The 27-year-old Hampshire batsman missed Tuesday's practice session due to high temperature.
A statement on the England and Wales Cricket Board Web site (www.ecb.co.uk) on Wednesday said Pietersen had responded well to a course of antibiotics
England, who trail India 1-0, have not lost a home series since 2001 when they were defeated by Australia.
Pietersen, who hit a century in the drawn first Test at Lord's, has not missed a Test since making his debut against Australia at the same ground two years ago.
Squad: Michael Vaughan (capt), Alastair Cook, Andrew Strauss, Kevin Pietersen, Paul Collingwood, Ian Bell, Matt Prior (wk), Stuart Broad, Chris Tremlett, Monty Panesar, Ryan Sidebottom and James Anderson.