Disease surveillance staff in multiple Indian locations are looking for the “contacts” of a 76-year-old US tourist diagnosed with the novel coronavirus in Bhutan on Thursday after spending 10 days in India.

The contact-tracing efforts in Guwahati, Calcutta and other sites the tourist had passed through are part of the standard protocol to find those who recently came in contact with confirmed coronavirus cases and monitor their health, officials said.

The tourist was confirmed as infected at 11pm on March 5 and the test result was validated at 12.30am on March 6, the Bhutan Prime Minister’s Office said in a media release.

The patient, who had arrived in Bhutan on a Drukair flight from Guwahati on March 2 and did not have fever on arrival, developed fever, sore throat and cough on March 5.

The patient, travelling with his 59-year-old partner, had flown out of Washington DC on February 18 and toured India between February 21 and March 1, the Bhutan PMO said. Health authorities in Bhutan had by Friday traced 90 contacts of the patient, covering the three days before the diagnosis in Bhutan.

The number of contacts over the patient’s 10-day period in India could run into “several hundreds”, an official with the Integrated Disease Surveillance Programme told The Telegraph.

The IDSP units will look for possible contacts in Guwahati, Calcutta and several other places visited by the tourist, the official said.

In Bhutan, the contact-tracers looked for people the patient had associated with during his itinerary — starting from Paro International Airport to Thimphu to Punakha and back and a teashop and sites he had visited for lunch and snacks.

Indian health officials on Friday did not provide any details about the patient’s itinerary in India.

An unconfirmed social media post claimed the patient had visited Mumbai, Calcutta and Guwahati and spent a few days on a cruise along the Brahmaputra.

Virologists say the coronavirus has an incubation period of up to 14 days and although virus transmission is likely to take place during the phase when infected people are symptomatic, some transmission during late incubation stage cannot be ruled out.

The Indian health ministry on Friday confirmed one additional case of coronavirus — a person in Delhi with a travel history to Malaysia and Thailand — taking the cumulative total to 31, of whom 16 are Italians. The 31 include the earliest three patients in Kerala who have since recovered and been discharged.

Sections of infectious disease specialists believe that India should brace itself for rising coronavirus cases, given the patterns of spread observed across the world. “It will be foolhardy not to expect the coronavirus to at some point spread locally here,” said T. Jacob John, an emeritus professor of medical virology at the Christian Medical College, Vellore.

Senior health officials assert that the health ministry has enhanced India’s state of preparedness, keeping in reserve isolation wards in government hospitals and increasing the infrastructure for sample collection and coronavirus tests. The health ministry has also asked private hospitals to maintain a pool of beds to manage coronavirus patients.

The health ministry has appealed to the public to adopt standard precautions such as frequent hand-washing, maintaining their distance from people with symptoms and following respiratory etiquette to minimise the risk of picking up the infection.

India has over the past seven weeks screened over 650,000 passengers arriving from the most-affected countries before beginning the screening of all international passengers this week.

The Centre on Friday said that government employees need not mark their biometric attendance up to March 31, citing “concerns that the most common method of transmission of virus seems to be through infected surfaces”.

Congress chairperson Sonia Gandhi on Friday wrote to the party’s chief ministers to strengthen their states’ capacity for tests, early detection and containment, and to ensure an adequate supply of personal protection equipment at public health-care facilities. She asked the state governments to issue advisories to avoid large public gatherings.