Shielding device for endoscopic procedures during lower gastrointestinal endoscopy.

Objectives: The coronavirus pandemic significantly impacted endoscopic practice. During lower gastrointestinal endoscopy, infectious substances disseminate; therefore, we developed an infection control device (STEP-L) for lower gastrointestinal endoscopy and examined its usefulness. Methods: STEP-L wraps around the patient's buttocks and covers the endoscope. Using lower endoscopy training models, three endoscopists performed 18 colonoscopies with STEP-L (group S) and without (group C). Endoscopic insertion time and pigmented areas of ​​gloves and diapers after the examination were compared between both groups. Results: Insertion of the endoscope up to the cecum was possible in all 18 examinations. The insertion time to the cecum was 52.4 ± 19.0 s in group S and 53.9 ± 13.3 s in group C. The pigmented areas of the ​​gloves measured 39,108.0 ± 16,155.3 pixels in group C, but were significantly reduced to 2610.5 ± 4333.8 pixels in group S (p < 0.05). The pigmented areas of the diapers measured 2280.9 ± 3285.2 pixels in group C, but were significantly reduced to 138.0 ± 82.9 pixels in group S (p < 0.05). Conclusions: Using STEP-L does not change the insertion time, and is technically feasible. STEP-L significantly reduces the adhesion of virtual pollutants to the surroundings, suggesting that this device is useful for infection control during lower gastrointestinal endoscopy.

Antiviral Effect of Candies Containing Persimmon-Derived Tannin against SARS-CoV-2 Delta Strain.

Inactivation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the mouth has the potential to reduce the spread of coronavirus disease 2019 (COVID-19), due to the virus being readily transmitted by dispersed saliva. Persimmon-derived tannin has strong antioxidant and antimicrobial activity owing to its strong adhesion to proteins, and it also exhibited antiviral effects against non-variant and Alpha-variant SARS-CoV-2 in our previous study. In this study, we first demonstrated the antiviral effects of persimmon-derived tannin against the Delta variant of SARS-CoV-2 in vitro via the plaque assay method. We then examined the effects of candy containing persimmon-derived tannin. Remarkably, the saliva samples provided by healthy volunteers while they were eating tannin-containing candy showed that the virus titers of the SARS-CoV-2 Delta variant were suppressed. In addition, we found that the SARS-CoV-2 viral load in saliva from patients with COVID-19 collected immediately after they had eaten the tannin-containing candy was below the level of detection via PCR for SARS-CoV-2. These data suggest that adding persimmon-derived tannin to candy and holding such candy in the mouth is an effective method for inactivating SARS-CoV-2 in saliva, and the application of this approach shows potential for inhibiting the transmission of COVID-19.

New Countermeasures Against Infections with/after COVID-19: Is Chlorine Dioxide a Useful and Safe Disinfectant?

Pandemics of microorganism are serious problem such as corona virus induced disease 2019(COVID-19), and the infectious diseases rapidly transmitted via airborne or aerosol among community space. To prevent aerosol infections, ozone and chlorine dioxide gases are practical methods in room air. However, ozone requires relatively high concentrations for this purpose, which might be toxic to humans present in the room. On the other hand, the low concentration of chlorine dioxide gas and aqueous solution are sufficiently effective against aerosol infection for the causative microorganism, and it is expected that when it is used in combination with a high-efficiency particulate air filter, it will be highly safe with high prevention effect and cost effectiveness.

Experimental Methods of Investigating Airborne Indoor Virus-Transmissions Adapted to Several Ventilation Measures.

This study introduces a principle that unifies two experimental methods for evaluating airborne indoor virus-transmissions adapted to several ventilation measures. A first-time comparison of mechanical/natural ventilation and air purification with regard to infection risks is enabled. Effortful computational fluid dynamics demand detailed boundary conditions for accurate calculations of indoor airflows, which are often unknown. Hence, a suitable, simple and generalized experimental set up for identifying the spatial and temporal infection risk for different ventilation measures is more qualified even with unknown boundary conditions. A trace gas method is suitable for mechanical and natural ventilation with outdoor air exchange. For an accurate assessment of air purifiers based on filtration, a surrogate particle method is appropriate. The release of a controlled rate of either trace gas or particles simulates an infectious person releasing virus material. Surrounding substance concentration measurements identify the neighborhood exposure. One key aspect of the study is to prove that the requirement of concordant results of both methods is fulfilled. This is the only way to ensure that the comparison of different ventilation measures described above is reliable. Two examples (a two-person office and a classroom) show how practical both methods are and how the principle is applicable for different types and sizes of rooms.

