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. 2020 Sep 1:M20-0928. doi: 10.7326/M20-0928

Figure 1. The block X outbreak and suggested transmission route.

Figure 1. The block X outbreak and suggested transmission route. A. Epidemiologic curve with patients from the same family shown in the same color. The possible infectious period for each group of patients with the same symptom onset date is estimated to be from 2 days before onset to their hospitalization dates. B. Floor plan for the second through 28th floors of block X, showing locations of bathrooms in -02 flats. C. Suggested transmission route from toilet flushing to the escape of gas in the drainage system containing bioaerosols into the master bathrooms of the -02 flats on the second to 29th floors. The dried-out water seals are shown with U-traps in red; escaped gas flow in the drainage system into a bathroom is shown by a red plume. Drawing is not to scale.

A. Epidemiologic curve with patients from the same family shown in the same color. The possible infectious period for each group of patients with the same symptom onset date is estimated to be from 2 days before onset to their hospitalization dates. B. Floor plan for the second through 28th floors of block X, showing locations of bathrooms in -02 flats. C. Suggested transmission route from toilet flushing to the escape of gas in the drainage system containing bioaerosols into the master bathrooms of the -02 flats on the second to 29th floors. The dried-out water seals are shown with U-traps in red; escaped gas flow in the drainage system into a bathroom is shown by a red plume. Drawing is not to scale.