A study has suggested that 10% of one species of bat in Scotland has been exposed to the rabies virus.
Tests are being carried out on Scotland's bats
The research was carried out by Scottish Natural Heritage following the death of a conservation worker last year.
However, it has stressed that none of the creatures had the live virus.
Infection experts said that the risk to the public from bats remained "minimal".
The advice which was issued following the death of David McRae last November has not been changed.
The 56-year-old, from Angus, failed to recover from European Bat Lyssavirus (EBL), a type of rabies found in several northern European countries.
He was the first person to be killed by rabies in Britain for 100 years.
Mr McRae's death prompted the SNH study, which was carried out during the summer. The aim was to assess the extent of the disease in bats.
Researchers have been concentrating on the Daubenton's bat, which is believed to be the species responsible for biting Mr McRae.
It is commonly found in trees, buildings and caves in Scotland.
Researchers tested the blood and saliva of 171 of the live bats and found that none of the creatures had the live virus.
However, one in 10 was carrying rabies antibodies, which suggested that they had been in contact with the disease.
Researchers also tested 12 of the more common pipistrelle bats and found no evidence of rabies antibodies.
Professor Colin Galbraith, SNH's director of science, said: "The interpretation of the preliminary results must be treated with caution given the relatively small number of bats sampled and the fact that further field and laboratory work is required to validate the preliminary findings.
"We are now undertaking some further work before the bats move into hibernation, and are gearing up for further studies next spring.
"The initial findings from this pilot study will greatly assist the further development of this work."
He said that the presence of antibodies among the Daubenton's bat appeared to vary from roost to roost.
The advice on how to minimise any risk from bats remains unchanged.
"The public should avoid handling bats if at all possible, and anyone working with bats should be vaccinated against rabies," he said.
Professor Bill Reilly, of the Scottish Centre for Infection and Environmental Health, said: "The risk to the public at large from bats remains minimal.
David McRae died after being bitten by a bat
"There is nothing in these preliminary findings to suggest any change to the current advice given to the public, and bat workers in particular.
"Anyone bitten or scratched by a bat should immediately wash the wound with soap and water and seek medical advice.
"This is the first research work of its type to take place in Scotland and complements a similar study underway in Lancashire."
However, he said further work was required due to the "groundbreaking" nature of the project.