Page 123 - 2020 JSOM Winter

An Ongoing Series

Leptospirosis

Elena M. Crecelius, MD *; Mark W. Burnett, MD 2
1

ABSTRACT
Leptospirosis is caused by an infection with bacteria of the with fever, chills, headaches, cough, muscle aches, nausea,
Leptospira species. These spirochetes are carried by a variety and vomiting. Muscular aches most commonly occur in the
of wild and domestic animals. Humans can become infected calves and lower back. The presence of reddened conjunctiva,
with these bacteria; leptospirosis most commonly occurs in the sometimes with associated hemorrhage, is a distinctive finding
tropics and subtropics. Military personnel are at risk of infec- of leptospirosis. Other illnesses to consider in the differential
3
tion through deployment in the field. diagnosis include malaria, dengue, zika, influenza, and murine
typhus.
Keywords: leptospirosis; tropics; subtropics; bacteria
The secondary phase of leptospirosis is caused by the immune
system’s response to the illness. Continued fever and inflam-
mation of the meninges or eyes are most common during this
Background
phase. In 5% to 10% of patients, severe illness occurs and can
Leptospirosis is caused by an infection with a tightly coiled, include yellowing of the skin and eyes, kidney failure, bleeding
gram-negative spirochete bacteria of the Leptospira species. in the lungs, brain or intestines, and abnormal heart rhythms.
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These spirochetes are carried by a variety of wild and domestic Renal and liver failure in combination as a result of a lepto-
animals, including dogs, livestock, and rodents, and are shed spirosis infection is known as Weil disease. Some patients will
into the environment through their urine. These bacteria can go into shock. The death rate of severe illness is 5% to 15%. 3
live for months in damp soil or fresh water in warmer climates.
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Humans can become infected with these bacteria when they Diagnosis
come into contact with infected animals or contaminated soil
or water. Leptospires get into the human body through the eyes Use of both serological testing and cultures is ideal to diagnose
or mouth or via broken skin. Approximately 1 million people leptospirosis. However, seroconversion alone demonstrating an
worldwide are infected with leptospirosis annually, causing an increase in antibodies against leptospirosis is diagnostic. The
estimated 60,000 deaths. Leptospirosis most commonly oc- patient’s blood should be sent for serological antibody testing,
2
curs in the tropics and subtropics (Figure 1). The exposure risk performed at least 10 days apart. Samples of blood, cerebrospi-
is higher for people who frequently have contact with moist nal fluid and urine can be cultured to look for Leptospira and
soil or fresh water and increases after heavy rainfall or natural should be obtained before treatment with antibiotics if possi-
disasters. Recreational activities, including freshwater swim- ble, but treatment should never be delayed if the diagnosis has
ming, adventure races, and water sports, have been associated been made clinically and testing is not readily available. Cul-
with outbreaks of leptospirosis. Military personnel are at risk tures require use of media specific to Leptospira with regular
of infection through deployment in the field, and outbreaks dark field microscopy and incubation for up to 16 weeks. If
have been associated with jungle operations training. isolated in culture, leptospires can be identified with molecular
or serologic testing. Negative testing results do not rule out the
diagnosis of leptospirosis, especially if appropriate antibiotics
Clinical Presentation
were initiated early in the course of the illness.
The majority of those infected with leptospires will have a brief
self-resolving febrile illness or no symptoms at all, whereas Treatment and Prevention
others will become severely ill. Symptoms may occur between
a few days to a month after exposure. For symptomatic pa- All patients with severe illness should be transferred to a
tients, the initial phase of leptospirosis usually lasts 1 week higher level of care. Antibiotic therapy is sometimes effective

*Correspondence to elena.m.crecelius.mil@mail.mil
1 CPT Crecelius is a resident physician in pediatrics at Tripler Army Medical Center in Hawaii. She is a graduate of the Indiana University School
of Medicine. COL Burnett is currently chief of pediatrics at Tripler Army Medical Center in Hawaii. He is board certified in pediatrics and
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pediatric infectious diseases and has served overseas in Korea, Germany, Kosovo, Iraq, Afghanistan, and Kuwait and as the JSOTF-P surgeon in
the Philippines. He is a graduate of the University of Wisconsin-Madison and the Medical College of Wisconsin.
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