Detection of Suspended SARS-CoV-2 in Indoor Air Using an Electrostatic Sampler

A prototype virus sampler using electrostatic precipitation has been developed to investigate aerosol infection by SARS-CoV-2. The sampler consists of a discharge electrode placed inside a vial, and a thin layer of viral lysis buffer at the bottom, working as a collection electrode. The sampler was operated with the sampling air flow rate of 40 L/min. Collection efficiency of the sampler is about 80% for 25nm to 5.0µm diameter particles. We sampled the air of a food court of a commercial facility, a connecting corridor of a clouded train station, and two office rooms (A and B) in September 2021, just after the 5th peak of COVID-19 in Japan. The analysis using a RT-qPCR detected the virus RNA in the air of the office A, B and the food court. Estimated concentration of the virus in the air determined by calibration curve was 2.0 x 102, 7.8 x 102, and 0.6 - 2.4 x 102 copies/m3, in the office A, B, and the food court, respectively. These results indicate that the sampler using electrostatic precipitation can detect SARS-CoV-2 in indoor air. It could be developed as a risk assessment method for aerosol infection.

Mystery of Mesenteric Lymph Adenitis

The etiological factors are confusing for provisional diagnosis and the differential diagnosis of mesenteric lymph adenitis; it may be virus like Dengue, Herpes and Epstein - Barr virus. Bacterial infections like Tuberculosis of the intestine through contaminated unpasteurized cattle milk or Mycobacterium tuberculosis through infected swallowed sputum. T. Gondii, Yesinia enterocolitica, pseudo tuberculosis infection. Lupus vulgaris in the face at the mucocutaneous junctions is a reactivation of already existing tuberculosis facilitates clinical diagnosis. Fungal infections like mucor mycosis, aspergillus, Fusarium producing neutropenia, Histoplasma capsulatum, Cryptococcus aerosol infection from droppings of pigeons on the AC machines. Kikuchi-Fujimoto’s disease (KFD) . Autoimmune causative factors. A study to reveal the mystery on patients with above symptoms and signs to rule out infections or a complication of follicular lymphoma.

Efficacy and immunogenicity of different BCG doses in BALB/c and CB6F1 mice when challenged with H37Rv or Beijing HN878

Two strains of mice (BALB/c and CB6F1) were vaccinated with a range of Bacille Calmette-Guérin (BCG) Danish doses from 3 × 105 to 30 CFU/mouse, followed by aerosol infection with Mtb (H37Rv or West-Beijing HN878 strain). The results indicated that both strains of mice when infected with HN878 exhibited significant protection in their lungs with BCG doses at 3 × 105—3000 CFU (BALB/c) and 3 × 105—300 CFU (CB6F1). Whereas, a significant protection was seen in both strains of mice with BCG doses at 3 × 105—300 CFU when infected with H37Rv. A significant increase in the frequencies of BCG-specific IFNγ+ IL2+ TNFα+ CD4 T cells in the BCG doses at 3 × 105—3000 CFU (BALB/c) and 3 × 105—300 CFU (CB6F1) was seen. The IFNγ+ IL2+ TNFα+ CD4 T cells correlated with the Mtb burden in the lungs of HN878 infected mice (BALB/c and CB6F1) whereas, IFNγ+ TNFα+ CD4 T cells correlated with the BALB/c mice infected with H37Rv or HN878. The BCG dose at 3000 CFU (an equivalent single human dose in the mice by body weight) is protective in both strains of mice infected with H37Rv or HN878 and may serve an interesting dose to test new TB vaccine in a preclinical animal model.

Possibility of new shielding device for upper gastrointestinal endoscopy

Background and study aims Infection control is essential when performing endoscopic procedures, especially during the COVID-19 pandemic. Therefore, we have developed a new shielding device called STEP for infection control in upper gastrointestinal endoscopy. Patients and methods STEP consists of a mask worn by the patient and a drape that is connected to the mask and covers the endoscope. A suction tube attached to the mask prevents aerosols from spreading. The endoscopist operates the endoscope through the drape. Three endoscopists performed a total of 18 examinations using an upper endoscopy training model with and without STEP. Endoscopic images were evaluated by three other endoscopists, using a visual analog scale. We also simulated contact, droplet, and aerosol infection and evaluated the utility of STEP. Results All examinations were conducted without a problem. Mean procedure time was 126.3 ± 11.6 seconds with STEP and 122.3 ± 10.0 seconds without STEP. The mean visual analog score was 90.7 ± 10.1 with STEP and 90.4 ± 10.0 without STEP. In the contact model, adherence of simulated contaminants was 4.9 ± 1.4 % without STEP and 0 % with STEP. In the droplet model, the number of simulated contaminants attached to the paper was 338 273 ± 90 735 pixels without STEP and 0 with STEP. In the aerosol model, the total number of particles was 346 837 ± 9485 without STEP and was significantly reduced to 222 ± 174 with STEP. Conclusions No effect on examination time or endoscopic image quality was observed when using STEP in upper gastrointestinal endoscopy. Using STEP reduced the diffusion of simulated contaminants in all three infection models.

