Leptospirosis is a bacterial disease spread by infected animals like cattle, pigs, and rodents. It has affected over 600 people in Kerala since January 2018, killing 30. It is caused by bacteria called Leptospira interrogans found in infected animal urine. People can get infected when the bacteria enter breaks in skin or mucous membranes. Symptoms include fever, headache, muscle pains and jaundice. It is diagnosed through blood or urine tests and treated with antibiotics. Preventive measures include proper sanitation, killing rats, and avoiding contact with contaminated soil or water.