Mamata Banerjee on Tuesday said her government was in the process of carrying out a mega door-to-door surveillance across Bengal for a month to identify persons with severe acute respiratory illness (Sari) and influenza-like illness (Ili) cases.

The drive is to pick up on early warning signals in the war against Covid-19.

The chief minister issued a statement on Facebook, the day after the inter-ministerial central team (IMCT) assigned to south Bengal had accused her government of “weak surveillance and tracking”.

“Massive door-to-door surveillance has been ongoing since the past one month to identify Severe Acute Respiratory Illness and Influenza-like Illness cases across West Bengal. This Herculean effort has been undertaken by 60,000 specially trained Asha (accredited social health activist) and health workers non-stop for the past four weeks,” wrote Mamata.

“The surveillance gives us early warning signals and is an important proactive step in fighting Covid-19,” she added.

Her government directed all districts to conduct the survey following a recommendation by Nobel laureate economist Abhijit Vinayak Banerjee, the head of the global advisory board counselling the chief minister on the state’s Covid-19 response policy.

The economist urged Mamata to set up a reporting structure for widening the ambit of random testing, based on inputs from the grassroots so as to contain hotspots and minimise the spread of the disease.

“During the period of April 7 to May 3, 5.57 crore-plus total household visits have been conducted. 872 cases of persons with Sari and 91,515 cases of persons with Ili have been identified and given necessary health advice,” wrote the chief minister on Tuesday.

“375 people have also been admitted to different health facilities. 62 of them have tested positive for Covid-19 with the affected being treated at our hospitals,” she added.

Mamata’s statement came in the wake of the letter from the south Bengal IMCT leader, Apurva Chandra,to Bengal chief secretary Rajiva Sinha on Monday.

In the letter, Chandra said Bengal’s Covid-19 mortality rate was 12.8 per cent and it was the highest in the country, attributing it to “low testing and weak surveillance and tracking”.

“The surveillance efforts are ongoing and we will not stop till we together defeat novel coronavirus in Bengal,” wrote Mamata.

Trinamul secretary-general Partha Chatterjee questioned the motive of the Centre and the IMCTs. “The central teams didn’t, at all, come here to help us. If the intention was to assist the states worst affected, they would have sent teams to Gujarat and Haryana before Bengal…. Besides, they did not adhere to social distancing or quarantine norms.”