Harmful Micro-Organisms: Leptospirosis / Weil's Disease from rats

Construction workers may be exposed to a type of Leptospirosis called Weil's Disease . This page tells you how to control this risk and why. You also need to be aware of the general information on micro-organisms.

What you must do

Follow the Assess, Control and Review model. Pay particular attention to the following things:


Identify and assess: The risk of Weil's disease is linked to areas where rats are or have been present. Work is considered higher risk where there is evidence of rat infestation. This is most likely to be during refurbishment or demolition work. Other potential situations include work linked to canals, rivers or sewers.


Control: Where Weil's disease is known / assumed to be present, control this risk by:

General controls – follow the general controls for harmful micro-organisms. Pay particular attention to:

  • wearing protective clothing like gloves
  • following good basic hygiene including regular hand-washing and avoiding hand to mouth/eye etc contact
  • taking rest breaks, including meals and drinks, away from the work area;
  • washing cuts and grazes immediately with soap and running water Cover all cuts, abrasions and other breaks in the skin with waterproof dressings and/or gloves.


Supervise: Ensure that controls are effective and used by the workers.

What you should know

The Weil's disease form of leptospirosis is contracted from the urine of infected rats. The bacteria get into your body through cuts and scratches or through the lining of the mouth, throat and eyes after contact with infected urine or contaminated water. It is a rare condition in the UK. The disease starts with flu-like symptoms such as a headache or muscle pains. More severe cases can lead to meningitis, kidney failure and other serious conditions. In rare cases the disease can be fatal.

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Updated 2022-02-09