Identification and Characterization of Pectate Lyase as a Novel Allergen in Artemisia sieversiana Pollen.

INTRODUCTION: Artemisia species are widely spread in north hemisphere. Artemisia sieversiana pollen is one of the common pollen allergens in the north of China. At present, seven allergens were identified and had been listed officially from A. sieversiana pollen, but the remaining allergens are still insufficiently studied, which need to be found. METHODS: Pectate lyase was purified from the extracts of A. sieversiana pollen by anion exchange, size exclusion, and HPLC-hydrophobic interaction chromatography. The gene of A. sieversiana pectate lyase (Art si pectate lyase) was cloned and expressed in Escherichia coli. The enzyme activity and circular dichroism (CD) spectrum of natural and recombinant proteins were analyzed. The allergenicity of Art si pectate lyase was characterized by enzyme-linked immunosorbent assay (ELISA), Western blot, inhibition ELISA, and basophil activation test. The allergen's physicochemical properties, three-dimensional structure, sequence profiles with homologous allergens and phylogenetic tree were analyzed by in silico methods. RESULTS: Natural Art si pectate lyase (nArt si pectate lyase) was purified from A. sieversiana pollen extracts by three chromatographic strategies. The cDNA sequence of Art si pectate lyase had a 1191-bp open reading frame encoding 396 amino acids. Both natural and recombinant pectate lyase (rArt si pectate lyase) exhibited similar CD spectrum, and nArt si pectate lyase had higher enzymatic activity. Moreover, the specific immunoglobulin E (IgE) binding rate against nArt si pectate lyase and rArt si pectate lyase was determined as 40% (6/15) in patients' serum with Artemisia species pollen allergy by ELISA. The nArt si pectate lyase and rArt si pectate lyase could inhibit 76.11% and 47.26% of IgE binding activities to the pollen extracts, respectively. Art si pectate lyase was also confirmed to activate patients' basophils. Its structure contains a predominant motif of classic parallel helical core, consisting of three parallel ß-sheets, and two highly conserved features (vWiDH, RxPxxR) which may contribute to pectate lyase activity. Moreover, Art si pectate lyase shared the highest sequence identity of 73.0% with Art v 6 among currently recognized pectate lyase allergen, both were clustered into the same branch in the phylogenetic tree. CONCLUSION: In this study, pectate lyase was identified and comprehensively characterized as a novel allergen in A. sieversiana pollen. The findings enriched the allergen information for this pollen and promoted the development of component-resolved diagnosis and molecular therapy of A. sieversiana pollen allergy.

Comparison of the therapeutic effects of medication therapy, specific immunotherapy and anti-IgE (Omalizumab) in patients with hay fever.

Background: Hay fever, characterized by seasonal allergic reactions, poses a significant health challenge. Existing therapies encompass standard drug regimens, biological agents, and specific immunotherapy. This study aims to assess and compare the effectiveness of anti-IgE (omalizumab), medication therapy, and subcutaneous immunotherapy (SCIT) for hay fever. Methods: Conducted as a retrospective cohort study, this research involved 98 outpatient hay fever patients who underwent routine medication, omalizumab treatment, or SCIT before the onset of the spring pollen season. A follow-up was performed one month after the start of the pollen season. The comprehensive symptoms and drug scores were used to evaluate patients with different intervention methods, facilitating a comparative analysis of therapeutic outcomes. Results: Compared with before treatment, the symptoms of patients treated with the three methods were all significantly relieved, and the medication score were significantly reduced. Patients treated with omalizumab demonstrated higher symptoms and medication scores than SCIT group before treatment, but similar scores after treatment, which were both lower than medicine treatment group. After treatment with omalizumab or SCIT, patients in both groups had significantly lower medication scores than the medication group and were close to no longer using medication for symptom relief. The mountain juniper-sIgE was significantly higher after treatment than before treatment in both medicine treatment group and omalizumab treatment group. Conclusion: Omalizumab and SCIT offer superior effects than medication therapy in hay fever patients.

Identification of Pla a 7 as a novel pollen allergen group in Platanus acerifolia pollen.

