Investigating COVID-19 transmission in a tertiary hospital in Hanoi, Vietnam using social network analysis.

OBJECTIVES: In March 2020, a COVID-19 outbreak in a major referral hospital in Hanoi, Vietnam led to 7664 patients and staff being sent into lockdown for 2 weeks, and more than 52,200 persons across 49 provinces being quarantined. We assessed SARS-CoV-2 transmission patterns during this to-date largest hospital outbreak in Vietnam using social network analysis (SNA). METHODS: We constructed a directed relational network and calculated network metrics for 'degree', 'betweenness', 'closeness' and 'eigenvector' centrality to understand individual-level transmission patterns. We analysed network components and modularity to identify sub-network structures with disproportionately big effects. RESULTS: We detected 68 connections between 46 confirmed cases, of whom 27 (58.7%) were ancillary support staff, 7 (15.2%) caregivers, 6 (13%) patients and 2 (4.4%) nurses. Among the 10 most important cases selected by each SNA network metric, transmission dynamics clustered in 17 cases, of whom 12 (70.6%) cases were ancillary support staff. Ancillary support staff also constituted 71.1% of cases in the dominant sub-network and 68.8% of cases in the three largest sub-communities. CONCLUSIONS: We identified non-clinical ancillary support staff, who are responsible for room service and food distribution in hospital wards in Vietnam, as a group with disproportionally big impacts on transmission dynamics during this outbreak. Our findings call for a holistic approach to nosocomial outbreak prevention and response that includes both clinical and non-clinical hospital staff. Our work also shows the potential of SNA as a complementary outbreak investigation method to better understand infection patterns in hospitals and similar settings.

New record and dietary ecology of a poorly known frog, Amolopsshihaitaoi Wang, Li, Du, Hou & Yu, 2022 (Amphibia, Anura, Ranidae), from Ha Giang Province, Vietnam.

Background: The Hekou Torrent Frog (Amolopsshihaitaoi) was recently discovered from southern China and northern Vietnam in 2022. The knowledge about natural history and feeding ecology of this species is virtually lacking. New information: Based on our recent fieldwork in northern Vietnam, we report a new population of A.shihaitaoi from Ha Giang Province. In this study, we provide novel data on the diet of A.shihaitaoi, based on stomach content analyses of 36 individuals (17 males and 19 females). A total of 36 prey categories with 529 items, comprising 515 items of invertebrates and 14 unidentified items, were found in the stomachs of A.shihaitaoi. The dominant prey items of the species were Hymenoptera (Formicidae), Orthoptera (Acrididae), Lepidoptera (Lepidoptera other), Mantodea (Mantidae) and Araneae. The importance index (Ix) of prey categories ranged from 7.1% to 11.5%. Hymenoptera (Formicidae) had the highest frequency of prey items, found in 36 stomachs.

More of the same: a diminutive new species of the Limnonectes kuhlii complex from northern Vietnam (Anura: Dicroglossidae).

A new species in the dicroglossid genus Limnonectes known only from Ha Giang province, Vietnam is described. Analysis of DNA sequence data from the mitochondrial 12S and 16S gene regions places the species within the Limnonectes kuhlii Complex and demonstrates it to be the sister taxon to an Indochinese clade containing L. isanensis, L. jarujini, L. megastomias, and L. taylori. The new species occurs in syntopy with L. bannaensis. Both molecular and morphological data support the recognition of this lineage as a new species. Notably, the relatively diminutive size of this species distinguishes Limnonectes nguyenorum sp. nov. from all other members of the L. kuhlii Complex.