Leptospirosis

• Leptospirosis is infection by a spiral-shaped bacterium that affects the skin, eyes, muscles, kidneys, and liver; leptospirosis is carried by rodents
• Leptospirosis is a bacterial disease that affects humans and animals.
• Without treatment, Leptospirosis can lead to kidney damage, meningitis (inflammation of the membrane around the brain and spinal cord), liver failure, respiratory distress, and even death.
• It is caused by bacteria of the genus Leptospira.
• In humans, it can cause a wide range of symptoms, some of which may be mistaken for other diseases.
• Some infected persons, however, may have no symptoms at all.

Leptospirosis in kidney

Cause

• Leptospira are long, thin, motile spirochetes.
• They may be free-living or associated with animal hosts and survive well in fresh water, soil, and mud in tropical areas.
• Organisms are antigenically complex, with over 250 known pathogenic serologic variants. Although certain geographic regions contain specific leptospiral serovars and species, the serologic characterization of an isolate is not an absolute predictor of its species designation.

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Global burden of leptospirosis

Infection

• The bacteria that cause leptospirosis are spread through the urine of infected animals, which can get into water or soil and can survive there for weeks to months. Many different kinds of wild and domestic animals carry the bacterium.

• These can include, but are not limited to:

• Cattle
• Pigs
• Horses
• Dogs
• Rodents
• Wild animals

When these animals are infected, they may have no symptoms of the disease.

Infected animals may continue to excrete the bacteria into the environment continuously or every once in a while for a few months up to several years.

Liver of an unknown animal infected with leptospirosis

Humans can become infected through:

• Contact with urine (or other body fluids, except saliva) from infected animals.
• Contact with water, soil, or food contaminated with the urine of infected animals.
• The bacteria can enter the body through skin or mucous membranes (eyes, nose, or mouth), especially if the skin is broken from a cut or scratch.
• Drinking contaminated water can also cause infection.
• Outbreaks of leptospirosis are usually caused by exposure to contaminated water, such as floodwaters.
• Person to person transmission is rare.

Signs and Symptoms

In humans, Leptospirosis can cause a wide range of symptoms, including:

• High fever
• Headache
• Chills
• Muscle aches
• Vomiting
• Jaundice
• Red eyes
• Abdominal pain
• Diarrhea
• Rash

Conjunctival suffusion of the eyes due to leptospirosis

Many of these symptoms can be mistaken for other diseases.

• The time between a person’s exposure to a contaminated source and becoming sick is 2 days to 4 weeks.
• Illness usually begins abruptly with fever and other symptoms.

Phases

Leptospirosis may occur in two phases:

• After the first phase (with fever, chills, headache, muscle aches, vomiting, or diarrhea) the patient may recover for a time but become ill again.

Diffuse pulmonary haemorrhages of the lungs infected by leptospirosis

Pregnant women

• Leptospirosis during pregnancy can cause fetal complications including fetal death or abortion.
• The case fatality rate for leptospirosis is approximately 5%–15% among patients with severe illness.
• Among patients with severe pulmonary hemorrhagic syndrome, the case fatality rate can exceed 50%.

Signs and symptoms of leptospirosis

Risk of Exposure

• Leptospirosis occurs worldwide, but is most common in temperate or tropical climates.
• It is an occupational hazard for many people who work outdoors or with animals, such as:
• Farmers
• Mine workers
• Sewer workers
• Slaughterhouse workers
• Veterinarians and animal caretakers
• Fish workers
• Dairy farmers
• Military personnel

Risk factors

• The disease has also been associated with swimming, wading, kayaking, and rafting in contaminated lakes and rivers.
• As such, it is a recreational hazard for campers or those who participate in outdoor sports.
• The risk is likely greater for those who participate in these activities in tropical or temperate climates.
• In addition, incidence of Leptospirosis infection among urban children appears to be increasing.

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Leptospirosis flow chart

Laboratory Testing

• Antibodies for leptospirosis develop between 3-10 days after symptom onset, thus any serologic test must be interpreted accordingly – negative serologic test results from samples collected in the first week
• of illness do not rule out disease, and serologic testing should be repeated on a convalescent sample collected 7-14 days after the first.
• In the acute phase of illness, leptospires are present in the blood (septicemia) for approximately the first 4–6 days of illness.

• IgM-based commercial assays, such as:
• ELISA IgM
• ImmunoDOT
• Lateral flow tests
• IgM assays are screening tests and results should be confirmed using one of the confirmatory methods below.

Sequelae and complications

• Clinical course is highly variable. Most cases involve flu-like symptoms (fever, chills, muscle aches, headaches).
• Other symptoms may include conjunctivitis, vomiting, diarrhea, stomach pain, jaundice, cough, and rarely, a skin rash.
• About 10 percent of people with leptospirosis develop severe disease, including kidney or liver failure, meningitis, difficulty breathing, bleeding, and meningitis.
• Case fatality rate is 5 to 15% in cases with severe clinical illness.

Prevention

• The risk of acquiring leptospirosis can be greatly reduced by not swimming or wading in water that might be contaminated with animal urine, or eliminating contact with potentially infected animals.
• Protective clothing or footwear should be worn by those exposed to contaminated water or soil because of their job or recreational activities.

Leptospirosis Resources
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