Pest control is a very important element to consider for keeping the rodent population to a minimum and for sites located next to a river or in an urban area are likely to pose more of a risk.
It is good practice to inform staff of the risk due to possible presence of rats in a maltings environment.
If you are working in an area where rats may have been it is advisable to wear gloves or to thoroughly wash your hands particularly before eating or drinking. Do not disturb or move any pest control bait boxes and if you see evidence of pests report this to your line manager.
Symptoms of leptospirosis (Weils disease) are a flu like illness with persistent and severe headache leading to vomiting and should be reported to your doctor immediately. Make sure you tell the Dr that you might have been in contact with rat urine.
Further guidance may be obtained at http://www.hse.gov.uk/construction/healthrisks/hazardous-substances/harmful-micro-organisms/leptospirosis-weils-disease.htm
There is also a good guidance document – INDG84