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This study explored the physical properties of MAX phase borides, M2GaB (M = Sc, V, Nb, Ta), aided by the density functional theory (DFT) for the first time. The optimized lattice constants were obtained by minimizing the total energy. We checked the thermodynamic stability by computing the formation energies. We calculated the electronic band structure, density of states (DOS), and charge density mapping to reveal the electronic ground state and bonding nature. The computed stiffness constants (Cij) confirmed the mechanical stability of the investigated compounds. Young's modulus, shear modulus, bulk modulus, and Poison's ratio have been computed using Cij. We calculated the Pugh's ratio, Poisson's ratio, and Cauchy pressure to judge the ductility/brittleness. The Vickers hardness values were calculated. The anisotropic properties of M2GaB compounds were studied by the elastic moduli's directional projections and the anisotropy indices' calculations. We have discussed the acoustic behavior of the M2GaB phases. We have also investigated the Grüneisen parameter, the Debye temperature ϴD, the thermal expansion coefficient, the specific heat, the Helmholtz free energy, the entropy, the internal energy, and the lattice thermal conductivity (Kph) of these borides. To determine the suitability as thermal barrier coating (TBC) materials or whether the compounds are appropriate for high-temperature applications, the minimum thermal conductivity (Kmin) and melting temperature (Tm) have also been calculated. The compounds' dynamical stability was examined using the phonon dispersion curves. The optical parameters have been studied, and it has been found that these compounds are compatible as coating materials to reduce solar heating.

The M2GaB (M = Ti, Zr, Mo, Hf) MAX phase borides were investigated in the present study. We have calculated the fracture toughness, brittleness index, acoustic behavior, Mulliken bond-overlap population, theoretical Vickers hardness, f-index, phonon, charge density mapping, and thermodynamic and optical properties via the density functional theory (DFT). To assess the correctness of our calculations, we revisit the lattice constants, band structure, density of states, elastic constants, mechanical stabilities, and dynamic stabilities. We studied these compounds' formation energies, elastic constants Cij, and phonon dispersion curves to evaluate their chemical, mechanical, and dynamical stability. The fracture toughness and brittleness index were calculated to determine the crack extension and damage tolerance resistance. The acoustic behavior was also studied. The Mulliken bond population was used to investigate the distribution of electrons between the atomic bonds and to determine the compounds' Vickers hardness. Calculating the f-index, we analyzed the bonding strength along the a- and c-directions. The essential thermodynamic properties of M2GaB (M = Ti, Zr, Mo, Hf) compounds were calculated to understand their thermal response at different temperatures and possible applications. Finally, we computed the optical properties to assess their electronic response to the incident photon and predict the possibility of their use.

Intro: Avian influenza viruses (AIV) have been frequently detected in live bird markets (LBMs), primarily in urban areas LBMs are potential sources of AIV, especially for spillover to other species, including humans. We aimed to investigate the diversity, prevalence, and associated risk factors of circulating AIVs in peri-urban and rural markets in Bangladesh. Methods: We collected 200 pool environmental fecal or offal swabs samples from 63 LBMs in 4 sub-districts between 2017 and 2018. We tested the samples for the AIV matrix gene (M-gene) followed by H5, H7, and H9 subtypes using real-time reverse transcriptase-polymerase chain reaction (rRT-PCR). We conducted a univariable analysis and then generalized linear mixed model (GLMM) to identify the associated risk factors of AIV. Findings: We found an 80.95% (95% CI: 69.09-89.75) overall prevalence of AIV at the LBM level. Stall level prevalence for both A/H5 and A/H9 was 7.5% (95% CI: 4.26-12.07) and for HA/untyped was 25.5% (95% CI: 19.61-32.13). We did not find any samples positive for A/H7. In GLMM, we considered LBMs as random effects which did not show any extra variability in the model. In GLMM, we identified peri-urban market, presence of ducks, no separation of sick birds, source of birds from the middlemen, cleaning with water only, access of dogs, throwing wastage in an open place, and observed wild birds, were significantly associated with AIV contamination at stall level in LBMs. Conclusion: We found a high level of different AIVs circulating in the LBMs in the peri-urban and rural areas. A lack of proper biosecurity practices in the poultry stalls could risk AIV spillover from poultry to humans. We recommend continuous monitoring for the emergence of novel strains of AIV and ensuring the biosecurity practices in LBMs in peri-urban and rural settings.

