Global control of tuberculosis: current status and future prospects

Tuberculosis is a zoonotic disease that is caused by mycobacterium tuberculosis complex and can infect humans, livestock, and wildlife. It spreads primarily through the respiratory tract and was the leading cause of death due to a single infectious disease before the COVID-19 pandemic. TB is a global public health emergency that has reemerged over the past few decades. Substantial efforts are needed to achieve the goals of the End TB Strategy. The World Health Organization has estimated that approximately 9.9 million people worldwide contracted TB in 2020 and that approximately 140,000 of the 10 million new cases of active TB in 2019 were zoonotic TB. During the COVID-19 pandemic, the number of new TB diagnoses and reports decreased sharply, from 7.1 million in 2019 to 5.8 million in 2020, returning to 2012 levels far below the approximately 10 million TB cases in 2020. Simultaneously, the global decrease in the absolute number of TB deaths until 2019 was followed by an increase in 2020 in four of the six WHO regions and most of the 30 high-TB-burden countries. Therefore, extensive immediate actions worldwide are required to restore the health system, and innovations are needed to accelerate progress toward a tuberculosis-free world.

A novel strategy for the detection of SARS-CoV-2 variants based on multiplex PCR-MALDI-TOF MS (preprint)

Background The second wave of coronavirus disease 2019 (COVID-19) has been incessantly causing catastrophe worldwide, and the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants causes further uncertainty regarding epidemic risk. Here, a novel strategy for the detection of SARS-CoV-2 variants using multiplex PCR coupled with MALDI-TOF MS was developed. Methods Plasmids carrying gene sequences containing 9 mutation types in 7 mutated sites (HV6970del, N501Y, K417N, P681H, D614G, E484K, L452R, E484Q and P681R) in the receptor-binding domain of the spike protein of SARS-CoV-2 variants were synthesized. Using the nucleic acid sequence of SARS-CoV-2 nonvariant and a synthetic SARS-CoV-2-variant-carrying plasmid, a MALDI-TOF MS method based on the single-base mass probe extension of multiplex PCR amplification products was established to detect the above nine mutation types. The detection limit of this method was determined via the concentration gradient method. Twenty-one respiratory tract pathogens (9 bacteria, 11 respiratory viruses) and pharyngeal swab nucleic acid samples from healthy people were selected for specific validation. Sixteen samples from COVID-19 patients were used to verify the accuracy of this method. Results The 9 mutation types could be detected simultaneously by triple PCR amplification coupled with MALDI-TOF MS. SARS-CoV-2 and all six variants (B.1.1.7, B.1.351, B.1.429, B.1.526, P.1 and B.1.617) could be identified. The detection limit for all 9 sites was 1.5×10 3 copies. The specificity of this method was 100%, and the accuracy of real-time PCR CT values less than 30 among positive samples was 100%. This method is open and extensible, and can be used in a high-throughput manner, easily allowing the addition of new mutation sites as needed to identify and track new SARS-CoV-2 variants as they emerge. Conclusions Multiplex PCR-MALDI-TOF MS provides a new detection option with practical application value for SARS-CoV-2 and its variant infection. Key point An all-in-one SARS-CoV-2 variant identification method based on a multiplex PCR-MALDI-TOF MS system was developed. All of the SARS-CoV-2 variants can be identified based on 9 types of 7 mutated sites of RBD of spike protein using this method.

Role of the SphK-S1P-S1PRs pathway in invasion of the nervous system by SARS-CoV-2 Infection

Abstract Global spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is still ongoing. Before an effective vaccine is available, the development of potential treatments for resultant coronavirus disease 2019 (COVID-19) is crucial. One of disease hallmarks is hyper-inflammatory responses, which usually leads to a severe lung disease. Patients with COVID-19 also frequently suffered from neurological symptoms such as acute diffuse encephalomyelitis, brain injury and psychiatric complications. The metabolic pathway of sphingosine-1-phosphate (S1P) is a dynamic regulator of various cell types and disease processes, including the nervous system. It has been demonstrated that S1P and its metabolic enzymes, regulating neuroinflammation and neurogenesis, exhibit important functions during viral infection. S1P receptor 1 (S1PR1) analogs including AAL-R and RP-002 inhibit pathophysiological responses at the early stage of H1N1 virus infection and then play a protective role. Fingolimod (FTY720) is an S1P receptor modulator and is being tested for treating COVID-19. Our review provides an overview of SARS-CoV-2 infection and critical role of the SphK-S1P-SIPR pathway in invasion of SARS-CoV-2 infection, particularly in the central nervous system (CNS). This may help design therapeutic strategies based on the S1P-mediated signal transduction, and the adjuvant therapeutic effects of S1P analogs to limit or prevent the interaction between the host and SARS-CoV-2, block the spread of the SARS-CoV-2, and consequently treat related complications in the CNS.

Detection of SARS-CoV-2 nucleic acid in CSF by ultrahigh depth sequencing in a patient with COVID-19 and neurological dysfunction: a case report (preprint)

Background: SARS-Coronavirus-2 (SARS-CoV-2), the pathogen of coronavirus disease 2019 (COVID-19), not only infects the respiratory tract, but also other organs. About a third of the inpatients of COVID-19 have neurological symptoms and in vitro experiments revealed that SARS-CoV-2 could infect human neural progenitor cells and brain organoids. However, the traditional test often reports negative owing to the low number of virus in the cerebrospinal fluid. To date, timely diagnosis of central nervous system infection of SARS-CoV-2 remains a challenge.Case presentation: On day 14 of COVID-19, seizures, maxillofacial convulsions, intractable hiccups and significant increase in intracranial pressure developed in a 56-year-old man. The RT-PCR of SARS-CoV-2 was negative. SARS-CoV-2 nucleic acid were detected in cerebrospinal fluid (CSF) by ultrahigh depth sequencing. The patient was successfully treated after 14 days of mechanical ventilation and treatment of pneumonia and neurological dysfunction.Conclusions: This case suggests SARS-CoV-2 can invade the central nervous system and relevant examinations with CSF including ultrahigh depth sequencing of SARS-CoV-2 are needed among COVID-19 patients with neurological dysfunction.