Phenotypic characterization of gamma delta (γδ) T cells in chickens infected with or vaccinated against Marek's disease virus.

Marek's disease (MD) vaccines reduce the incidence of MD but cannot control virus shedding. To develop new vaccines, it is essential to elucidate mechanisms of immunity to Marek's disease virus (MDV) infection. In this regard, gamma delta (γδ) T cells may play a significant role in prevention of viral spread and tumor surveillance. Here we demonstrated that MDV vaccination induced interferon (IFN)-γ+CD8α+ γδ T cells and transforming growth factor (TGF)-ß+ γδ T cells in lungs. γδ T cells from MDV-infected chickens exhibited cytotoxic activity. Importantly, γδ T cells from the vaccinated/challenged group exhibited maximum cytotoxic activity following ex vivo stimulation. These results suggest that MDV vaccines activate effector γδ T cells which may be involved in the development of protective immune responses against MD. Further, it was demonstrated that MDV infection increases the frequency of a subpopulation of γδ T cells expressing membrane-bound TGF-ß in MDV-infected birds.

Coxiella burnetii infections in mice: Immunological responses to contemporary genotypes found in the US.

Coxiella burnetii is an obligate intracellular bacterium that causes the human disease Q fever, which can manifest as an acute flu-like illness or a long-term chronic illness, such as endocarditis. Three genotypes (ST8, ST16, and ST20) of Coxiella burnetii are commonly found in the contemporary US and are associated with specific animal hosts. Although all three genotypes have been isolated from humans with Q fever, studies comparing virulence between C. burnetii sequence types have been rare. Here, groups of mice were infected via aerosol inoculation with isolates derived from cow's milk, environmental, animal, and human samples. Mice were monitored for weight loss and blood samples were takenweekly. Animals were euthanized at 2- and 12-weeks post-infection, and bacterial burden was determined for tissues by real-time PCR. The levels of anti-Coxiella antibodies and selected inflammatory cytokines were determined for serum samples. Weight loss and splenomegaly were observed in mice infected with ST20 and ST16 isolates but were absent in the mice infected with ST8 isolates. Bacterial concentrations in the tissues were lower in the ST8 isolates at 2 weeks post-infection relative to all other isolates. ST16 and ST20 isolates induced robust antibody and cytokine responses, while ST8 isolates produced significantly lower anti-C. burnetii titers early in the infection but saw increased titers in some animals several weeks post-infection. The data suggest that the ST8 isolates are less virulent in this mouse model, as they produce less robust antibody responses that are slow to develop, relative to the ST16 and ST20 isolates.

The Peptidoglycan-associated lipoprotein Pal contributes to the virulence of Burkholderia mallei and provides protection against lethal aerosol challenge.

BURKHOLDERIA MALLEI: is a highly pathogenic bacterium that causes the fatal zoonosis glanders. The organism specifies multiple membrane proteins, which represent prime targets for the development of countermeasures given their location at the host-pathogen interface. We investigated one of these proteins, Pal, and discovered that it is involved in the ability of B. mallei to resist complement-mediated killing and replicate inside host cells in vitro, is expressed in vivo and induces antibodies during the course of infection, and contributes to virulence in a mouse model of aerosol infection. A mutant in the pal gene of the B. mallei wild-type strain ATCC 23344 was found to be especially attenuated, as BALB/c mice challenged with the equivalent of 5,350 LD50 completely cleared infection. Based on these findings, we tested the hypothesis that a vaccine containing the Pal protein elicits protective immunity against aerosol challenge. To achieve this, the pal gene was cloned in the vaccine vector Parainfluenza Virus 5 (PIV5) and mice immunized with the virus were infected with a lethal dose of B. mallei. These experiments revealed that a single dose of PIV5 expressing Pal provided 80% survival over a period of 40 days post-challenge. In contrast, only 10% of mice vaccinated with a PIV5 control virus construct survived infection. Taken together, our data establish that the Peptidoglycan-associated lipoprotein Pal is a critical virulence determinant of B. mallei and effective target for developing a glanders vaccine.

