New Delhi, March 19 (IANS): Citing the evolving nature of Covid-19 transmission, the Indian Council of Medical Research (ICMR) on Thursday said that surveillance is being expanded to areas where the cases have been reported.

"In view of the evolving nature of Covid-19 transmission, the surveillance is being expanded to include more areas, especially areas where Covid-19 cases have been reported," the apex health research body said.

It said it is closely monitoring the presence of community transmissions in the country. "Since February 15, ICMR has initiated sentinel surveillance to detect community transmission of Covid-19."

The surveillance sites have been scaled up from 16 sites till February 29 to 51 sites by March 15, it stated.

"Till date, a total of 826 samples of the people suffering from severe acute respiratory infection, influenza like illnesses have been tested at the sites. None of the samples were found positiv," ICMR said.

The country on Thursday registered 22 fresh cases of Covid-19 thus taking the number of affecteed people to 173. At least four people have died, one each from Punjab, Karnataka, Delhi and Maharashtra.