The coronavirus disease 2019 (COVID-19) outbreak that originated in Wuhan, China, spread to more than 100 countries within 2 months of when the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was identified in January 2020.^1,2 Following the Wuhan lockdown and other extreme social-distancing measures conducted by the Chinese government, several countries with widespread outbreaks implemented similar measures, including shutting down entire cities or communities, banning international or domestic travel, conducting border control with symptom screening, and implementing isolation and quarantine.

A variety of serovars of the food-borne pathogen Vibrio parahaemolyticus normally cause infection. Since 1996, the O3:K6 strains of this pathogen have caused pandemics in many Asian countries, including Taiwan. For a better understanding of these pandemic strains, the recently isolated clinical O3:K6 strains from India, Japan, Korea, and Taiwan were examined in terms of pulsed-field gel electrophoresis (PFGE) typing and other biological characteristics. After PFGE and cluster analysis, all the O3:K6 strains were grouped into two unrelated groups. The recently isolated O3:K6 strains were all in one group, consisting of eight closely related patterns, with I1(81%) and I5(13%) being the most frequent patterns. Pattern I1 was the major one for strains from Japan, Korea, and Taiwan. All recently isolated O3:K6 strains carried the thermostable direct hemolysin ( tdh ) gene. No significant difference was observed between recently isolated O3:K6 strains and either non-O3:K6 reference strains or old O3:K6 strains isolated before 1996 with respect to antibiotic susceptibility, the level of thermostable direct hemolysin, and the susceptibility to environmental stresses. Results in this study confirmed that the recently isolated O3:K6 strains of V. parahaemolyticus are genetically close to each other, while the other biological traits examined were usually strain dependent, and no unique trait was found in the recently isolated O3:K6 strains.

Comprehensive case investigation and contact tracing are crucial to prevent community spread of COVID-19. We demonstrated a utility of using traditional contact tracing measures supplemented with symptom tracking and contact management system to assist public health workers with high efficiency. A centralized contact tracing system was developed to support data linkage, cross-jurisdictional coordination, and follow-up of contacts’ health status. We illustrated the process of how digital tools support contact tracing and management of COVID-19 cases and measured the timeliness from case detection to contact monitoring to evaluate system performance. Among the 8051 close contacts of the 487 confirmed cases (16.5 close contacts/case, 95% CI [13.9–19.1]), the median elapsed time from last exposure to quarantine was three days (IQR 1–5). By implementing the approach of self-reporting using automatic text-messages and web-app, the percentage of health status updates from self-reporting increased from 22.5% to 61.5%. The high proportion of secondary cases detected via contact tracing (88%) might reduce the R0 to under one and minimize the impact of local transmission in the community. Comprehensive contact tracing and management with complementary technology would still be a pillar of strategies for containing outbreaks during de-escalation or early in the next wave of COVID-19 pandemic.