Derbyshire were at the centre of a swine flu scare but it was Essex who looked out of sorts as Chris Rogers reeled off his second double-century of the season to leave his team in charge of the LV County Championship promotion clash at Derby.

Rogers was one of six Derbyshire players feeling unwell but he batted superbly on a green pitch to score an unbeaten 204, his sixth championship hundred of the summer and his fourth in seven innings, after Essex had put the home side in.

The Derbyshire captain also passed 2,000 runs for the campaign, sharing century stands with Garry Park and Dan Redfern to take his team to 368 for three in a game they have to win to have a chance of going up.

It was an excellent response by Derbyshire who had seamer Tim Groenewald ruled out of the game on Tuesday and then had to send pace bowler Tom Lungley home before the start of play with suspected swine flu.

Four other players were also under the weather but Essex, who went into the match occupying the second promotion place, failed to take advantage by bowling poorly in helpful conditions.

Graham Napier beat the bat a number of times but the other bowlers could not maintain a consistent line and Rogers and Wayne Madsen gave Derbyshire a solid platform with a stand of 61.

Chris Wright broke through in the 17th over when he switched ends to have Madsen lbw for 16 as the South African fell across the crease but Rogers and Park added 121 in 30 overs.

Rogers drove Danish Kaneria for his 10th four to reach 50 off 78 balls and although Napier had no luck in a testing spell after lunch, Essex could not put the batsmen under any sustained pressure.

Park passed 50 for the ninth time this summer when he cover-drove David Masters for his eighth four but on 57, he edged Wright to first slip.

Rogers became the first Derbyshire batsman since Chris Adams in 1996 to score six hundreds in a season and Essex must have known it was not going to be their day when he edged Masters into his stumps without removing a bail on 134.

Essex's problems mounted when Kaneria went off with an Achilles tendon problem and Derbyshire had passed 300 before the visitors claimed a second new ball.

It brought an immediate reward when Wright got Redfern to drive away from his body to be caught at gully two short of a half-century and give Essex their first point of the game.

Kaneria was able to return but Rogers greeted him by pulling the leg-spinner for six as he completed the seventh double-century of his career and his third for Derbyshire off 290 balls.

It was his second double in consecutive games at Derby and when bad light ended play one over early he had put a big dent in Essex's hopes of playing Division One cricket next year.