The <<>> in the UK has announced that the vet who became ill after working on the farm where an outbreak of bird flu has occurred, has tested negative for the virus.
However in the second incident in two days the HPA says another worker is undergoing hospital tests for the H5N1 virus.
Both had been working at the Bernard Matthews poultry unit in Holton, Suffolk where bird flu was confirmed last week.
The HPA says the worker had complained of respiratory problems and the tests are a precautionary measure; test results will be available tomorrow.
The HPA spokesman says they do not expect anyone working at the farm to test positive for the avian virus but say it is likely that a number of people will report respiratory problems in the following weeks and they would have to be tested to ensure they had not picked up the virus.
The cleaning and disinfecting by experts of the huts where the infected turkeys were housed is continuing and 159,000 turkeys at the farm have culled as a precaution following the outbreak.
The bird flu expect the disinfecting process to be completed in the next 24 hours.
Health officials in Britain have informed it's European Union partners that they do not believe there is a link between the outbreak of bird flu at the Bernard Matthews farm and two recent cases in Hungary, where Matthews also has poultry interests.
Experts from DEFRA however have told the EU they are still trying to trace the source of the outbreak following a comment from a senior EU health official that there was "obviously" a link between the British and Hungarian cases, as the H5N1 strain of the virus was virtually identical in both countries.
The British and Hungarian outbreaks are the first in Europe for more than six months, and occurred within days of each other.
With experts in Britain still baffled as to the source of the outbreak in Suffolk, officials in Brussels say no wild birds had been discovered bearing the virus, despite widespread monitoring, and there was no case for bans on imports of British poultry.