KOZHIKODE: The unknown source of the pregnant woman confirmed of COVID-19 has raised concern among the health workers. The health department has asked 50 people who came in contact with the woman to go into quarantine. A doctor and four nurses of the private hospital who treated the woman are among the 50. Meantime, restrictions have been tightened in four places announced as containment zone after a security employee who committed suicide has been confirmed of the virus.