BACKGROUND: Platanus acerifolia is recognized as a source of allergenic pollen worldwide. Currently, five Platanus acerifolia pollen allergens belonging to different protein families have been identified, in which profilin and enolase were characterized by our group recently. Besides, we also screened and identified a novel allergen candidate as triosephosphate isomerase, which was different from already known types of pollen allergens. However, the role of this novel allergen group in Platanus acerifolia pollen allergy was unclear. Therefore, we further investigated the allergenicity and clarify its clinical relevance in this study. METHODS: The natural triosephosphate isomerase from Platanus acerifolia pollen was purified by three steps of chromatography and identified by mass spectrometry. The cDNA sequence of this protein was matched from in-house transcripts based on internal peptide sequences, which was further confirmed by PCR cloning. The recombinant triosephosphate isomerase was expressed and purified from E. coli. Allergenicity analysis of this protein was carried out by enzyme linked immunosorbent assay, immunoblot, and basophil activation test. RESULTS: A novel allergen group belonging to triosephosphate isomerase was firstly identified in Platanus acerifolia pollen and named as Pla a 7. The cDNA of Pla a 7 contained an open reading frame of 762 bp encoding 253 amino acids. The natural Pla a 7 displayed 41.4% IgE reactivity with the patients' sera by ELISA, in which the absorbance value showed correlation to the serum sIgE against Platanus acerifolia pollen extract. Inhibition of IgE-binding to pollen extracts reached 26%-94% in different Pla a 7-positive sera. The recombinant Pla a 7 exhibited weaker IgE-reactivity in ELISA than its natural form, but showed comparable activity in immunoblot. The allergenicity was further confirmed by basophil activation test. CONCLUSIONS: Triosephosphate isomerase (Pla a 7) was first recognized as pollen allergen in Platanus acerifolia pollen, which is a completely different type of pollen allergen from those previously reported. This finding is essential to enrich information on allergen components and pave the way for molecular diagnosis or treatment strategies for Platanus acerifolia pollen allergy.

Identification and characterization of natural PR-1 protein as major allergen from Humulus japonicus pollen.

BACKGROUND: The Humulus japonicus pollen is one of the most common allergenic pollens in China. However, little is unveiled regarding the allergenic components in Humulus japonicus pollen. Our study aimed to purify and identify the pathogenesis-related 1 (PR-1) protein from Humulus japonicus pollen, and to characterize the molecular and immunochemical properties of this novel allergen. METHODS: The natural PR-1 protein (named as Hum j PR-1) was purified from Humulus japonicus pollen extracts with a combined strategy of chromatography, and identified by mass spectrometry. The coding sequence of Hum j PR-1 was confirmed by cDNA cloning. The recombinant Hum j PR-1 was expressed and purified from Escherichia coli. The allergenicity was assessed by immunoblot, enzyme-linked immunosorbent assay (ELISA), inhibition ELISA, and basophil activation test using Humulus japonicus allergic patients' whole blood. The physicochemical properties and 3-dimensional structure of it were comprehensively characterized by in silico methods. RESULTS: The allergenicity analysis revealed that 76.6 % (23/30) of the Humulus japonicus pollen allergic patients displayed specific IgE recognition of the natural Hum j PR-1. The cDNA sequence of Hum j PR-1 had a 516-bp open reading frame encoding 171 amino acids. Physicochemical analysis indicated that Hum j PR-1 was a stable and relatively thermostable protein. Hum j PR-1 shared a similar 3-dimensional folding pattern with other homologous allergens, which was a unique αßα sandwich structure containing 4 α-helices and 6 antiparallel ß-sheets, encompassing 4 conserved CAP domain. CONCLUSION: The natural PR-1 was firstly purified and characterized as a major allergenic allergen in Humulus japonicus pollen. These findings would contribute to developing diagnostic and therapeutic strategies for Humulus japonicus pollinosis.

The top 100 most cited articles in anaphylaxis: a bibliometric analysis.

