Identification of thresholds on population density for understanding transmission of COVID-19

Pathways of transmission of coronavirus (COVID-19) disease in the human population are still emerging. However, empirical observations suggest that dense human settlements are the most adversely impacted, corroborating a broad consensus that human-to-human transmission is a key mechanism for the rapid spread of this disease. Here, using logistic regression techniques, estimates of threshold levels of population density were computed corresponding to the incidence in the human population. Regions with population densities greater than 3000 person per square mile in the United States have about 95% likelihood to get infected with COVID-19. Since case numbers of COVID-19 dynamically changed each day until November 30, 2020, ca. 4% of US counties were at 50% or higher risk of COVID-19 transmission. While threshold on population density is not the sole indicator for predictability of coronavirus in human population, yet it is one of the key variables on understanding and rethinking human settlement in urban landscapes. Plane language SummaryPopulation density is certainly one of the key factors influencing the transmission of infectious diseases like COVID-19. It is approximated that in continental United States, population density of 1192 per square mile and higher presents 50% probability of getting infected with COVID-19. Key PointsO_LIBased on data from the USA, the population density of 1192 persons per square mile represented a 50% or higher probability of risk of transmission of COVID-19. C_LIO_LIAbout 35 counties in the USA are at very high risk of transmission potential (95% or higher) for COVID-19. C_LIO_LIAnalysis shows the vulnerability of urban towns to respiratory infectious disease C_LI

Delta Variant SARS-CoV-2 infections in pediatric cases during the second wave in India

The aim of this study was to identify the SARS-CoV-2 lineages circulating in the pediatric population of India during the second wave of the pandemic. Clinical and demographic details linked with the nasopharyngeal/oropharyngeal swabs (NPS/OPS) collected from SARS-CoV-2 cases (n=583) aged 0-18 year and tested positive by real-time RT-PCR were retrieved from March to June 2021.Symptoms were reported among 37.2% of patients and 14.8% reported to be hospitalized. The E gene CT value had significant statistical difference at the point of sample collection when compared to that observed in the sequencing laboratory. Out of these 512 sequences 372 were VOCs, 51 were VOIs. Most common lineages observed were Delta, followed by Kappa, Alpha and B.1.36, seen in 65.82%, 9.96%, 6.83% and 4.68%, respectively in the study population. Overall, it was observed that Delta strain was the leading cause of SARS-CoV-2 infection in Indian children during the second wave of the pandemic. We emphasize on the need of continuous genomic surveillance in SARS-CoV-2 infection even amongst children.

Viable SARS-CoV-2 in the air of a hospital room with COVID-19 patients

BackgroundThere currently is substantial controversy about the role played by SARS-CoV-2 in aerosols in disease transmission, due in part to detections of viral RNA but failures to isolate viable virus from clinically generated aerosols. MethodsAir samples were collected in the room of two COVID-19 patients, one of whom had an active respiratory infection with a nasopharyngeal (NP) swab positive for SARS-CoV-2 by RT-qPCR. By using VIVAS air samplers that operate on a gentle water-vapor condensation principle, material was collected from room air and subjected to RT-qPCR and virus culture. The genomes of the SARS-CoV-2 collected from the air and of virus isolated in cell culture from air sampling and from a NP swab from a newly admitted patient in the room were sequenced. FindingsViable virus was isolated from air samples collected 2 to 4.8m away from the patients. The genome sequence of the SARS-CoV-2 strain isolated from the material collected by the air samplers was identical to that isolated from the NP swab from the patient with an active infection. Estimates of viable viral concentrations ranged from 6 to 74 TCID50 units/L of air. InterpretationPatients with respiratory manifestations of COVID-19 produce aerosols in the absence of aerosol-generating procedures that contain viable SARS-CoV-2, and these aerosols may serve as a source of transmission of the virus. FundingPartly funded by Grant No. 2030844 from the National Science Foundation and by award 1R43ES030649 from the National Institute of Environmental Health Sciences of the National Institutes of Health, and by funds made available by the University of Florida Emerging Pathogens Institute and the Office of the Dean, University of Florida College of Medicine. Research in contextO_ST_ABSEvidence before this studyC_ST_ABSVarious studies report detection of SARS-CoV-2 in material collected by air samplers positioned in clinics and in some public spaces. For those studies, detection of SARS-CoV-2 has been by indirect means; instead of virus isolation, the presence of the virus in material collected by air samplers has been through RT-PCR detection of SARS-CoV-2 RNA. However, questions have been raised about the clinical significance of detection of SARS-CoV-2 RNA, particularly as airborne viruses are often inactivated by exposure to UV light, drying, and other environmental conditions, and inactivated SARS-CoV-2 cannot cause COVID-19. Added value of this studyOur virus isolation work provides direct evidence that SARS-CoV-2 in aerosols can be viable and thus pose a risk for transmission of the virus. Furthermore, we show a clear progression of virus-induced cytopathic effects in cell culture, and demonstrate that the recovered virus can be serially propagated. Moreover, we demonstrate an essential link: the viruses we isolated in material collected in four air sampling runs and the virus in a newly admitted symptomatic patient in the room were identical. These findings strengthen the notion that airborne transmission of viable SARS-CoV-2 is likely and plays a critical role in the spread of COVID-19. Implications of all the available evidenceScientific information on the mode of transmission should guide best practices Current best practices for limiting the spread of COVID-19. Transmission secondary to aerosols, without the need for an aerosol-generating procedure, especially in closed spaces and gatherings, has been epidemiologically linked to exposures and outbreaks. For aerosol-based transmission, measures such as physical distancing by 6 feet would not be helpful in an indoor setting and would provide a false-sense of security. With the current surges of cases, to help stem the COVID-19 pandemic, clear guidance on control measures against SARS-CoV-2 aerosols are needed.