Possible aerosol transmission of COVID-19 and special precautions in dentistry.

Since its emergence in December 2019, corona virus disease 2019 (COVID-19) has impacted several countries, affecting more than 90 thousand patients and making it a global public threat. The routes of transmission are direct contact, and droplet and possible aerosol transmissions. Due to the unique nature of dentistry, most dental procedures generate significant amounts of droplets and aerosols, posing potential risks of infection transmission. Understanding the significance of aerosol transmission and its implications in dentistry can facilitate the identification and correction of negligence in daily dental practice. In addition to the standard precautions, some special precautions that should be implemented during an outbreak have been raised in this review.

Vascular permeability in the brain is a late pathogenic event during Rift Valley fever virus encephalitis in rats.

Rift Valley fever virus (RVFV) is a zoonotic disease of livestock that causes several clinical outcomes in people including febrile disease, hemorrhagic fever, and/or encephalitis. After aerosol infection with RVFV, Lewis rats develop lethal encephalitic disease, and we use this as a model for studying disease mechanisms of RVFV infection in the brain. Permeability of the brain vasculature in relation to virus invasion and replication is not known. Here, we found that vascular permeability in the brain occurred late in the course of infection and corresponded temporally to expression of matrix metalloproteinase-9 (MMP-9). Virus replication was ongoing within the central nervous system for several days prior to detectable vascular leakage. Based on this study, vascular permeability was not required for entry of RVFV into the brain of rats. Prevention of vascular leakage late in infection may be an important component for prevention of lethal neurological disease in the rat model.

The characteristics of hDPP4 transgenic mice subjected to aerosol MERS coronavirus infection via an animal nose-only exposure device.

BACKGROUND: Middle East respiratory syndrome coronavirus (MERS-CoV), which is not fully understood in regard to certain transmission routes and pathogenesis and lacks specific therapeutics and vaccines, poses a global threat to public health. METHODS: To simulate the clinical aerosol transmission route, hDPP4 transgenic mice were infected with MERS-CoV by an animal nose-only exposure device and compared with instillation-inoculated mice. The challenged mice were observed for 14 consecutive days and necropsied on days 3, 5, 7, and 9 to analyze viral load, histopathology, viral antigen distribution, and cytokines in tissues. RESULTS: MERS-CoV aerosol-infected mice with an incubation period of 5-7 days showed weight loss on days 7-11, obvious lung lesions on day 7, high viral loads in the lungs on days 3-9 and in the brain on days 7-9, and 60% survival. MERS-CoV instillation-inoculated mice exhibited clinical signs on day 1, obvious lung lesions on days 3-5, continuous weight loss, 0% survival by day 5, and high viral loads in the lungs and brain on days 3-5. Viral antigen and high levels of proinflammatory cytokines and chemokines were detected in the aerosol and instillation groups. Disease, lung lesion, and viral replication progressions were slower in the MERS-CoV aerosol-infected mice than in the MERS-CoV instillation-inoculated mice. CONCLUSION: hDPP4 transgenic mice were successfully infected with MERS-CoV aerosols via an animal nose-only exposure device, and aerosol- and instillation-infected mice simulated the clinical symptoms of moderate diffuse interstitial pneumonia. However, the transgenic mice exposed to aerosol MERS-CoV developed disease and lung pathology progressions that more closely resembled those observed in humans.

Knowledge and Apprehension of Dental Patients about MERS-A Questionnaire Survey.

