BACKGROUND Primary spinal cord(PSC)glioblastoma(GB)is an extremely rare but fatal primary tumor of the central nervous system and associated with a poor prognosis.While typical tumor imaging features are generally eas...BACKGROUND Primary spinal cord(PSC)glioblastoma(GB)is an extremely rare but fatal primary tumor of the central nervous system and associated with a poor prognosis.While typical tumor imaging features are generally easy to recognize,glioblastoma multiforme can have a wide range of imaging findings.Atypical GB is often misdiagnosed,which usually delays the optimal time for treatment.In this article,we discuss a clinical case of pathologically confirmed PSC GB under the guise of benign tumor imaging findings,as well as the most recent literature pertaining to PSC GB.CASE SUMMARY A 70-year-old female complained of limb weakness lasting more than 20 d.Irregular masses were observed inside and outside the left foramina of the spinal canal at C7-T1 on medical imaging.Based on the imaging features,radiologists diagnosed the patient with schwannoma.Tumor resection was performed under general anesthesia.The final histopathological findings revealed a final diagnosis of PSC GB,world health organization Grade IV.The patient subsequently underwent a 4-wk course of radiotherapy(60 Gy in 20 fractions)combined with temozolomide chemotherapy.The patient was alive at the time of submission of this manuscript.CONCLUSION Atypical GB presented unusual imaging findings,which led to misdiagnosis.Therefore,a complete recognition of imaging signs may facilitate early accurate diagnosis.展开更多
This article introduces the history of the integration of Chinese and Western medicine,from Zhang Xichun,a representative of the Huitong School of Chinese and Western Medicine,and the historical"abolition of trad...This article introduces the history of the integration of Chinese and Western medicine,from Zhang Xichun,a representative of the Huitong School of Chinese and Western Medicine,and the historical"abolition of traditional Chinese medicine",and"the scientificization of Chinese medicine"to"Integration of traditional Chinese medicine and Western medicine",passing the tortuous development.The integration of traditional Chinese and Western medicine has achieved fruitful results from the intense divergence in understanding to education,scientific research,clinical practice,and theoretical research.This article discusses the development process of the integration of traditional Chinese and Western medicine in detail from multiple dimensions such as history,reality,theory,and practice.In particular,it introduces Zhang Xichun's views and practice of integrated traditional Chinese and Western medicine,the theory and practice of modern integrated traditional Chinese and Western medicine,the main achievements of integrated traditional Chinese and western medicine,and typical cases of integrated traditional Chinese and western medicine.It provides reference for the vast number of integrated Chinese and Western medicine workers.展开更多
Wilson disease (WD) is an uncommon recessive genetic disorder affecti叩 copper metabolism. Cardiac, neurological, hepatic and renal manifestations are well defined, nevertheless approximately 30% of patients debut wit...Wilson disease (WD) is an uncommon recessive genetic disorder affecti叩 copper metabolism. Cardiac, neurological, hepatic and renal manifestations are well defined, nevertheless approximately 30% of patients debut with neuropsychiatric symptoms. These psychiatric alterations resulting from the accumulation of this heavy metal in the basal ganglia are some how less specific. We present a short review of psychiatric symptoms of WD and describe a case of a 37-year-old woman diagnosed with WD who presented neuropsychiatric symptoms and had a consequent delay in diagnosis and causal treatment. Patients who develop WD starti叩 with a predominance of neuropsychiatric symptoms tend to manifest hepatic symptoms later, therefore have a longer delay of diagnosis and a poorer outcome than patients with hepatic symptoms. An early diagnosis ofWD can avoid irreversible neurological damage.展开更多
OBJECTIVE: To study the sonographic features and patterns of cystic renal carcinomas. METHODS: Thirteen cases of cystic renal carcinoma confirmed by operation and pathology were examined by ultrasonography, and the cy...OBJECTIVE: To study the sonographic features and patterns of cystic renal carcinomas. METHODS: Thirteen cases of cystic renal carcinoma confirmed by operation and pathology were examined by ultrasonography, and the cystic walls, septa and solid mural nodules were studied. RESULTS: Solid mural nodules of some cases and irregular thickening of the cystic walls and septa were characteristic findings for the ultrasonic diagnosis of cystic renal carcinomas. According to their pathologic mechanisms and sonographic features, cystic renal carcinomas were classified into 3 patterns: unilocular cystic mass, multiloculated cystic mass and cystic-solid mass. CONCLUSIONS: Typical cystic renal carcinomas can be well diagnosed, while atypical cases may be misdiagnosed as benign renal cysts by ultrasonography. Color Doppler ultrasonography and needle aspiration guided by ultrasonography are helpful in the diagnosis of these atypical cases.展开更多
