Leptospirosis is an illness caused by a tiny corkscrew shaped bacteria (spirochete) that cannot be seen with the naked eye (microscopic). The illness is caused when a human comes in contact with the contaminated urine, or water contaminated with urine, from an infected animal. The most typical sources for the spirochete are:

  • Rodents and other small animals.

  • Livestock (cattle and pigs).

  • Dogs.

Human illness most often occurs during the summer and fall. The spirochette enters the human body through broken skin or through mucous membranes, which are the membranes lining:

  • The mouth.

  • Birth canal (vagina).

  • Eyes.

  • Nose.

This infection is not contagious from person to person.


There are no symptoms that are typical of this disease. Most common is a mild and self limited illness. This is an illness that goes away without treatment. Symptom from this illness will go away after 3 to 7 days and include:

  • Fever.

  • Headache.

  • Muscle aches and pains.

Rarely other ailments occur including:

  • Meningitis, a type of inflammation of the membranes surrounding the brain causing headache and sleepiness )

  • Hepatitis, a inflammation of the liver causing nausea, vomiting, loss of appetite, dark urine, yellowing of the skin and pain or tenderness over the liver can occur.

Symptoms do not begin until five to fourteen days after the spirochete enters the body. Death from infection is very rare. When it occurs, it is usually due to a combination of kidney, liver and bone marrow failure with bleeding into the skin, urine and bowels (intestine).


The diagnosis is typically made with blood tests. By testing the liquid (serum) from a clotted specimen of blood for antibodies to the spirochete. Very special cultures of blood, fluid from around the brain and spinal cord or urine may also be done to grow the spirochete, but these tests are not commonly done.


This illness can usually be treated effectively with an antibiotic (tetracycline).