Leptospirosis
It is a bacterial disease that occurs in many domestic and wild animals, is endemic worldwide, but the highest incidence is in tropical and subtropical areas. Transmission to humans usually occurs through contact with water or damp soil contaminated by the urine of infected animals. Travelers at increased risk, such as those who engage in recreational water activities, hikers, bikers or adventure travellers should consider chemoprophylaxis with doxycycline 200 mg orally once a week, beginning 1-2 days before and continuing throughout the period of exposure. No human vaccine is available in the US.