Health protection – guidance


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.

Zoonotic diseases (zoonoses): guidance, data and analysis


The ‘common animal-associated infections quarterly report: 2014’ summarises confirmed cases of zoonoses reported in England and Wales.

For previous reports, see the health protection website archive.