The number of COVID-19 positive cases increased to four on Friday with the confirmation of another case in the Vizianagaram district. A middle-aged migrant labourer, who came back four weeks ago from Vijayawada, was tested positive. He belonged to Vompilli village of Bondapalli mandal. District Collector M. Hari Jawaharlal directed officials to conduct survey for all his family members, relatives and villagers. He said that all the officials should be alert since three labourers, including two women, were already tested positive a couple of days ago. He said that all the labourers, who were in quarantine centres, should cooperate with the district administration and undergo tests instead of insisting that they be allowed to go to their native places.