were randomly screened for depression. Long form of Geriatric Depression Scale (GDS- 30) was used with cut off score at 22. The Pearson’s Chi-squared test, student’s t test, and multiple logistic regression were used to assess the association of depression in the elderly with its risk factors. Result: In our study, the prevalence of depression in the elderly was 14.4% (95% CI: 11.6- 17.8). Mean age of study population was 68.5 ± 7.7 years. Depression in the elderly had significant association with female gender [OR=2.7 (95% CI 1.4- 5.0)], not being consulted for major decisions [OR=2.7 (95% CI 1.5- 4.7)], presence of any chronic morbidity [OR=2.4 (95% CI 1.3- 4.5)], spending day without doing any activity, work or hobby [OR=3.8 (2.1- 7.1)], and death of any close relative in the last 1 year [OR=2 (1.1- 3.7)] after adjustment of various factors. Conclusion: Our study revealed that the prevalence of depression in the elderly was 14.4% in a rural community of north India.