Profile of Tuberculosis in Children and Adolescent at Dr. Soetomo General Hospital Surabaya

Introduction: Tuberculosis is one of ten leading causes of death worldwide, including Indonesia. Indonesia is one of seven countries that causes 64% deaths due to tuberculosis. Tuberculosis is caused by Mycobacterium tuberculosis through droplet nuclei in the air. It can occur to any group age, including children and adolescent, if there is a contact history of people with tuberculosis infection. In 2016, one million children had tuberculosis and around 250,000 children died because of tuberculosis. This study aimed to know the profile of tuberculosis in children and adolescent at Dr. Soetomo General Hospital Surabaya.Methods: This was a descriptive study using retrospective approach. Sample of this study was collected from electronic medical record provided by Dr. Soetomo General Hospital Surabaya using statistic formula of single sample for estimated population proportions of children and adolescent with tuberculosis from 2013-2017, with total samples of 149 people.Results: There were 149 samples of children and adolescent patients with tuberculosis. Most of the children were mostly 0-4 years old and 57% were female. 84% of the children had been immunized with BCG and classified as moderate, and 35% were under nutritional status. This study showed that 67% of the children in household contacts of adult tuberculosis patients also had tuberculosis. The most frequent symptoms of tuberculosis in children and adolescent were fever (72%) and cough (80%).Conclusion: Tuberculosis in children and adolescent is more likely to occur in children than adolescent, especially children within group age of 0-4 years old. The number of pulmonary tuberculosis in children and adolescent are higher than extrapulmonary tuberculosis.

Beyond well-mixed: a simple probabilistic model of airborne disease transmission in indoor spaces

We develop a simple model for assessing risk of airborne disease transmission that accounts for non-uniform mixing in indoor spaces and is compatible with existing epidemiological models. A database containing 174 high-resolution simulations of airflow in classrooms, lecture halls, and buses is generated and used to quantify the spatial distribution of expiratory droplet nuclei for a wide range of ventilation rates, exposure times, and room configurations. Imperfect mixing due to obstructions, buoyancy, and turbulent dispersion results in concentration fields with significant variance. The spatial non-uniformity is found to be accurately described by a shifted lognormal distribution. A well-mixed mass balance model is used to predict the mean, and the standard deviation is parameterized based on ventilation rate and room geometry. When employed in a dose-response function risk model, infection probability can be estimated considering spatial heterogeneity that contributes to both short- and long-range transmission.

Sheet Barrier and Intubating Stylet

Coronavirus disease 2019 (COVID-19), a respiratory syndrome caused by SARS-CoV-2, can be transmitted through respiratory droplets and aerosols of droplet nuclei. Aerosol-generating medical procedures (AGMP) are needed to take care of critically ill patients but place health care providers at risk of infection. With limited supplies of personal protective equipment (PPE), barrier systems were developed to help protect health care providers during tracheal intubation. The video intubating stylet shows promise to become the preferred intubation device in conjunction with plastic sheet barriers during the COVID-19 pandemic.

Separation and Disinfection of Contagious Aerosols from the Perspective of SARS-CoV-2

An assessment was performed on methods of separating and disinfecting airborne droplet nuclei containing viruses, such as SARS-CoV-2. The droplet nuclei originate from evaporating aerosols emitted by the coughing, singing, sneezing, etc. of infected humans. Based on empirical data and theoretical analysis, we successively determined: (i) the particle number distribution of nuclei versus the nucleus diameter, (ii) the statistical distribution of the viral content in the droplet nuclei starting from a uniform random distribution of viruses in the mucus, (iii) the particle number distribution of droplet nuclei containing at least one virus particle, and (iv) the effectiveness of methods for removing and disinfecting nuclei containing one or more virus particles from indoor air; viz., ventilation with fresh air, filtering with porous media, such as HEPA, and centrifugal separation and simultaneous disinfection, particularly with a rotational particle separator (RPS). Indoor aerosol removal with RPS supplemented with HEPA to arrest tiny volumes of very small particles was found to be the most effective. It is as good as particle removal through ventilation with clean air over long periods of time. An RPS facilitates direct elimination of viruses in the collected nuclei by flushing with a disinfection liquid. The components of an RPS are recyclable. Combining HEPA with an RPS extends the service time of HEPA by almost two orders of magnitude compared to the relatively short service time of stand-alone HEPA filters.