<strong>Background: </strong>The December 2019 Chinese epidemic of Corona Virus Disease [COVID-19], which erupted in Wuhan, South China, was declared a pandemic, by the World Health Organization [WHO], on ...<strong>Background: </strong>The December 2019 Chinese epidemic of Corona Virus Disease [COVID-19], which erupted in Wuhan, South China, was declared a pandemic, by the World Health Organization [WHO], on 12<sup>th</sup> January 2020. The worldwide spread from China was rapid, but Africa was the last port-of-call. Her first diagnosed case was two months after China’s, on 14<sup>th</sup> February, 2020 in Egypt. The morbidity and mortality rates have, however, remained lower in Africa than in the developed world, and analysts believe that it was more of a temporary respite, since Africa’s poor health infrastructure will become her eventual albatross. <strong>Methodology:</strong> Data were collected on COVID-19 and records of the socio-economic capacity of Africa by accessing the relevant previous and current peer-reviewed publications from multiple search engines on internet. The data were, then, collated and comparatively analyzed. <strong>Results: </strong>The available data revealed that Africa had, mostly, the milder forms of COVID-19, and so, morbidity and mortality were low. Her shrinking elderly population and hot climate were believed to be contributory, but lately, as the pandemic spread, the role of these factors was not exactly predictive. Being low on healthcare infrastructure, Africa could tenaciously leverage on the supportive and preventive measures prescribed by WHO, while the world awaited a vaccine. The role of ventilators in the care of critically ill patients, also, came under scrutiny as some workers were questioning the underlying pathology, and advocating a paradigm shift from high-tech positive end expiratory pressure ventilation to plasmapheresis and packed cell transfusion. <strong>Conclusion:</strong> Africa faces a huge challenge with COVID-19, but the predicted heavy mortalities may be reduced by some local confounding factors, control of spread and re-focusing of critical care away from the expensive and unavailable ventilators.展开更多
BACKGROUND There are a few cases of lateral lymph node(LLN)metastasis(LLNM)of T1 rectal cancer.Moreover,LLNM is easily missed,especially in patients with early-stage rectal cancer.To our knowledge,the possibility of b...BACKGROUND There are a few cases of lateral lymph node(LLN)metastasis(LLNM)of T1 rectal cancer.Moreover,LLNM is easily missed,especially in patients with early-stage rectal cancer.To our knowledge,the possibility of bilateral LLNM before surgery has not been reported in previous studies.CASE SUMMARY A 36-year-old woman underwent endoscopic submucosal dissection at a local hospital owing to a clinical diagnosis of a rectal polyp.The pathology report showed a diagnosis of T1 rectal mucinous adenocarcinoma.She was considered to have bilateral LLNM after the examination at our hospital.Laparoscopic total mesorectal excision plus bilateral LLN dissection was performed and the pathological outcomes indicated unilateral LLNM.The patient received longcourse adjuvant chemoradiotherapy with no recurrence or metastasis observed during the 1-year follow-up period.CONCLUSION T1 rectal cancer could lead to LLNM and possibly,bilateral LLNM.Therefore,adequate clinical evaluation is essential for these patients.展开更多
Background:At 10 a.m.on January 23,2020 Wuhan,China imposed a 76-day travel lockdown on its 11 million residents in order to stop the spread of COVID-19.This lockdown represented the largest quarantine in the history ...Background:At 10 a.m.on January 23,2020 Wuhan,China imposed a 76-day travel lockdown on its 11 million residents in order to stop the spread of COVID-19.This lockdown represented the largest quarantine in the history of public health and provides us with an opportunity to critically examine the relationship between a city lockdown on human mobility and controlling the spread of a viral epidemic,in this case COVID-19.This study aims to assess the causal impact of the Wuhan lockdown on population movement and the increase of newly confirmed COVID-19 cases.Methods:Based on the daily panel data from 279 Chinese cities,our research is the first to apply the synthetic control approach to empirically analyze the causal relationship between the Wuhan lockdown of its population mobility and the progression of newly confirmed COVID-19 cases.By using a weighted average of available control cities to reproduce the counterfactual outcome trajectory that the treated city would have experienced in the absence of the lockdown,the synthetic control approach overcomes the sample selection bias and policy endogeneity problems that can arise from previous empirical methods in selecting control units.Results:In our example,the lockdown of Wuhan reduced mobility inflow by approximately 60%and outflow by about 