Karnataka Congress state president DK Shivakumar tested positive for Covid-19 on Tuesday.
The senior Congress leader has been admitted to a private hospital in Bengaluru.
Shivakumar has been touring the state extensively to assess damages due to floods.
The touring was also aimed at strengthen the party's district units.
Earlier, Karnataka Chief Minister BS Yediyurappa and Leader of Opposition Siddaramaiah had tested positive for coronavirus.
Yediyurappa and Siddaramaiah have been discharged after being cured.
Five ministers from the southern state have also tested positive for Covid-19.
India's Covid-19 infection tally jumped to over 3,167,320 on Tuesday.
India recorded more than 60,970 fresh infections in the last 24 hours.
There are around 704,340 active cases, a decline of 6,423 from Monday.
Over 58,385 people have succumbed to the disease till date.
