Chinese Center for Disease Control and Prevention

About: Chinese Center for Disease Control and Prevention is a government organization based out in Beijing, China. It is known for research contribution in the topics: Population & Acquired immunodeficiency syndrome (AIDS). The organization has 16037 authors who have published 15098 publications receiving 423452 citations. The organization is also known as: China CDC & CCDC.

Genesis and Spread of Newly Emerged Highly Pathogenic H7N9 Avian Viruses in Mainland China.

Abstract: The novel low-pathogenic avian influenza A H7N9 viruses (LPAI H7N9 viruses) have been a threat to public health since their emergence in 2013 because of the high rates of mortality and morbidity that they cause. Recently, highly pathogenic variants of these avian influenza A H7N9 viruses (HPAI H7N9 viruses) have emerged and caused human infections and outbreaks among poultry in mainland China. However, it is still unclear how the HPAI H7N9 virus was generated and how it evolved and spread in China. Here, we show that the ancestor virus of the HPAI H7N9 viruses originated in the Yangtze River Delta region and spread southward to the Pearl River Delta region, possibly through live poultry trade. After introduction into the Pearl River Delta region, the origin LPAI H7N9 virus acquired four amino acid insertions in the hemagglutinin (HA) protein cleavage site and mutated into the HPAI H7N9 virus in late May 2016. Afterward, the HPAI H7N9 viruses further reassorted with LPAI H7N9 or H9N2 viruses locally and generated multiple different genotypes. As of 14 July 2017, the HPAI H7N9 viruses had spread from Guangdong Province to at least 12 other provinces. The rapid geographical expansion and genetic evolution of the HPAI H7N9 viruses pose a great challenge not only to public health but also to poultry production. Effective control measures, including enhanced surveillance, are therefore urgently needed.IMPORTANCE The LPAI H7N9 virus has caused five outbreak waves in humans and was recently reported to have mutated into highly pathogenic variants. It is unknown how the HPAI H7N9 virus originated, evolved, and disseminated in China. In this study, we comprehensively analyzed the sequences of HPAI H7N9 viruses from 28 human and 21 environmental samples covering eight provinces in China that were taken from November 2016 to June 2017. The results show that the ancestor virus of the HPAI H7N9 viruses originated in the Yangtze River Delta region. However, the insertion of four amino acids into the HA protein cleavage site of an LPAI H7N9 virus occurred in late May 2016 in the Pearl River Delta region. The mutated HPAI H7N9 virus further reassorted with LPAI H7N9 or H9N2 viruses that were cocirculating in poultry. Considering the rapid geographical expansion of the HPAI H7N9 viruses, effective control measures are urgently needed.

Modeling the viral dynamics of SARS-CoV-2 infection.

Abstract: Coronavirus disease 2019 (COVID-19), an infectious disease caused by the infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is spreading and causing the global coronavirus pandemic. The viral dynamics of SARS-CoV-2 infection have not been quantitatively investigated. In this paper, we use mathematical models to study the pathogenic features of SARS-CoV-2 infection by examining the interaction between the virus, cells and immune responses. Models are fit to the data of SARS-CoV-2 infection in patients and non-human primates. Data fitting and numerical simulation show that viral dynamics of SARS-CoV-2 infection have a few distinct stages. In the initial stage, viral load increases rapidly and reaches the peak, followed by a plateau phase possibly generated by lymphocytes as a secondary target of infection. In the last stage, viral load declines due to the emergence of adaptive immune responses. When the initiation of seroconversion is late or slow, the model predicts viral rebound and prolonged viral persistence, consistent with the observation in non-human primates. Using the model we also evaluate the effect of several potential therapeutic interventions for SARS-CoV-2 infection. Model simulation shows that anti-inflammatory treatments or antiviral drugs combined with interferon are effective in reducing the duration of the viral plateau phase and diminishing the time to recovery. These results provide insights for understanding the infection dynamics and might help develop treatment strategies against COVID-19.

Drug prescribing indicators in village health clinics across 10 provinces of Western China.

Abstract: Methods. A total of 20 125 prescriptions were collected from 680 primary health clinics in villages from 40 counties in 10 provinces of Western China. Five measurements were used to assess the irrational drug use: percentage of encounters with an antibiotic prescribed, average number of drugs per encounter, percentage of encounters with an injection prescribed, percentage of drugs prescribed by generic name and percentage of drugs prescribed from National Essential Medicines List or Formulary. Index of Rational Drug Prescribing (IRDP) was used as an indicator of rational drug use. Results. The percentage of prescriptions containing antibioticswas 48.43%, while the average number of drugs per prescription was 2.36, and the percentage of injection prescriptions was 22.93%. The percentage of drugs prescribed by generic name was 64.12%, and the percentage of drugs prescribed from the National Essential Drug List was 67.70%. The IRDP of the present study was 3.32 with the optimal level of 5. There are also some regional variations in these measurements. Conclusions. The study provides some evidence of irrational use of drugs to a great extent in rural areas of Western China. Overuse of injection and overuse of antibiotics were the most prominent manifestations of such irrational drug prescribing.