50%.A significant reduction of new cases was observed within four days of the lockdown.The increase in new cases declined by around 50%during this period.However,the suppression effect became less discernible after this initial period of time.A 2.25-fold surge was found for the increase in new cases on the fifth day following the lockdown,after which it died down rapidly.Conclusions:Our study provided urgently needed and reliable causal evidence that city lockdown can be an effective short-term tool in containing and delaying the spread of a viral epidemic.Further,the city lockdown strategy can buy time during which countries can mobilize an effective response in order to better prepare.Therefore,in spite of initial widespread skepticism,lockdowns are likely to be added to the response toolkit used for any future pandemic outbreak.展开更多
This study applies OLS,panel regression and Granger causality test to investigate the impact of the Coronavirus disease 2019(Covid-19)outbreak on the global equity markets during the early stage of the pandemic.We fin...This study applies OLS,panel regression and Granger causality test to investigate the impact of the Coronavirus disease 2019(Covid-19)outbreak on the global equity markets during the early stage of the pandemic.We find that the Covid-19 outbreak has a significant negative impact on the overall equity index return of the eight economies even at 0.1%significance level.Furthermore,the pandemic has a more significant impact on the European countries than on the East Asian economies.The results have three main implications.Firstly,policy makers should react fast to mitigate the impact of a crisis.Secondly,investors should be aware of an outbreak of disease or other risks and adjust their investments accordingly.Furthermore,the Covid-19 outbreak results in a shift of power from the west to the east.展开更多
To introduce the epidemical, pathological, and clinical characteristics as well as the diagnostic and therapeutical experiences of endomyocardial fibrosis(EMF) in China. [WT5”BX] Data sources.[WT5”BZ]A CMBdisc searc...To introduce the epidemical, pathological, and clinical characteristics as well as the diagnostic and therapeutical experiences of endomyocardial fibrosis(EMF) in China. [WT5”BX] Data sources.[WT5”BZ]A CMBdisc search was done of the Chinese language literature published from January 1983 through June 1997 about EMF and/or restrictive cardiomyopathy. A manual search was then done for other contributions, including abstracts, between January 1965 and June 1997. [WT5”BX] Results. [WT5”BZ]Eighty seven Chinese cases of EMF were collected in this paper. There were 49 men and 38 women, with a mean age of 28±13 years(range, 8 to 68 years). The distribution of the cases is mainly in the south of China. Combined right and left ventricular disease occurs in 48 percent of cases, with pure right ventricular involvement occurring in 42 percent and pure left ventricular involvement in the remaining 10 percent of patients who are examined postmortem. The diagnosis of EMF was confirmed in 21 cases at autopsy, and in 66 cases by echocardiography, angiocardiography, and/or endomyocardial biopsy which showed the characteristic changes. Clinically, right sided disease is the commonest variety. Endocardiectomy and tricuspid(n=7) or mitral(n=1) valves replacement have been performed in 8 patients. There were 2 operative deaths. Six patients had a satisfactory recovery postoperatively and living well in the follow up duration. [WT5”BX] Conclusion.展开更多
We report on the dynamic scaling of the diffusion growth phase of the COVID-19 epidemic in Europe.During this initial diffusion stage,the European countries implemented unprecedented mitigation polices to delay and su...We report on the dynamic scaling of the diffusion growth phase of the COVID-19 epidemic in Europe.During this initial diffusion stage,the European countries implemented unprecedented mitigation polices to delay and suppress the disease contagion,although not in a uniform way or timing.Despite this diversity,we find that the reported fatality cases grow following a power law in all European countries we studied.The difference among countries is the value of the power-law exponent 3.5<α<8.0.This common attribute can prove a practical diagnostic tool,allowing reasonable predictions for the growth rate from very early data at a country level.We propose a model for the disease-causing interactions,based on a mechanism of human decisions and risk taking in interpersonal associations.The model describes the observed statistical distribution and contributes to the discussion on basic assumptions for homogeneous mixing or for a network perspective in epidemiological studies of COVID-19.展开更多
