13. Mar, 2019

Leptospira (Weils Disease) & rats in compost

The www,carryoncomposting page on Rats in Compost Bin (http://www.carryoncomposting.com/416920198)  has been updated to include more information on Leptospirosis (Weils Disease). A shorter version is given below 

Leptospira is spread in rats' urine and can survive in water for several months  which plays an important role as a source of transmission of leptospirosis to man and other animals.  There is a small risk of catching Weil’s Disease from contact with soil or compost contaminated by rats but by far the highest risk is to  farmers and vets is from contact with infected urine or blood followed by  fishermen, water sports enthusiasts following contact with  contaminated. 

While in the UK the risk to humans is small, with  less than 40 cases reported in England and Wales every year  it is probably a good idea to wear gloves when handling garden compost and  to cover cuts or grazes and to reduce the risk of contamination of compost by rat urine .

 Temperatures below 4°C and above 37C° will kill Leptospira which has an optimum temperature of  25˚C, needs  a moist atmosphere and a  pH near neutral. 

In general compost does not present a problem as even if rats have contaminated the bin. Once the compost is applied to and mixed with the soil, the level of bacteria will be so low  that vegetables grown in it will be safe to cook and eat as normal. However, if  a cold compost bin  or heap is known to have been rat-infested it might be advisable to use the compost  in the flower garden or as a mulch round established trees. It is best not to use it  round low growing  fruits or vegetables that are going to be eaten raw and the edible parts may be in contact with the soil or compost e.g. radish, celery, cucumber, strawberry.

Vegetables, fruit and  herbs should always be washed  Temperatures below 4°C and above 37C° will kill the leptospira bacteria.