The epidemiology of COVID-19 cases and the successful containment strategy in Hong Kong-January to May 2020

BACKGROUND: Hong Kong, a Special Administrative Region of China, recorded its first confirmed coronavirus disease 2019 (COVID-19) case on 23 January 2020. We reviewed the case epidemiology and the various public health measures implemented from January to May 2020. METHODS: The epidemiological and clinical characteristics of the cases recorded in different phases of the epidemic were described and compared, and the effectiveness of the public health measures implemented were reviewed using the changes in the daily number of confirmed cases and the interval from symptom onset to hospital admission. RESULTS: Between January and May 2020, 1084 confirmed COVID-19 cases were reported, about 70% of which had a history of travel during the incubation period. The case fatality ratio was 0.4%. The local epidemic progressed through four phases: (1) preparedness and imported infection from mainland China, (2) local transmission, (3) imported infection from overseas countries associated with local transmission, and (4) controlled imported infection with limited local transmission, with an eventual reduction of the daily case number and minimization of the onset-to-admission interval. Various public health measures, including enhanced surveillance, border control, and social distancing, were introduced in phases in response to the prevailing local and global situations. DISCUSSION: The overall containment strategy in Hong Kong led to a stabilization of the number of cases and the absence of a community-wide outbreak during the 4.5 m after the first case was reported. This strategy of containment might serve as an example for future planning of preparedness and response against novel infectious agents

Population genomic analyses of protected incense trees Aquilaria sinensis reveal the existence of genetically distinct subpopulations

The incense tree Aquilaria sinensis (Thymelaeaceae) can produce agarwood with commercial values and is now under threat from illegal exploitation in Hong Kong, impairing the local population and biodiversity. Together with other species of Aquilaria, it is listed in the CITES Appendix II, which strictly regulates its international trade. To understand the population structure of A. sinensis and to make relevant conservation measures, we have sequenced 346 individuals collected in Hong Kong and southern mainland China. Population genomic analyses including principal component analysis, neighbor-joining tree construction, ADMIXTURE, and hierarchical pairwise-FST analyses suggested that genetically distinct populations are contained in certain areas. Genomic scan analyses further detected single-nucleotide polymorphism (SNP) outliers related to plant defense, including the CYP71BE gene cluster. In addition to the population analyses, we have developed a modified hexadecyltrimethyl-ammonium bromide (CTAB) DNA extraction protocol for obtaining DNA from agarwood samples in this study, and resequencing of DNA extracted from two agarwood samples using this method allows us to successfully map to the sample corresponding localities in the phylogenetic tree. To sum up, this study suggested that there is a genetically distinct subpopulation of incense tree in Hong Kong that would require special conservation measures and established a foundation for future conservation measures

Clostridium difficile infection outbreak in a male rehabilitation ward, Hong Kong (China), 2011

Clostridium difficile is an anaerobic, gram-positive bacterium, capable of sporulation when environmental conditions no longer support its growth. The sporulation capacity enables the organism to persist in the environment for extended periods of time. Clostridium difficile is the main pathogen accountable for antibiotic-associated colitis and for 15% to 25% of cases of nosocomial antibiotic-associated diarrhoea. Major risk factors such as increased severity of underlying illness, increased age, prior antimicrobial use and gastric acid suppressors have been identified for Clostridium difficile

Epidemiology of human influenza A(H7N9) infection in Hong Kong

Background/Purpose: We conducted a case series study to review the epidemiology of human influenza A(H7N9) infection reported in Hong Kong. Methods: We reviewed case records of confirmed human cases of influenza A(H7N9) infection reported in Hong Kong in the 2013–2014 winter season. We compared the median viral shedding duration and interval from illness onset to initiation of oseltamivir treatment between severe and mild cases. We estimated the incubation period of influenza A(H7N9) virus from cases with a single known date of poultry exposure. Results: A total of 10 cases were reported and all were imported infection from Mainland China. Four patients died and the cause of death was related to influenza A(H7N9) infection in two patients. The median interval from illness onset to initiation of oseltamivir treatment for the severe cases (4.5 days) was significantly longer than the mild cases (2 days; p = 0.025). Severe cases had a significantly longer viral shedding duration than mild cases (p = 0.028). The median incubation period for cases with a single known exposure date was 4 days. Nasopharyngeal aspirate taken from the 88 close contacts of the 10 patients all tested negative for influenza A virus using reverse transcription polymerase chain reaction. Conclusion: Delayed administration of antiviral treatment may be associated with a more severe illness for influenza A(H7N9) infection. Despite our aggressive contact tracing policy with laboratory testing of all close contacts, no secondary case was identified which implied that the potential of human-to-human transmission of the circulating influenza A(H7N9) virus remains low

The genome of the deep-sea anemone <i>Actinernus</i> sp. contains a mega-array of ANTP-class homeobox genes