Bibliometric analysis is helpful to determine the most influential studies in a specific field. A large number of publications in anaphylaxis have been published. However, no bibliometric analysis of anaphylaxis was conducted based on our known. The aim of this study is to identify the top 100 most cited articles in anaphylaxis and analyze their bibliometric characteristics. We searched in the Web of Science core database on November 20, 2021. Articles were listed in descending order by their total citations. Hence the top 100 most cited articles in anaphylaxis were identified and analyzed. Bibliometric indicators included: year of publication, total number of citations and average citations per year (ACY), journal of publication and impact factor (IF), countries, institutes, and authors, which were analyzed by Biblioshiny. Co-occurrence was used to visualize the classification and hotspots. The top 100 most cited articles were published between 1991 and 2017. The largest number of articles was published in a single interval in 2006-2008. Total citations of the 100 articles were between 155 and 1241 and were positively correlated with the number of articles published in each 3-year interval. The top100 articles were published in 34 different journals. The Journal of Allergy and Clinical Immunology published the most (n = 41). The corresponding authors of the top100 articles were from 13 different countries, mostly in North America and Europe. Statistical analysis revealed a positive correlation between total number of citations and ACY (r = 0.670, p < 0.01) and between total number of citations and IF (r = 0.219, p < 0.05), whereas a negative correlation between ACY and length of time since publication (r = - 0.697, p < 0.01). The research focuses were classified into three clusters: (1) the epidemiology and management. (2) the risk factor and treatment. (3) the assessment and diagnosis. COVID-19 vaccines, drug allergy and management were the recent major topics. This bibliometric analysis reveals the progress and hotspots of research in anaphylaxis, which may lay a foundation for further research.

Integrated metabolomics and lipidomics study of patients with atopic dermatitis in response to dupilumab.

Background: Atopic dermatitis (AD) is one of the most common chronic inflammatory skin diseases. Dupilumab, a monoclonal antibody that targets the interleukin (IL)-4 and IL-13 receptors, has been widely used in AD because of its efficacy. However, metabolic changes occurring in patients with AD in response to dupilumab remains unknown. In this study, we integrated metabolomics and lipidomics analyses with clinical data to explore potential metabolic alterations associated with dupilumab therapeutic efficacy. In addition, we investigated whether the development of treatment side effects was linked to the dysregulation of metabolic pathways. Methods: A total of 33 patients with AD were included in the current study, with serum samples collected before and after treatment with dupilumab. Comprehensive metabolomic and lipidomic analyses have previously been developed to identify serum metabolites (including lipids) that vary among treatment groups. An orthogonal partial least squares discriminant analysis model was established to screen for differential metabolites and metabolites with variable importance in projection > 1 and p < 0.05 were considered potential metabolic biomarkers. MetaboAnalyst 5.0 was used to identify related metabolic pathways. Patients were further classified into two groups, well responders (n = 19) and poor responders (n = 14), to identify differential metabolites between the two groups. Results: The results revealed significant changes in serum metabolites before and after 16 weeks of dupilumab treatment. Variations in the metabolic profile were more significant in the well-responder group than in the poor-responder group. Pathway enrichment analysis revealed that differential metabolites derived from the well-responder group were mainly involved in glycerophospholipid metabolism, valine, leucine and isoleucine biosynthesis, the citrate cycle, arachidonic acid metabolism, pyrimidine metabolism, and sphingolipid metabolism. Conclusion: Serum metabolic profiles of patients with AD varied significantly after treatment with dupilumab. Differential metabolites and their related metabolic pathways may provide clues for understanding the effects of dupilumab on patient metabolism.

Purification and characterization of enolase as a novel allergen in Platanus acerifolia pollen.

