What is already known on this topic? Clusters of COVID-19 cases often happened in small settings (e.g., families, offices, school, or workplaces) that facilitate person-to-person virus transmission, especially from a common exposure. What is added by this report? On January 10 and 11, 2021, an individual gave three product promotional lectures in Tonghua City, Jilin Province, that ultimately led to a 74-case cluster of COVID-19. Our investigation determined the outbreak to be an import-related COVID-19 superspreading cluster event in which elderly, retired people were exposed to the infected individual during his promotional lectures, which were delivered in a confined space and lasted several hours. What are the implications for public health practice? Routine activities, such as attending a lecture in a classroom, can provide an environment conducive to COVID-19 superspreading events because respiratory viruses can spread easily and widely. We suggest local government to strengthen infection control management, reduce unnecessary indoor large gathering activities, and promote wearing of masks, especially during wintertime in the north of China. Health education for elderly people should promote use of effective personal protection and emphasize the importance of wearing masks.

A new genus, Paramolotra Tong & Li, gen. nov., including two new species, Paramolotra pome Tong & Li, sp. nov. (♂♀) and Paramolotra metok Tong & Li, sp. nov. (♂♀), is described from Tibet, China. Morphological descriptions and photographic illustrations of the two new species are given.

No abstract

What is already known on this topic? Contact tracing and testing with isolated medical care of identified cases is a key strategy for interrupting chains of transmission of COVID-19 and reducing mortality associated with COVID-19. At the early phases of the COVID-19 pandemic, due to test capacity limitations, case finding often started from suspected cases. What is added by this report? The index patient infected 74 individuals who were close contacts that were identified through contact tracing, and exposed individuals were monitored in quarantine with daily polymerase chain reaction (PCR) testing. All individuals were asymptomatic initially, but all PCR-positive individuals eventually developed symptoms. Infectivity was documented up to 8 days before being confirmed as a symptomatic case, approximately 4 days before turning PCR positive. What are the implications for public health practice? During an outbreak, we suggest tracing close contacts from both PCR-positive individuals and suspected cases, rather than from suspected cases alone. Due to the long period of infectivity before turning PCR positive or developing symptoms, close contacts that had contact with a newly PCR positive case within 4 days should be judged as at risk of being infected; close contacts that had contact within 8 days of a newly symptomatic case should be judged as at risk being infected.

Two new species of the genus Sinamma Lin & Li, 2014, Sinamma quadrata Tong & Li, sp. nov. (male, female) and Sinamma yingae Tong & Li, sp. nov. (male, female) are described from Guangdong, China. The geographic distribution of the genus is updated and a key to all known species is provided.