Introduction: The emergence of anovel coronavirus identified in patients with unknown cause of acute respiratory disease in Wuhan, China at the end of 2019 has caused aglobal outbreak. The causative coronavirus was later named as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the disease caused by SARS-CoV-2 was named as Coronavirus Disease-2019 (COVID-19). As of 10 August 2020, more than 19,718,030 confirmed cases and 728,013 deaths have been reported. COVID-19 is spread via respiratory droplets which are inhaled into the lungs. Areas covered: In this article, we summarized the knowledge about the causative pathogen of COVID-19 and various diagnostic methods in this pandemic for better understanding of the limitations and the nuances of virus testing for COVID-19. Expert opinion: In this pandemic, rapid and accurate identification of COVID-19 patients are critical to break the chain of infection in the community. RT-PCR provides a rapid and reliable identification of SARS-CoV-2 infection. In the future, molecular diagnostics will still be the gold standard and nextgeneration sequencing can help us to understand more on the pathogenesis and detect novel mutations. It is believed that more sophisticated detection methods will be introduced to detect SARS-CoV-2 as earliest as possible.

Purpose:The aim of this study was to determine the repeatability of high-and lowcontrast visual acuity (VA) measurements at near. Methods: Fifty-five normal subjects were recruited. Inclusion criteria included visual acuity of at least 0.00 logarithm of minimum angle of resolution (logMAR) on each eye at distance. One eye was selected for this study, either the one with a better acuity or randomly chosen if there was no difference between the two eyes. Near VA was measured in a random order with the PolyU high-contrast (PolyU-HC), the PolyU low-contrast (PolyU-LC), the Precision high-contrast (P-HC) and the Precision low-contrast (P-LC) charts at 400 mm. Measurements were repeated after one to two weeks. Repeatability was presented using the 95% limits of agreement between visits. Results: The between-visit repeatability was Ϯ0.063 logMAR for high-contrast and Ϯ0.141 for low-contrast using the PolyU charts. The between-visit repeatability was Ϯ0.120 logMAR for high-contrast and Ϯ0.110 for low-contrast using the Precision charts. Seventeen subjects had high-contrast VA better than -0.10 logMAR using Precision chart, which could not be measured by PolyU chart. The mean difference between high-and low-contrast VA was 0.108 from the Precision charts (median difference of 0.10 or one line). Conclusions:The Precision charts could measure high-contrast near VA to threshold level. Practitioners should be aware of a VA difference of more than one line in repetitive measurement, at both high and low contrast. A difference in near high-and low-contrast VA of more than one line may warrant further investigation.

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Prophylaxis and treatment with oseltamivir effectively controlled a community outbreak of pandemic influenza A (H1N1) in China. The genetic makeup of strains of different generations seemed to be stable. Travel in confined settings might accelerate the transmission of pandemic influenza in a community outbreak.