ABSTRACT
An epidemiological investigation was carried out on a local cluster of outbreak caused by imported cases of Coronavirus Disease 2019 (COVID-19) in rural areas of Chengdu in December 2020, to find out the source of infection and the chain of transmission. According to Prevention and Control Protocol for COVID-19 (Version 7), field epidemiological investigation was adopted, combined with big data technology, video image investigation, gene sequencing and other methods to carry out investigation into COVID-19 cases and infections source tracing, analyze the epidemiological association, and map the chain of transmission. From December 7 to 17, 2020, 13 local COVID-19 confirmed cases and 1 asymptomatic case were diagnosed in Chengdu, of which 12 cases (85.71%) had a history of residence and activity in the village courtyard of Taiping (TP), Pidu (P) District, Chengdu. From November 8, 2020 to November 28, 2020, a group of inbound people form Nepal were transferred to the designated entry personnel quarantine hotel of P District which was adjacent to the TP village. During quarantine, there were 5 cases who tested positive for COVID-19. Through gene sequencing alignment, genes of local cases and Nepalese imported cases from the same period are homologous, all belong to the lineage of L2.2.3 (B.1.36 according to Pangolin lineage typing method). According to the results of field epidemiological investigation and gene sequencing analysis, the index case was most likely infected by contact with household waste of quarantine site. Under the situation of normalization prevention and control of COVID-19, sentinel monitoring of fever clinics in primary medical institutions is the key to early detection of the epidemic. The multi-department joint epidemiological investigation and the application of gene technology are the core links of the investigation and traceability of modern infectious diseases. The allocation of public health resources in rural areas needs to be strengthened. We need to improve the capacity for early surveillance and early warning of the epidemic in rural areas.
Subject(s)
COVID-19 , Epidemics , Disease Outbreaks , Humans , Quarantine , SARS-CoV-2ABSTRACT
Objective: To analyze the clinical characteristics of 34 COVID-19 cases and to provide the basis for the prevention and control of the epidemic disease. Methods: Thirty-four COVID-19 patients diagnosed with RT-PCR in the isolation ward of the Fourth People's Hospital of Ningxia Hui autonomous region (infectious diseases hospital) from the January 22 to February 4, 2020 were selected as the research subjects. The clinical data were collected. Excel was used to describe the relationship between clinical classification and age distribution, contact history and date of onset. SPSS 25.0 statistical software was used for analysis. The general information, clinical symptoms, blood test, virus nucleic acid test results, epidemiology, CT imaging, treatment and prognosis were analyzed. Results: There were 5 mild cases (5/34), 24 ordinary cases (24/34), 5 severe cases (5/34). The elderly was more common in severe patients. The main clinical symptoms were fever (27/34)and dry cough(26/34). The peripheral blood showed normal or decreased leukocyte count (33/34), decreased lymphocyte count (12/34). The increase of C-reactive protein (CRP) and D-dimer was related to the severity of the disease. Some patients had mild liver and kidney damage. Six patients were diagnosed through 3 or more times of nucleic acid tests. Sixteen cases had Wuhan related history,13 cases were close contacts, 5 cases had no confirmed route. The clustered infections were found in 6 families. In typical cases, CT showed single or multiple patchy ground glass shadow with thickening of interlobular septum. In severe cases, diffuse lesions of both lungs were found, with ground glass shadow, consolidation shadow and strip shadow coexisting. Thirty-four patients were treated with interferon-α and Lopinavir/Ritonavir with good prognosis. Conclusions: The clinical characteristics of COVID-19 were similar to that of general viral pneumonia but with strong infectivity. Close contact and family aggregation caused disease outbreaks. COVID-19 could not be excluded if two nucleic acid tests were negative and high-resolution CT was helpful for differential diagnosis. Early detection, early isolation, early diagnosis and early treatment are important for good prognosis. The effectiveness of antiviral drugs needs to be further verified.