Intro: The avian influenza virus (AIV) subtype H9N2 is endemic in domestic poultry in most Asian countries and occasionally spillover to humans. On the report of a suspected human A/H9 outbreak, a multidisciplinary team investigated the source of infection and extent of the outbreak in a rural village between February 2-4, 2017. Methods: We surveyed the community within a 1km radius of the index case house. Anthropologists conducted observation and key informant interviews to understand the human poultry interaction and poultry rearing practices. We collected swab samples and data from poultry (n=55) and humans (n=18). We tested all samples using specific real-time RT-PCR for influenza virus A (M gene), followed by subtype H5, H7, H9, and N2 and sequenced. Findings: We observed backyard poultry frequently scavenged inside and outside the kitchen and bedroom. The poultry farmers reported that children were involved in bird-raising activities and kept their chickens inside their living room at night. They handled sick poultry and slaughtered it without personal protective equipment. They rarely used soap after handing and slaughtering poultry and threw the poultry offal and entrails in the nearest water body or bushes. All human samples were negative against AIV. None of the poultry samples were positive for H5 and H7. H9N2 prevalence was 16.4% (n=9/55; 95%CI: 7.8-28.8) in bird level and 23.8% (n=5/21; 95%CI: 8.2-47.2) in farm level. Phylogenetic analysis of the H9N2 sequences suggests that these are like the previously circulated Bangladeshi G1-like lineage. Conclusion: The investigation revealed that H9N2 was circulating in the rural community and highlighted the significance of monitoring and characterizing AIV to understand the emergence of novel strains in poultry and the risk of spillover to humans. Human and poultry interaction with risky behavioral practices might facilitate transmitting the AIV from poultry to humans.

Intro: Poultry, like Pigeons and quail farming, is a growing sector in Bangladesh. However, the role of pet birds in Avian Influenza Virus (AIV) transmission is not fully understood. Hence, this study aimed to investigate the prevalence and risk factors of AIV subtypes in pigeons and quails at LBMs. Methods: We collected oropharyngeal and cloacal swab samples from 626 birds in 8 districts of Bangladesh from 2017 to 2021. We tested samples for the matrix gene (M gene) followed by H5, H7, and H9 subtypes using rRT-PCR. We then used statistical modeling to investigate the seasonal and temporal patterns and risk factors of AIV. Findings: The prevalence of AIV in pigeons is 17.36%, and in quail is 38.75%. The prevalence of A/H5, A/H9, and A/H5/H9 in quail is 4.17%, 17.92%, and 1.67%, respectively. Furthermore, the prevalence of A/H5, A/H9, and A/H5/H9 in pigeons is 2.85%, 2.59%, and 0.26%. The AIV infection was higher in dry than in wet seasons in both species. The mixed-effect logistic regression model showed that the vendors having waterfowl (AOR: 2.13; 95% CI: 1.04-4.33), purchasing birds from wholesale market (AOR: 2.96; 95% CI: 1.48-5.92), mixing sick birds with healthy ones (AOR: 1.60; 95% CI: 1.04-2.45) and mingling unsold birds with new birds (AOR: 3.07; 95% CI: 2.01-4.70) were significantly more likely to be positive against AIV. The odds of AIV were more than twice as high in quail (AOR: 2.57; 95% CI: 1.61-4.11) as in pigeons. Moreover. The sick and dead birds had a fourfold higher risk of AIV infection (AOR: 4.19; 95% CI: 2.38-7.35) than healthy birds. Conclusion: Our study revealed that proper hygienic practices at the vendors in LBM are not maintained. We recommend improving biosecurity practices at vendor level in LBM to limit the risk of AIV infection in pigeons and quail in Bangladesh.

Intro: In January 2017, a highly pathogenic avian influenza (HPAI) H5N1 outbreak was reported at a chicken farm in Dhamrai, Bangladesh. Subsequently, we investigated outbreak settings to determine the extent of the outbreak and whether HPAI has been circulating in the live bird market (LBM) and among wild birds and to identify possible associated risk factors of infection. Methods: We surveyed nearly all LBMs (N=45) in outbreak areas. We collected oropharyngeal swab samples from dead crows (N=3) and environmental pool samples from LBMs (N=116). We tested the swabs using real-time RT-PCR for Mgene and followed HA and NA subtyped and sequenced. We conducted a univariable analysis and then generalized linear mixed model (GLMM) to identify the associated risk factors of AIV contamination at LBMs. Findings: The team observed house crows feeding on poultry wastage in neighboring LBMs, and results expressed that, in crows, 100% (n=3; 95%CI: 29-100) were positive for A/H5N1. Of the 116 environmental samples, 36% (n=42; 95% CI: 27.5-45.6) were positive for AIV, including: A/H5 4.3% (n=5; 95% CI: 1.4-9.7), A/H9 6% (n=7; 95% CI: 2.5-12.1), 1% A/H5/H9 co-infection (n=1; 95%CI: 0.02-4.7) and A/untyped 25% (n=29; 95% CI: 17.4-33.9). In the multivariable model, we identified multiple poultry species, improper disposal of offal, slaughtering of poultry, and access of wild birds were associated with AIV contamination at the shop level. Phylogenetic analysis based on HA and NA genes suggests H5N1 in the crows and LBM is similar to the Bangladeshi 2.3.2.1a clade that circulated in 2011. Conclusion: The investigation suggests multiple AIV subtypes circulating in LBMs and crows. Outbreak settings serve as an effective tool to detect major AIVs that pose a public health risk and lay a foundation for both veterinary and public health officials if one or more of these viruses causes outbreaks or significant disease in birds or humans.

