The coronavirus that was detected in the five locally infected patients in South China's Guangdong province was highly homologous with the virus sequence of Hong Kong pandemic strain, a senior health official said in Guangzhou, Guangdong's provincial capital, over the weekend.
"The homology percentage is 99.99 percent," Duan Yufei, director of Guangdong Provincial Health Commission, said.
Guangdong Provincial Health Commission, together with the provincial public security department, Shenzhen and Shanwei city centers for disease control immediately carried out virus screening, tracing and finding out the virus transmission context after the province, which borders Hong Kong and Macao, reported six new domestic cases reported earlier this month.
The nasopharyngeal swab samples of five cases of infection were quickly taken to determine and analyze the three generations of virus genome sequence.
It was found that the viral gene sequences of these cases were highly homologous, Duan said at a press conference in Guangzhou on Saturday.
"By comparing and analyzing the genome sequences of nearly 80,000 new coronavirus strains in the global database, it was found that these five cases belonged to a HK branch as it is highly homologous with the virus sequences of Hong Kong epidemic strains," Duan said.
A 41-year-old woman working at a Hema Fresh Supermarket was detected to be a COVID-19 patient when she returned to her home town in Shanwei, a coastal city in eastern part of Guangdong, on Aug 14.
In addition, three of her family members and two of her co-workers at the supermarket later reported positive results in nucleic acid testing. But they had no symptoms.
They became the first small group of patients that were locally infected in the province since April 29, as only imported cases were reported in the province before them, said Duan.
The province's situation and risk of further outbreak of COVID-19 has put under control thanks to concrete and effective measures taken to fight against the pandemic, he said.
As of Saturday, Guangdong, which has a population of more than 115 million, reported only one confirmed case and another eight asymptomatic patients - five in Shanwei and three in Shenzhen.