Erie County Health officials say three staff members of the California delegation have tested positive for the norovirus.
Health Commissioner Peter Schade said no additional testing will be conducted.
The tests -- conducted in a state lab -- were announced Wednesday morning.
In all, 11 staff members from the California delegation became ill over the weekend after flying from California to Ohio to attend the Republican National Convention in Cleveland.
The staff works as aides to the delegates, planning events and itinerary.
The sick have been confined to their hotel rooms at the Kalahari resort in Sandusky.
Schade said the illness had not spread to the California delegates and their work at the RNC has not be interrupted.
There have been no new illnesses reported within the group since Monday.
Those who are ill have suffered nausea, diarrhea and fever. The illness cannot be treated with antibiotics and must run its course.
The Investigator Tom Meyer broke the story early Tuesday morning on social media.