BACKGROUND: The pollen from Platanus acerifolia (P. acerifolia) is one of the main causes of allergic disorders. To date, only 4 allergens have been identified from this pollen. But previous studies showed that there still exist under-recognized allergens in it. The aim of this study was to comprehensively investigate the newly identified enolase (Pla a 6) as a novel allergen in the P. acerifolia pollen. METHODS: The natural (n) Pla a 6 was purified by combined chromatographic strategies. According to the identified internal peptides, the cDNA sequence encoding this allergen was matched from the mRNA-sequencing results of P. acerifolia pollen, which was further amplified and cloned. The recombinant (r) Pla a 6 was expressed and purified from E. coli. The allergenicity of this novel allergen was characterized by enzyme linked immunosorbent assay (ELISA), Western blot, inhibition ELISA, and basophil activation test (BAT). RESULTS: A novel allergen from P. acerifolia pollen, named as Pla a 6 was thoroughly studied, which contained an open reading frame of 1338 bp encoding 445 amino acids. The IgE-binding activity of nPla a 6 was initially proved by Western-blot, and a similar IgE-binding pattern to rPla a 6 was also exhibited. Moreover, the positivity for specific IgE against rPla a 6 was tested as 45.95% (17/37) by ELISA, and IgE binding to pollen extract could be inhibited up to 45.77% by 10 µg/ml of rPla a 6. The protein was also confirmed to activate patients' basophils. CONCLUSIONS: In this study, a novel allergen belonging to enolase family was comprehensively investigated and characterized through its natural and recombinant forms in P. acerifolia pollen. The study will contribute to the development of novel molecular-based diagnostic and therapeutic approaches for P. acerifolia pollen allergy.

Nano-silica particles synergistically IgE-mediated mast cell activation exacerbating allergic inflammation in mice.

Background: Allergic respiratory diseases have increased dramatically due to air pollution over the past few decades. However, studies are limited on the effects of inorganic components and particulate matter with different particle sizes in smog on allergic diseases, and the possible molecular mechanism of inducing allergies has not been thoroughly studied. Methods: Four common mineral elements with different particle sizes in smog particles were selected, including Al2O3, TiO2, Fe2O3, and SiO2. We studied the relationship and molecular mechanism of smog particle composition, particle size, and allergic reactions using mast cells, immunoglobulin E (IgE)-mediated passive cutaneous anaphylaxis (PCA) model, and an ovalbumin (OVA)-induced asthmatic mouse model in vitro and in vivo, combined with transmission electron microscopy, scanning transmission X-ray microscopy analysis, and transcriptome sequencing. Results: Only 20 nm SiO2 particles significantly increased ß-hexosaminidase release, based on dinitrophenol (DNP)-human serum albumin (HSA) stimulation, from IgE-sensitized mast cells, while other particles did not. Meanwhile, the PCA model showed that Evan's blue extravasation in mice was increased after treatment with nano-SiO2 particles. Nano-SiO2 particles exposure in the asthmatic mouse model caused an enhancement of allergic airway inflammation as manifested by OVA-specific serum IgE, airway hyperresponsiveness, lung inflammation injury, mucous cell metaplasia, cytokine expression, mast cell activation, and histamine secretion, which were significantly increased. Nano-SiO2 particles exposure did not affect the expression of FcϵRI or the ability of mast cells to bind IgE but synergistically activated mast cells by enhancing the mitogen-activated protein kinase (MAPK) signaling pathway, especially the phosphorylation levels of the extracellular signal-regulated kinase (ERK)1/2. The ERK inhibitors showed a significant inhibitory effect in reducing ß-hexosaminidase release. Conclusion: Our results indicated that nano-SiO2 particles stimulation might synergistically activate IgE-sensitized mast cells by enhancing the MAPK signaling pathway and that nano-SiO2 particles exposure could exacerbate allergic inflammation. Our experimental results provide useful information for preventing and treating allergic diseases.

CYSLTR1 rs320995 (T927C) and GSDMB rs7216389 (G1199A) Gene Polymorphisms in Asthma and Allergic Rhinitis: A Proof-of-Concept Study.

