India on Sunday issued a travel advisory urging “everyone to refrain” from visiting China and saying all those who have returned from China after January 15 could face quarantine in efforts to lower the risk of fresh importation of the novel coronavirus.

The advisory came after health authorities earlier on Sunday reported a second patient positive for the coronavirus in Kerala who, as the first patient detected in the state earlier this week, has had a recent travel history to China.

“The two positive cases in Kerala are being monitored and are clinically stable,” the health ministry said in a statement.

Airport units across India had until Sunday screened over 58,600 passengers from 445 commercial flights. Passengers from Singapore and Thailand are also now being screened along with passengers from China, the health ministry said.

The health ministry said the nationwide disease surveillance programme has picked up 142 travellers with symptoms who have been sent to different hospitals with isolation facilities. Among them, 130 have been tested and 128 found negative for the coronavirus.

The World Health Organisation (WHO), in its situation report up to Saturday, had documented 11,953 confirmed patients and 259 deaths in China and 132 patients in 23 countries. The coronavirus is a respiratory virus that can cause life-threatening pneumonia.

Although the outbreak is still centred around Hubei province in China, accounting for 60 per cent of all cases since its start likely in December, multiple countries have already reported human-to-human transmission.

The WHO said on Saturday that fresh human-to-human transmissions outside China have been reported from Japan, Germany and Thailand. In France, a health worker who had treated two probable patients with coronavirus was found positive.

Infectious disease experts said India’s advisory urging no travel to China is likely prompted by the growing scale of the epidemic as well as reports of human-to-human transmission emerging from countries other than China.

Virologists have since the start of the outbreak underscored the challenges that India will face if persons infected with the coronavirus somehow remain undetected or unrecognised and mingle with others when they are capable of spreading the virus.

The WHO said currently available information suggests that symptomatic patients are the main drivers of transmission and asymptomatic infection may be rare. Persons who are symptomatic could spread the virus through coughs or sneezes.

The health ministry had last month urged all those who have returned from China to report to health authorities if they develop any symptoms within four weeks of their return.