In-vitro scolicidal activity of Mallotus philippinensis (Lam.) Muell Arg. fruit glandular hair extract against hydatid cyst Echinococcus granulosus

OBJECTIVE@#To investigate new scolicidal agent from natural resources to cope with the side effects associated with synthetic drugs in Echinococcosis.@*METHODS@#The scolicidal potential of methanolic fruit powder extract (10 and 20 mg/mL) of Mallotus philippinensis (M. philippinensis) was investigated. Viability of protoscoleces was confirmed by trypan blue exclusion method, where mortality was observed at concentration of 10 and 20 mg/mL in 60 min treatment against Echinococcus granulosus (E. granulosus), under in-vitro conditions with reference to the known standard drug Praziquantel®.@*RESULTS@#At concentration 10 and 20 mg/mL, the mortality rate was observed 97% and 99% respectively for 60 min treatment; while up to 93% mortality was observed with 20 mg/mL for only 10 min treatment. The concentration above 20 mg/mL for above 2 h showed 100% mortality, irrespective of further incubation.@*CONCLUSIONS@#As compared with the standard anti-parasitic drug Praziquantel our extract has significant scolicidal activity with almost no associated side effects.

Evaluation of antimicrobial activity and bronchodialator effect of a polyherbal drug-Shrishadi

<p><b>OBJECTIVE</b>To investigate antimicrobial and bronchodialator effect of hydroalcholic extract of polyherbal drug Shirishadi containing Shirisha (Albezzia lebbeck), Nagarmotha (Cyprus rotandus) & Kantakari (Solanum xanthocarpum).</p><p><b>METHODS</b>Antimicrobial activity was evaluated by disc diffusion method and MIC, MBC, MFC were calculated by micro dilution method. Hydroalcholic extract of this preparation was investigated for its phytochemical analysis, phenol and flavonoid were determined by spectrophotometric method and in vivo bronchodilator effect was analysed by convulsion time.</p><p><b>RESULTS</b>The phytochemical tests revealed presence of alkaloids, anthraquinones, carbohydrates, flavonoids, saponins and tannins. The antimicrobial result showed the MIC of 6.25 mg/mL against Staphylococcus aureus and 12.5 mg/mL for Escherichia coli and 12.5 mg/mL against remaining bacteria tested, with strong antifungal activity. The maximum inhibition zone is found against Pseudomonas aeruginosa with MIC 16 mg/mL. Drug showed significant bronchodilator effect with 27.86% & 36.13% increase in preconvulsion time of guinea pigs pretreated with 100 & 200 mg/kg body weight of extract.</p><p><b>CONCLUSIONS</b>The study reveals that the extracts possess antibacterial activity and antifungal activity in a dose dependent manner. This antimicrobial property may be due to presence of several saponins, further studies are highly needed for the drug development.</p>

Recent advances in various emerging vescicular systems：An overview

Liposomes have been widely investigated since 1970 as drug carriers for improving the delivery of therapeutic agents to specific sites in the body. As a result, numerous improvements have been made to make this technology potential the treatment of certain diseases in the clinics. This review mainly focused on various aspects related to the vesicular system, including method of preparation, stabilization, drawbacks, and applications. Various types of vesicular systems such as liposomes, niosomes, transfersomes, pharmacosomes, and nanoparticle have been discussed briefly along with some other emerging vescicular systems (photosomes, archaesomes, genosomes, cryptosomes, discomes) focusing on cell specific gene transfer, photodynamic therapy and ligand mediated drug targeting. Present applications of the liposomes are in the immunology, dermatology, vaccine adjuvant, eye disorders, brain targeting, infective disease and in tumour therapy. The new developments in this field are of specific binding properties of a drug-carrying liposome to a target cell such as a tumor cell and specific molecules in the body (antibodies, proteins, peptides etc), stealth liposomes which are especially used as carriers for hydrophilic (water soluble) anticancer drugs like doxorubicin, mitoxantrone and bisphosphonate-liposome mediated depletion of macrophages. This review would help researchers working in the area of liposomal drug delivery.