Kolkata, Jan 3 : With the Covid infection spreading fast, the state is facing a major challenge in imparting treatment to the patients because several health workers, including doctors, nurses and support staff in different government hospitals have been infected by the virus. According to sources in the state health department, most of them either have been under treatment in the hospital itself or are in home isolation forcing the hospital authorities to run the health-care system with a skeleton workforce. The state health department data shows that at least 70 people, including the principal, several doctors and nurses in the National Medical College and Hospital -- one of the premier government hospitals in the Covid healthcare in the state -- are infected by the virus. Sources in the department also said that at least 37 doctors and nurses have been infected in the Calcutta Medical College and Hospital -- the central hospital in the Covid healthcare in the state and another 42 medical staff have been infected by the virus in R.Ahmed Dental College and hospital -- the only government dental college in the state. The situation in R. Ahmed Dental College is such that the authorities had to empty the entire hostel. "The infection among the doctors, nurses and medical support staff is causing a real concern for the health department. They are the main pillar in running the healthcare system. We could face the challenges of the last two waves successfully because of the tireless support of the medical fraternity. We are trying to negotiate the problem with the limited staff," a senior health department official said. Meanwhile, the state government has announced partial restrictions after a rapid increase of Covid virus in the state. In the last seven days there has been a 12-fold increase of daily infection heralding the advent of the third wave in the state. On Monday, the infection rate in the state was 439 but on Sunday it rose to 6,152 -- a twelve time increase in the infection rate. The rate of increase in the last seven days has been alarmingly upward. When on Wednesday the daily rate of infection crossed the 1,000-mark for the first time in the last 177 days, recording 1089, on Thursday the rate increased to 2128, on Friday it was 3415, on Saturday 4653 -- a daily increase of 1,000 or more. On Sunday it showed a daily increase of more than 1,500 taking the figure of daily infection to 6,153. Kolkata recorded the highest rate of infection among the districts recording more than half of the infection. According to data available with the state health department, 3194 people were found positive in the city on Saturday followed by North 24 Parganas that had the daily infection of 994 positive cases and Howrah has recorded a daily infection of 595 cases. /IANS