Background and Objective: Asthma and allergic rhinitis have been reported to be strongly associated with genetic factors. The aim of this study was to evaluate the accuracy of the TaqMan-MGB (minor groove binder) qPCR method for detecting CYSLTR1 rs320995 (T927C) and GSDMB rs7216389 (G1199A) gene polymorphisms as well as to explore the association of CYSLTR1 rs320995 and GSDMB rs7216389 polymorphisms with genetic susceptibility of Chinese patients with asthma and allergic rhinitis. Methods: In this study, 310 asthmatic patients and 60 healthy individuals were recruited in Peking Union Medical College Hospital. The CYSLTR1 rs320995 (T927C) and GSDMB rs7216389 (G1199A) gene polymorphisms in each group were analyzed by TaqMan-MGB qPCR and DNA sequencing which was regarded as the gold standard. After the validation of this method, additional 71 patients with allergic rhinitis and 72 patients with asthma combined with allergic rhinitis were selected and tested by using TaqMan-MGB qPCR. Results: The TaqMan-MGB qPCR results were fully consistent with DNA sequencing results (Kappa = 1, P<0.001). In addition, the results of the TaqMan-MGB qPCR assay were not affected by bilirubin and lipids. We found differential distribution of CYSLTR1 rs320995 genotypes in female patients with asthma combined with allergic rhinitis (χ 2=6.172, P=0.046, statistical power = 0.591). Specifically, the TT genotype is more frequent in women suffering from asthma with allergic rhinitis, whereas the TC genotype is more prevalent in healthy women. However, no such associations were observed in the GSDMB rs7216389 polymorphism. Conclusion: We have established a reliable TaqMan-MGB qPCR method for the detection of CYSLTR1 rs320995 and GSDMB rs7216389 polymorphisms. Moreover, the CYSLTR1 rs320995 polymorphism may be associated with genetic susceptibility of Chinese female patients with asthma and allergic rhinitis. Multicenter studies with larger sample sizes are required in the future.

A new cysteine protease allergen from Ambrosia trifida pollen: proforms and mature forms.

Giant ragweed (Ambrosia trifida) pollen is closely associated with respiratory allergy in late summer and autumn, and the prevalence of giant ragweed pollen allergy progressively increases. Compared with short ragweed (Ambrosia artemisiifolia), allergenic components from giant ragweed pollen are poorly investigated. To promote component-resolved diagnosis and treatment for giant ragweed pollen allergy, it becomes necessary to identify and characterize unknown allergens from giant ragweed pollen. In the present study, we identified and characterized a new cysteine-protease (CP) allergen from giant ragweed pollen, named as Amb t CP. The cloned Amb t CP gene encoded 387 amino acids. Recombinant Amb t CP (rAmb t CP) and natural Amb t CP (nAmb t CP) were purified by high-affinity Ni2+ resin and immunoaffinity chromatography respectively. During refolding, purified rAmb t CP could autocatalytically converted to its mature forms displaying a higher enzymatic activity. Moreover, the autocatalytic conversion of proforms to mature forms of nAmb t CP could cause their amount to change in giant ragweed pollen extracts. Then, the allergenicity of Amb t CP was characterized: 23 (33.8%) of 68 Chinese patients with ragweed pollen allergy showed positive IgE binding to nAmb t CP by enzyme-linked immunosorbent assay (ELISA); the result of subsequent ELISA showed that IgE-binding activity of proforms and mature forms of rAmb t CP was different, with positive rate of 39.1% (9/23) and 47.8% (11/23) respectively; Amb t CP showed IgE cross-reactivity with the CP components from short ragweed, Artemisia annua and Artemisia sieversiana pollen. Our findings will help to promote component-resolved diagnosis and treatment for giant ragweed pollen allergy, standardize allergen products and individualize allergen-specific immunotherapy.

Molecular and immunochemical characterization of profilin as major allergen from Platanus acerifolia pollen.

BACKGROUND: The Platanus acerifolia (P. acerifolia) pollen is one of the most common causes of allergic respiratory symptoms in China. However, the allergenic components in P. acerifolia are not fully studied yet. The study aimed to determine the molecular and immunochemical characterization of the profilin from P. acerifolia pollen. METHODS: The coding sequence of profilin was amplified, cloned, and then expressed in Escherichia coli BL21 cells and purified by nickel affinity chromatography. Protein refolding was followed by structural characterization and homology 3D model building. The allergenicity and cross-reactivity were assessed by ELISA, immunoblotting, or basophil activation test (BAT) using the sera of P. acerifolia allergic patients. RESULTS: The cDNA sequence of profilin was cloned with a 396 bp open reading frame coding for 131 amino acids. The molecular weight of the profilin was approximately 14 kDa, and the predicted structure consisted of 3 α-helixes and 7 ß-sheets. Physicochemical analysis indicated the profilin was a stable, relatively thermostable, and relatively conserved protein. The allergenicity determined by ELISA, western blot, and BAT suggested 76.9% (30/39) of the P. acerifolia pollen allergic patients displayed specific IgE recognition of the profilin. The profilin shared > 80% sequence identity with Pop n 2, the profilin from Populus nigra, and observed a significant cross-reactivity with Pop n 2 in IgE-inhibition assay. CONCLUSION: Profilin, as one of the major component allergens in P. acerifolia pollen, was identified and characterized at molecular and immunochemical levels in this study. These findings would contribute to developing diagnostic and therapeutic strategies for P. acerifolia pollen allergic patients.