Regarding to the actual situation of the new coronavirus disease 2019 epidemic,social factors should be taken into account and the increasing growth trend of confirmed populations needs to be explained.A proper model ...Regarding to the actual situation of the new coronavirus disease 2019 epidemic,social factors should be taken into account and the increasing growth trend of confirmed populations needs to be explained.A proper model needs to be established,not only to simulate the epidemic,but also to evaluate the future epidemic situation and find a pilot indicator for the outbreak.The original susceptible-infectious-recover model is modified into the susceptible-infectious-quarantine-confirm-recover combined with social factors(SIDCRL)model,which combines the natural transmission with social factors such as external interventions and isolation.The numerical simulation method is used to imitate the change curve of the cumulative number of the confirmed cases and the number of cured patients.Furthermore,we investigate the relationship between the suspected close contacts(SCC)and the final outcome of the growth trend of confirmed cases with a simulation approach.This article selects four representative countries,that is,China,South Korea,Italy,and the United States,and gives separate numerical simulations.The simulation results of the model fit the actual situation of the epidemic development and reasonable predictions are made.In addition,it is analyzed that the increasing number of SCC contributes to the epidemic outbreak and the prediction of the United States based on the population of the SCC highlights the importance of external intervention and active prevention measures.The simulation of the model verifies its reliability and stresses that observable variable SCC can be taken as a pilot indicator of the coronavirus disease 2019 pandemic.展开更多
基金Supported by the “Excellent Doctoral Dissertation Incubation Grant of First Clinical School of Guangzhou University of Chinese Medicine”,No. YB201903
文摘BACKGROUND Primary spinal cord(PSC)glioblastoma(GB)is an extremely rare but fatal primary tumor of the central nervous system and associated with a poor prognosis.While typical tumor imaging features are generally easy to recognize,glioblastoma multiforme can have a wide range of imaging findings.Atypical GB is often misdiagnosed,which usually delays the optimal time for treatment.In this article,we discuss a clinical case of pathologically confirmed PSC GB under the guise of benign tumor imaging findings,as well as the most recent literature pertaining to PSC GB.CASE SUMMARY A 70-year-old female complained of limb weakness lasting more than 20 d.Irregular masses were observed inside and outside the left foramina of the spinal canal at C7-T1 on medical imaging.Based on the imaging features,radiologists diagnosed the patient with schwannoma.Tumor resection was performed under general anesthesia.The final histopathological findings revealed a final diagnosis of PSC GB,world health organization Grade IV.The patient subsequently underwent a 4-wk course of radiotherapy(60 Gy in 20 fractions)combined with temozolomide chemotherapy.The patient was alive at the time of submission of this manuscript.CONCLUSION Atypical GB presented unusual imaging findings,which led to misdiagnosis.Therefore,a complete recognition of imaging signs may facilitate early accurate diagnosis.
文摘This article introduces the history of the integration of Chinese and Western medicine,from Zhang Xichun,a representative of the Huitong School of Chinese and Western Medicine,and the historical"abolition of traditional Chinese medicine",and"the scientificization of Chinese medicine"to"Integration of traditional Chinese medicine and Western medicine",passing the tortuous development.The integration of traditional Chinese and Western medicine has achieved fruitful results from the intense divergence in understanding to education,scientific research,clinical practice,and theoretical research.This article discusses the development process of the integration of traditional Chinese and Western medicine in detail from multiple dimensions such as history,reality,theory,and practice.In particular,it introduces Zhang Xichun's views and practice of integrated traditional Chinese and Western medicine,the theory and practice of modern integrated traditional Chinese and Western medicine,the main achievements of integrated traditional Chinese and western medicine,and typical cases of integrated traditional Chinese and western medicine.It provides reference for the vast number of integrated Chinese and Western medicine workers.
文摘Wilson disease (WD) is an uncommon recessive genetic disorder affecti叩 copper metabolism. Cardiac, neurological, hepatic and renal manifestations are well defined, nevertheless approximately 30% of patients debut with neuropsychiatric symptoms. These psychiatric alterations resulting from the accumulation of this heavy metal in the basal ganglia are some how less specific. We present a short review of psychiatric symptoms of WD and describe a case of a 37-year-old woman diagnosed with WD who presented neuropsychiatric symptoms and had a consequent delay in diagnosis and causal treatment. Patients who develop WD starti叩 with a predominance of neuropsychiatric symptoms tend to manifest hepatic symptoms later, therefore have a longer delay of diagnosis and a poorer outcome than patients with hepatic symptoms. An early diagnosis ofWD can avoid irreversible neurological damage.