Intro: We investigated two poultry mortality events in northwest Bangladesh, one in backyard poultry in Pabna in March 2017 and another in a commercial layer farm in Mymensingh in January 2018, to determine and molecularly characterize the etiological agent and to assess putative risk factors of disease outbreaks in both areas. Methods: We collected pooled swab samples from affected birds and environmental pooled swabs from affected and neighboring commercial poultry farms, backyard poultry, and live bird markets (LBM). We tested samples using specific real-time RT-PCR for influenza virus A (M gene), followed by HA and NA subtypes and sequenced and performed mutation analysis. Findings: We detected the H5N1 virus in the affected birds and all production and trading systems at both outbreak sites. Phylogenetic analysis of H5N1sequences revealed that the outbreaks were caused by reassortant of clade 2.3.2.1a H5N1 virus, which had also been detected in poultry at LBMs in Dhaka during an overlapping period. We identified several mutations likely to affect possible phenotypic changes, such as increased mammalian adaptation, reduced susceptibility to antiviral agents, and reduced host antiviral response. Investigation into poultry-keeping practices showed that most of the households, farms, and LBMs did not employ adequate biosecurity and hygiene, where (i) backyard poultry were typically reared in farmers’ dwellings, (ii) slaughter remnants were being discarded in the open where wild birds were scavenging waste, and (iii) farmers and vendors were generally not employing hand sanitizing after handling poultry. Conclusion: The investigation revealed that the relatedness of H5N1 strains across large spatial scales is high, suggesting a readily spreading and continuing evolution of the virus. Thus, the results contribute to sketching a bleak picture of the current AIV situation, the necessity for ongoing surveillance to track the evolution of H5N1 viruses in Bangladesh, and that adequate mitigation measures are urgently required.

Intro: Rift valley fever (RVF) and Q fever are vector-borne zoonotic diseases affecting both humans and many animal species, and are responsible for a high rate of abortion in infected domestic ruminants. Although animals are the main source of RVF and Q fever outbreaks in humans globally, the disease remains underestimated in Bangladesh. In order to fill this gap, we conducted a cross- sectional study to determine the seroprevalence of RVF and Q fever and to identify the potential risk factors associated with their infection in domestic ruminants in Bangladesh. Methods: We collected 568 blood samples from camels (n = 36), cattle (n = 56), sheep (n = 357), and goats (n = 119) from three districts in Bangladesh between 2017 and 2018. We administered a pre-tested questionnaire during sample collection. We tested serum samples using a competitive enzyme linked immunosorbent assay (c-ELISA) to detect RVF and G fever specific immunoglobulin (IgG). Findings: The overall seroprevalence of Q fever was 8.45% (n = 48; 95% CI: 06.3–11.0), comprising of camel-16.67%, goats-10.08%, sheep-7.84%, and cattle-3.57%. Seroprevalence was higher in adults (n = 45; 10.3%), fair body condition (n = 6; 19.35%), and animals fed on a zero-grazing system (n = 43; 11.23%). In a multivariable logistic regression model, animal species and body condition score were significantly associated with Q fever seroprevalence (p

Background: Nipah virus (NiV) infection, often fatal in humans, is primarily transmitted in Bangladesh through the consumption of date palm sap contaminated by Pteropus bats. Person-to-person transmission is also common and increases the concern of large outbreaks. This study aimed to characterize the molecular epidemiology, phylogenetic relationship, and the evolution of the nucleocapsid gene (N gene) of NiV. Methods: We conducted molecular detection, genetic characterization, and Bayesian time-scale evolution analyses of NiV using pooled Pteropid bat roost urine samples from an outbreak area in 2012 and archived RNA samples from NiV case patients identified during 2012–2018 in Bangladesh. Results: NiV-RNA was detected in 19% (38/456) of bat roost urine samples and among them; nine N gene sequences were recovered. We also retrieved sequences from 53% (21 out of 39) of archived RNA samples from patients. Phylogenetic analysis revealed that all Bangladeshi strains belonged to NiV-BD genotype and had an evolutionary rate of 4.64 × 10−4 substitutions/site/year. The analyses suggested that the strains of NiV-BD genotype diverged during 1995 and formed two sublineages. Conclusion: This analysis provides further evidence that the NiV strains of the Malaysian and Bangladesh genotypes diverged recently and continue to evolve. More extensive surveillance of NiV in bats and human will be helpful to explore strain diversity and virulence potential to infect humans through direct or person-to-person virus transmission.