Identification of Per a 13 as a novel allergen in American cockroach.

BACKGROUND: Cockroaches are an important source of indoor allergens. Environmental exposure to cockroach allergens is closely associated with the development of immunoglobulin E (IgE)-mediated allergic diseases. However, the allergenic components in the American cockroaches are not fully studied yet. In order to develop novel diagnostic and therapeutic strategies for cockroach allergy, it is necessary to comprehensively investigate this undescribed allergen in the American cockroach. METHODS: The full-length cDNA of the potential allergen was isolated from the cDNA library of the American cockroach by PCR cloning. Both the recombinant and natural protein molecules were purified and characterized. The allergenicity was further analyzed by enzyme linked immunosorbent assay, immunoblot, and basophil activation test using sera from cockroach allergic patients. RESULTS: A novel allergen belonging to glyceraldehyde 3-phosphate dehydrogenase (GAPDH) was firstly identified in the American cockroach and named as Per a 13. The cDNA of this allergen is 1255 base pairs in length and contains an open reading frame of 999 base pairs, encoding 332 amino acids. The purified Per a 13 was fully characterized and assessed to react with IgEs from 49.3 % of cockroach allergic patients, and patients with allergic rhinitis were more sensitized to it. Moreover, the allergenicity was further confirmed by immunoblot and basophil activation test. CONCLUSIONS: We firstly identified GAPDH (Per a 13) in the American cockroach, which is a novel type of inhalant allergen derived from animal species. These findings could be useful in developing novel diagnostic and therapeutic strategies for cockroach allergy.

The Diagnosis and Management of Allergic Reactions Caused by Chinese Materia Medica.

Traditional Chinese medicines (TCM) have been used in China for thousands of years. Although TCM has been generally perceived to be safe, adverse reactions to Chinese materia medica (CMM) have been reported. Most of the adverse reactions are allergic in nature, but other mechanisms may play a role. This review focuses on the mechanism and clinical presentation of these allergic reactions. Allergic reactions can occur as a result of the active and inactive ingredients of CMM. Impurities and chemicals generated during the production process can also lead to allergic or adverse reactions. Environmental factors such as temperature, humidity, and light can cause changes in the allergenicity of drugs. Human error in formulating CMM drugs also contributes to adverse drug reactions. The management of allergic reactions to CMM includes taking a good history, avoidance of medications in the same class as those which caused prior reactions, the proper training of staff, adherence to manufacturer guidelines and expiration dates, evaluation of benefit and risk balance, and the formulation of a risk management strategy for the use of CMM. A small test dose of a considered drug before using, improvements in drug purification technology, and proper storage and clinical administration help reduce allergic reactions due to CMM.

Systemic Contact Dermatitis: The Routes of Allergen Entry.

Systemic contact dermatitis (SCD) is a generalized reactivation of type IV hypersensitivity skin diseases in individuals with previous sensitization after a contact allergen is administered systemically. Patients with SCD may consider their dermatitis unpredictable and recalcitrant since the causative allergens are difficult to find. If a patient has a pattern of dermatitis suggestive of SCD but fails to improve with conventional treatment, SCD should be taken into consideration. If doctors are not familiar with the presentations of SCD and the possible routes of allergen sensitization and exposure, the diagnosis of SCD may be delayed. In this work, we summarized all of the routes through which allergens can enter the body and cause SCD, including oral intake, local contact (through skin, inhalation, nasal spray and anal application), implants, and other iatrogenic or invasive routes (intravenous, intramuscular, intraarticular, and intravesicular). This will provide a comprehensive reference for the clinicians to identify the culprit of SCD.

Management and Treatment of COVID-19: The Chinese Experience.

