Leptospirosis

Abstract

Leptospirosis is a leading zoonotic disease for morbidity and mortality in humans globally. Occupational health nurses should teach workers and the public about leptospirosis and the importance of disrupting the infection source through rodent control, animal vaccination, and flood prevention.

Leptospirosis, a leading zoonotic disease for morbidity and mortality in humans, is a bacterial infection caused by Leptospira that occurs most often in tropical or subtropical regions (Centers for Disease Control and Prevention [CDC], 2018a; Schneider et al., 2017). Globally, over one million cases occur annually including around 60,000 deaths; the United States records approximately 100 to 150 leptospirosis cases each year, mainly in Hawaii and Puerto Rico. This nationally notifiable disease is spread by the urine of infected rodents, dogs, cattle, pigs, horses, and wildlife; bacteria can live for months in urine-contaminated water or soil (CDC, 2018a). Leptospirosis illustrates the One Health idea of the interconnection between people, animals, plants, and shared environment (CDC, 2018c).

Working with animals or in wet environments increases the risk for leptospirosis; dangerous job tasks are any that expose workers to contaminated water or soil, especially when skin is lacerated or abraded. At greatest risk are hog and dairy farmers; fishing, mining, sewer, and slaughterhouse workers; agricultural workers, particularly in sugar cane and rice fields; veterinarians and animal caretakers; emergency responders after floods; and military personnel (CDC, 2018b; World Health Organization [WHO], 2018). Industrial swine operations create hazards for workers due to the massive amounts of hog urine excreted daily, and in surrounding communities when floods or excessive rains cause hog urine to saturate fields and fresh water sources. Lakes and rivers contaminated with animal urine pose a recreational hazard for anyone swimming, wading, kayaking, and rafting in tropical or warm climates (CDC, 2018b). Leptospirosis is transmitted through direct contact with the urine or products of conception from infected animals; indirectly via contaminated floodwater, rivers, streams, raw sewage, and soil; and through ingestion of urine-contaminated plants, food, or water. Bacteria enter the body via mucous membranes, conjunctiva, and broken skin. Transmission between humans is rare, yet there are documented cases from dog bites, sexual intercourse, and breast milk (CDC, 2018a).

The incubation period for leptospirosis is 2 to 30 days, but symptoms usually start within 5 to 14 days after exposure. Most victims are asymptomatic or have mild flu-like symptoms with fever, headache, myalgia, conjunctival suffusion, abdominal pain, vomiting, diarrhea, cough, skin rash, and jaundice. In severe cases, renal and liver failure, pulmonary hemorrhage, aseptic meningitis, cardiac arrhythmias, pulmonary insufficiency, and hemodynamic collapse may develop. Combined renal and liver failure from leptospirosis is labeled Weil’s disease. Up to 15% of patients with severe illness may die, while the case fatality rate can exceed 50% when severe pulmonary hemorrhagic syndrome occurs (CDC, 2018a). Early treatment affects the severity of leptospirosis, and antibiotic therapy without waiting for laboratory confirmation is recommended. Contact CDC INFO at 800-232-4636 for questions about diagnostic testing. Oral doxycycline (100 mg twice daily) is recommended for mild symptoms, and intravenous penicillin or ceftriaxone is generally effective in severe illness (CDC, 2018a).

Occupational health nurses should teach workers and the public about leptospirosis and the importance of disrupting the infection source through rodent control, animal vaccination, and flood prevention (WHO, 2018). Worksite and community training is needed on how to interrupt transmission of leptospirosis: avoiding contact with food contaminated with floodwater or rodent urine; refraining from wading, swimming, bathing, swallowing, or submersion in potentially contaminated waters after heavy rainfall or flooding; using personal protective equipment including rubber boots, waterproof clothing, and gloves; covering open wounds with waterproof dressings; and boiling or chemically treating contaminated drinking water (CDC, 2018a; WHO, 2018). Chemoprophylaxis with oral doxycycline may help prevent outbreaks after floods and be effective among military personnel or disaster workers when exposure is unavoidable (CDC, 2018a; Schneider et al., 2017).