Background

Leptospirosis is an infection caused by pathogenic bacteria called Leptospires. It is a zoonosis that is transmitted directly or indirectly from animals to humans. The transmission between humans is very rarely. The number of human cases in Taiwan is 27 to 203 a year and it often peaks seasonally, especially in summer.

Leptospira is long corkscrew-shaped bacteria, and may cause disease in humans by 277 serotypes divided into 25 serogroups. The most common serotype is L. shermani (Leptospira santarosai serovar Shermani) in Taiwan. It could infect both the wild and domestic animals, primarily rodents, and transmitted to human through contact of mucous membranes or (broken) skin with water (swimming or immersion), moist soil or vegetation contaminated with the urine of infected animals. Therefore, the risk factor is high chance to contact contaminated environment or between humans and infected animals. The workers such as farmer, Miners, Veterinarians, fishermen and solders are the risk group.

The most effective protective measures are to prevent contact with the urine of infected animals, the tissue of infected animals or a contaminated environment, and to control animal carrier, e.g. rodents.

Epidemiology

Leptospirosis occurs worldwide but is most common in tropical and subtropical areas, and the incidence correlates directly with high rainfall. In Taiwan, epidemics can occur mainly in the plum rain season and typhoon from May to October. In 2009, the typhoon Morakot caused severe flooding in southern Taiwan, there are 203 cases.

Leptospirosis Surveillance in Taiwan

1. Taiwan National Infectious Disease Statistics System–Leptospirosis
2. Self-reporting through the toll-free 1922 hotline or the local health bureau.

Prevention and Control

To prevent leptospirosis, avoid contact with infected animals and control the reservoir animals.

1. At-risk workers should wear protective clothing (boots, gloves, aprons).
2. Avoid exposure to contaminated urine splashes or contaminated soil or water.
3. Prevent rodent infestation by using snap traps and poison baits, and keep the environment scrupulously clean.
4. Isolate the infected animals and clean and remove any contaminated excreta.
5. Immunize pets or farm animals.
6. Disinfect contaminated areas.

FAQs

1. What is Leptospirosis?
   • Leptospirosis is an acute bacterial disease caused by Leptospires. The incubation period is 10 days (range, 2–30 days). Symptoms include fever, headache, conjunctival suffusion, muscle aches,jaundice, haemorrhages, meningitis and renal failure. Generally, the clinical course in human ranges from mild to lethal with a broad spectrum of symptoms and clinical signs.
2. How are Leptospirosis transmitted?
   • Leptospirosis is very rarely spread directly from person to person. It is transmitted to people by the animals, e.g. rats, that are infected with the Leptospires. People become infected with Leptospires when contact with the urine of infected animals, the tissue of infected animals or a contaminated environment.
3. What can be done to reduce the risk of Leptospirosis? 
   • The best way to ward off infection is to avoid contact with potentially infected animals or the water and soil that might be contaminated with the infected animal urine. At-risk workers exposed to contaminated water or soil should be protected by wearing protective clothing (boots, gloves, aprons).

More Information

1. WHO| Leptospirosis 
2. USA CDC| Leptospirosis