INTRODUCTION: Middle East Respiratory Syndrome (MERS) is a disease caused by beta corona virus. From April 11(th) to 9(th) June 2014, World Health Organization (WHO) reported a total of 402 laboratory confirmed cases of MERS from KSA, out of which 132 cases were reported from Riyadh alone. AIM: The aim of this study was to assess the knowledge and apprehension of patients about MERS visiting Al Farabi College of Dentistry, Riyadh, Saudi Arabia. MATERIALS AND METHODS: A cross-sectional questionnaire based survey was conducted which consisted of 10 self-prepared questions. A total of 404 patients participated in this study. RESULTS: Three hundred and forty patients had heard about MERS. Nearly a quarter of the patients (25.74%) were apprehensive about undergoing dental treatment because of MERS. A little more than half of the patients (50.99%) knew that camel was a source of Middle East Respiratory Syndrome-Corona virus. Most of the patients (80.72%) were aware of the infection control measures to be followed by dentist and 138 patients claimed they took some precaution when present inside the dental college. CONCLUSION: Majority of the patients had heard about MERS and was aware of the infection control measures. However, some patients were apprehensive about undergoing dental treatment because of MERS. Further steps need to be taken to educate the patient's about transmission of MERS and infection control measures in a dental hospital.

Assessment of the awareness level of dental students toward Middle East Respiratory Syndrome-coronavirus.

BACKGROUND: Infection prevention and control measures are critical to prevent the possible spread of Middle East Respiratory Syndrome-coronavirus (MERS-CoV) in healthcare facilities. Therefore, healthcare workers should be aware of all procedures concerning prevention of and protection from MERS-CoV. OBJECTIVE: The aim of this study is to improve the knowledge of the dental students and evaluate their awareness about MERS-CoV. MATERIALS AND METHODS: A questionnaire was made according to MOH information and 200 dental students (Al-Farabi Colleges, Jeddah) were interviewed to evaluate their knowledge about MERS-CoV. RESULTS: More than half of the dental students (54%) interviewed had good knowledge about the etiology, symptoms, and treatment of MERS-CoV. Measurements for infection control and protection were also known (79%). The sources of information for the students were: college (27%), MOH (25%), media (24%), and social community (23%), while 17% of the students interviewed had no idea about it. CONCLUSION: Dental students had good knowledge about MERS-CoV. However, more information still must be provided by MOH and college for the medical staff.

Toll-like receptors are critical for clearance of Brucella and play different roles in development of adaptive immunity following aerosol challenge in mice.

Brucella spp. cause undulant fever in humans and brucellosis in variety of other animals. Both innate and adaptive immunity have been shown to be important in controlling Brucella infection. Toll-like receptors (TLRs) represent a group of pattern recognition receptors (PRRs) that play critical roles in the host innate immune response, as well as development of adaptive immunity. In the current report, we investigated the role of TLR signaling in the clearance of Brucella and development of adaptive immunity in TLR2(-/-), TLR4(-/-), or MyD88(-/-) mice following aerosol exposure to B. melitensis 16 M. Consistent with previous reports, MyD88 is required for efficient clearance of Brucella from all three organs (lung, spleen, and liver). The results reveal Th2-skewed immune responses in TLR2(-/-) mice late in infection and support a TLR2 requirement for efficient clearance of Brucella from the lungs, but not from the spleen or liver. Similarly, TLR4 is required for efficient clearance of Brucella from the lung, but exhibits a minor contribution to clearance from the spleen and no demonstrable contribution to clearance from the liver. Lymphocyte proliferation assays suggest that the TLRs are not involved in the development of cell-mediated memory response to Brucella antigen. Antibody detection reveals that TLR2 and 4 are required to generate early antigen-specific IgG, but not during the late stages of infection. TLR2 and 4 are only transiently required for IgM production and not at all for IgA production. In contrast, MyD88 is essential for antigen specific IgG production late in infection, but is not required for IgM generation over the course of infection. Surprisingly, despite the prominent role for MyD88 in clearance from all tissues, MyD88-knockout mice express significantly higher levels of serum IgA. These results confirm the important role of MyD88 in controlling infection in the spleen while providing evidence of a prominent contribution to protection in other tissues. In addition, although TLR4 and TLR2 contribute little to control of spleen infection, a significant contribution to clearance of lung infection is described.