Kashgar, in the Xinjiang Uygur autonomous region, is testing around 4.75 million people for the novel coronavirus, after routine testing at a garment factory found a 17-year-old female worker was an asymptomatic carrier of the virus.

With samples taken from more than 4.47 million residents by 4 pm on Monday, and test results obtained for 2.13 million people, 163 more asymptomatic cases have been detected, all of them in the early phase of infection.

That means, although more new cases might be reported in the following days as the results of the tests come through－the testing is due to be completed on Tuesday－the cluster appears to have been nipped in the bud.

Despite this, it is urgent for the authorities to reconstruct the transmission chain to trace the source of the outbreak. Especially, since the source of the outbreak in Urumqi, capital of Xinjiang, from July 15 to Sept 7－when 1,064 people were found infected with the virus, among whom 238 were asymptomatic cases－is still not yet known.

But with the National Health Commission sending its expert task force to Kashgar on Sunday, and the emergency response mechanism triggered in the city, there is no cause for undue concern and no reason to think that this may herald a second wave of the virus in the country.

Not only because Kashgar is thousands of kilometers away from China's populous inland area, but also because the government has accumulated enough experience to effectively deal with the sporadic re-emergence of new infections, as proved with the outbreak in Urumqi in mid-July and the one in Qingdao, Shandong province, earlier this month.

In both cases, the local authorities resorted to a policy of early detection, early testing, early quarantine and early treatment and curbed the spread of the virus within a short time, while economic activities and social lives in other parts of the country carried on as normal. The valuable experience gained will certainly guide Kashgar in its fight against the virus.

That supermarkets and shopping malls in Kashgar remain open－though all schools except universities are closed through Friday as required by anti-epidemic measures－speaks of the confidence of the local health authorities, which will be further strengthened after the results of all the tests are known.

Given Kashgar's location, the cluster of infections highlight not only the necessity of implementing the country's tried and tested pandemic control measures, but also that of strengthening vigilance to prevent cross-border transmission of the virus.