文摘OBJECTIVE: To study the sonographic features and patterns of cystic renal carcinomas. METHODS: Thirteen cases of cystic renal carcinoma confirmed by operation and pathology were examined by ultrasonography, and the cystic walls, septa and solid mural nodules were studied. RESULTS: Solid mural nodules of some cases and irregular thickening of the cystic walls and septa were characteristic findings for the ultrasonic diagnosis of cystic renal carcinomas. According to their pathologic mechanisms and sonographic features, cystic renal carcinomas were classified into 3 patterns: unilocular cystic mass, multiloculated cystic mass and cystic-solid mass. CONCLUSIONS: Typical cystic renal carcinomas can be well diagnosed, while atypical cases may be misdiagnosed as benign renal cysts by ultrasonography. Color Doppler ultrasonography and needle aspiration guided by ultrasonography are helpful in the diagnosis of these atypical cases.
文摘<strong>Background: </strong>The December 2019 Chinese epidemic of Corona Virus Disease [COVID-19], which erupted in Wuhan, South China, was declared a pandemic, by the World Health Organization [WHO], on 12<sup>th</sup> January 2020. The worldwide spread from China was rapid, but Africa was the last port-of-call. Her first diagnosed case was two months after China’s, on 14<sup>th</sup> February, 2020 in Egypt. The morbidity and mortality rates have, however, remained lower in Africa than in the developed world, and analysts believe that it was more of a temporary respite, since Africa’s poor health infrastructure will become her eventual albatross. <strong>Methodology:</strong> Data were collected on COVID-19 and records of the socio-economic capacity of Africa by accessing the relevant previous and current peer-reviewed publications from multiple search engines on internet. The data were, then, collated and comparatively analyzed. <strong>Results: </strong>The available data revealed that Africa had, mostly, the milder forms of COVID-19, and so, morbidity and mortality were low. Her shrinking elderly population and hot climate were believed to be contributory, but lately, as the pandemic spread, the role of these factors was not exactly predictive. Being low on healthcare infrastructure, Africa could tenaciously leverage on the supportive and preventive measures prescribed by WHO, while the world awaited a vaccine. The role of ventilators in the care of critically ill patients, also, came under scrutiny as some workers were questioning the underlying pathology, and advocating a paradigm shift from high-tech positive end expiratory pressure ventilation to plasmapheresis and packed cell transfusion. <strong>Conclusion:</strong> Africa faces a huge challenge with COVID-19, but the predicted heavy mortalities may be reduced by some local confounding factors, control of spread and re-focusing of critical care away from the expensive and unavailable ventilators.
文摘BACKGROUND There are a few cases of lateral lymph node(LLN)metastasis(LLNM)of T1 rectal cancer.Moreover,LLNM is easily missed,especially in patients with early-stage rectal cancer.To our knowledge,the possibility of bilateral LLNM before surgery has not been reported in previous studies.CASE SUMMARY A 36-year-old woman underwent endoscopic submucosal dissection at a local hospital owing to a clinical diagnosis of a rectal polyp.The pathology report showed a diagnosis of T1 rectal mucinous adenocarcinoma.She was considered to have bilateral LLNM after the examination at our hospital.Laparoscopic total mesorectal excision plus bilateral LLN dissection was performed and the pathological outcomes indicated unilateral LLNM.The patient received longcourse adjuvant chemoradiotherapy with no recurrence or metastasis observed during the 1-year follow-up period.CONCLUSION T1 rectal cancer could lead to LLNM and possibly,bilateral LLNM.Therefore,adequate clinical evaluation is essential for these patients.
文摘Background:At 10 a.m.on January 23,2020 Wuhan,China imposed a 76-day travel lockdown on its 11 million residents in order to stop the spread of COVID-19.This lockdown represented the largest quarantine in the history of public health and provides us with an opportunity to critically examine the relationship between a city lockdown on human mobility and controlling the spread of a viral epidemic,in this case COVID-19.This study aims to assess the causal impact of the Wuhan lockdown on population movement and the increase of newly confirmed COVID-19 cases.Methods:Based on the daily panel data from 279 Chinese cities,our research is the first to apply the synthetic control approach to empirically analyze the causal relationship between the Wuhan lockdown of its population mobility and the progression of newly confirmed COVID-19 cases.By using a weighted average of available control cities to reproduce the counterfactual outcome trajectory that the treated city would have experienced in the absence of the lockdown,the synthetic control approach overcomes the sample selection bias and policy endogeneity problems that can arise from previous empirical methods in selecting control units.Results:In our example,the lockdown of Wuhan reduced mobility inflow by approximately 60%and outflow by about 50%.A significant reduction of new cases was observed within four days of the lockdown.The increase in new cases declined by around 50%during this period.However,the suppression effect became less discernible after this initial period of time.A 2.25-fold surge was found for the increase in new cases on the fifth day following the lockdown,after which it died down rapidly.Conclusions:Our study provided urgently needed and reliable causal evidence that city lockdown can be an effective short-term tool in containing and delaying the spread of a viral epidemic.Further,the city lockdown strategy can buy time during which countries can mobilize an effective response in order to better prepare.Therefore,in spite of initial widespread skepticism,lockdowns are likely to be added to the response toolkit used for any future pandemic outbreak.
