Leptospirosis

Description

• Zoonotic disease caused by Leptospira interrogans, a spirochete bacteria
• Spread via contact with infected water; outbreaks common during increased rainfall or during floods

Epidemiology

Incidence

• 100 to 200 annual U.S. cases; 50% in Hawaii
• Estimated incidence 0.1 to 10/100,000 worldwide
• Most cases occur in tropical climates; can occur in temperate areas
• Outbreaks can occur following increased rainfall or during floods.

Etiology and Pathophysiology

• Caused by L. interrogans, a spirochete harbored in mammals (usually rodents) and shed into water or soil
• There are >25 serogroups and 250 serovars; illness severity not linked to type
• Organism is inoculated through breaks in the skin or contact with mucous membranes.
• Spirochetes migrate through the lymphatic and vascular system to cause disease.
• Life cycle is completed when spirochetes infect the kidneys and urinary tract and are excreted into fresh water or soil.

Pregnancy Considerations

• Disease can be spread transplacentally to cause fetal complications; risk of abortion as high as 50%
• Leptospira can be transmitted through breast milk (1).

Risk Factors

• Frequent animal contact (farmers, veterinarians, abattoirs)
• Fresh water exposure (military personnel, aid workers, adventure racers)
• Increased rainfall or floods, particularly in tropical environments

General Prevention

• Avoid contaminated water.
• Wear protective clothing/gear.
• Consume clean water.