RESUMO
We report the first local transmission of the SARS-CoV-2 Delta variant in mainland China. All 167 infections could be traced back to the first index case. Daily sequential PCR testing of the quarantined subjects indicated that the viral loads of Delta infections, when they first become PCR+, were on average [~]1000 times greater compared to A/B lineage infections during initial epidemic wave in China in early 2020, suggesting potentially faster viral replication and greater infectiousness of Delta during early infection. We performed high-quality sequencing on samples from 126 individuals. Reliable epidemiological data meant that, for 111 transmission events, the donor and recipient cases were known. The estimated transmission bottleneck size was 1-3 virions with most minor intra-host single nucleotide variants (iSNVs) failing to transmit to the recipients. However, transmission heterogeneity of SARS-CoV-2 was also observed. The transmission of minor iSNVs resulted in at least 4 of the 30 substitutions identified in the outbreak, highlighting the contribution of intra-host variants to population level viral diversity during rapid spread. Disease control activities, such as the frequency of population testing, quarantine during pre-symptomatic infection, and level of virus genomic surveillance should be adjusted in order to account for the increasing prevalence of the Delta variant worldwide.
RESUMO
Objective To investigate the influence and effect of treating with low dose roxithromycin on airway inflammation in asthma who have been smoking patients .Methods Forty-six patients with mild to moderate asthma who had been smoking were assigned to group A and group B randomly .The patients in group A received inhaling salmeterol/fluticasone(50/250 μg) ,one puff bid ,2 times/day .The patients in group B treated with oral roxithromycin dispersible tablet 0 .15 g/d combining with inhaling salme-terol/fluticasone(50/250 μg) ,one puff bid ,2 times/day .The patients of two groups had been treated for 4 weeks .The lung func-tion ,cells and interleukin-8(IL-8) in induced sputum of patients in the two groups were measured before and after treatment .Results There was negative correlation between the FEV 1% and the number of eosinophile granulocyte ,neutrophil and the concentration of IL-8 in induced sputum of the patients(P<0 .01) .The number of neutrophil ,eosinophile granulocyte and the level of IL-8 of the patients in group B decreased more than those in the group A after 4 weeks of treatment(P<0 .05) .Furthermore the PEF and FEV1% of the patients in group B were ameliorated significantly than those in group A (P<0 .01) .Conclusion The treatment of roxithromycin combining with salmeterol/fluticasone on patients with asthma who smoke can not only reduce the number of eosino-phile granulocyte ,neutrophil and the level of IL-8 in induced sputum significantly ,but also ameliorate the PEF and FEV1% of them significantly .