Evaluation of the Efficacy of Doxycycline, Ciprofloxacin, Levofloxacin and Co-trimoxazole using in vitro and in vivo models of Q fever.

Q fever, caused by the intracellular pathogen Coxiella burnetii , is traditionally treated using tetracycline antibiotics, such as doxycycline. Doxycycline is often poorly tolerated and antibiotic resistant strains have been isolated. In this study, we have evaluated a panel of antibiotics (doxycycline, ciprofloxacin, levofloxacin, and, co-trimoxazole) against C. burnetii using in vitro methods (determination of MIC using liquid and solid media; efficacy assessment in a THP cell infection model) and in vivo methods (wax moth larvae and mouse models of infection). In addition, the schedule for antibiotic treatment has been evaluated, with therapy initiated at 24 h pre or post challenge. Both doxycycline and levofloxacin limited overt clinical signs during treatment in the AJ mouse model of aerosol infection, but further studies are required to investigate the possibility of disease relapse or incomplete bacterial clearance after the antibiotics are stopped. Levofloxacin was well tolerated and therefore warrants further investigation as an alternative to the current recommended treatment with doxycycline.

Controlled administration of aerosolized SARS-CoV-2 to K18-hACE2 transgenic mice uncouples respiratory infection and anosmia from fatal neuroinvasion

The development of a tractable small animal model faithfully reproducing human COVID-19 pathogenesis would arguably meet a pressing need in biomedical research. Thus far, most investigators have used transgenic mice expressing the human ACE2 in epithelial cells (K18-hACE2 transgenic mice) that are intranasally instilled with a liquid SARS-CoV-2 suspension under deep anesthesia. Unfortunately, this experimental approach results in disproportionate high CNS infection leading to fatal encephalitis, which is rarely observed in humans and severely limits this model's usefulness. Here, we describe the use of an inhalation tower system that allows exposure of unanesthetized mice to aerosolized virus under controlled conditions. Aerosol exposure of K18-hACE2 transgenic mice to SARS-CoV-2 resulted in robust viral replication in the respiratory tract, anosmia, and airway obstruction, but did not lead to fatal viral neuroinvasion. When compared to intranasal inoculation, aerosol infection resulted in a more pronounced lung pathology including increased immune infiltration, fibrin deposition and a transcriptional signature comparable to that observed in SARS-CoV-2-infected patients. This model may prove useful for studies of viral transmission, disease pathogenesis (including long-term consequences of SARS-CoV-2 infection) and therapeutic interventions.

Examination of preventive effect and safety of chlorine dioxide on nosocomial pneumonia

Nosocomial infections originate in hospitals. An example of this nosocomial pneumonia, which develops in patients around 48 hours after admission. It has a high mortality rate and occurs in a large number of patients. Professor Kaoru Obinata, Department of Pediatrics, Juntendo University Urayasu Hospital, Japan, is exploring a novel technique to combat nosocomial pneumonia and other nosocomial infections. This involves the safe and effective application of chlorine dioxide in medical settings and is particularly novel given that, in high doses, chlorine dioxide is toxic and can cause severe irritation and burns. Obinata and the team are looking at the use of chlorine dioxide gas in conventional induction countermeasures. The researchers believed that, used in combination with a high-efficiency particulate air (HEPA) filter, this method will be highly safe and boast high prevention effect and cost effectiveness. The team has found that chlorine dioxide aqueous solution is effective against various bacteria, viruses and fungi at a lower concentration than sodium hypochlorite solution and that that low-concentration of chlorine dioxide gas is effective against airborne bacteria and viruses, as well as adherent bacteria and viruses. Using mouse models, they have shown it to be effective against aerosol infection for the influenza virus and against influenza-like illness in humans. Next, the researchers will find a means of ensuring that the concentration of chlorine dioxide can be kept to safe and constant levels to ensure the effects are beneficial and not harmful.

TLR2 on CD4+ and CD8+ T cells promotes late control of Mycobacterium tuberculosis infection

Although a role for TLR2 on T cells has been indicated in prior studies, in vivo stimulation of TLR2 on T cells by Mtb and its impact on Mtb infection has not been tested. Furthermore, it is not known if the enhanced susceptibility to Mtb of Tlr2 gene knockout (ko) mice is due to its role in macrophages, on T cells or both. To address TLR2 on T cells, we generated Tlr2fl/flxCd4cre/cre mice, which lack expression of TLR2 on both CD4 and CD8 T cells, to study the in vivo role of TLR2 on T cells after aerosol infection with virulent Mtb. Deletion of TLR2 in CD4+ and CD8+ T cells reduces their ability to be co-stimulated by TLR2 ligands for cytokine production. These include both pro- (IFN-g, TNF-a) and anti-inflammatory cytokines (IL-10). Deletion of TLR2 in T cells did not affect early control but did result in decreased late control of Mtb in the lungs of infected mice. This suggests that T cell co-stimulation by mycobacterial TLR2 ligands in vivo is important for control of infection during the chronic phase of Mtb infection in the lung.