Samples were taken from up to 50 people on Tuesday who had contact with the clinic's horses to see whether any have contracted the dangerous virus. Four horses at the clinic came down with the infection, which is able to jump from horses to humans. Two staff have already tested positive for the disease and are in a Brisbane hospital.
Testing on the 36 horses still being held at the clinic have so far returned negative results.
The virus can take up to a fortnight to incubate so negative test results this week will bolster confidence that they are in the clear.
Meanwhile, results are still awaited to see whether two more horses from Cannonvale, near Prosperpine, have Hendra virus. One was euthanized. The horses are from the same property where a horse died from the disease last week.