The characteristics, diagnosis and epidemiology of infections caused by spirochaetes of the genus Leptospira (Leptospires).


Leptospirosis is a zoonosis caused by spiral-shaped bacteria of the genus Leptospira (also referred to as leptospires).

Leptospires may be either:

  • pathogenic, which cause disease in animals or humans
  • saprophytic, which are free-living in surface waters and are not known to cause disease

Pathogenic leptospires belong the sub-group Leptospira interrogans, and non-pathogenic to the subgroup Leptospira biflexa.

Over 250 known pathogenic serovars exist, which infect different species of animals. The animals can spread the leptospires in their urine. Nearly all mammals are capable of carrying the bacteria’ and may spread the disease among others of their own kind, and to other species, including man. Common animal reservoirs include:

  • rodents
  • cattle
  • pigs

Leptospirosis is more common in tropical areas of the world and is still uncommon in the UK.

NHS Choices has further information on leptospirosis, including symptoms and treatment.


The National Leptospirosis Service (NLS) is the national laboratory reference centre for the diagnosis of leptospirosis.

The Rare and Imported Pathogens Laboratory (RIPL) is a specialist centre for advice and diagnosis for a wide range of unusual viral and bacterial infections including leptospirosis.


PHE has completed a pilot enhanced surveillance study (see protocol aimed at improving our understanding of leptospirosis in the UK to enable further development of guidance and policy. The pilot survey was closed at the end of December 2017 and will be evaluated to decide long term surveillance.

The ‘common animal-associated infections quarterly report’ summarises confirmed cases of zoonoses reported in England and Wales.

For previous reports, see the health protection website archive.

The annual reports on zoonoses include information on leptospirosis infection in humans and animals.

Published 15 July 2013
Last updated 12 March 2018 + show all updates
  1. Page updated regarding the completion of the pilot enhanced surveillance study.
  2. Added information on a pilot enhanced surveillance system.
  3. First published.