[Omicron Variant of SARS-CoV-2 and Its Potential Impact on Dental Practice].

The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been raging across the world for over two years, but the daily reported numbers of new infections and deaths are still increasing. The newly identified Omicron variant has significant changes in its transmissibility and pathogenicity due to the multiple mutations in the spike protein, posing new challenges to the global public health. World Health Organization has categorized Omicron as a variant of concern (VOC). The spread of SARS-CoV-2 and its variants has caused disruptions to the dental practice worldwide. During the course of diagnosis and treatment of dental care, face-to-face communication at close quarters, droplets, aerosols, and exposure to saliva and blood increase the risks of SARS-CoV-2 transmission. The emergence of new variants, especially the Omicron variant, has formed new challenges to dental healthcare provision. In addition, oral tissues, including the tongue and oral mucosa, can overexpress the angiotensin converting enzyme 2 (ACE2), which is also the binding receptors of SARS-CoV-2. As a result, the oral cavity is one of the target sites of SARS-CoV-2 infection. SARS-CoV-2 infection in oral cavity may cause different oral complications, such as loss of taste. However, there are few reports about Omicron and the other variants of SARS-CoV-2 and their impacts on dental healthcare provision. Herein we made an overview of the Omicron variant and its characteristics, including its pathogenicity and immune evasion, and its potential impact on dental practice. We also proposed some control measures with the aim of reducing the possible transmission of SARS-CoV-2 and its variants during dental care.

The dynamic landscape of parasitaemia dependent intestinal microbiota shifting at species level and the correlated gut transcriptome during Plasmodium yoelii infection (preprint)

Background Malaria, caused by Plasmodium , is a global life-threatening infection disease especially during the COVID-19 pandemic. However, it is still unclear about the dynamic change and the interactions between intestinal microbiota and host immunity. Here, we investigated the change of intestinal microbiome and transcriptome during the whole Plasmodium infection process in mice to analyze the dynamic landscape of parasitaemia dependent intestinal microbiota shifting and related to host immunity. Results There were significant parasitaemia dependent changes of intestinal microbiota and transcriptome, and the microbiota was significantly correlated to the intestinal immunity. We found that (i) the diversity and composition of the intestinal microbiota represented a significant correlation along with the Plasmodium infection in family, genus and species level; (ii) the up-regulated genes from the intestinal transcriptome were mainly enriched in immune cell differentiation pathways along with the malaria development, particularly, naive CD4+ T cells differentiation; (iii) the abundance of the parasitaemia phase-specific microbiota represented a high correlation with the phase-specific immune cells development, particularly, Th1 cell with family Bacteroidales BS11 gut group, genera Prevotella 9, Ruminococcaceae UCG 008, Moryella and specie Sutterella* , Th2 cell with specie Sutterella* , Th17 cell with family Peptococcaceae , genus Lachnospiraceae FCS020 group and spices Ruminococcus 1*, Ruminococcus UGG 014* and Eubacterium plexicaudatum ASF492, Tfh and B cell with genera Moryella and species Erysipelotrichaceae bacterium canine oral taxon 255. Conclusion There was a remarkable dynamic landscape of the parasitaemia dependent shifting of intestinal microbiota and immunity, and a notable correlation between the abundance of intestinal microbiota.

The microbial coinfection in COVID-19.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel ß-coronavirus, is the main pathogenic agent of the rapidly spreading pneumonia called coronavirus disease 2019 (COVID-19). SARS-CoV-2 infects much more people, especially the elder population, around the world than other coronavirus, such as SARS-CoV and MERS-CoV, which is challenging current global public health system. Beyond the pathogenesis of SARS-CoV-2, microbial coinfection plays an important role in the occurrence and development of SARS-CoV-2 infection by raising the difficulties of diagnosis, treatment, prognosis of COVID-19, and even increasing the disease symptom and mortality. We summarize the coinfection of virus, bacteria and fungi with SARS-CoV-2, their effects on COVID-19, the reasons of coinfection, and the diagnosis to emphasize the importance of microbial coinfection in COVID-19. KEY POINTS: • Microbial coinfection is a nonnegligible factor in COVID-19. • Microbial coinfection exacerbates the processes of the occurrence, development and prognosis of COVID-19, and the difficulties of clinical diagnosis and treatment. • Different virus, bacteria, and fungi contributed to the coinfection with SARS-CoV-2.