Eighty-five troopers of the Border Security Force (BSF) were found to be infected with the novel coronavirus on Wednesday, taking the total number of infected persons in the central paramilitary forces to over 350.

Among these 85 personnel are five BSF troopers, including two head constables and a driver, who had accompanied the inter-ministerial central team during its visit to Calcutta. They were admitted to MR Bangur Hospital on Wednesday.

“While performing operational and essential duties, 85 more BSF personnel have been infected with Covid-19. It is reiterated that in each establishment of the BSF, all SOPs (standard operating procedures) are strictly being followed. Instructions of the ministry of health are being enforced and religiously followed to check the spread of the pandemic,” said a BSF spokesperson.

With 85 new cases reported in the BSF on Wednesday, the total number of infected persons in the force has reached 152. They are mainly personnel posted in Delhi, Tripura, Jodhpur and Calcutta.

The BSF, with a strength of 2.5 lakh personnel, is primarily tasked with guarding the Indian borders with Pakistan and Bangladesh, apart from rendering a variety of duties in the country’s internal security domain.

The Calcutta headquarters of the BSF’s south Bengal unit has sent as many as 70 personnel to quarantine.

Officers in Calcutta refused to comment on whether the members of the central team led by Apurva Chandra, additional secretary of the ministry of defence, should also be quarantined.

The team had arrived in Calcutta on April 20 and left for New Delhi on May 4 after assessing Covid-19 containment measures in Bengal.

Initially, the team had put up at the BSF guest house in Ballygunge and used the force’s vehicles to move around.

“We have sent a detailed report to our headquarters (in New Delhi) about how many of our staff have tested corona-positive in the aftermath of the team’s visit,” said Y.B. Khurania, BSF inspector-general (South Bengal Frontier). “I can’t comment on anything more.”

Several doctors and virologists said the central team should be sent to quarantine because they did come in contact with the five corona-positive personnel during the course of their visit.

“If someone comes within one metre of a positive patient for 15 minutes, then he is a fit case for quarantine,” said a senior doctor of the School of Tropical Medicine. “Since these personnel were asymptomatic, how would one know how much time the members of the central team had collectively spent talking to them?”

Even before the five tested positive on Tuesday, one of the drivers of the escort vehicle leading the central team had been found to have been infected with the novel coronavirus. He is already at MR Bangur.

“Six others have been quarantined in connection with that case,” said an officer.

The Central Reserve Police Force (CRPF), the country’s biggest paramilitary force, has so far reported 145 Covid-19 cases and the Indo-Tibetan Border Police (ITBP) 45 cases.

Nearly 20 cases have also been reported in the Central Industrial Security Force (CISF) and the Sashastra Seema Bal (SSB).

All these paramilitary forces function under the Union home ministry.

Two floors of the BSF headquarters in south Delhi’s Lodhi Road were sealed on Monday after a staff member tested positive. A day earlier the CRPF headquarters within the same complex was sealed when a head constable, attached to the office as a bus driver, tested positive for Covid-19.

Sources in the BSF said the headquarters was reopened on Wednesday while the CRPF headquarters continues to remain sealed and the top brass have been working from home.

The ongoing spike in the Covid positive cases among the personnel has triggered a scare in the paramilitary forces and has become a cause of concern for the home ministry.

Sources said the ministry had sought a report from the CRPF’s top brass after a sub-inspector of the force belonging to its 31st battalion in Delhi who had tested positive and died last week.

The battalion had so far reported 135 positive cases, the biggest number of such cases in a single battalion among the paramilitary forces.

Personnel of the 31st battalion are believed to have contracted the virus from a nursing assistant in the force. The nursing assistant, deployed with the 162nd battalion in north Kashmir’s Kupwara, was at his home on leave in Noida when he followed orders and reported to the closest battalion, the 31st battalion, stationed in Delhi.

Last month, nearly 150 CRPF officers posted at the headquarters, including director-general A.P. Maheshwari, had been home-quarantined after coming into direct or indirect contact with the force’s chief medical officer who had tested positive. All of them later tested negative.

“The ministry has sought a report from the top brass of the paramilitary forces seeking explanation for the surge in positive cases. They have also been instructed to contact-trace personnel who might have come in touch with infected colleagues,” said a ministry official.