文摘This study applies OLS,panel regression and Granger causality test to investigate the impact of the Coronavirus disease 2019(Covid-19)outbreak on the global equity markets during the early stage of the pandemic.We find that the Covid-19 outbreak has a significant negative impact on the overall equity index return of the eight economies even at 0.1%significance level.Furthermore,the pandemic has a more significant impact on the European countries than on the East Asian economies.The results have three main implications.Firstly,policy makers should react fast to mitigate the impact of a crisis.Secondly,investors should be aware of an outbreak of disease or other risks and adjust their investments accordingly.Furthermore,the Covid-19 outbreak results in a shift of power from the west to the east.
文摘To introduce the epidemical, pathological, and clinical characteristics as well as the diagnostic and therapeutical experiences of endomyocardial fibrosis(EMF) in China. [WT5”BX] Data sources.[WT5”BZ]A CMBdisc search was done of the Chinese language literature published from January 1983 through June 1997 about EMF and/or restrictive cardiomyopathy. A manual search was then done for other contributions, including abstracts, between January 1965 and June 1997. [WT5”BX] Results. [WT5”BZ]Eighty seven Chinese cases of EMF were collected in this paper. There were 49 men and 38 women, with a mean age of 28±13 years(range, 8 to 68 years). The distribution of the cases is mainly in the south of China. Combined right and left ventricular disease occurs in 48 percent of cases, with pure right ventricular involvement occurring in 42 percent and pure left ventricular involvement in the remaining 10 percent of patients who are examined postmortem. The diagnosis of EMF was confirmed in 21 cases at autopsy, and in 66 cases by echocardiography, angiocardiography, and/or endomyocardial biopsy which showed the characteristic changes. Clinically, right sided disease is the commonest variety. Endocardiectomy and tricuspid(n=7) or mitral(n=1) valves replacement have been performed in 8 patients. There were 2 operative deaths. Six patients had a satisfactory recovery postoperatively and living well in the follow up duration. [WT5”BX] Conclusion.
文摘We report on the dynamic scaling of the diffusion growth phase of the COVID-19 epidemic in Europe.During this initial diffusion stage,the European countries implemented unprecedented mitigation polices to delay and suppress the disease contagion,although not in a uniform way or timing.Despite this diversity,we find that the reported fatality cases grow following a power law in all European countries we studied.The difference among countries is the value of the power-law exponent 3.5<α<8.0.This common attribute can prove a practical diagnostic tool,allowing reasonable predictions for the growth rate from very early data at a country level.We propose a model for the disease-causing interactions,based on a mechanism of human decisions and risk taking in interpersonal associations.The model describes the observed statistical distribution and contributes to the discussion on basic assumptions for homogeneous mixing or for a network perspective in epidemiological studies of COVID-19.
文摘Regarding to the actual situation of the new coronavirus disease 2019 epidemic,social factors should be taken into account and the increasing growth trend of confirmed populations needs to be explained.A proper model needs to be established,not only to simulate the epidemic,but also to evaluate the future epidemic situation and find a pilot indicator for the outbreak.The original susceptible-infectious-recover model is modified into the susceptible-infectious-quarantine-confirm-recover combined with social factors(SIDCRL)model,which combines the natural transmission with social factors such as external interventions and isolation.The numerical simulation method is used to imitate the change curve of the cumulative number of the confirmed cases and the number of cured patients.Furthermore,we investigate the relationship between the suspected close contacts(SCC)and the final outcome of the growth trend of confirmed cases with a simulation approach.This article selects four representative countries,that is,China,South Korea,Italy,and the United States,and gives separate numerical simulations.The simulation results of the model fit the actual situation of the epidemic development and reasonable predictions are made.In addition,it is analyzed that the increasing number of SCC contributes to the epidemic outbreak and the prediction of the United States based on the population of the SCC highlights the importance of external intervention and active prevention measures.The simulation of the model verifies its reliability and stresses that observable variable SCC can be taken as a pilot indicator of the coronavirus disease 2019 pandemic.