Droplet Nuclei Caustic Formations In Exhaled Vortex Rings

Vortex ring structures occur in light or hoarse cough configurations. These instances consist of short impulses of exhaled air resulting to a self-contained structure that can travel large distances. The present study is the first implementation of the second order Fully Lagrangian Approach (FLA) for three-dimensional realistic flow-fields obtained by means of Computational Fluid Dynamics (CFD) and provides a method to calculate the occurrence and the intensity of caustic formations. The carrier phase flow field is resolved by means of second order accurate Direct Numerical Simulation (DNS) based on a Finite Difference approach for the momentum equations, while a spectral approach is followed for the Poisson equation using Fast Fourier Transform (FFT). The effect of the undulations of the carrier phase velocity due to large scale vortical structures and turbulence is investigated. The evaluation of the higher order derivatives needed by the second order FLA is achieved by prefabricated least squares second order interpolations in the three dimensions. The method allows for the simulation of the clustering of droplets and droplet nuclei exhaled in ambient air in conditions akin to light cough. Given the ambiguous conditions of vortex-ring formation during cough instances, three different formation numbers n = UT /D are assumed, i.e. underdeveloped (n = 2), ideal (n = 3.7) and over-developed VRs (n = 6). The formation of clusters results in the spatial variance of the airborne viral load. This un-mixing of exhumed aerosols is related to the formation of localised high viral load distributions that can be linked to super-spreading events.

Effects of Air Purifiers on the Spread of Simulated Respiratory Droplet Nuclei and Virus Aggregates

The present study was performed to quantitatively evaluate the effects of air purifiers on the spread of COVID-19 and to suggest guidelines for their safe use. To simulate respiratory droplet nuclei and nano-sized virus aggregates, deionized water containing 100 nm of polystyrene latex (PSL) particles was sprayed using a vibrating mesh nebulizer, and the changes in the particle number concentration were measured for various locations of the particle source and air purifier in a standard 30 m3 test chamber. The spread of the simulated respiratory droplet nuclei by the air purifier was not significant, but the nano-sized aggregates were significantly affected by the airflow generated by the air purifier. However, due to the removal of the airborne particles by the HEPA filter contained in the air purifier, continuous operation of the air purifier reduced the number concentration of both the simulated respiratory droplet nuclei and nano-sized aggregates in comparison to the experiment without operation of the air purifier. The effect of the airflow generated by the air purifier on the spread of simulated respiratory droplet nuclei and nano-sized aggregates was negligible when the distance between the air purifier and the nebulizer exceeded 1 m.

An experimental approach to analyze aerosol and splatter formation in a dental practice

The flow velocity, trajectories, and size distribution of droplets produced during a dental scaling procedure using a Cavitron ultrasonic scalar (CUS) has been investigated by optical flow tracking velocimetry and shadowgraphy measurements. The droplet sizes are found to vary from 5 -500 µm; these correspond to droplet nuclei that could carry viruses. The droplet velocities also vary between 0.7 m/s and 1.3 m/s. These observations confirm the critical role of aerosols in the transmission of disease during dental procedures, providing invaluable knowledge for developing protocols and procedures to ensure the safety of both dentists and patients especially during COVID-19 pandemic.

Measuring interpersonal transmission of expiratory droplet nuclei in close proximity

Increasing evidence supports the significant role of short-range airborne transmission of viruses when in close contact with a source patient. A full-scale ventilated room (Cleanliness: ISO 14644–1 Class 5) and two face-to-face standing breathing thermal manikins were used to simulate a source individual and a susceptible person. Monodisperse particle generation and measurement techniques were used to evaluate the effect of virus-laden droplet nuclei size on short-range airborne transmission risk. We analysed four particle sizes (1.0, 1.5, 2.5, and 5.0 µm) to simulate the transport of exhaled droplet nuclei within an interpersonal distance of 0.5 m. The results indicated that the size distribution of airborne droplet nuclei could significantly influence transmission, with the inhalation fraction decreasing with increasing droplet nuclei size. Additionally, results showed that proximity to the source manikin could influence transmission. Inhalation fraction decreased with increasing interpersonal distance, fitting well with the 1/ d rule of droplet nuclei concentration decay. Our findings improve the understanding of the mechanism of the disease transmission.