Members of the phylum Cnidaria include sea anemones, corals and jellyfish, and have successfully colonized both marine and freshwater habitats throughout the world. The understanding of how cnidarians adapt to extreme environments such as the dark, high-pressure deep-sea habitat has been hindered by the lack of genomic information. Here, we report the first chromosome-level deep-sea cnidarian genome, of the anemone Actinernus sp., which was 1.39 Gbp in length and contained 44 970 gene models including 14 806 tRNA genes and 30 164 protein-coding genes. Analyses of homeobox genes revealed the longest chromosome hosts a mega-array of Hox cluster, HoxL, NK cluster and NKL homeobox genes; until now, such an array has only been hypothesized to have existed in ancient ancestral genomes. In addition to this striking arrangement of homeobox genes, analyses of microRNAs revealed cnidarian-specific complements that are distinctive for nested clades of these animals, presumably reflecting the progressive evolution of the gene regulatory networks in which they are embedded. Also, compared with other sea anemones, circadian rhythm genes were lost in Actinernus sp., which likely reflects adaptation to living in the dark. This high-quality genome of a deep-sea cnidarian thus reveals some of the likely molecular adaptations of this ecologically important group of metazoans to the extreme deep-sea environment. It also deepens our understanding of the evolution of genome content and organization of animals in general and cnidarians in particular, specifically from the viewpoint of key developmental control genes like the homeobox-encoding genes, where we find an array of genes that until now has only been hypothesized to have existed in the ancient ancestor that pre-dated both the cnidarians and bilaterians

The genome of the deep-sea anemone <i>Actinernus</i> sp. contains a mega-array of ANTP-class homeobox genes

This study was supported by Hong Kong Research Grant Council Collaborative Research Fund CRF (grant no. C4015-20EF), General Research Fund GRF (grant no. 14100420), CUHK Direct Grant (grant nos. 4053489 and 4053547), Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) (grant nos. HJ202101, SMSEGL20SC01 and SMSEGL20SC02) and Major Project of Basic and Applied Basic Research of Guangdong Province (grant no. 2019B030302004).Members of the phylum Cnidaria include sea anemones, corals and jellyfish, and have successfully colonized both marine and freshwater habitats throughout the world. The understanding of how cnidarians adapt to extreme environments such as the dark, high-pressure deep-sea habitat has been hindered by the lack of genomic information. Here, we report the first chromosome-level deep-sea cnidarian genome, of the anemone Actinernus sp., which was 1.39 Gbp in length and contained 44 970 gene models including 14 806 tRNA genes and 30 164 protein-coding genes. Analyses of homeobox genes revealed the longest chromosome hosts a mega-array of Hox cluster, HoxL, NK cluster and NKL homeobox genes; until now, such an array has only been hypothesized to have existed in ancient ancestral genomes. In addition to this striking arrangement of homeobox genes, analyses of microRNAs revealed cnidarian-specific complements that are distinctive for nested clades of these animals, presumably reflecting the progressive evolution of the gene regulatory networks in which they are embedded. Also, compared with other sea anemones, circadian rhythm genes were lost in Actinernus sp., which likely reflects adaptation to living in the dark. This high-quality genome of a deep-sea cnidarian thus reveals some of the likely molecular adaptations of this ecologically important group of metazoans to the extreme deep-sea environment. It also deepens our understanding of the evolution of genome content and organization of animals in general and cnidarians in particular, specifically from the viewpoint of key developmental control genes like the homeobox-encoding genes, where we find an array of genes that until now has only been hypothesized to have existed in the ancient ancestor that pre-dated both the cnidarians and bilaterians.Publisher PDFPeer reviewe

Folic acid supplementation modifies b-adrenoceptor-mediated in vitro lipolysis of obese/diabetic (+db/+db) mice

The effects of folic acid (5.7 and 71 μg/kg, 4 weeks) consumption on the β-adrenoceptors (β-ARs)–elicited lipolysis in vitro of the abdominal adipocytes of lean/control (+m/+db) and obese/diabetic (+db/+db) mice (female) were investigated. β-AR agonists (salbutamol, a β2-AR agonist; BRL 37344 and CGP 12177, β3-AR agonists; adrenaline, a β-AR agonist)–mediated lipolysis, β2-, and β3-ARs protein expression of the adipose tissues after folic acid consumption were evaluated. Our results demonstrate that a smaller magnitude of the basal (spontaneous) and the β-AR agonists–triggered lipolysis was observed in +db/+db mice, and folic acid supplementation (71 μg/kg) resulted in an improvement of both the baseline and the β-ARs–mediated lipolysis. In controls, a lower β2-and β3-ARs protein expression of the adipose tissues was detected in +db/+db mice, compared to +m/+db mice. In both strains fed with folic acid (71 μg/kg), a reduction of β2-AR protein expression was observed compared to the respective controls. In +db/+db mice, folic acid (5.7 and 71 μg/kg) consumption caused a dose-dependent increase of β3-AR protein expression compared to controls. We demonstrate that lipolysis elicited by β-AR (β2- and β3-ARs) agonists was blunted in +db/+db mice. Folic acid consumption has significant modulatory effects on β-ARs protein expression and lipolysis

Additional file 1 of Determination of ITS1 haplotypes of Fritillariae Cirrhosae Bulbus by amplicon sequencing

Additional file 1: Fig. S1. a) Maximum likelihood tree of ITS1 sequences from Fritillaria major ASVs and the T5177 reference sequence (highlighted in green) as well as 7 Lilium species (highlighted in orange); b) Loci of SmaI recognition site CCCGGG and its mutated forms of CTCGGG, CCACGGG and others, indicated by green, yellow, blue and grey, respectively; c) heatmap showing presence or absence of major ASVs in Fritillariae Cirrhosae Bulbus (FCB) and non-FCB species. F. hupehensis was found to be carried major ASVs with SmaI recognition site CCCGGG, which was due to the misidentification of T4940 as F. hupehensis or T4940 was mixed into a batch of F. hupehensis sample; d) heatmap showing the relative abundance of major ASVs in each FCB and non-FCB species