Purpose: Bangladesh has faced recurrent house crow (Corvus splendens) mortality incidents due to highly pathogenic avian influenza (HPAI) viruses since 2011. We investigated one such event in Dhaka in 2017 to detect and molecularly characterize the avian influenza virus (AIV) in crows and poultry from nearby live bird markets (LBMs). Methods & Materials: We collected cloacal and oropharyngeal swabs from moribund and dead crows (N=163) and environmental samples from 16 neighboring LBMs (N=145). We tested all samples using specific q-PCR for influenza A (M gene) H5/H7/H9/N1/N2/N6. All H5 positive samples were inoculated into embryonated eggs for virus culture. We performed conventional RT-PCR and Sanger sequencing of the isolated viruses and used MEGAX for phylogenetic analysis. Results: We identified 3 house crow roosts that had evidence of crow morbidity and mortality and crows feeding on poultry offal and wastage in neighboring LBMs. Ninety-one percent of crows (n=149; 95% Confidence Interval (CI):86-95) were positive for A/H5 including 89.3% for H5N1 (n =118), 2.0% for H5N6 (n = 3) and 8.7% H5Nx (n = 13). Among LBMs samples, 58.3% were positive with A/H5 (n=60; 95%CI:33-49), containing 88.3% H5N1 (n=53), 3.3% H5N6 (n=2), 8.3% H5NX (n=5); 8.7% for A/H9N2 (n=9), 6.8% for A/H5N1/H9N2 (n=7) and 26.2% for A/untypable (n=27). None of the crow and LBM samples were positive for H7. Phylogenetic analysis based on HA and NA genes of H5N1 and H5N6 suggests that the virus belonging to clade 2.3.2.1a and 2.3.4.4B respectively. Conclusion: Data findings suggest that multiple subtypes of H5 including H5Nx are circulating in both crows and poultry; surprisingly co-circulation of H5 subtypes in LBMs without mortality in chickens. The virus may thus have been transmitted to crows while they were feeding on poultry waste in the LBMs. Whether the virus is non-pathogenic in chickens but pathogenic in crows or it rapidly evolved in crows to become pathogenic and because mortality is unresolved. We suggest improved LBM biosecurity measures to reduce the risk of influenza virus spillover to wild birds, which would also benefit avoiding spill-over risks to humans and Bangladesh being at the epicenter of the next pandemic.

Purpose: Highly pathogenic avian influenza (H5N1) has caused ≥550 reported outbreaks in poultry and wild birds in Bangladesh since 2007. Responding to reports of a crow mortality event in Rajshahi, a multidisciplinary team investigated the crow mortalities to identify the etiologic agent, source of the infection, and characterize the extent of the outbreak between January 15th and February 20th, 2017. Methods & Materials: We surveyed house crow roosts, neighboring poultry farms, and live bird market (LBM) in the outbreaks areas and observed roosting and feeding behavior of crows. We collected cloacal and oropharyngeal swabs from moribund and dead crows (N=58), environmental samples from 12 LBM (N=162), and 14 poultry farms (N=65) as well as samples from 28 severe acute respiratory illness (SARI) patients as part of existing hospital-based influenza surveillance. All samples were tested using specific real-time RT-PCR for influenza virus A (M gene) and followed by subtype H5, H7 and H9, and N1. Results: Ninety-one percent of crows (n=53;95% Confidence Interval (CI): 81-97%) were positive for A/H5N1. Among LBMs samples, 37.6% (n=61, 95%CI: 30-46) were positive for influenza A including 55.7% for H5N1 (n=34), 9.8% for H9N2 (n=6), 4.9% for H5N1/H9N2 (n=3), 29.5% for influenza A/untypable (n=18). Of the poultry farm samples, 10.7% (n=7; 95%CI: 4-21) were positive for influenza A comprising 14.3% of A/H9 (n=1) and 85.7% (n=6) of A/untypable. None of the crow and LBM samples were positive for H7. All human samples were negative for influenza A. Phylogenetic analysis based on the sequence of HA and NA gene suggesting a new reassortant of clade 2.3.2.1a that previously circulated in 2015. Conclusion: Our findings suggest that multiple subtypes of avian influenza viruses are circulating in LBMs without mortality in poultry. Crows may have been infected by consuming dead poultry and their waste. Continued surveillance of both poultry and wild birds is needed for early detection of novel viral introductions, to trace the transmission route, and to reduce public health risks. Improved LBMs biosecurity measures are needed to reduce the risk of influenza virus spillover to wild birds or people in Bangladesh.