"We've got a few reserves here, with 'Delhi Belly' we've had to fly some in," team principal Martin Whitmarsh told Reuters on Saturday.
"We've peaked at four down and I'm told we're at two down today," he added.
"Nowadays with RRA (the cost-saving Resource Restriction Agreement) you can't operate (with missing staff) so some teams flew people out on standby. We had people on standby in the UK for every position in the team.
"They had to have a bag packed and be ready for the phone call," said Whitmarsh. "So we flew two people out as subs. We had to if we had people who weren't likely to back (fit) quickly enough."
While teams have sourced some of their food locally, much of it has been flown out from Europe and drivers are being careful about what they eat in a land famed for fiery curries and consequent stomach upsets.
Sauber had a team PR fall sick but none of the other teams approached by Reuters reported any problems.