Objective: To determine the dynamic changes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in respiratory and fecal specimens in children with coronavirus disease 2019 . Methods: From January 17, 2020 to February 23, 2020, three paediatric cases of COVID-19 were reported in Qingdao, Shandong Province, China. Epidemiological, clinical, laboratory, and radiological characteristics and treatment data were collected. Patients were followed up to March 10, 2020, and dynamic profiles of nucleic acid testing results in throat swabs and fecal specimens were closely monitored. Results: Clearance of SARS-CoV-2 in respiratory tract occurred within two weeks after abatement of fever, whereas viral RNA remained detectable in stools of pediatric patients for longer than 4 weeks. Two children had fecal SARS-CoV-2 undetectable 20 days after throat swabs showing negative, while that of another child lagged behind for 8 days.Conclusions: SARS-CoV-2 may exist in children's gastrointestinal tract for a longer time than respiratory system. Persistent shedding of SARS-CoV-2 in stools of infected children raises the possibility that the virus might be transmitted through contaminated fomites. Massive efforts should be made at all levels to prevent spreading of the infection among children after reopening of kindergartens and schools.

BACKGROUND AND OBJECTIVES: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a newly identified pathogen that mainly spreads by droplets. Most published studies have been focused on adult patients with coronavirus disease 2019 (COVID-19), but data concerning pediatric patients are limited. In this study, we aimed to determine epidemiological characteristics and clinical features of pediatric patients with COVID-19. METHODS: We reviewed and analyzed data on pediatric patients with laboratory-confirmed COVID-19, including basic information, epidemiological history, clinical manifestations, laboratory and radiologic findings, treatment, outcome, and follow-up results. RESULTS: A total of 74 pediatric patients with COVID-19 were included in this study. Of the 68 case patients whose epidemiological data were complete, 65 (65 of 68; 95.59%) were household contacts of adults. Cough (32.43%) and fever (27.03%) were the predominant symptoms of 44 (59.46%) symptomatic patients at onset of the illness. Abnormalities in leukocyte count were found in 23 (31.08%) children, and 10 (13.51%) children presented with abnormal lymphocyte count. Of the 34 (45.95%) patients who had nucleic acid testing results for common respiratory pathogens, 19 (51.35%) showed coinfection with other pathogens other than SARS-CoV-2. Ten (13.51%) children had real-time reverse transcription polymerase chain reaction analysis for fecal specimens, and 8 of them showed prolonged existence of SARS-CoV-2 RNA. CONCLUSIONS: Pediatric patients with COVID-19 presented with distinct epidemiological, clinical, and radiologic characteristics from adult patients. Nearly one-half of the infected children had coinfection with other common respiratory pathogens. It is not uncommon for pediatric patients to have prolonged fecal shedding of SARS-CoV-2 RNA during the convalescent phase.

Natural selection endows animals with the abilities to store lipid when food is abundant and to synthesize lipid when it is limited. However, the relevant adaptive strategy of lipid metabolism has not been clearly elucidated in fish. This study examined the systemic metabolic strategies of Nile tilapia to maintain lipid homeostasis when fed with low- or high-fat diets. Three diets with different lipid contents (1%, 7%, and 13%) were formulated and fed to tilapias for 10 weeks. At the end of the feeding trial, the growth rate, hepatic somatic index, and the triglyceride (TG) contents of serum, liver, muscle, and adipose tissue were comparable among three groups, whereas the total body lipid contents and the mass of adipose tissue increased with the increased dietary lipid levels. Overall quantitative PCR, western blotting and transcriptomic assays indicated that the liver was the primary responding organ to low-fat (LF) diet feeding, and the elevated glycolysis and accelerated biosynthesis of fatty acids (FA) in the liver is likely to be the main strategies of tilapia toward LF intake. In contrast, excess ingested lipid was preferentially stored in adipose tissue through increasing the capability of FA uptake and TG synthesis. Increasing numbers, but not enlarging size, of adipocytes may be the main strategy of Nile tilapia responding to continuous high-fat (HF) diet feeding. This is the first study illuminating the systemic adaptation of lipid metabolism responding to LF or HF diet in fish, and our results shed new light on fish physiology.