With more than 1,800,000 cases and 110,000 deaths globally, COVID-19 is one of worst infectious disease outbreaks in history. This paper provides a critical review of the available evidence regarding the lessons learned from the Chinese experience with COVID-19 prevention and management. The steps that have led to a near disappearance of new cases in China included rapid sequencing of the virus to establish testing kits, which allowed tracking of infected persons in and out of Wuhan. In addition, aggressive quarantine measures included the complete isolation of Wuhan and then later Hubei Province and the rest of the country, as well as closure of all schools and nonessential businesses. Other measures included the rapid construction of two new hospitals and the establishment of "Fangcang" shelter hospitals. In the absence of a vaccine, the management of COVID-19 included antivirals, high-flow oxygen, mechanical ventilation, corticosteroids, hydroxychloroquine, tocilizumab, interferons, intravenous immunoglobulin, and convalescent plasma infusions. These measures appeared to provide only moderate success. Although some measures have been supported by weak descriptive data, their effectiveness is still unclear pending well controlled clinical trials. In the end, it was the enforcement of drastic quarantine measures that stopped SARS-CoV-2 from spreading. The earlier the implementation, the less likely resources will be depleted. The most critical factors in stopping a pandemic are early recognition of infected individuals, carriers, and contacts and early implementation of quarantine measures with an organised, proactive, and unified strategy at a national level. Delays result in significantly higher death tolls.

Clinical Pathway for Early Diagnosis of COVID-19: Updates from Experience to Evidence-Based Practice.

The COVID-19 pandemic is a significant global event in the history of infectious diseases. The SARS-CoV-2 appears to have originated from bats but is now easily transmissible among humans, primarily through droplet or direct contact. Clinical features of COVID-19 include high fever, cough, and fatigue which may progress to ARDS. Respiratory failure can occur rapidly after this. The primary laboratory findings include lymphopenia and eosinopenia. Elevated D-dimer, procalcitonin, and CRP levels may correlate with disease severity. Imaging findings include ground-glass opacities and patchy consolidation on CT scan. Mortality is higher in patients with hypertension, cardiac disease, diabetes mellitus, cancer, and COPD. Elderly patients are more susceptible to severe disease and death, while children seem to have lower rates of infection and lower mortality. Diagnostic criteria and the identification of persons under investigation have evolved as more data has emerged. However, the approach to diagnosis is still very variable from region to region, country to country, and even among different hospitals in the same city. The importance of a clinical pathway to implement the most effective and relevant diagnostic strategy is of critical importance to establish the control of this virus that is responsible for more and more deaths each day.

The deadly coronaviruses: The 2003 SARS pandemic and the 2020 novel coronavirus epidemic in China.

The 2019-nCoV is officially called SARS-CoV-2 and the disease is named COVID-19. This viral epidemic in China has led to the deaths of over 1800 people, mostly elderly or those with an underlying chronic disease or immunosuppressed state. This is the third serious Coronavirus outbreak in less than 20 years, following SARS in 2002-2003 and MERS in 2012. While human strains of Coronavirus are associated with about 15% of cases of the common cold, the SARS-CoV-2 may present with varying degrees of severity, from flu-like symptoms to death. It is currently believed that this deadly Coronavirus strain originated from wild animals at the Huanan market in Wuhan, a city in Hubei province. Bats, snakes and pangolins have been cited as potential carriers based on the sequence homology of CoV isolated from these animals and the viral nucleic acids of the virus isolated from SARS-CoV-2 infected patients. Extreme quarantine measures, including sealing off large cities, closing borders and confining people to their homes, were instituted in January 2020 to prevent spread of the virus, but by that time much of the damage had been done, as human-human transmission became evident. While these quarantine measures are necessary and have prevented a historical disaster along the lines of the Spanish flu, earlier recognition and earlier implementation of quarantine measures may have been even more effective. Lessons learned from SARS resulted in faster determination of the nucleic acid sequence and a more robust quarantine strategy. However, it is clear that finding an effective antiviral and developing a vaccine are still significant challenges. The costs of the epidemic are not limited to medical aspects, as the virus has led to significant sociological, psychological and economic effects globally. Unfortunately, emergence of SARS-CoV-2 has led to numerous reports of Asians being subjected to racist behavior and hate crimes across the world.