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@#Objective To summarize and analyze the epidemiological and clinical characteristics of COVID-19 Omicron variant cases in makeshift hospital, and the influence of age, sex and vaccination status on the disease duration, so as to provide reference for the prevention and control of the COVID-19 epidemic. Methods The epidemiological and clinical characteristics of COVID-19 cases admitted to makeshift hospital of National Convention and Exhibition Center (Shanghai) from April 9 to May 31, 2022 were retrospectively described and analyzed, and further cohort analysis was conducted to determine the influence of age, sex and vaccination status on the disease duration of COVID-19 cases in the author's branch hospital. Results Among the 174 466 COVID-19 cases in makeshift hospital, most of them were male, accounting for 59.38%. The infected cases were mainly young and middle-aged people aged 18-59 years old, accounting for 83.50%, followed by 12.30% of the elderly group over 60 years old; the average hospital stay was 7.40 days; the proportion of patients with fever was less than 27.79%; 15.37% (26 817/174 466) of the patients complicated with underlying diseases, and the top three were hypertension, diabetes and coronary heart disease. The proportion of people who received COVID-19 vaccine accounted for 79.56% (13 799/17 956), of which the highest proportion of three doses was 44.09%. The disease duration of 17 956 COVID-19 cases in the author's branch of makeshift hospital was 10.18 (7.34, 13.05) days. The disease duration in the elderly group was the longest with 11.34 (8.35, 14.37) days, followed by 11.17 (9.07, 14.33) days in the preschool group, 10.37 (8.14, 13.34)· days in the middle-aged group, 10.07 (7.37, 12.37) days in the school-age group, and 9.34 (7.05, 12.16) days in the young group. There was significant difference in the overall distribution of disease duration among the five groups (H=550.479 P<0.01). The disease duration in each age group basically showed a V-shaped distribution. The disease duration was 10.27 (7.34, 12.57) days in males and 10.10 (7.25, 13.09) days in females, and there was no significant difference (Z=-1.505 P>0.05). The disease duration of vaccinated patients was 10.24 (7.35, 13.05) days, and that of unvaccinated patients was 9.47 (7.09, 12.47) days. There was significant difference between the two groups (Z=-4.338 P<0.01). Conclusions COVID-19 Omicron variant cases have a high proportion of males, mainly young and middle-aged, and the proportion of fever patients is less than 30%. The disease duration is significantly lower than that of the original strain in Wuhan, and shows "V" distribution with each age group. Sex had no effect on the disease duration. COVID-19 vaccination did not have a clinical effect on the disease duration.
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@#Abstract: Objective To establish an animal model of BALB/c mice infected with Burkholderia pseudomallei through the nose (inhalation route), provides a reliable animal model for the follow-up studies on the virulence of melioidosis and the pathogenesis of acute melioidosis. Methods The experiment was carried out through infecting with Burkholderia pseudomallei through the nose (inhalation route). The pathophysiological response, visceral pathological damage and bacterial colonization of the mice infected with Burkholderia pseudomallei were observed by gross anatomy, histopathology and tissue homogenate count, and the biological characteristics of the mouse model of acute melioidosis were analyzed accordingly. Then we compared the physiological responses in BALB/c mice between the Burkholderia pseudomallei and non-pathogenic Burkholderia thailandensis. Results In the model of acute nasal infection with Burkholderia thailandensis, most death happened between the 3rd to 5th day after infection, 3×105-3×106 CFU was the suitable dose for acute fatal melioidosis model of BALB/c mice, and the medium lethal dose was about 3×104-3×105 CFU. Both gross anatomy and tissue HE staining showed that abscesses or necrosis were found in the lung, spleen and liver, especially in the spleen and lung, which was positively correlated with the challenge dose. Viable bacteria was isolated from the blood, lung, spleen and liver of Burkholderia pseudomallei-infected mice, and the bacteria account colonization was related to tissue specificity. The concentration of live bacteria isolated from in the blood was the highest [Log2 value: (10.28±0.34) CFU/mL], and the organ with the maximum quantity of bacteria was the lung [Log2 value: (7.54±2.11) CFU/total organ]. It has been reported that the biological effects of Burkholderia pseudomallei and its homologous non-pathogenic Burkholderia thailandensis were similar at the cellular level, like multi-nuclear giant cell formation and active intracellular replication, while it is still unclarrified in the differences of virulence in mice. In this study, it was proved that Burkholderia thailandensis was not fatal to mice even at a high dose (8×107CFU), or detected from mice infected with it via nasal. Conclusion We successfully established a reliable BALB/c mouse model (acute lethal model) of melioidosis via nasal infection, described its biological characteristics, and identified the different biological responses between Burkholderia pseudomallei and its homologous non-pathogenic Burkholderia thailandensis in mice.
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The experiment aimed to specifically monitor the passage of lactobacilli